EA041145B1 - PHARMACEUTICAL COMPOSITIONS CONTAINING PRIDOPIDINE DERIVATIVES, THEIR USE FOR THE TREATMENT OF A PATIENT SUFFERING WITH A NEURODEGERATIVE DISEASE OR A NEURODEGENERATIVE DISORDER - Google Patents

Description

This application claims priority over U.S. Provisional Application No. 62/076,436, filed November 6, 2014, and U.S. Provisional Application, filed June 30, 2014, the entire contents of which are hereby incorporated by reference.

Descriptions of publications cited in this application in full are included here as references in order to more fully describe the state of the art at the date of the invention described here.

State of the art

Pridopidine (ACR16, TV-7820, Huntexil) is a unique compound developed for the treatment of patients with motor symptoms associated with Huntington's disease. Its chemical name is 4-(3-(methylsulfonyl)phenyl)-1-propylpiperidine, and its Chemical Registry number is 882737-42-0 (U.S. Patent Application Publication No. US-2013-0267552-A1). Methods for the synthesis of pridopidine and a pharmaceutically acceptable salt thereof are described in US Pat. No. 7,923,459. U.S. Patent No. 6,903,120 describes pridopidine for the treatment of Parkinson's disease, dyskinesias, dystonias, Tourette's disease, iatrogenic and non-iatrogenic psychosis and hallucinosis, mood and anxiety disorders, sleep disorder, autism spectrum disorders, ADHD, Huntington's disease, age-related cognitive decline and disorders associated with alcohol and drug addiction.

The essence of the invention

The invention provides a pharmaceutical composition containing pridopidine or a pharmaceutically acceptable salt thereof, a pharmaceutically acceptable carrier and at least one compound or a pharmaceutically acceptable salt thereof, which has the structure:

where the amount of each of the compounds (1-7) in the pharmaceutical composition is not more than 10% relative to the concentration of pridopidine.

The invention also provides a pharmaceutical composition containing an amount of pridopidine and at least one of compound 1, compound 2, compound 3, compound 4, compound 5, compound 6 and compound 7, where

a) compound 1 is present in the pharmaceutical composition in an amount of not more than 10% area in relation to the concentration of pridopidine, based on HPLC determination, or

b) Compound 2 is present in the pharmaceutical composition in an amount of not more than 10% area in relation to the concentration of pridopidine, based on HPLC determination, or

c) Compound 3 is present in the pharmaceutical composition in an amount of not more than 10 area % relative to the concentration of pridopidine, based on HPLC determination, or

d) compound 4 is present in the pharmaceutical composition in an amount of not more than 10% area in relation to the concentration of pridopidine, based on HPLC determination, or

e) compound 5 is present in the pharmaceutical composition in an amount of not more than 10% area in relation to the concentration of pridopidine, based on HPLC determination, or

f) compound 6 is present in the pharmaceutical composition in an amount of not more than 10% area in relation to the concentration of pridopidine, based on HPLC determination, or

g) compound 7 is present in the pharmaceutical composition in an amount of not more than 10% of the area in relation to the concentration of pridopidine, based on the determination by HPLC.

The present invention also provides the use of a pharmaceutical composition for the treatment of a patient afflicted with a neurodegenerative disease or a neurodegenerative disorder.

The invention also provides the use of a pharmaceutical composition for the treatment of a patient afflicted with Huntington's disease.

Brief description of several types of figures

Fig. 1 - typical chromatogram of control sample 1 a.

Fig. 2 is a typical chromatogram of control sample 2b.

- 1 041145

Detailed description of the invention

This invention provides a pharmaceutical composition containing pridopidine or a pharmaceutically acceptable salt thereof, a pharmaceutically acceptable carrier and a compound or a pharmaceutically acceptable salt thereof, which has the structure:

where the amount of each of the compounds (1-7) in the pharmaceutical composition is not more than 10% relative to the concentration of pridopidine.

In one embodiment, the weight ratio of compound to weight of pridopidine in the composition is 90:10 to 10:90 or 85:15 or 15:85.

In one embodiment, the compound has the structure SOjCHi ί| 1 he or his salt. In one embodiment, the compound has the structure EO2CH3 X or a salt thereof. In one embodiment, the compound has the structure O ₂ S —3O ₂ LN “-pr or a salt thereof. In one embodiment, the compound has the structure 30CH3 (Hs ^it or its salt. L SChCH _a ώ X f f

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In one embodiment, the compound has the structure

or its salt.

In one embodiment, the compound has the structure SOjCHs

or its salt.

In one embodiment, the compound has the structure

or its salt.

The invention also provides a pharmaceutical composition containing an amount of pridopidine and at least one of compound 1, compound 2, compound 3, compound 4, compound 5, compound 6 and compound 7, where

a) compound 1 is present in the pharmaceutical composition in an amount of not more than 10% area in relation to the concentration of pridopidine, based on HPLC determination, or

b) Compound 2 is present in the pharmaceutical composition in an amount of not more than 10% area in relation to the concentration of pridopidine, based on HPLC determination, or

c) Compound 3 is present in the pharmaceutical composition in an amount of not more than 10 area % relative to the concentration of pridopidine, based on HPLC determination, or

d) compound 4 is present in the pharmaceutical composition in an amount of not more than 10% area in relation to the concentration of pridopidine, based on HPLC determination, or

e) compound 5 is present in the pharmaceutical composition in an amount of not more than 10% area in relation to the concentration of pridopidine, based on HPLC determination, or

f) compound 6 is present in the pharmaceutical composition in an amount of not more than 10% area in relation to the concentration of pridopidine, based on HPLC determination, or

g) compound 7 is present in the pharmaceutical composition in an amount of not more than 10% of the area in relation to the concentration of pridopidine, based on the determination by HPLC.

In one variant:

a) Compound 1 is present in the pharmaceutical composition in an amount of not more than 0.15 area %, based on the concentration of pridopidine, based on HPLC determination, or

b) Compound 2 is present in the pharmaceutical composition in an amount of not more than 0.15 area % relative to the concentration of pridopidine, based on HPLC determination, or

c) Compound 3 is present in the pharmaceutical composition in an amount of not more than 0.15 area % relative to the concentration of pridopidine, based on HPLC determination, or

d) Compound 4 is present in the pharmaceutical composition in an amount of not more than 0.15 area %, based on the concentration of pridopidine, based on HPLC determination, or

e) Compound 5 is present in the pharmaceutical composition in an amount of not more than 0.15 area % relative to the concentration of pridopidine, based on HPLC determination, or

f) Compound 6 is present in the pharmaceutical composition in an amount of not more than 0.15 area % relative to the concentration of pridopidine, based on HPLC determination.

In another variant:

a) Compound 1 is present in the pharmaceutical composition in an amount of more than 0.01 area %, and not more than 0.15 area %, based on the concentration of pridopidine, based on HPLC determination, or

b) compound 2 is present in the pharmaceutical composition in an amount of more than 0.01% area, and not more than 0.15% area, in relation to the concentration of pridopidine, based on HPLC determination, or

c) Compound 3 is present in the pharmaceutical composition in an amount of more than 0.03 area %, and not more than 0.15 area %, based on the concentration of pridopidine, based on HPLC determination, or

d) compound 4 is present in the pharmaceutical composition in an amount of more than 0.01% area,

- 3 041145 and not more than 0.15% of the area, in relation to the concentration of pridopidin, based on the determination by the method

HPLC, or

e) compound 5 is present in the pharmaceutical composition in an amount of more than 0.01% area, and not more than 0.15% area, in relation to the concentration of pridopidine, based on the determination by the method

HPLC, or

f) compound 6 is present in the pharmaceutical composition in an amount of more than 0.01% area, and not more than 0.15% area, in relation to the concentration of pridopidine, based on HPLC determination.

In another variant:

a) compound 1 is present in the pharmaceutical composition in an amount of less than 0.04 area % relative to the concentration of pridopidine, based on HPLC determination, or

b) Compound 2 is present in the pharmaceutical composition in an amount of less than 0.05 area %, based on the concentration of pridopidine, based on HPLC determination, or

c) compound 3 is present in the pharmaceutical composition in an amount of less than 0.05 area %, based on the concentration of pridopidine, based on HPLC determination, or

d) compound 4 is present in the pharmaceutical composition in an amount of less than 0.04 area %, based on the concentration of pridopidine, based on HPLC determination, or

e) Compound 5 is present in the pharmaceutical composition in an amount of less than 0.04 area %, based on the concentration of pridopidine, based on HPLC determination, or

f) Compound 6 is present in the pharmaceutical composition in an amount of less than 0.04 area %, based on the concentration of pridopidine, based on HPLC determination.

In another variant:

a) compound 1 is present in the pharmaceutical composition in an amount of less than 0.01 area % relative to the concentration of pridopidine, based on HPLC determination, or

b) compound 2 is present in the pharmaceutical composition in an amount of less than 0.01 area % relative to the concentration of pridopidine, based on HPLC determination, or

c) Compound 3 is present in the pharmaceutical composition in an amount of less than 0.03 area % relative to the concentration of pridopidine, based on HPLC determination, or

d) compound 4 is present in the pharmaceutical composition in an amount of less than 0.01 area % relative to the concentration of pridopidine, based on HPLC determination, or

e) compound 5 is present in the pharmaceutical composition in an amount of less than 0.01 area % relative to the concentration of pridopidine, based on HPLC determination, or

f) Compound 6 is present in the pharmaceutical composition in an amount of less than 0.01 area % relative to the concentration of pridopidine, based on HPLC determination.

In one embodiment, at least two of compound 1, compound 2, compound 3, compound 4, compound 5, and compound 6 are present. In another embodiment, at least three of compound 1, compound 2, compound 3, compound 4, Compound 5, and Compound 6. In another embodiment, at least four of Compound 1, Compound 2, Compound 3, Compound 4, Compound 5, and Compound 6 are present. In another embodiment, at least five of Compound 1 are present. , compounds 2, compounds 3, compounds 4, compounds 5 and compounds 6. In another embodiment, compound 1, compound 2, compound 3, compound 4, compound 5 and compound 6 are present. In another embodiment, at least compound 1 is present In another embodiment, at least compound 3 is present.In another embodiment, at least compound 4 is present.

In one embodiment, the pharmaceutical composition contains pridopidine hydrochloride.

In one embodiment, the pharmaceutical composition is in the form of a capsule, tablet, or liquid suspension. In another embodiment, the pharmaceutical composition is in an oral dosage form.

In one embodiment, the oral dosage form of the pharmaceutical composition contains 22.5-315 mg of pridopidine. In another embodiment, the oral dosage form contains 45-250 mg of pridopidine. In another embodiment, the oral dosage form contains 45-135 mg of pridopidine. In another embodiment, the oral dosage form contains 90-315 mg of pridopidine. In another embodiment, the oral dosage form contains about 22.5 mg of pridopidine. In another embodiment, the oral dosage form contains about 45 mg of pridopidine. In another embodiment, the oral dosage form contains about 67.5 mg of pridopidine. In another embodiment, the oral dosage form contains about 90 mg of pridopidine. In another embodiment, the oral dosage form contains about 100 mg of pridopidine. In another embodiment, the oral dosage form contains about 112.5 mg of pridopidine. In another embodiment, the oral dosage form contains about 125 mg of pridopidine. In another embodiment, the oral dosage form contains about 135 mg of pridopidine. In another embodiment, the oral dosage form contains about 150 mg of pridopidine. In another embodiment, the oral dosage form contains about 180 mg of pridopidine. In another embodiment, the oral dosage form contains about 200 mg of pridopidine. In another embodiment, the oral dosage form contains about 250 mg of pridopidine. In another embodiment, the oral dosage form contains about 315 mg of pridopidine. In another embodiment, an oral dosage form

- 4 041145 receive for administration once a day. In another embodiment, the oral dosage form is prepared for administration more than once a day.

The invention also provides a process for the preparation of Compound 1, comprising the step of oxidizing 4-hydroxy-4-(3-(methylthio)phenyl)-1-propylpiperidin-1-ium chloride with an oxidizing agent to obtain compound 1. In one embodiment, the oxidizing agent is peroxide, preferably hydrogen peroxide. In another embodiment, the oxidizing agent is peroxide. In another embodiment, the oxidizing agent is hydrogen peroxide.

This invention also provides a method for obtaining compound 2, which includes the steps:

a) reacting 3-bromothioanisole with ethyl 3-(4-oxopiperidin-1-yl)propanoate to give 1(3-hydroxy-3,3-bis(3-(methylthio)phenyl)propyl)-4-(3-( methylthio)phenyl)piperidin-4-ol,

b) dehydrating 1-(3-hydroxy-3,3-bis(3-(methylthio)phenyl)propyl)-4-(3-(methylthio)phenyl)piperidin-4-ol obtained in step a) with a dehydrating agent to obtain 1-(3,3-bis(3-(methylthio)phenyl)allyl)-4-(3-(methylthio)phenyl)-1,2,3,6-tetrahydropyridine,

c) oxidation of 1-(3,3-bis(3-(methylsulfonyl)phenyl)allyl)-4-(3-(methylsulfonyl)phenyl)-1,2,3,6tetrahydropyridine obtained in step b) with an oxidizing agent with obtaining 1-(3,3-bis(3(methylsulfonyl)phenyl)allyl)-4-(3-(methylsulfonyl)phenyl)-1,2,3,6-tetrahydropyridine, and

d) hydrogenation of 1-(3,3-bis(3-(methylsulfonyl)phenyl)allyl)-4-(3-(methylsulfonyl)phenyl)-1,2,3,6tetrahydropyridine obtained in step c) with a hydrogenating agent c obtaining compound 2.

