WO1995027489A1 - Composition for treating neurological disorders - Google Patents

Abstract

The invention relates to a method of treating neurological disorders associated with neurotransmitter deficit in a mammal comprising administering to the mammal a therapeutically effective amount of a combination of: (i) at least one neurotransmitter release enhancer, (ii) at least one dopamine precursor, and (iii) at least one aromatic amino acid decarboxylase inhibitor. The invention also relates to compositions and kits containing the same.

Description

T I TLE

COMPOSITION FOR TREATING NEUROLOGICAL DISORDERS

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part of our copending application U.S.S.N. 08/225874 filed April 11, 1994, the disclosures of which is incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to a method of treating neurological disorders associated with neurotransmitter deficit in a mammal comprising administering to the mammal a therapeutically effective amount of a combination of: (i) at least one neurotransmitter release enhancer, (ii) at least one dopamine precursor, and (iii) at least one aromatic amino acid decarboxylase inhibitor. This invention also relates to compositions and kits containing the same.

BACKGROUND OF THE INVENTION

The hypothesis that the symptoms of neurodegenerative diseases such as Parkinson's Disease are the result of reduced neuronal function has led to the development of therapies aimed at reversing these deficits. In an attempt at neurotransmitter replacement, neurotransmitter precursor supplementation has been used to treat neurodegenerative diseases. Cotzias, et al. New Engl . J. Med. 276:374-379 (1967). The dopamine precursor L-dopa ((L)-3-(3,4- dihydroxyphenyDalanine) , in combination with the peripheral aromatic acid decarboxylase inhibitor carbidodopa, is a known combination which is commercially available as Sinemet® or Sinemet® CR, and provides a clinically demonstrated improvement in Parkinson's disease. Goetz, et al., Neurology 37:875- 878 (1987). Therapies involving these single agents alone have been shown to be ineffective in treating Parkinson's Disease. The presumed biochemical mechanism attributing to this effect is the reversal of the dopamine deficits associated with this disorder. ' Another means of enhancing neurotransmission is to increase stimulated, but not basal, release of neurotransmitterε, thereby specifically increasing normal synaptic activity. Substituted oxindoleε such as 3,3-biε(4-pyridinylmethyl)-l-phenylindolin-2-one are agents under investigation as a palliative treatment for the dementia associated with Alzheimer's disease. Compounds of this structural type have been shown to enhance potassium(K⁺)-stimulated release of tritium from rat brain slices preloaded with [³H]choline, [3H]dopamine, and [^H]serotonin without affecting basal efflux. Nickolson et al. , Drug Dev. Res . 19:285-300 (1990); Zaczek et al. Neuroεci . Lett . (1993); Zaczek et al., Drug Dev. Res . 29:203-208 (1993).

These neurotransmitter release enhancers also have an effect on K⁺-stimulated release of endogenous dopamine (3-hydroxytyramine) and 3,4- dihydroxyphenylacetic acid (DOPAC; a dopamine metabolite) , as demonstrated by a method employing high performance liquid chromatography with electrochemical detection (HPLC-EC) . Previous studies have shown that precursor loading enhances the release of striatal dopamine. Ng et al., Science, 170:76-77 (1970); Snyder and Zigmond, Brain Res . , 508:181-187 (1990).

The present invention is based on an unexpected and surprising synergy found with a combination therapy involving neurotransmitter release enhancers, dopamine precursors and aromatic decarboxylase inhibitors which has been neither disclosed nor suggested by the prior art. Such a therapy provides a new and highly beneficial method for the treatment of neurological disorders.

SUMMARY OF THE INVENTION

The present invention provides a method of treating neurological disorders associated with neurotransmitter deficit in a mammal comprising administering to the mammal a therapeutically effective amount of a combination of: (i) at least one neurotransmitter release enhancer, such as a compound of Formula (I) (shown below); (ii) at least one dopamine precursor; and (iii) at least one aromatic amino acid decarboxylase inhibitor. The present invention is also directed to compositions and pharmaceutical kits containing the same. Such combination therapy provides surprisingly efficient and effective methodology for use in the treatment of neurological disorders.

DETAILED DESCRIPTION OF THE INVENTION

This present invention provides a method of treating neurological disorders associated with neurotransmitter deficit in a mammal comprising administering to the mammal, in combination, a therapeutically effective amount of: (i) at least one neurotransmitter release enhancer, such as of the Formula (I) (shown below); (ii) at least one dopamine precursor; and (iii) at least one aromatic amino acid decarboxylase inhibitor.

In the present invention, it has been discovered that the administration of a neurotransmitter release enhancer such as of Formula (I) (component (i) ) in combination with a dopamine precursor (component (ii) ) may result in an unexpected synergistic effect in the release of endogenous dopamine. Thus, the amount of endogenous dopamine which is released when a neurotransmitter release enhancer is administered in combination with a dopamine precursor is greater than the additive effect of each agent when administered alone. This is a remarkable and unexpected effect in view of what is currently known in the literature. This synergistic combination is expected to greatly increase the efficacy of single agent or multiple agent treatments of neurological disorders associated with neurotransmitter deficits, such as Alzheimer's Disease and Parkinson's Disease, disorders which are associated with dopamine deficits.