In one embodiment, the dehydrating agent is a strong acid, preferably sulfuric acid. In one embodiment, the dehydrating agent is a strong acid. In another embodiment, the dehydrating agent is sulfuric acid. In another embodiment, the oxidizing agent is peroxide. In another embodiment, the oxidizing agent is hydrogen peroxide. In another embodiment, the hydrogenating agent is hydrogen.

This invention also provides a method for obtaining compound 3, including the steps:

a) reacting 3-bromothiophenol and 1,4-dibromobutane to give 1,4-bis((3bromophenyl)thio)butane,

b) oxidizing 1,4-bis((3-bromophenyl)thio)butane obtained in step a) with an oxidizing agent to give 1,4-bis((3-bromophenyl)sulfonyl)butane,

c) reacting 4-pyridinylboronic acid with 1,4-bis((3-bromophenyl)sulfonyl)butane obtained in step b) to give 1,4-bis((3-(pyridin-4-yl)phenyl)sulfonyl ) butane,

d) reacting 1-iodopropane with 1,4-bis((3-(pyridin-4-yl)phenyl)sulfonyl)butane obtained in step c) to give 4,4'-((butane-1,4 -diyldisulfonyl)bis(3,1-phenylene))bis(1propylpyridin-1-ium),

e) adding a reducing agent to 4,4'-((butan-1,4-diyldisulfonyl)bis(3,1phenylene))bis(1-propylpyridin-1-ium) iodide obtained in step d) to obtain 1, 4-bis((3-(1-propyl1,2,3,6-tetrahydropyridin-4-yl)phenyl)sulfonyl)butane, and

f) hydrogenating 1,4-bis((3-(1-propyl-1,2,3,6-tetrahydropyridin-4-yl)phenyl)sulfonyl)butane obtained in step e) with a hydrogenating agent to give compound 3.

In one embodiment, the oxidizing agent is a peroxide, preferably hydrogen peroxide. In another embodiment, the oxidizing agent is peroxide. In another embodiment, the oxidizing agent is hydrogen peroxide. In another embodiment, the reducing agent is sodium borohydride. In another embodiment, the hydrogenating agent is hydrogen.

This invention also provides a method for obtaining compound 4, including the steps:

a) Epoxidizing 4-(3-(methylsulfonyl)phenyl)-1-propyl-1,2,3,6-tetrahydropyridine with an epoxidizing agent to give (1S,6S)-6-(3-(methylsulfonyl)phenyl)-3- propyl-7-oxa-3azabicyclo[4.1.0]heptane, and

b) nucleophilic discovery of (1S,6S)-6-(3-(methylsulfonyl)phenyl)-3-propyl-7-oxa-3azabicyclo[4.1.0]heptane epoxide from step a) with a nucleophile to give compound 4.

In one embodiment, the epoxidizing agent is sodium bromate. In another embodiment, the nucleophile is hydrogen.

The invention also provides a process for the preparation of compound 5, comprising the step of reacting pridopidine with a peroxide to form compound 5. In one embodiment, the peroxide is hydrogen peroxide.

This invention also provides a process for the preparation of compound 6, comprising the step of reacting 4-(3-(methylsulfonyl)phenyl)piperidine with 1-chloro-2-methylpentane to obtain compound 6.

This invention also provides a method for obtaining compound 7, including the steps:

a) dehydrating 4-hydroxy-4-(3-(methylsulfonyl)phenyl)-1-propylpiperidin-1-ium chloride with a dehydrating agent to give 4-(3-(methylthio)phenyl)-1-propyl-1,2 hydrogen sulfate, 3,6tetrahydropyridin-1-ium,

b) oxidation of 4-(3-(methylthio)phenyl)-1-propyl-1,2,3,6-tetrahydropyridin-1-ium hydrogen sulfate from step b) with an oxidizing agent to give compound 7.

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In one embodiment, the dehydrating agent is a strong acid, preferably sulfuric acid. In another embodiment, the dehydrating agent is a strong acid. In another embodiment, the dehydrating agent is sulfuric acid. In another embodiment, the oxidizing agent is a peroxide, preferably hydrogen peroxide. In another embodiment, the oxidizing agent is peroxide. In another embodiment, the oxidizing agent is hydrogen peroxide.

The present invention also provides the use of a pharmaceutical composition for the treatment of a patient afflicted with a neurodegenerative disease or a neurodegenerative disorder.

The present invention also provides the use of a pharmaceutical composition for the treatment of a patient afflicted with Huntington's disease.

The present invention also provides a method for preparing a pharmaceutical composition containing pridopidine, comprising:

a) receiving a batch of pridopidine drug product;

b) performing a batch sample stability test;

c) determining the total amount of at least one of Compound 1, Compound 2, Compound 3, Compound 4, Compound 5, and Compound 6 in a batch sample after HPLC stability testing; And

d) obtaining a pharmaceutical composition from a batch after stability testing, if the batch sample after stability testing contains:

i) not more than 0.15% of compound 1, based on the concentration of pridopidine, or ii) not more than 0.15% of compound 2, based on the concentration of pridopidine, or iii) not more than 0.15% of compound 3, based on concentration of pridopidine, or iv) not more than 0.15% of compound 4, relative to the concentration of pridopidine, or

v) not more than 0.15% of compound 5, based on the concentration of pridopidine, or vi) not more than 0.15% of compound 6, based on the concentration of pridopidine.

In one embodiment, the method also includes step e) selling the lot if, in step d), the lot is approved for sale.

Each option described here is considered to apply to each of the other options described. Thus, all combinations of the various options described herein are included within the scope of this invention.

For example, the elements specified in the packaging and pharmaceutical composition options can be used in the applications described here.

Terms.

In this specification, and unless otherwise indicated, each of the following terms has the following definition.

As used herein, pridiopidin means a pridopidine base or a pharmaceutically acceptable salt thereof, including pridopidine hydrochloride. Preferably, in any embodiments of the present invention, as described, pridopidine is in the form of a hydrochloride.

As used herein, a drug substance refers to an active ingredient in a drug product or a composition containing the active ingredient before it is formulated into a drug product that provides pharmacological activity or other direct effect in the diagnosis, treatment, mitigation, treatment or prevention of a disease, or affects the structure or any function of the human or animal body.

As used herein, a drug product refers to a formulated or final dosage form containing a drug substance as well as at least one pharmaceutically acceptable carrier.

As used herein, an isolated compound is a compound isolated from the crude reaction mixture after a positive isolation event. The act of isolation involves separating the compound from other known components of the crude reaction mixture, with some impurities, unknown by-products, and residual amounts of other known components of the crude reaction mixture that can be made up. Purification is an example of a positive act of selection.

As used herein, stability testing refers to tests performed at specific time intervals and under various environmental conditions (eg, temperature and humidity) to see if, and to what extent, a drug product degrades beyond a specified shelf life. The specific conditions and timing of testing are such that they reinforce the conditions that the drug is expected to experience during the period of validity. For example, detailed requirements for stability testing for finished pharmaceutical products are codified in 21 C.F.R 211,166, the entire content of which is incorporated here by reference.

As used herein, in the context of a numerical value or range, means ±10% of the numerical value or specified range.

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As used herein, approximately in the context of a numerical value or range means ±5% of the numerical value or specified range.

As used herein, the amount of a compound, measured in milligrams, refers to the milligrams of the compound present in a formulation, regardless of the form of the formulation. The amount of the compound of 40 mg means that the amount of the compound in the preparation is 40 mg, regardless of the form of the preparation. Thus, when the form contains a carrier, the mass of carrier required to provide a 40 mg dose of the compound will be greater than 40 mg due to the presence of the carrier.

As used herein, treating and treating includes, for example, inhibition, regression, or stasis of a disease, disorder, or condition. Reducing or alleviating a disease or condition as used herein means lessening or lessening the symptoms of that disease or condition. Inhibiting the development of a disease or complication of a disease in a patient as used herein means preventing or reducing the development of a disease and/or complication of a disease in a patient.

Administering to a patient means delivering, dispensing, or applying drugs, medicaments, or therapeutic agents to a patient to alleviate, treat, or reduce symptoms associated with a condition, such as a pathological condition.

The drug substance of the present invention, for example pridopidine hydrochloride, may be administered in admixture with suitable pharmaceutical diluents, additives, excipients or carriers (collectively referred to herein as a pharmaceutically acceptable carrier) suitably selected for the intended form of administration and in accordance with conventional pharmaceutical practices. Capsules or tablets may contain suitable binders, lubricating agents, disintegrating agents, diluents, coloring agents, anti-caking agents and antifreeze agents.

The unit dosage form of the compounds used in the method in accordance with this invention may contain a single compound or a mixture thereof with additional therapeutic agents.

The dose or unit dosage form of pridopidine, measured in milligrams, refers to the milligrams of pridopidine hydrochloride present in the formulation, regardless of the form of the formulation. A standard dosage form may contain a single compound or a mixture of compounds. The unit dosage form can be prepared for oral dosage forms such as tablets, capsules, pills, powders and granules. For example, the dose or unit dosage form of pridopidine may be 22.5, 45, or 67.5 mg.

As used herein, a pharmaceutically acceptable ingredient is one that is suitable for use in humans and/or animals without causing undesirable side effects (such as toxicity, irritation, and allergic reaction) with a reasonable benefit/risk ratio.

This invention also includes all isotopes of atoms present in the compounds described herein, including impurities. Isotopes include atoms that have the same atomic number but different mass numbers. As a general example, and without limitation, isotopes of hydrogen include tritium and deuterium. Isotopes of carbon include C-13 and C-14.

As used herein, the detection limit for an analytical method used in screening or testing for the presence of a compound in a sample is a threshold below which the compound in the sample cannot be detected by the analytical method used. The limits of detection of this HPLC method for determining an impurity in a sample containing pridopidine may vary depending on the method and the impurity or impurities being determined. For example, the detection limit of a typical HPLC method for the determination of compounds 1, 2, 4, 5 and 6 is 0.01 area%, and the detection limit for the determination of compound 3 is 0.03% of the area.

As used herein, the limit of quantitation for an analytical method used in screening or testing for the presence of a compound in a sample is the threshold below which the compound in the sample cannot be quantified by the analytical method used. The quantitation limits for this HPLC method for determining an impurity in a sample containing pridopidine may vary depending on the impurity or impurities being determined. For example, the quantitation limit of the generic HPLC method for quantifying compounds 1, 4, 5, and 6 is 0.04 area%, and the quantitation limit for compound 3 is 0.05 area%. The limit of quantitation for compound 2 is 0.05 area%.

Compound characterization refers to any quality that a compound exhibits, such as retention time peaks as determined by 1H nuclear magnetic spectroscopy, mass spectroscopy, infrared, ultraviolet or fluorescence spectrophotometry, gas chromatography, thin layer chromatography, high performance liquid chromatography, elemental analysis, Ames test, dissolution, stability and any other quality that can be determined by an analytical method. Once the characteristics of a compound are known, the information can be used, for example, to screen or test for the presence of the compound in a sample.

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In this description, NBC means no more than. In this specification, MCH means less than.

Impurities are measured by reverse phase HPLC unless otherwise noted.

As used herein, the term effective amount refers to the amount of a component that is sufficient to produce the desired therapeutic response without undesirable side effects (such as toxicity, irritation, or allergic reaction) with a reasonable benefit/risk ratio when used in the method of the present invention, i.e., .e. therapeutically effective amount. The specific effective amount will vary according to such factors as the particular condition being treated, the physical condition of the patient, the type of mammal being treated, the duration of treatment, the nature of the concomitant therapy (if any), and the particular compositions used and the structure of the compounds and derivatives thereof.

In this description, obtaining a medicinal product for commercial sale means the actions taken to obtain for commercial sale. Examples include, but are not limited to, dyeing, coding, stamping, drug product packaging.

It will be appreciated that if a parameter interval is given, all integers within that interval, and their tenths, are also represented in this invention. For example, 20-40 mg includes 20.0, 20.1, 20.2, 20.3 mg, etc. up to 40.0 mg.

Pharmaceutically acceptable salts.

Active compounds for use in accordance with this invention may be presented in any form suitable for the intended administration. Suitable forms include pharmaceutically (ie physiologically) acceptable salts and pre - or prodrugs in accordance with this invention.

Examples of pharmaceutically acceptable addition salts include, without limitation, non-toxic inorganic and organic acid addition salts such as hydrochloride, hydrobromide, nitrate, perchlorate, phosphate, sulfate, formate, acetate, aconate, ascorbate, benzenesulfonate, benzoate, cinnamate, citrate, embonate, enanthate, fumarate, glutamate, glycolate, lactate, maleate, malonate, almond, methanesulfonate, naphthalene-2-sulfonate, phthalate, salicylate, sorbate, stearate, succinate, tartrate, toluene-psulfonate, and the like. Such salts can be prepared by methods well known and described in the art.

pharmaceutical compositions.

Although the compounds for use in accordance with this invention may be administered in the form of a crude compound, it is preferable to administer the active ingredients, optionally in the form of physiologically acceptable salts, in a pharmaceutical composition together with one or more adjuvants, excipients, carriers, buffers, diluents and/or other conventional pharmaceutical additives.

In one embodiment, the invention provides pharmaceutical compositions comprising the active compounds, or pharmaceutically acceptable salts or derivatives thereof, together with one or more pharmaceutically acceptable carriers, so, and optionally, other therapeutic and/or prophylactic ingredients are known and used in the art. The carrier(s) must be acceptable in the sense of being compatible with the other ingredients of the composition and not detrimental to the recipient.

In table. 1 shows the structures of compounds 1-8.

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Table 1

4-(3- Compound 1 Potential impurity in pridopidine. SOjCHj (methylsulfonyl)phenyl)- 1- propylpiperi din-4-ol 1-(3,3- 50gCH1 bis(3- Compound 2 Potential impurity in pridopidine. SQsCHa ό v (methylsulfonyl)phenyl)propyl)-4-(3- (methylsulfo SHZH nyl)phenyl)pi peridone 1,4-bis((3- Compound 3 Potential impurity in pridopidine. o ₂ s - ^x 3 A — 'Pr (1- propylpiperi din-4- yl)phenyl)sul phonyl)butane (3R,4S)-4- Compound 4 Potential impurity in pridopidine. SOjCHa ^IV . (3- (methylsulfonyl)phenyl)- 1- propylpiperi din-3-ol 1-oxide 4- Compound 5 Potential impurity in pridopidine. ZORSNz ] ,0' (3- (methylsulfonyl)phenyl)- 1- propylpiperi Dina 12- _{SO2CH3 _} methylpentyl) Compound Λ -4- (3- 6 (methylsulfo nyl)phenyl)pi peridine 4-(3- Compound 7 SOCH _3dy (methylsulfinyl)phenyl)1-propyl- 1, 2, 3, 6- tetrahydropi ridin 4-(3- Compound 8 _{SO2CH3 _} (methylsulfonyl)phenyl)1-propyl- 1, 2, 3, 6- tetrahydropi ridin

This invention will be better understood on reading the detailed description of the experiments, which is presented below, but the person skilled in the art will easily understand that the described in detail

- 9 041145 specific experiments are only illustrative of the present invention, which is more fully described in the claims below.

Detailed description of experiments.

Examples

Example 1 Preparation of compound 1 (4-(3-(methylsulfonyl)phenyl)-1-propylpiperidin-4-ol).

To a suspension of 4-hydroxy-4-(3-(methylthio)phenyl)-1-propylpiperidin-1-ium chloride (140 g, 348 mmol) in 710 ml of water was added 1.5 g of sodium tungstate dihydrate and the mixture heated to 45 °C. 102 ml of 33% H2O2 are added over 20 minutes at 45-55°C. The suspension dissolves after adding 20 ml. The solution was then stirred at 48-51°C for 30 min, after which HPLC showed no starting material and two new peaks, one at RT 2.68 min (82.3%) and the other at RT 3.66 min (11. 8%). After additional stirring for 2 hours and 45 minutes, HPLC showed that the peak at RT of 2.68 minutes decreased to 7.5% and the peak at RT of 3.66 minutes increased to 88.5%. After another 45 min the mixture is cooled to 20°C, and 500 ml of toluene and 150 ml of ~5 M NaOH are added to the reaction mixture. After stirring for 5 minutes, the mixture is poured into a separating funnel. The solubility of the product in toluene is low. Most of the product settles as a very viscous liquid at the bottom. The aqueous phase (and the main part of the product) is separated, the toluene phase is washed successively with 5% Na ₂ SO ₃ solution and brine and dried over MgSO ₄ . The aqueous phase is extracted with 500 ml DCM. The organic phase is separated and washed successively with 5% Na ₂ SO ₃ solution and water and dried over MgSO ₄ . Both extracts are concentrated on a rotary evaporator. 500 ml of heptane are added to both residues and the suspensions are stirred at room temperature for 2 hours. The precipitates are filtered, washed with heptane and dried. From the DCM extract, 83.8 g of a white powder were obtained, HPLC purity 98.8%, 1H-NMR analysis 97.9%. (13.7 g of a white powder was obtained from the toluene extract, HPLC purity 98.0%).

NMR identification analysis of compound 1.

Compound 1

The data presented in table. 2 and 3 are determined using a 78.95 mg sample of Compound 1, solvent 0.55 ml DMSO-D ₆ , 99.9% atom D and using a Bruker Avance III 400 MHz instrument.

- 10 041145

Table 2. Assignment of 1H NMR ^a,<

³ N shift (ppm) Integral Multiplicity Assignment COP : g cross- geeks MMC cross peaks 8.07 1 t, J=l,7 Hz H5 H1 ^b , NZ ^b C1, cs, C4 ^b , C6 ^b , C8 7.82 1 D, J=7.9 Hz NZ H2, H5 ^b C1, C5, C4 ^b , C8 7.79 1 D, J=7.9 Hz H1 H2, H5 ^b NW, C4 ^b , C5 7.59 1 t, J=7.9 Hz H2 H1, NZ C3, C4, C5 ^b , C6, C8 ^b 5, 08 3.21 1 3 With With H17 H18 - C8, C9, C13 C6 ^b 2, 67 2 D, J=ll,5 Hz nude, H12 nude, H13, , H12, , H9 C8 ^b , C9 ^b , SU, C12, C13 ^b 2.37 2 t, J=ll,6 Hz nude, H12 nude H13 , H12, , H9 C8 ^b , SU, C13 ^b C9 ^b , C12, , C14 2.28 2 t, J=7.3 Hz H14 H15 SU, C15, C12. C16 1.97 2 dt, J=12.5 and 4.1 Hz H9, H13 nude H13 , H12, , H9 C9, C12, SU, C13 1.60 2 D, J=12.8 Hz H9, H13 nude H13 , H12, , H9 C8, C9, C13 1.46 2 hex, J=7.5 Hz H15 H14 , H16 C14, C15 0.87 3 t, J=7.5 Hz H16 H15 C14, C15

assignment based on signal pairing pattern, coupling constants and chemical shifts, ^b weak signal, ^c spectrum adjusted by residual solvent peak (2.5 ppm). Table 3. Assignment of ¹³ C NMR ^a,b

¹³ C shift (ppm) Assignment ¹³ S Shift (ppm) Assignment 151.9 C4 60.2 C14 140.6 C6 49.0 SU, C12 130.1 NW 43.6 C18 129.0 C2 38.0 C9, C13 124.9 C1 19, 8 C15 123.3 C5 12.0 C16 70.0 C8

the assignment is based on chemical shifts and 1H- ^13C combinations obtained in SHOP and GMC experiments, ^b spectrum is adjusted by the solvent peak (39.54 ppm).

Example 2 Preparation of compound 2 (1-(3,3-bis(3-(methylsulfonyl)phenyl)propyl)-4-(3(methylsulfonyl)phenyl)piperidine).

Preparation of ethyl 3-(4-oxopiperidin-1-yl)propanoate (starting material for compound 2)

- 11 041145

Ethanol (1550 mL) is poured into a 4 L 3-necked round bottom flask equipped with an overhead stirrer, then 125 g (814 mmol, 1 eq) 4-piperidone monohydrate and 225 g (1628 mmol, 2 eq) potassium carbonate are added. Ethyl 3-chloropropanoate (111 g, 1 eq.) is added and the reaction mixture is stirred for 3 h, after which HPLC shows that the product has reached only 10% of the area. Add another 0.5 equiv. K ₂ CO ₃ (56.2 g) and stirring continued at 24°C. After 45 h, the total product reaches 86% of the area (HPLC). Add another 0.2 eq. K ₂ CO ₃ and the reaction mixture is stirred for another 4.5 h at 35°C after which HPLC shows 96% of the area of the product. The mixture is filtered through a sintered glass filter, washed with 200 ml of ethanol and concentrated in vacuo to 156 g of a yellow oil, which is distilled in a vacuum of 2 mmHg. Art. in the bath 156°C. The main fraction is distilled at 120°C to obtain 97.8 g (60%) 99.3% area (HPLC).

Preparation of 1-(3-hydroxy-3,3-bis(3-(methylthio)phenyl)propyl)-4-(3-(methylthio)phenyl)piperidin-4ol (compound 2, 1st intermediate)

Me S

U 1-(3-Hyloxy-3 _g 3-Bis(3(ynylthio)phenyl) prolyl)-4-(3-methylthio)phenyl)piperidin-4-ol

3-Bromothioanisole (170.3 g; 0.84 mol, 3.2 eq.) and THF (700 ml) were charged into a 2 L flask stirred under nitrogen and cooled in a dry ice/acetone bath to -74°C. . A solution of nhexyllithium in hexane (2.3 M; 237.4 g; 0.77 mol, 3.0 eq.) was added and the reaction mixture became slightly yellowish. Stirring is continued for another 30 minutes at -74°C. A solution of ethyl 3-(4-oxopiperidin-1yl)propanoate (50.2 g; 0.26 mol, 1 eq.) in THF (100 mL) was added over 1 h 15 min to the reaction mixture and stirring was continued for another 30 min at -74°C to obtain a clear yellow solution. Cooling is stopped and the reaction mixture is heated to -40°C. A solution of HCl (33%; 90 g, 0.82 mol, 3.1 eq.) in water (100 ml) was added dropwise over 20 min to give a light yellow emulsion at +8°C. The light yellow organic phase is separated, washed with water (3x200 ml) and extracted twice with aqueous HCl (33% HCl 40g/300 ml water) to give a lower yellow phase (234 g). The organic upper clear phase is evaporated down to 159 g of a solution and the precipitate obtained during concentration is filtered to give 19.1 g of a yellow sticky precipitate. The precipitate is combined with the lower yellow phase, methanol (50 ml) and THF (200 ml) are added and distilled (67° C., 248 g distilled). Heptane (200 ml) is added, the two liquid phases are stirred for 20 min at 40° C. and cooled to RT. The upper heptane phase is discarded and water (200 ml) is added to the viscous yellow residue. After stopping the stirring and decanting the colorless water, 182 g of a very viscous light yellow residue are obtained (HPLC: 82% area).

Preparation of 1-(3,3-bis(3-(methylthio)phenyl)allyl)-4-(3-(methylthio)phenyl)-1,2,3,6tetrahydropyridine (compound 2, 2nd intermediate)

she tra hydro pyridine

2-propanol (200 ml) was added to the viscous light yellow residue and the reaction mixture was distilled at atmospheric pressure to give 200 ml of an azeotropic distillate to give a dark yellow oil to which methanol (50 ml), 2-propanol (350 ml) and conc. sulfuric acid (36.5 g, 0.35 mol, 1.35 eq.). The reaction mixture is heated for 26 hours (mixture temperature 81-84° C., steam temperature 79° C.) and about 440 ml of distillate are collected. At the end the temperature reaches 87°C and

- 12 041145 the promotional mixture foams. After cooling, toluene (100 ml) and water (200 ml) are added and the reaction mixture is heated to reflux (87° C.). The heating is stopped and after cooling three phases are formed. The lower oil phase was washed with water (2x200 ml) and concentrated by vacuum distillation to give a dark yellow viscous residue. Water (300 ml) is added and the mixture is refluxed, then cooled to 40° C. and the aqueous phase is decanted to give about 200 g of an orange cloudy liquid (HPLC: 82 area %), which is used in the next step.

Preparation of 1-(3,3-bis(3-(methylsulfonyl)phenyl)allyl)-4-(3-(methylsulfonyl)phenyl)-1,2,3,6tetrahydropyridine (compound 2, 3rd intermediate)

To 200 g of the orange cloudy liquid from the previous step, add 500 ml of water, sodium tungstate dihydrate (2 g, 6 mmol) and concentrated sulfuric acid (20 ml). The mixture is heated to 35°C and 33% H2O2 is added dropwise over 1 hour, during which time the yellow viscous mass on the flask bath slowly dissolves and the temperature rises to 55°C, then slowly decreases to 42°C. The reaction mixture is heated to 50°C for 2 h and add another 32 g of 33% H ₂ O ₂ . The reaction is continued for another 4 hours at 50° C. and an additional 20 g of 33% H2O2 is added. After 2 hours the reaction mixture is cooled (25°C) and basified to pH 12 with 50% NaOH solution. Water (300 ml) was added and removed after 20 minutes of mechanical stirring. An additional 200 ml of water is added, mechanically stirred for 20 minutes and removed to give 158.2 g of a very viscous yellow mass (HPLC: 75.4% area). This mass is heated for 30 min 4 times with butanol (200 ml at 95°C, 200 ml at 100°C, 400 ml at 100°C and 700 ml at 114°C) and twice with acetic acid (8 ml and 250 ml at 95° C.) to give a light brown oil which is used in the next step (114.9 g, HPLC: 89% area).

Preparation of 1-(3,3-bis(3-(methylsulfonyl)phenyl)propyl)-4-(3-(methylsulfonyl)phenyl)piperidine (compound 2)

The light brown oil from the previous step (114.9 g, HPLC: 89% area) is added to a 2 liter autoclave with 550 ml of acetic acid and 10% Pd/C catalyst (25 g, 23.5 mmol). Hydrogen (120 ^psi ) is introduced and the reaction mixture is heated to 90° C. for 16 hours. After cooling, the catalyst is filtered, washed with acetic acid (50 ml) and the clear yellowish filtrate is concentrated in vacuo to give 134 g of a brown viscous residue (HPLC : 82% area). Water (300 ml) is added, alkalinized (40% NaOH, pH>12) and extracted with 120 ml dichloromethane and, after concentration, 77.2 g of a brown sticky mass is obtained (HPLC: 83% area). The residue is treated with butanol (5x100 ml, 95° C.), cooled and the butanol phase over the aqueous phase is filtered. A total of 74.9 g of a solid is obtained which is dissolved in 200 ml of acetone and the clear yellow solution is evaporated to give 70.1 g of a dark yellow clear viscous solution. The residue is treated with heptane (2x100 ml, 95°C), cooled and decanted. Evaporation on a rotary evaporator gives a pale yellow foamy solid (65.1 g, HPLC: 84% area). The solid is dissolved in 200 ml of dichloromethane, 85 g of silica are added and the mixture is evaporated and loaded onto a 1.32 kg silica gel column which is eluted with dichloromethane with 0.5-3.0% methanol and 0.5% triethylamine.

Compound 2 is isolated to give 25.8 g, HPLC: 93.2% area, 1H-NMR analysis: 91.2%.

- 13 041145

NMR analysis of the identity of compound 2. Compound 2

The data presented in table. 4 and 5 are determined using a sample of 62.03 mg of Compound 2, solvent 0.6 ml CDCl ₃ , 99.8% atom D and the instrument is a Bruker Avance III 400 MHz.

Table 4. Assignment of ¹ H NMR ^a,c

SH shift (ppm) Integral Multiplicity Assignment COP cross- peaks MMC cross peaks 7.87 2 With H2 0 H22 ^b , H24 ^b C16, C21 ^b , C22, C24 7.72- 4 m Hl, H5, H2, H23 C1, sz, 7.80 H22 C5, C8, C20, C24 7.47- 6 m H2, NC, H1, NC, Cl, C4, 7.56 H23, H24 H20, H22 C5, C6, C8, C16, C19, C21, C20, C22, C24 ^b 4.33 1 t, J=7,l H16 H15 C14 ^b , Hz C15, C19, C20, C24 3, 05 9 With H18, H25 - - 2.94 4 D, J=ll,5 NUDE H12 NU, H12, C8, C9 ^b , Hz H9, H13 SU, C12, C13 ^b 2.53- 1 m H8 H9, H13 C3 ^b , C4, 2, 62 C5 ^b , C9, C13, C10 ^b , C12 ^b 2.24- 4 m H14, H15 H16 SU, C12, 2.34 C14, C15, C16, C19 2.02 2 t, J=ll,5 NU, H12, NU, H12, C8, C9 ^b , Hz H9, H13 SU, C12, C13 ^b , C14 1.72- 4 m H9, H13 H8, NU, C4 ^b , C8, 1.85 H12 C9, C10 ^b , C12 ^b , C13

assignment based on signal pairing pattern, coupling constants and chemical shifts, ^b weak signal, ^c spectrum adjusted by residual solvent peak (7.28 ppm). ____________ Table 5. Assignment of ¹³ С NMR ^{a, b} ____________

¹³ S OFFSET (ppm) Assignment ¹³ S Shift (ppm) Assignment

- 14 041145

148.0 C4 125.6 C5 145.5 C19 125.2 C1 141.0 C21 55.9 C14 140.6 C6 54.0 SU, C12 133.2 C24 48.2 C16 132.3 NW 44.51 C18 129.9 C23 44.48 C25 129.5 C2 42.4 C8 126.7 C20 32.3 C9, C13 125.7 C22 31.8 C15

the assignment is based on chemical shifts and 1H- ^13C combinations obtained in SHOPG and GMC experiments, ^b spectrum is adjusted by the solvent peak (77.16 ppm).

Example 3 Preparation of compound 3 (1,4-bis((3-(1-propylpiperidin-4-yl)phenyl)sulfonyl)butane).

Preparation of 1,4-bis((3-bromophenyl)thio)butane (compound 3, 1st intermediate)

SH

1,4-bis((3-bramphenyl)thio)bulane

KOH (56.2 g) was added to methanol (1200 ml) over 15 minutes. The clear solution is cooled in a water bath to 0°C. A solution of 3-bromothiophenol (150.2 g, 0.79 mol) in methanol (200 ml) was added over 50 minutes keeping the temperature at 1-3°C. A solution of 1,4-dibromobutane (86.5 g; 0.40 mol) in methanol (150 ml) was added over 40 minutes to give a yellow cloudy mixture. After stirring for an additional 4 h, the reaction mixture becomes cloudy, and it is stirred for another 20 h at 25°C. The suspension is filtered and washed with water (3x100 ml) and methanol (2x100 ml) to give 239 g of a wet white solid which is dried to 163.6 g (94.6% yield, HPLC: 97.9%).

Preparation of 1,4-bis((3-bromophenyl)sulfonyl)butane (compound 3, 2nd intermediate)

To a solution of 1,4-bis-(3-bromophenylthio)butane (155.0 g, 0.358 mol) in acetic acid (1500 ml) was added sodium tungstate dihydrate (2.5 g, 0.0075 mol) and the suspension heated for water bath up to 45°C. 50% H ₂ O ₂ (300 ml, 5.28 mol) was added dropwise to the reaction mixture over 3.5 h while maintaining the temperature at 45-55°C. The reaction mixture is stirred for another 3 hours at 45°C and 16 hours at 23°C.

The off-white suspension is filtered, washed with water (3x200 ml) and air dried to give 179.6 g (99% yield of crude product, HPLC: 92.2% product, 7.1% by-product). The crude product (175 g) is added to toluene (1400 ml) and heated to >85°C for distillation. The distillation is stopped when the water is no longer distilled (180 ml of toluene and 10 ml of water). The clear reaction mixture is cooled and filtered after stirring overnight at ambient temperature. The bright colorless crystals are washed (150 ml toluene) and dried to give 156.1 g of product (86.7% yield, HPLC: product 96.0%, main by-product 3.5%).

Obtaining 1,4-bis ((3- (pyridin-4-yl) phenyl) sulfonyl) butane (compound 3, 3rd intermediate compound) but .... it is in

1 _g 4-bis((3-(pyridin-4-yl)phenyl)sulfonyl)bulane

To a solution of 1,4-bis-((3-bromophenyl)sulfonyl)butane (92.0 g, 185 mmol) and butanol (1.0 L) was added 4-pyridinylboronic acid (75.0 g, 610 mmol), carbonate potassium (172 g, 1.24 mol) and trans-dichlorobis(triphenylflosphine)palladium catalyst (2.0 g, 2.8 mmol). The violet suspension is heated with stirring under nitrogen to 90-95°C for 1 hour. The reaction mixture turns brown and heating is continued for more than 4 hours.

More 4-pyridinylboronic acid (3.5 g, 28 mmol) was added and the reaction mixture was heated

- 15 041145 up to 100°C for 1 hour. Heating is stopped, water (600 ml) is added and the temperature is sharply reduced to 60°C. The resulting dark gray suspension is stirred overnight at ambient temperature and filtered (slowly). The filter cake is washed with water (100 ml) to obtain 153 g of a wet solid, which is suspended in hot acetone (2x1 l, 50°C). Then the solid is suspended with 0.5 l of water at 65°C, then 2x1 and slurry of acetone. The acetone solution is combined and concentrated on a rotary evaporator to give 90.3 g of a pale yellow solid (yield: 91%, HPLC: 91.8% area).

Preparation of 4,4'-((butan-1,4-diyldisulfonyl)bis(3,1-phenylene))bis(1-propylpyridin-1-ium) iodide (compound 3, 4th intermediate)

To a solution of 1,4-bis-((3-(pyridin-4-yl)phenyl)sulfonyl)butane (85.8 g, 160 mmol) and butanol (450 ml) is added mmol). The stirred mixture is heated up to 9095° C. under nitrogen atmosphere and maintained at this temperature for 6 hours. The dark yellow suspension is then cooled to room temperature and maintained at this temperature for 15 hours. The yellow clear solution is then decanted and butanol (300 ml). The mixture is heated to 70°C, while it dissolves. Heating is continued to 95° C. and a light brown suspension is obtained. Heating is stopped and the mixture is cooled to 40°C. The yellow cloudy liquid is decanted and the dark yellow solid is filtered to give 173.5 g (HPLC: 84 area %), which is used as is in the next step.

Preparation of 1,4-bis((3-(1-propyl-1,2,3,6-tetrahydropyridin-4-yl)phenyl)sulfonyl)butane (compound 3, 5th intermediate)

Methanol (450 ml) was added to the solid crude starting material (173.5 g from the previous step) and the mixture was heated to reflux to give a dark yellowish-red clear solution which, after cooling, gave two phases, the lower one weighing 150 g (HPLC : 88.4% area, yield corrected to area percent: 131 g, 157 mmol). Methanol (400 ml) was added and the mixture was cooled (0°C). Sodium borohydride (23.75 g, 624 mmol, 4 eq.) is added and the reaction mixture is heated to RT and stirred for another 9 h. Work-up includes concentration of filtrates and precipitation from butanol and methanol, several suspensions in butanol, extraction with hot butanol from water and finally active carbon treatment of the product dissolved in hot butanol to give 63.0 g (HPLC: 85 area %), which is used as is in the next step.

Preparation of 1,4-bis((3-(1-propylpiperidin-4-yl)phenyl)sulfonyl)butane (compound 3)

I,4-bis((3-(1-nropylpiperidin-4-yl)phenyl)sulfonyl)butane

The product from the previous step (60.0 g, 51 g by HPLC is 85% area, 87 mmol) is added to the autoclave with 350 ml of acetic acid. A suspension of 10% Pd/C catalyst (10 g, 9.4 mmol) in water (80 ml) is added. The air is changed to nitrogen and then hydrogen (150 psi ² ) is introduced and the reaction mixture is heated to 85°C for 6 hours. After cooling, the catalyst is filtered, washed with acetic acid (2x30 ml) and water (2x30 ml) and concentrated in vacuo to give 98 g of a slightly brownish viscous residue. The residue is dissolved with water (200 ml), filtered (to remove traces of carbon) and washed with 50 ml of water. To the slightly brownish solution was added concentrated NaOH up to pH 13 and the mixture was stirred for 30 minutes. The substantial precipitate is filtered off to give 78.1 g of a slightly beige wet solid. The wet solid is mixed with water (100 ml) and toluene (300 ml), heated up to 87°C for 30 min, and the dark yellow aqueous phase is separated. The organic phase is filtered and cooled to 30°C. After 4 hours, the suspension is filtered, washed with 20 ml of toluene and dried to give 40.8 g of an off-white solid (HPLC: 74.4% area). Then the solid is suspended in toluene (260 ml) and water (40 ml) and heated to 85°C. The colorless aqueous phase is separated and the toluene phase is filtered, cooled to 5°C for 2 hours and filtered to obtain,

- 16 041145 after drying, 38.0 g of an off-white solid (HPLC: 81.5% area). The solid is then crystallized twice from toluene (300 ml, heated to 90° C., cooled to 3° C., filtered, washed with 30 ml of toluene, dried) to give 31.2 g, HPLC: 96.9 area%, NMR analysis: 93.9%.

NMR Compound Identity Analysis 3.

Compound 3

The data presented in table. 6 and 7 are determined using a sample of 47.82 mg of compound 3, solvent 1.0 ml of DMSO-E ₆ , 99.9% atom D and the instrument is a Bruker Avance III 400 MHz.

Table 6. Assignment of *H NMR ^a,c

SH shift (ppm) Integral Multiplicity Assignment COP cross- peaks MMC cross peaks 7, 68- 2 m H5 H1 ^b , NZ ^b C1, sz, 7.70 C8 7, 66 2 dt, J=7.5 and 1.2 Hz H1 H5 ^b , H2 NW, C5 7, 63 2 D, J=7.7 Hz NZ H2, H5 ^b Cl, C5, C8 7.55 2 t, J=7.5 Hz H2 H1, NC C1 ^b , C3 ^b , C4, C6 3.30- 3.37 4 m H18 H19 C19 2.95 4 D, J=ll,5 Hz NUDE H12 NU, H12, H9, H13 C8 ^b 2, 61 2 t, J=ll,9 Hz H8 H9, H13 - 2.25 4 t, J=7.2 Hz H14 H15 SU, S12, S15, S16 1.96 4 t, J=ll,9 Hz NUDE H12 NU, H12, H9, H13 - 1.76 4 e, J=12.6 Hz H9, H13 H8, H9, NU, H12, H13 1, 62- 1.71 4 m H9, H13 H8, H9, NU, H12, H13 su ^b , C12 ^b , C9 ^b , C13 ^b 1.59- 1.65 4 m H19 H18 C19 ^b 1.43 4 sextet, J=7.3 Hz H15 H14, H16 C14, C16 0.86 3 t, J=7.2 Hz H16 H15 C14, C15

^and assignment is based on a pattern of signal pairing, coupling constants, and chemical shifts. Due to the low concentration of dissolved material, some of the expected MMC signals were obscured by background noise, ^b a weak signal, ^with the spectrum being corrected by the residual solvent peak (2.5 ppm).

- 17041145

Table 7. Assignment of ¹³ C NMR ^a,b

¹³ C shift (ppm) Assignment ¹³ S Shift (ppm) Assignment 147.9 C6 53.7 SU, S12, S18 139.2 C4 41.7 C8 132.2 NW 32.8 C9, C13 129.4 C2 20.7 C19 125.7 C5 19, 7 C15 125.2 C1 11.9 C16 60.2 C14

the assignment is based on chemical shifts and 1H- ^13C combinations obtained in SHOPG and GMC experiments, ^b spectrum is adjusted by the solvent peak (39.54 ppm).

Example 4 Preparation of Compound 4 ((3R,4S)-4-(3-(methylsulfonyl)phenyl)-1-propylpiperidin-3ol)

Preparation of (1S,6S)-6-(3-(methylsulfonyl)phenyl)-3-propyl-7-oxa-3-azabicyclo[4.1.0]heptane

ACR778 (1Ξ _g 6Ξ)-6-(3-(meshipsulfonip)phenyl)-3-propyl-7-oxa-Zazabicycle[4-1.0]heptane

Compound 8 (229 g, 820 mmol, 1 eq.) and 2N sulfuric acid (1147 ml, 112 g sulfuric acid, 1.147 mol, 1.4 eq.) are added to a 4 liter reactor at room temperature. The light yellow reaction mixture is stirred and sodium bromate (126 g, 836 mmol, 1.02 eq.) is added. The mixture turns yellow and the temperature drops (endothermic dissolution). After 30 minutes the reaction temperature reaches 35°C and the mixture is further heated to 40°C for 6 hours to obtain a dark yellow solution with a precipitate at the bottom of the reactor. Toluene (2 L) and NaOH (24%, 546 g, 131 g NaOH, 3.28 mol, 4.0 eq.) are added and the reaction mixture is vigorously stirred for 1 h at 42°C. The reaction mixture is then poured into a 4 L separating funnel. The dark aqueous phase is removed and the dark red organic phase is washed with 1.1 L of 5% sodium sulfite solution and 1 L of 20% brine. The organic phase is then concentrated on a rotary evaporator (50° C., 90-65 mbar, finally at 45 mbar) to give 111 g of a dark red oil with crystals in the flask. GC analysis (5 mg red oil dissolved in 0.6 ml toluene) showed a 53% area product, unknown peaks 29 and 5.2 area%, and 0.4% compound 8. The product was recovered in the next step.

Preparation of (3S,4R)-4-(3-(methylsulfonyl)phenyl)-1-propylpiperidin-3-ol (compound 4)

(3S, 4O -4 - (3 - (meylsulfnyl) phenyl) -1 - pro1ishpileridin- 3 - ol

The epoxide from the previous step (111 g 53% GC purity, 62.0 g, 210 mmol, 1 eq) was dissolved in ethanol (1.2 L) over 1 h. The red mixture was poured into a 2 L Parr reactor and the solution added 10% Pd/C (14.6 g, dry) in ethanol (50 ml). The mixture is reacted with hydrogen (4 bar) at 30° C. for 10 h. Pd/C is filtered through Celite and the filtrate is concentrated on a rotary evaporator to give 108 g of a red oil (65 area % product by GC). The product is added to 200 g of silica gel, 0.5% triethylamine in dichloromethane is added and the mixture is concentrated and loaded onto a 620 g silica gel column. Purification is carried out with 0.5% triethylamine in dichloromethane to give 28 g of a solid residue (97.0 area% by GC). The residue is heated to reflux in 34 ml of dichloromethane until completely dissolved to obtain a clear red solution, which is slowly cooled while removing some of the solvent in a stream of nitrogen over the solvent. The precipitate is filtered and washed with dichloromethane (5 ml) to give 20 g of a white solid, HPLC:

99.0% area, 1H-NMR analysis: 99.4%.

NMR Analysis of compound identity 4.

Compound 4

The data presented in table. 8 and 9 are determined using a 54.06 mg sample of Compound 4, solvent 0.55 ml DMSO-D ₆ , 99.9% D atom, and the instrument is a Bruker Avance III 400 MHz.

_______________ Table 8. Assignment of ¹ H NMR ^{a, c} _______________

SH shift (ppm) Integral Multiplicity Assignment KS cross- peaks MMC cross peaks 7.85 1 With H5 H1 ^b , NZ ^b H2 ^b , C1, sz, C8 7.75 1 D, J=7.9 Hz H1 H2 H5 ^b NZ ^b , C5, C3, C2 ^b 7, 65 1 D, J=7.7 Hz NZ H2, H5 ^b H1 ^b , Cl, C5, C8 7.55 1 t, J= 7.6 Hz H2 H1, H5 ^b NZ, C4, C6 4.15 1 D, J=7.5 Hz H17 H13 C12 ^b , C13 3.78 3, 18 1 3 d, J=6.6 Hz s H13 H18 H12 = , H17 C9 ^b C6 2.92- 2.97 2 m NUDE H12 H9, H12 nude, C8, SU, C13 ^b 2.76 1 dt, J=13.0 and 3.3 Hz H8 H9 C3 ^b , C4, C5 ^b 2.19- 2.32 3 m H14, H9 H9, H15 nude, SU, C12, C15, C16 2.16 1 d, J=ll,5 Hz H12 H12 SU, C14 2.00 1 t, J=ll,2 Hz NUDE H9, NUDE C8 ^b , C12 1.54 1 D, J=12.3 Hz H9 H9, NUDE C13 ^b 1.46 2 sextet, J=7.3 Hz H15 H14 , H16 C14, C16 0.88 3 t, J=7.3 Hz H16 H15 C14, C15

^and assignment based on pattern of signal pairing, coupling constants and chemical shifts, ^b weak signal, ^c spectrum adjusted by residual solvent peak (2.5 ppm).

- 19 041145

Table 9. Assignment of ¹³ C NMR ^a,b

¹³ C shift (ppm) Assignment ¹³ S Shift (ppm) Assignment 145.6 C4 59, 8 C14 140.4 C6 53.3 SU 133.3 NW 45.6 C8 128.8 C2 43.6 C18 126.3 C5 25, 2 C9 124.4 C1 19, 3 C15 67.8 C13 11.9 C16 60.1 C12

the assignment is based on chemical shifts and 1H- ^13C combinations obtained in SHOPG and GMC experiments, ^b spectrum is adjusted by the solvent peak (39.54 ppm).

Example 5 Preparation of compound 5 (4-(3-(methylsulfonyl)phenyl)-1-propylpiperidine 1-oxide).

"Me

0-2O-® if] ^H 2 ° 2 ~ t II ^N x / X "

1-oxide 4-(3-.

ACR16 (methylsulfonyl)phenyl)-1-\propylpiperidine

Pridopidine (50.0 g, 178 mmol, 1 eq.) is dissolved in methanol (250 ml) and 33% hydrogen peroxide (20 ml, 213 mmol, 1.2 eq.). The reaction mixture is heated and maintained at 40° C. for 20 hours. The reaction mixture is then concentrated on a rotary evaporator to give 71 g of a light yellow oil. Water (400 ml) is added and the suspension is extracted with isopropyl acetate (150 ml) which, after separation, contains unreacted pridopidine and the aqueous phase contains 91% of the area of compound 5 (HPLC). The product is then washed with dichloromethane (400 ml), then the pH of the aqueous phase is adjusted to 9 with sodium hydroxide. After phase separation, the aqueous phase is washed again with dichloromethane (200 ml) to obtain 100% of the area of compound 5 in the aqueous phase (HPLC). The product is then extracted from the aqueous phase into butanol (1x400 ml, 3x200 ml) and the butanol phases are combined and concentrated on a rotary evaporator to give 80 g of a yellow oil (HPLC: 100% area of compound 5). The oil is washed with water (150 ml) to remove salts and the water is extracted with butanol. The organic phases are combined and concentrated on a rotary evaporator to give 43 g of a white solid which is suspended in MTBE for 1 hour, filtered and dried to give 33 g of a solid which melts on standing in air. After drying under high vacuum (2 mbar, 60° C., 2.5 h) 32.23 g of pure compound 5 are obtained (HPLC: 99.5 area %, 1H-NMR analysis: 97.4%).

NMR Analysis of compound identity 5.

Compound 5

The data presented in table. 10 and 11 are determined using a sample of 63.06 mg of compound 5, solvent 1.2 ml of DMSO-D ₆ , 99.9% atom D, and the instrument is a Bruker Avance III 400 MHz.

- 20 041145

Table 10. Assignment ^! H NMR ^ac

SH shift (ppm) Integral Multiplicity Assignment COP cross- peaks MMC cross peaks 7.81 1 shs H5 — C1, sz, C8 7.78- 7.80 1 m H1 H2 NW, C5 7, 63- 7, 66 1 m NZ H2 C1, C4 ^b , C5, C8 7.59- 7, 63 1 m H2 H1, NC C1 ^b , C4, C6 3.27 2 t, J=ll,2 Hz NUDE H12 H9, NU, H12, H13 C8, C9, C13 3.23 3 With H18 - C1 ^b , C6 3, 07- 3, 11 2 m H14 H15 SU, S12, S15, S16 3, 02 2 D, J=13,l Hz NUDE H12 H9, NU, H12, H13 C8, C9 ^b , C13 ^b 2.81 1 t, J=12.7 Hz H8 H9, H13 C3b, C4, C5b, C9, C13, SU, C12 2.39- 2 m H9, H13 H8, H9, C4, C8, 2.50 NU, H12, H13 SU, C12, C9, C13 1, ΙΟ- Ι, 89 2 m H15 H14, H16 C14, C16 1, 64 2 e, J=12.8 Hz H9, H13 H8 ^b , H9, H10 ^b , H12 ^b , H13 C4b, C8b, Xu, C12b 0.90 3 t, E=7.5Hz H16 H15 C14, C15

^and assignment is based on signal pairing pattern, coupling constants and chemical shifts, ^b weak signal, ^with spectrum adjusted by residual solvent peak (2.5 ppm). Table 11. Assignment of ¹³ C NMR ^a,b

¹³ S OFFSET (ppm) Assignment ¹³ S Shift (ppm) Assignment 146.9 C4 63.4 CIO, C12 141.0 C6 43.5 C18 132.1 NW 39, 4 C8 129.6 C2 27.3 C9, C13 125.0 C1 15, 1 C15 124.9 C5 11.3 C16 72.4 C14

^and the assignment is based on chemical shifts and *H- ¹³ C combinations obtained in GSOPG and GMC experiments, ^b spectrum is adjusted by the solvent peak (39.54 ppm).

-21 041145

Example 6 Preparation of Compound 6 (1-(2-methylpentyl)-4-(3-(methylsulfonyl)phenyl)piperidine).

KI (28.4 g, 171 mmol, 1 eq.) and potassium carbonate (47.4 g, 343 mmol, 2 eq.) are added to a 1 liter autoclave. 4-(3-(methylsulfonyl)phenyl)piperidine (41 g, 171 mmol, 1 eq.) was dissolved in acetonitrile (420 ml) and the mixture was added to an autoclave followed by 1-chloro-2-methylpentane (25.8 ml , 188 mmol, 1.1 eq.). The autoclave is closed and the reaction mixture is heated under nitrogen to 120° C. for 30 hours. The reaction mixture is cooled and filtered. The cake was washed with acetonitrile and the filtrate was concentrated in vacuo to give 70 g of crude product with the following HPLC areas: 60% compound 6, 1% 4-(3-(methylsulfonyl)phenyl)piperidine and 10% by-product. The crude product is dissolved in toluene (350 ml) and about 20 g of solid is filtered. The toluene phase was washed with water (200 ml) and concentrated on a rotary evaporator to give 35.5 g (73% of product area by HPLC). The residue is then dissolved in ethyl acetate (180 ml) and cooled in an ice bath. 33 ml of an 18% HCl solution in ethyl acetate was then added to the reaction mixture over 1 hour, and the mixture was stirred for another 1 hour. The resulting precipitate was then filtered, washed with ethyl acetate, and dried to give 36.3 g of a white solid (HPLC: 94% area). The product is recrystallized by dissolving in methanol (290 ml), heating to 70°C, adding ethyl acetate (400 ml) and cooling to room temperature. The precipitate is filtered, washed with ethyl acetate (60 ml) and dried in vacuo at 50° C. to give 28.3 g of compound 6 (HPLC: 99.5% area, NMR Identity analysis of compound 6. Compound 6

1H-NMR analysis: 99.6%).

The data presented in table. 12 and 13 are determined using a sample of 33.93 mg of compound 6, solvent 8 ml of DMSO-D ₆ , 99.9% atom D, and the instrument is a Bruker Avance III 400 MHz. At room temperature, two conformers are observed (about 10:1). Due to the superposition of the proton signals of the larger and smaller conformers and the relatively weak signal of the smaller isomer in the 2D spectrum, only some peaks of the smaller isomer in the 1H spectrum and the corresponding 1H-1H COZY crossovers are given. Due to the low solubility of the product in D ₆ -DMSO, some of the expected GMC signals are obscured by background noise.

Table 12. Assignment of 1H NMR ^a,c

shift (ppm) Integral Multiplicity Assignment COP cross- peaks MMC cross peaks 9, 88 1 shs NH NU, H12, H14 - 7.79- 7.84 2 m Hl, H5 H2, NC C1, sz, C5, C8 7, 62- 7, 66 2 m H2, NC Hl, H5 Cl, C4, C5, C6, C8 ^b 3.53- 3, 63 2 m NUDE H12 NUDE H12 - 3.23 3 With H18 - C5 ^b , C6 2.87- 3, 11 5 m H8, NU, H12, H14 H9, NU, H12, H13, H15 C9, C12 ^b , C13, C15, C16, C19 ^b 2.17- 2 m H9, H13 H8, H9, -

- 22 041145

2.34 NU, H12, H13 1,942.02 3 m H9, H13, H15 H8, H9, NU, H12, - 1.22- 1.45 3 m H19, H20 H15, H19, H20, H21 C20 1, ΙΟ- Ι, 21 1 m H19 H15, H20 C16, C20, C21 1.02 3 D, J=6.7 Hz H16 H15 C14, C15, C19 0.90 3 t, J=6.S Hz H21 H2 0 C19, C20 Smaller isomer 10, 14 1 shs NH NUDE H12 - 7.88 1 With H5 - - 7.75 1 d, J=5.5 Hz H1 H2 - 3.24- 3.31 4 m NUDE H12 H9, H13 - 1.86- 1.84 3 m H9, H13, H15 NU, H12, H16

^and assignment is based on signal pairing pattern, coupling constants and chemical shifts, ^b weak signal, ^c spectrum adjusted by residual solvent peak (2.5 ppm).

__________ Table 13. Assignment of ¹³ C NMR ^{a, b} _________

¹³ C shift (ppm) Assignment ¹³ S Shift (ppm) Assignment 145.9 C4 43.5 C18 141.1 C6 38.5 C8 131.9 NW 36, 4 C19 129.8 C2 29.20 and 29.24 C9, C13 125.3 C1 27.5 C15 124.9 C5 19, 1 C20 62.5 C14 18.0 C16 53, 1 SU 14.0 C21 51, 8 C12

^and the assignment is based on chemical shifts and 1H- ^13C combinations obtained in SHOPG and GMC experiments, ^b spectrum is adjusted by the solvent peak (39.54 ppm).

Example 7 Preparation of compound 7 (4-(3-(methylsulfinyl)phenyl)-1-propyl-1,2,3,6tetrahydropyridine).

chloride 4- (3- (meshylsulfinyl) phenyl) -1-prolyl-1 _g 2 _g 3 _g

Sulfuric acid (42.23 g, 0.431 mol, 1 eq.) is added to a mixture of 4-hydroxy-4-(3(methylsulfonyl)phenyl)-1-propylpiperidin-1-ium chloride (130 g, 0.431 mol, 1 eq. ) and toluene (650 ml) at room temperature. The resulting biphasic solution is refluxed for 1 hour and HPLC shows that the product reaches 95% area. The reaction mixture is cooled to 20° C. and the toluene phase is decanted to give a viscous residue which is diluted with water (600 ml) and

- 23 041145 neutralize with 2N NaOH to pH ~4.2. Hydrogen peroxide (50%, 32.21 g, 0.474 mol, 1.1 eq.) is added dropwise to the aqueous phase and the mixture is stirred at 60° C. for 1 h, after which the product reaches 96% area (HPLC).

Toluene (600 ml) is added to the reaction mixture and basified first with 25% NaOH (60 g) and finally with 10% NaOH up to pH 12. The phases are separated and the aqueous phase is re-extracted with toluene (2x100 ml). The combined toluene phases are washed with 5% sodium sulfite (150 ml), brine (150 ml) and water (150 ml). The toluene phase is then concentrated under vacuum on a rotary evaporator to give 111.3 g of an oil (HPLC area: 96.6%). Methanol (50 ml) is added to the residue and the mixture is filtered and cooled in an ice bath. Dry HCl in ethyl acetate is added up to pH 1-2 (120 ml) and 100 ml of ethyl ether is added to give a biphasic mixture. The mixture is inoculated with the product and precipitation begins. The reaction mixture was stirred in an ice bath (2-5° C.) for another 1 hour, filtered and washed with 1/3 ethyl acetate/ether (100 ml) to give 140 g of a very hygroscopic light yellow solid which was dried on a rotary evaporator for 2 h and stored under nitrogen in a state of deep freezing. Dry 4-(3(methylsulfinyl)phenyl)-1-propyl-1,2,3,6-tetrahydropyridine-HCl is a slightly yellowish solid (94.1 g, 79% yield, HPLC (254 nm): 96. 3% area, 1H-NMR analysis: 97.5%).

NMR Analysis of the identity of compound 7.

Compound 7

The data presented in table. 14 and 15 are determined using a sample of Compound 7, CDCl ₃ solvent, and the instruments are Bruker AMX500 and Avance III 800 MHz.

_________________ Table 14. Assignment of 1H NMR ^a

^X H shift (ppm) ^X H shift (ppm) Integral Multiplicity Assignment COP cross- peaks 2.63 2.66 2 t, 2x5.7 to NC H2 NZ 2.51 2.55 2 m NZ H2, H5, Nb 6, 10 6, 13 1 tt, 2x3.6 to Nb, 2x1.5 to NC H5 NZ, Nb 3.09 3, 13 2 m H6 NC, H5 2.35 2.39 2 m H7 H8 1.51 1.54 2 m H8 H7, H9 0.86 0.89 3 t, 2x7.4 up to H8 H9 H8 7.60 7.49 1 dt, 0.4 to H5', 2x1.8 to H4' and H6' H2' H4', H5', Nb' 7.37 7.40 1 ddd, 1.4 to Hb', 1.8 to H5', 7.6 to H2' H4' H2', H5', Nb' 7.36 7.37 1 dt, 0.4 to H2', 2x7.6 to H4' and Nb' H5' H2' H4', Nb' 7.41 7.44 1 ddd, 1.4 to H4', 1.8 to H5', 7.6 to H2' Nb' H2', H4', H5' 2.62 2.66 3 WITH H7' -

^and the spectrum is verified by the residual solvent peak (2.5 ppm), ^b after adding a small amount of C ₆ D ₆ .

- 24 041145

Table 15. Assignment of ¹³ C NMR ^a

¹³ S Shift (ppm) Assignment GMK ³ N cross-speaks ¹³ S Shift (ppm) Assignment GMK ³ N cross-speaks 49, 89 C2 С4,6,7 142.00 01' - 27, 68 NW C2,4,5 119.41 02' 04, 6, 3', 4' 133.67 C4 - 145.52 NW' - 123.57 C5 NW, 6, 1' 121.51 C4' 02'6' 52.90 C6 C2,4,5,7 128.97 05' - 60, 04 C7 C2, 6,8,9 127.19 C6' C2',4', 4 20, 02 C8 C7.9 43.70 07' 3' 11.72 C9 C7, 8

^and the spectrum is verified by the solvent peak (77.0 ppm).

Example 8 Analysis of the amounts of compounds 1, 2, 3, 4, 5 and 6 in a drug sample of pridopidine.

Compounds 1-7 are used to determine the purity of a composition containing pridopidine.

The method used to determine the assay and related substances in pridopidine HCl is a reverse phase HPLC method using an X-bridge phenyl column (or equivalent) and gradient elution with UV detection at 268 nm. The mobile phase consists of a mixture of methanol and an ammonium formate buffer.

Apparatus.

HPLC with gradient pump, column oven and UV sensor. Column: Waters, Xbridge Phenyl, 75x4.6 mm, 2.5 µm; or equivalent column.

Analysis instructions.

Reagents and solutions.

Solvents: methanol, HPLC grade; water, MilliQ-water or equivalent.

Reagents: ammonium formate, pure; ammonium hydroxide, 30% A.C.S; formic acid, pa.

Ammonium formate buffer, 1.00 mM, pH 8.90-9.10: Accurately measure 6.3-6.4 g of ammonium formate in a 1000 ml volumetric flask and add 2.5 ml of 30% ammonium hydroxide solution. Dissolve and dilute milliQ-water to 900 ml. Measure the pH of the solution. The pH should be between 8.90 and 9.10, otherwise adjust with ammonium hydroxide or formic acid. Dilute to volume and filter through a 0.45 µm HVLP filter.

Reference substances: control sample 1a: (pridopidine) (see Fig. 1); control sample 2b (compound 5, compound 1, compound 4, pridopidine, compound 8, compound 2, compound 6, compound 3).

Table 16

Phase Mobile phase A Solvent Ammonium formate buffer, 100 mM, pH 9.0 MilliQ water Quantity 100 ml 900 ml Mobile phase B Ammonium formate buffer, 100 mM, pH 9.0 100 ml MilliQ water 5 0 ml methanol 850 ml Dilution phase methanol 15 0 ml MilliQ water 850 ml

- 25 041145

Table 17. Analysis conditions

Flow 0.8 ml/min Gradient Time (min) Mobile phase B (%) 0 50 10 100 12 100 Equilibrium time 3 min. Wavelength 268 nm (4 nm bandwidth; reference voltage disabled) 190-400 nm (only for information in stability studies). Injection volume 2 0 µl Flushing the needle Wash cycles are set to two. Application of the dilution phase in the wash flask. Temperature 40°C

Table 18. Approximate hold times

Substance Time (min) Compound 5 19 Compound 1 2.4 Compound 4 3.5 pridopidin 4, 6 Compound 8 6, 1 Compound 2 7.5 Compound 6 8, 8 Compound 3 9, 9

Control preparation: use the dilution phase, Double test tubes for the control preparation (A and B).

Reference preparation A (only for related substances).

Use control sample 2b. Inject as is.

The control sample solution 2b is a solution of pridopidine (0.44 mg/ml free base), with the addition of approximately 1% of each of the impurities: Compound 5, Compound 1, Compound 4, Compound 8, Compound 2, Compound 6, and Compound 3.

Reference preparation B (for analysis only).

Double preparation (Bln B2).

Weigh 43-45 mg of reference pridopidin into a 50 ml volumetric flask. Add 25 ml of the dilution phase and shake or sonicate at ambient temperature until the reference substance is dissolved. Make up to volume with dilution phase. Concentration: 0.9 mg/ml pridopidin. The standard solution is stable for 48 hours when stored in daylight and at room temperature.

Reference preparation C (only for related substances).

One drug (C).

Dilute 1 ml of reference preparation B1 to 100 ml with the dilution phase. Further dilute 1 ml of this solution to 20 ml with the dilution phase (sensitivity standard, concentration corresponding to 0.05% of the sample concentration).

Sample preparation.

Dual preparation (sample A and B).

Weigh 43-45 mg of the pridopidin sample into a 50 ml volumetric flask. Add 25 ml of dilution phase and shake or sonicate at ambient temperature until sample dissolves. Make up to volume with dilution phase. Concentration: 0.9 mg/ml pridopidin. The sample solution must be prepared immediately before use.

Order of definitions.

When the system is balanced, the solutions are injected in the following order:

-26041145

Table 19

Solution Number of determinations/injections Analysis Related Substances Control A 3 (at least) 1 (at least) Control B 1 1 Reference A N/A 1 Reference C n/a 1 Reference B1 5 N/A Reference B2 1 N/A Sample A 1 1 Sample B 1 1 Reference B2 1 n/a

Calculation.

System stability.

for related substances.

R1) Control B should not have overlapping retention times of Compound 5, Compound 1, Compound 4, Pridopidine, Compound 8, Compound 2, Compound 6 and Compound 3.

R2) The retention time for the peak of pridopidin should be 4.6 ± 0.5 min.

R3) Compound 5, Compound 1, Compound 4, Pridopidine, Compound 8, Compound 2, Compound 6 and Compound 3 in Control 2b should be identifiable according to FIG. 2.

R4) The pridopidine peak at reference C must have a signal-to-noise ratio greater than or equal to 3.

R5) Calculate the number of ideal plates (N) and peak asymmetry factor (T) for the pridopidine peak in reference A. Number of ideal plates 2: 8000 and peak asymmetry factor 0.7-1.0.

R6) Calculate the degree of peak separation between compound 5 and compound 1 in the control sample 2b, it should be greater than or equal to 1.5.

R7) If there is a problem with compound 1 and compound 4 split peaks, they should be calculated as the sum of each split peak.

For analysis.

A1) Control B should not contain an overlapping peak at the retention time for pridopidine.

A2) The retention time for the peak of pridopidin should be 4.6 ± 0.5 min.

A3) Calculate the % RSD of the five areas of reference B1. RSD should be ~2.0%.

A4) Calculate the analysis of each injection of reference B2. The analysis should be in the range of 99101% wt./wt. analysis of reference B1.

A5) Calculate the number of ideal plates (N) and peak asymmetry factor (T) for the pridopidine peak in the first injection of reference B1. Number of ideal plates 2: 8000 and peak asymmetry ratio 0.7-1.0.

A6) Calculate the deviation between two analytical determinations (sample A and B) according to Equation 1. The deviation must be less than or equal to 2%.

(Analysis - Analysis 100 _;

L ------------------- < 2% (equation 1) (Analysis _L + Analysis _c ) x 0.5

The description of the analytical method presented here has been improved to include acceptance criteria for the number of ideal plates (N) and peak asymmetry factor (T) for the pridopidine peak.

Result.

for related substances.

The content of related substances should be calculated as % area and corrected with the relative response factor of the detector, and reported as % according to Equation 2.

% _x = area % _x hOKCHD _x (equation 2) % _x - percentage of impurity x, % area - % area of impurity x, calculated from the chromatogram,

OKCHDh - relative coefficient of sensitivity of the impurity detector x.

The following detector response factors apply.

Table 20

Name Detector response factor Compound 8 0.2 Compound 2 0.7

- 27 041145

The remaining related substances are corrected for OKCHD 1.

For analysis.

Calculate the analysis of pridopidin in % wt./wt. using the external standard method (see

below). Apply the average detector response factor obtained for five shots of reference B1 for calculation.

i\ - (equation 3)

A xf xLQQ ---- ⁵ ----- =pridopidine (% w/w) (equation^ f _x - average detector response factor of pridopidine from reference solution B1, c _xR - concentration of pridopidine in reference solution (mg/ml ), c _xS - sample solution concentration (mg/ml),

A _xR is the area of pridopidin in each injection of reference solution B1,

A _xS is the area of pridopidin in the chromatogram of the sample.

Table 21. Analytical methods for determining ________________ impurities in a medicinal substance ____________

Parameter Example number Method type Limit of quantitation (% mass) Limit of Quantitation (Area %) Limit of detection (% area) Compound Example 8 RP-HPLC 0.04 0.04 0.01 1 Compound Example 8 RP-HPLC 0.03 0.05 0.01 2 Compound Example 8 RP-HPLC 0.05 0.05 0.03 3 Compound 4 Example 8 RP-HPLC 0.04 0.04 0.01 Compound Example 8 RP-HPLC 0.04 0.04 0.01 5 Compound Example 8 RP-HPLC 0.04 0.04 0.01 6

During validation, the detector response factors for Compound 5, Compound 1, Compound 4, Compound 8, Compound 2, Compound 6 and Compound 3 were evaluated and compared with the detector response factor for pridopidine. The relative sensitivity coefficients of the impurity detector are presented in Table. 22.

Table 22. Relative coefficients _______________ of detector sensitivity __________________

Name Relative sensitivity coefficient of the detector (a pridopidine/P impurity) Compound 5 0.91 Compound 1 1.01 Compound 4 1.02 Compound 8 0.16 Compound 2 0.65 Compound 6 1.05 Compound 3 0.99

Example 9 Specification of Pridopidine Drug Substance Hydrochloride.

Table 23

Name Hold Time (min) Separation (tangential method) Compound 5 1.99 N/A Compound 1 2.42 3.3

- 28 041145

Pridopidin HCl is a white or almost white powder. The specifications of pridopidine HCl are as follows.

Table 24. Specification of pridopidine hydrochloride __________________

Test Acceptance criterion Method Description White or almost white powder visual assessment Lack of pieces passes Visual and tactile Identification IR Corresponds to the reference IR spectrum IR x-ray diffractogram Corresponds to the reference X-ray diffraction pattern DRP Chloride Positive Ph. Eur. Analysis, HPLC, % w/w 98.0-102.0 HPLC related substances, HPLC, area % Compound 5 <0.15 HPLC Compound 1 <0.15 HPLC Compound 4 <0.15 HPLC Compound 8 <0.15 HPLC Compound 3 <0.15 HPLC Test Acceptance criterion Method Compound 2 <0.15 HPLC Compound 6 <0.15 HPLC unknown impurities, each <0.10 HPLC Total impurities <0.50 HPLC

Example 10 Enhanced and long term stability in pridopidine HCl drug product.

Lots 1, 2, and 3 are manufactured according to current drug manufacturing and quality control practices and at a scale that matches the expected commercial scale. Batches 4 and 5 are produced according to the current synthetic route.

The stability program for each batch is detailed in Table 1 below. 25.

- 29 041145

Table 25 Stability Testing Program for Pridopidine HCl

The consignment 12 3 4 5 Lot size (kg) Stability study 99.7 97.2 96.6 14.9 105.4 Conditions 25°C/60% RH: 0, 3, 6, 9, 12, 25°C/60% RH: 0.3 storage and 18, 24, 36, 48 and 60 months 6, 9, 12, 18, 24, intervals 30°C/65% RH: 0, 3, 6, 9 and 12 36, 48 and 60 months testing months 30°C/65% RH: 0.3 40°C/75% RH: 0, 3 and 6 6, 9 and 12 months months 40°C/75% RH: 0, Zee 6 months Options Appearance, identification, Appearance, testing crystalline Form, identification, analysis, impurities, content crystalline water, microbiological form, analysis, standard impurities, water content, microbiological standard

Stability data for parties 1, 2, 3, 4 and 5 are presented in table. 26-37.

Table 26. Stability data for batch 1 of pridopidine HCl stored at 25°C/60% RH

Options Acceptance criterion Storage period (months) 0 3 6 9 12 18 24 36 48 Appearance Color and shape White powder White powder White powder White powder White powder White powder White powder White powder White powder Identification (by IR) Corresponds to the reference spectrum Sovpa- gives Sovpa- gives Sovpa- gives Sovpa- gives Sovpa- gives Sovpa- gives Sovpa- gives Sovpa- gives Sovpa- gives Crystalline form (according to DRP) Corresponds to the reference diffraction pattern Sovpa- gives Sovpa- gives Sovpa- gives Sovpa- gives Sovpa- gives Sovpa- gives Not planned Not planned Not planned Analysis (according to HPLC) [% w/w] 98.0-102.0 99.9 99.7 100.2 100.2 99.6 100.0 100.4 99.8 99.7 Impurities (according to HPLC) [% area] Compound 1 <0.15 0.05 0.05 0.05 0.05 0.05 <0.05 <0.05 <0.05 <0.05 Compound 4 <0.15 0.09 0.09 0.09 0.09 0.09 0.08 0.08 0.09 0.08 Each (Connection 8, Connection 3, Connection 2, Connection 6 and Connection 5) <0.15 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 Unknown <0.10 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05

- 30 041145

impurities each Total <0.50 0.14 0.15 0.14 0.14 0.14 0.08 0.08 0.09 0.08 Content water (according to KF) [% w/w] Run and record 0.03 0.03 0.02 0.01 0.02 <0.05 <0.05 0.06 <0.05 Microbiology High purity [CFU/g] OKAM <1000 <10 Not plan- rushes Not plan- rushes Not planned <10 Not plan- rushes Not plan- rushes Not plan- rushes Not planned OKDIPG <10 <10 Not planned Not planned Not planned <10 Not planned Not planned Not planned Not planned E. coli Absent — — — — — — — — —

Table 27. Stability data for lot 1 pridopidine HC1 stored at 40°C/75% RH

Options Acceptance criterion Storage period (months) 0 3 6 Appearance Color and shape White powder White powder White powder Identification (by IR) Corresponds to the reference spectrum matches matches matches Crystalline form (according to DDD)) Corresponds to the reference diffraction pattern matches matches matches Analysis (by HPLC) [% w/w] 98.0-102.0 99.9 99.7 100.1 Impurities (by HPLC) [area%] Compound 1 <0.15 0.05 0.05 0.05 Compound 4 <0.15 0.09 0.09 0.09 Each (Compound 8, Compound 3, Compound 2, Compound 6 and Compound 5 <0.15 <0.05 <0.05 <0.05 unknown impurities each <0.10 <0.05 <0.05 <0.05 Total <0.50 0.14 0.14 0.14 Water content (by CF) [% w/w] Run and record <0.1 <0.1 <0.1 Microbiological purity [CFU/g] OKAM <1000 <10 Not planned Not planned OKDIPG <10 <10 Not planned Not planned E. coli Absent — — —

Table 28 Stability data for Lot 2 of pridopidine HC1 stored at 25°C/60% RH

Options Acceptance criterion Storage period (months) 0 3 6 9 12 18 24 36 48 Appearance Color and shape White powder White powder White powder White powder White powder White powder White powder White powder White powder

-31 041145

Identification (by IR) Corresponds to the reference spectrum Sovpa- gives Sovpa- gives Sovpa- gives Sovpa- gives Sovpa- gives Sovpa- gives Sovpa- gives Sovpa- gives Sovpa- gives crystalline Corresponds Sovpa- Sovpa- Sovpa- Sovpa- Sovpa- Sovpa- Not Not Not form (according to DRP)) REFERENCE diffractogram gives gives gives gives gives gives plan- rushes plan- rushes plan- rushes Analysis (by HPLC) [% w/w] Impurities (by HPLC) [% area] 98.0-102.0 100.1 99.9 100.4 100.3 100.2 100.1 100.4 99.7 100.5 Compound 4 <0.15 0.05 0.05 0.05 0.05 0.05 <0.05 0.05 <0.05 <0.05 Each (Compound 1, Compound 8, Compound 3, Compound 2, Compound 6 and Compound 5) <0.15 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 Unknown impurities each <0.10 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 Total <0.50 0.05 0.05 0.05 0.05 0.05 <0.05 0.05 <0.05 <0.05 Water content (by CF) [% w/w] Microbiological [CFU/g] Run and record h cleanliness 0.03 0.02 0.01 0.01 0.02 <0.05 <0.05 <0.05 <0.05 OKAM <1000 <10 Not planned Not planned Not planned <10 Not planned Not planned Not planned Not planned OKDIPG <10 <10 Not planned Not planned Not planned <10 Not planned Not planned Not planned Not planned E. coli Absent — — — — — — — — —

Table 29. Stability data for batch 2 of pridopidine HCl stored at 40°C/60% RH

Options Acceptance criterion Storage period (months) 0 3 6 Appearance Color and shape White powder White powder White powder Identification (by IR) Corresponds to the reference spectrum matches matches matches crystalline form (according to PRD) ) Corresponds to the reference diffraction pattern matches matches matches Analysis (by HPLC) [% w/w] 98.0-102.0 100.1 99.6 100.6 Impurities (by HPLC) [area%] Compound 4 <0.15 0.05 0.05 0.05 Each (Connection 1, Compound 8, Compound 3, Compound 2, Compound 6 and Connection 5) <0.15 <0.05 <0.05 <0.05 unknown impurities each <0.10 Total <0.50 0.05 0.05 0.05 Water content (by CF) [% w/w] Run and record <0.1 <0.1 <0.1 Microbiological purity [CFU/g] OKAM <1000 <10 Not planned Not planned OKDIPG <10 <10 Not planned Not planned E. coli Absent — — —

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Table 30. Stability data for batch 3 of pridopidine HCl stored at 25°C/60% RH

Options Acceptance criterion Storage period (months) 0 3 6 9 12 18 24 36 48 Appearance Color and shape White powder White powder White powder White powder White powder White powder White powder White powder White powder Identification (by Corresponds Sovpa- Sovpa- Sovpa- Sovpa- Sovpa- Sovpa- Sovpa- Sovpa- Sovpa- IR) referential spectrum gives gives gives gives gives gives gives gives gives crystalline Corresponds Sovpa- Sovpa- Sovpa- Sovpa- Sovpa- Sovpa- Not Not Not form (according to DRP)) REFERENCE diffractogram gives gives gives gives gives gives plan- rushes plan- rushes plan- rushes Analysis (by HPLC) [% w/w] Impurities (by HPLC) 98.0-102.0 [% area] 100.5 99.8 100.4 100.6 100.0 100.1 100.5 100.2 100.5 Compound 4 <0.15 0.06 0.06 0.06 0.06 0.06 0.06 0.05 0.05 0.05 Each (Compound 1, Compound 8, Compound 3, Compound 2, Compound 6 and Compound 5) <0.15 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 Unknown impurities each <0.10 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 Total <0.50 0.06 0.06 0.06 0.06 0.06 0.06 0.05 0.05 0.05 Water content (by CF) [% w/w] Microbiological [CFU/g] Run and record purity 0.03 0.03 0.01 0.01 0.01 <0.05 <0.05 <0.05 <0.05 OKAM <1000 <10 Not planned Not planned Not planned <10 Not planned Not planned Not planned Not planned OKDIPG <10 <10 Not planned Not planned Not planned <10 Not planned Not planned Not planned Not planned E. coli Absent — — — — — — — — —

Table 31. Stability data for batch 3 of pridopidine HCl stored at 40°C/60% RH

Appearance Color and shape White powder White powder White powder Identification (by IR) Corresponds to the reference spectrum matches matches matches crystalline form (according to PRD) ) Corresponds to the reference diffraction pattern matches matches matches Analysis (by HPLC) [% w/w] 98.0-102.0 100.5 99.7 100.5 Impurities (by HPLC) [area%] Compound 4 <0.15 0.06 0.06 0.06 Each (Connection 1, Compound 8, Compound 3, Compound 2, Compound 6 and Compound 5) <0.15 <0.05 <0.05 <0.05 unknown impurities each <0.10 <0.05 <0.05 <0.05 Total <0.50 0.06 0.06 0.06 Water content (by CF) [% w/w] Run and record <0.1 <0.1 <0.1 Microbiological purity [CFU/g] OKAM <1000 <10 Not planned Not planned OKDIPG <10 <10 Not planned Not planned E. coli Absent — — —

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Table 32. Stability data for batch 4 of pridopidine HCl stored at 25°C/60% RH

Options Acceptance criterion Storage period (months) 0 3 6 9 12 18 24 36 Appearance Color and shape White powder White powder White powder White powder White powder White powder White powder White powder Identification (by IR) Corresponds to the reference spectrum matches matches matches matches matches matches matches Sovpa- gives Crystalline form (according to DDD)) Corresponds to the reference diffraction pattern e matches Not planned Not planned Not planned Not planned Not planned Not planned Not planned Analysis (by HPLC) [% w/w] 98.0-102.0 100.4 98.6 99.8 99.7 99.5 99.9 99.8 100.1 Impurities (by HPLC) [area%] Compound 4 <0.15 0.06 0.06 0.07 0.06 0.07 0.06 0.06 0.06 Compound 3 <0.15 0.06 <0.05 0.06 0.08 0.06 0.07 0.06 0.05 Compound 8 <0.15 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 Each (Connection 1, Compound 2, Compound 6, Compound 5 and Unknown impurities each) <0.10 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 Total <0.50 0.12 0, About 0.13 0.14 0.13 0.14 0.13 0.11 Water content (according to CF) [% w/w] Run and record 0.06 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 Microbiological purity [CFU/g] OKAM <1000 <10 Not plan- rushes Not planned Not plan- rushes Not planned Not plan- rushes Not planned Not planned OKDIPG <10 <10 Not planned Not planned Not planned Not planned Not planned Not planned Not planned E. coli Absent Not define lyatsya Not planned Not planned Not planned Not planned Not planned Not planned Not planned

Table 33 Stability Data for Lot 4 of Pridopidine HCl Stored at 40°C/60% RH

Options Criterion acceptable with tee Storage period (months) 0 3 6 9 12 Appearance Color and shape White powder White powder White powder White powder White powder Identification (by IR) Corresponds link spectrum matches matches matches matches matches Crystalline form (according to DDD)) Corresponds to the reference diffraction pattern matches Not planned Not planned Not planned matches Analysis (by HPLC) [% w/w] 98.0-102.0 100.4 99.0 99.5 100.0 99.6 Impurities (by HPLC) [% area] Compound 4 <0.15 0.06 0.07 0.07 0.06 0.06 Compound 3 <0.15 0.06 <0.05 0.07 0.07 0.06 Compound 8 <0.15 <0.01 <0.01 <0.01 <0.01 <0.01

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Each (Compound 1, Compound 2, Compound 6, Compound 5 and Unknowns each) <0.15 <0.05 <0.05 <0.05 <0.05 <0.05 Total <0.50 0.12 0.07 0.13 0.13 0.12 Water content (by CF) [% w/w] Run and record <0.1 <0.1 <0.1 <0.1 <0.1 Microbiological purity [CFU/g] OKAM <1000 <10 Not planned Not planned Not planned <10 OKDIPG <10 <10 Not planned Not planned Not planned <10 E. coli Absent Not determined Not planned Not planned Not planned Not determined

Table 34 Stability Data for Lot 4 of Pridopidine HCl Stored at 40°C/75% RH

Options Acceptance criterion Storage period (months) 0 3 6 Appearance Color and shape White powder White powder White powder Identification (by IR) Corresponds to the reference spectrum matches matches matches crystalline form (according to PRD) ) Corresponds to the reference diffraction pattern matches Not planned matches Analysis (by HPLC) [% w/w] Impurities (by HPLC) [% area! 98.0-102.0 1] 100.4 99.5 99.7 Compound 4 <0.15 0.06 0.07 0.07 Compound 3 <0.15 0.06 <0.05 0.07 Compound 8 <0.15 <0.01 <0.01 <0.01 Each (Compound 1, Compound 2, Compound 6, Compound 5 and Unknowns each) <0.15 <0.05 <0.05 <0.05 Total <0.50 0.12 0.07 0.13 Water content (by CF) [% w/w] Microbiological purity Run and record [CFU/g] 0.06 <0.05 <0.05 OKAM <1000 <10 Not planned <10 OKDIPG <10 <10 Not planned <10 E. coli Absent not defined Not planned Not determined

Table 35. Stability data for batch 5 of pridopidine HCl stored at 25°C/60% RH

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Identification (by IR) Corresponds to the reference spectrum matches matches matches matches matches matches matches crystalline Corresponds matches Not Not Not Not Not Not form (according to DRP)) REFERENCE diffractogram planned planned planned planned planned planned Analysis (according to HPLC) [% w/w] Impurities (HPLC) 98.0-102.0 [% area] 99.8 100.0 99.9 99.9 99.7 100.1 100.1 Compound 3 <0.15 0.10 0.09 0.07 0.09 0.11 0.11 0.07 Compound 8 <0.15 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 Each (Compound 1, Compound 5, Compound 4, Compound 2, Compound 6 and Unknowns each) <0.15 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 Total <0.50 0.10 0.09 0.07 0.09 0.11 0.11 0.07 Water content (by CF) [% w/w] Microbiologically Chased away and write down 1I purity [CFU/g] <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 OKAM <1000 Not planned Not planned Not planned Not planned Not planned Not planned Not planned OKDIPG <10 Not planned Not planned Not planned Not planned Not planned Not planned Not plan- etsya E. coli Absent Not plans- Xia Not plans- Xia Not plans- Xia Not plans- Xia Not plans- Xia Not planned Not planned

Table 36. Stability data for batch 5 of pridopidine HCl stored at 30°C/65% RH

Options Acceptance criterion Storage period (months) 0 3 6 9 12 Appearance Color and shape White powder White powder White powder White powder White powder Identification (by IR) Corresponds link spectrum matches matches matches matches matches Crystalline form (according to XRD) Corresponds to the reference diffraction pattern matches Not planned Not planned Not planned matches Analysis (by HPLC) [% w/w] 98.0-102.0 99.8 99.8 99.8 99.8 99.7 Impurities (HPLC) [area%] Compound 8 <0.15 <0.01 <0.01 <0.01 <0.01 <0.01 Compound 3 <0.15 0.10 0.10 0.07 0.10 0.10

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Each (Compound 5, Compound 4, Compound 1, Compound 2, Compound 6 and Unknown impurities each) <0.15 <0.05 <0.05 <0.05 <0.05 <0.05 Total <0.50 0.10 0.10 0.07 0.10 0.10 Water content (by CF) [% w/w] Run and record <0.05 <0.05 <0.05 <0.05 <0.05 Microbiological purity [CFU/g] ABOUT KAM <1000 Not planned Not planned Not planned Not planned <10 OKDIPG <10 Not planned Not planned Not planned Not planned <10 E. coli Absent Not planned Not planned Not planned Not planned Not I define

Table 37. Stability data for batch 5 of pridopidine HCl stored at 40°C/75% RH

Options Acceptance criterion Storage period (months) 0 3 6 Appearance Color and shape White powder White powder White powder Identification (by IR) Corresponds to the reference spectrum matches matches matches crystalline form (according to Corresponds to the reference matches Not planned matches PRD) ) diffractogram Analysis (by HPLC) [% w/w] 98.0-102.0 99.8 99.9 99.5 Impurities (by HPLC) [area%] Compound 8 <0.15 <0.01 <0.01 <0.01 Compound 3 <0.15 0.10 0.10 0.06 Each (Compound 5, Compound 4, Compound 1, Compound 2, Compound 6 and Unknown impurities each) <0.15 <0.05 <0.05 <0.05 Total <0.50 0.10 0.10 0.06 Water content (by CF) [% w/w] Run and record <0.05 <0.05 <0.05 Microbiological purity [CFU/g] ABOUT KAM <1000 Not planned Not planned <10 OKDIPG <10 Not planned Not planned <10 E. coli Absent Not planned Not planned Not determined

Summarized results from tables 26-37 and conclusions.

Appearance.

No significant change in color or shape is observed when stored at 40°C/75% RH for up to 6 months, at 30°C/65% RH for up to 12 months, or at 25°C/60% RH for up to for up to 48 months.

crystalline form.

No change in polymorphic form is observed when pridopidine HCl is stored at 40°C/75% RH for up to 6 months, and at 30°C/65% RH for up to 12 months. X-ray diffraction patterns recorded after 18 months at 25°C/60% RH showed no change. X-ray analyzes are performed again at the end of the long-term stability evaluation program (60 months).

Analysis.

When storing pridopidine HCl at 40°C/75% RH for up to 6 months, significant changes in the analysis are not observed. Also, significant changes are not observed when stored at 30°C/65% RH for up to 12 months, or at 25°C/60% RH for up to 48 months.

impurities.

Degradation of pridopidine HCl is not observed when the drug substance is stored at 40°C/75% RH for up to 6 months, at 30°C/65% RH for up to 12 months, or at 25°C/60% RH for up to up to 48 months.

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Water content.

No significant changes in water content are observed during storage of pridopidine.

HCl at 40°C/75% RH for up to 6 months, at 30°C/65% RH for up to 12 months, or at 25°C/60% RH for up to 48 months.

Conclusion.

No evidence of significant changes in the tested parameters was noted under any storage conditions. Pridopidine HCl is considered to be physically and chemically stable when stored at 40°C and 75% RH for up to 6 months, at 30°C/65% RH for up to 12 months, and at 25°C and 60% RH for up to up to 48 months.

Example 11 Forced Degradation Analysis.

The analysis of forced degradation is carried out for drug product and drug substance pridopidine HCl. The product under study is subjected to acid and alkaline hydrolysis, heat stress as a solid and in solution, oxidation, moisture stress and photolysis.

The study showed that pridopidine HCl is very stable under most of the conditions studied, with the exception of oxidative conditions, in which significant degradation is observed. The main degradation product is compound 5. There is also some degradation on alkaline hydrolysis, but only a slight overall degradation is observed when the main degradation product is identified.

The material balance is also examined and found to be good for all conditions studied.

Summary and conclusions from examples 10-11.

The amounts of organic impurities remain below the limits under all tested conditions for all time periods, as shown in example 10. Compound 5, which is the only potential degradation product known (example 11), remains low under all tested conditions, as shown in example 10 .

Example 12 Product specification for pridopidine HCl.

As detailed in Example 10, no degradation products were detected in pridopidine HCl under any storage conditions. In addition, no additional impurities were formed during the preparation of the medicinal product. Therefore, the same amounts of organic impurities Compound 1, Compound 2, Compound 3, Compound 4, Compound 5 and Compound 6 that are controlled in the drug substance remain in the drug product, and the acceptance criteria related to organic impurities Compound 1, Compound 2 , connection 3, connection 4, connection 5 and connection 6, which are described in detail in table. 22 apply to the medicinal product.

Example 13 Serial analysis of drug substance pridopidine HCl.

Several batches of pridopidine HCl drug substance are produced at different production facilities and then analyzed. All batches contain known impurities Compound 5, Compound 1, Compound 4, Compound 8, Compound 6 and Compound 3 in amounts below the 0.15% qualification limit.

Table 38. Analysis of the content of each of the impurities Compound 5, Compound 1, Compound 4, Compound 8, Compound 6, and Compound 3 in lots of APIs used for toxicity studies

Impurity/batch number Z Y X Compound 5 np np <0.05 Compound 1 np np 0.06 Compound 4 np <0.05 0.06 Compound 8 0.02 NP <0.05 Compound 6 NP <0.05 <0.05 Compound 2 np NP <0.05 Compound 3 np <0.05 <0.05 The largest impurity 0.15 <0.05 <0.05

NP - do not carry out.

Example 14 Serial Analysis of Pridopidine HCl Drug Product.

Several batches of pridopidine HCl drug product are produced at different manufacturing facilities and then analyzed.

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Claims (7)

Table 39. Analysis of batches of pridopidine HCl used for non-clinical and ____________________ clinical studies ____________________________ Batch number Related substances by HPLC [% area] Compound 5 Compound 1 Compound 4 (peak 1) Compound 8 Compound 3 (peak 2) Compound 2 Compound 6 (peak 3) Compound 9 Unknown impurities Total impurities Acceptance criterion <0.15 <0.15 <0.15 <0.15 <0.15 <0.15 <0.15 Recorded value <0.10 each <0.50 A — — — — — — — — — 0.51 IN — — — — — — — — — 0.26 WITH — — <0.05 — 0.06 — <0.05 — <0.05 0.06 D — — <0.05 — <0.05 — <0.05 — <0.05 <0.05 E — — <0.05 — <0.05 — <0.05 — 0.09 ¹ 0.09 F <0.05 <0.05 <0.05 0.07Error !Source sylkinenai Den. 0.07 1 — — 0.09 — BUT — BUT — 0.05 0.14 2 — — 0.05 — BUT — BUT — BUT 0.05 3 — — 0.05 — BUT — BUT — BUT 0.06 4 <0.05 <0.05 0.08 <0.05 0.07 <0.05 <0.05 <1 <0.05 0.15 5 <0.05 ² <0.05 <0.05 <0.05 0.10 <0.05 <0.05 <1 <0.05 0.10 G <0.05 0.06 <0.05 <0.01 0.10 <0.05 <0.05 <1 <0.05 0.15 H <0.05 0.07 <0.05 <0.01 0.08 <0.05 <0.05 <1 <0.05 0.14 I <0.05 <0.05 0.06 <0.01 0.11 <0.05 <0.05 <1 <0.05 0.17 J <0.05 <0.05 <0.05 <0.01 <0.05 <0.05 <0.05 1 <0.05 <0.05 TO <0.05 0.07 <0.05 <0.01 0.08 <0.05 <0.05 <1 <0.05 0.15 Compound 9 is 4-hydroxy-4-(3-(methylsulfonyl)phenyl)-1-propylpiperidin-1-ium chloride. CLAIM 1. A pharmaceutical composition containing pridopidine or a pharmaceutically acceptable salt thereof, a pharmaceutically acceptable carrier and at least one compound or a pharmaceutically acceptable salt thereof which has the structure where the amount of each of the compounds 1 and 4 in the pharmaceutical composition is more than 0.01% of the area, but not more than 10% of the area relative to the amount of pridopidine, based on the determination by HPLC. 2. The pharmaceutical composition according to claim 1, where the salt is a hydrochloride, hydrobromide, nitrate, perchlorate, phosphate, sulfate, formate, acetate, aconate, ascorbate, benzenesulfonate, benzoate, cinnamate, citrate, embonate, enanthate, fumarate, glutamate, glycolate , lactate, maleate, malonate, almond, methanesulfonate, naphthalene-2-sulfonate, phthalate, salicylate, sorbate, stearate, succinate, tartrate or toluene-psulfonate. 3. Pharmaceutical composition according to claim 1, containing pridopidine or its pharmaceutically acceptable salt and compound 1 or its pharmaceutically acceptable salt. 4. Pharmaceutical composition according to claim 1, containing pridopidine or its pharmaceutically acceptable salt, compound 1 and compound 4 or its pharmaceutically acceptable salt. 5. Pharmaceutical composition according to claim 1, where a) Compound 1 is present in the pharmaceutical composition in an amount of not more than 0.15 area %, based on the concentration of pridopidine, based on HPLC determination, or b) Compound 4 is present in the pharmaceutical composition in an amount of not more than 0.15 area % relative to the concentration of pridopidine, based on HPLC determination. 6. Pharmaceutical composition according to claim 1, where a) Compound 1 is present in the pharmaceutical composition in an amount greater than 0.01 area % and not greater than 0.15 area % relative to the concentration of pridopidine, based on HPLC determination, or b) compound 4 is present in the pharmaceutical composition in an amount of more than 0.01% area and not more than 0.15% area in relation to the concentration of pridopidine, based on HPLC determination. 7. Pharmaceutical composition according to claim 1, where a) compound 1 is present in the pharmaceutical composition in an amount of less than 0.04 area % relative to the concentration of pridopidine, based on HPLC determination, or -