Thus, it has been discovered that the neurotransmitter release enhancers of the present invention may be administered in combination with a dopamine precursor and an aromatic amino acid decarboxylase inhibitor, thereby reducing the doses of each drug required to achieve the amounts of neurotransmitter, such as dopamine, released. Moreover, it has been discovered that the use of the compounds of component (i) and component (ii) of the invention in combination results in a greater than additive dopamine releasing effect. Thus, the combination treatment of the present invention of components (i) , (ii) and component (iii) permits the use of lower doses of each component, with reduced adverse, toxic effects of each component. It also provides for a greater window of efficacy, since the same maximum tolerated doses can be administered before toxic effects associated with each agent are observed. A lower dosage minimizes the potential of side effects of the compounds, thereby providing an increased margin of safety relative to the

•a margin of safety for each component when used as a single agent.

As used herein, the term "neurotransmitter release enhancer" or "neurotransmitter release enhancing agent" refers to compounds or compositions which serve to increase the cellular release of one or more neurotransmitters and includes the compounds of Formula (I) described below. The neurotransmitter release enhancer compounds of Formula (I) are also described in Myers, et al., U.S. Patent No. 4,760,083 and Earl, et al., U.S. Patent No. 5,173,489, the disclosures of each of which are hereby incorporated herein by reference in their entirety. Other compounds and compositions are known and will be readily apparent to those skilled in the art, once armed with the present disclosure. Such neurotransmitter release enhancers may serve to increase the cellular release of one or more neurotransmitters, such as, for example, the neurotransmitters dopamine, acetylcholine, choline, serotonin, noradrenaline, adrenaline and glutamic acid. Preferably, the neurotransmitter release enhancers serve to increase the release of dopamine and/or acetylcholine, and are preferably the compounds of Formula (I) . The phrase "dopamine precursor", as used herein, denotes compounds which are the precursors of dopamine which form dopamine in a mammalian metabolic system. The phrase "aromatic amino acid decarboxylase inhibitor", as used throughout, refers to compounds which inhibit the aromatic amino acid decarboxylase enzyme.

By "therapeutically effective amount" it is meant an amount of component (i), component (ii) and component (iii) that when administered alone or in combination to a mammal is effective to treat the neurological disorder, such as by increasing the amount of the neurotransmitter(s) in deficit, especially the neurotransmitters dopamine and/or acetylcholine.

By "administered in combination", or the like, when referring to component (i) , component (ii) , and component (iii) of the present invention, it is meant that the components are administered concurrently to a mammal being treated. By concurrently, it is meant that each component may be administered at the same time or sequentially in any order at different points in time, however if not administered at the same time, they should be administered sufficiently closely in time so as to provide the desired treatment effect. Suitable dosing intervals and dosing order with such compounds will be readily apparent to those skilled in the art, once armed with the present disclosure. Preferably, all components are administered at the same time, and if not administered at the same time, preferably they are all administered less than one hour apart from one another. The present invention also includes pharmaceutical compositions (that is, combination products), such pharmaceutical compositions (combination products) comprising or consisting essentially of, in combination, a neurotransmitter release enhancing compound (such as Formula (I) ) , a dopamine precursor, and an aromatic amino acid decarboxylase inhibitor. Such compositions may be in solid or liquid dosage units, and may further include a suitable pharmaceutical carrier. , The present invention also includes pharmaceutical kits comprising or consisting essentially of a neurotransmitter release enhancer (such as compound of Formula (I)), together with a dopamine precursor, and with an aromatic amino acid decarboxylase inhibitor. In the kit, the neurotransmitter release enhancer, dopamine precursor and/or aromatic decarboxylase inhibitor may each be presented in separate vials as compounds, and/or in separate vials as compounds in combination with a pharmaceutically acceptable carrier. Alternatively, one or more of the neurotransmitter release enhancer dopamine precursor and/or aromatic decarboxylase inhibitor may be combined together in one or more vials, with or without a carrier. Thus, for example, the invention includes pharmaceutical kits comprising a separate vial comprising the neurotransmitter release enhancer compound of Formula (I), and a separate vial comprising a mixture of a dopamine precursor and an aromatic amino acid decarboxylase inhibitor, each vial also containing, if desired, a carrier.

The compositions and kits of the present invention may be employed in the treatment of neurological diseases characterized by deficit levels (that is, abnormally low levels) of a neurotransmitter, such as, for example, dopamine. Such diseases are well known and include, for example, Parkinson's Disease and Alzheimer's Disease, as well as other central nervous system disorders or degenerative diseases. The compositions and kits may also be employed for the standardization of biochemical assays dependant on defined levels of released neurotransmitters, such as dopamine. In the method of the present invention, the neurotransmitter release enhancing compound (such as a compound of Formula (I) ) may be administered in combination with a dopamine precursor to achieve a synergistic increase in neurotransmitter, such as the neurotransmitter dopamine. Synergy occurs when the effect (such as release of the neurotransmitter dopamine) of the compounds when administered in combination is greater than the additive effect of the compounds when administered alone as a single agent. The present invention provides for the combination with an aromatic amino acid decarboxylase inhibitor, which, when given concurrently, greatly enhances the effectiveness of dopamine precursor therapy. In general, a synergistic effect is most clearly demonstrated at suboptimal concentrations of the compounds. The method of the present invention provides for an enhanced effect of the three drugs when administered in combination. Thus, the claimed combination treatment allows for the use of lowered clinical doses and increases the window of efficacy. In view of the marginal effects associated with the presently approved therapies for treating diseases characterized by abnormally low levels of brain neurotransmitters like dopamine, such as Parkinson's Disease, the present invention provides an important advantage over current therapies.

Dopamine precursors useful in the method, compositions, and pharmaceutical kits of the present invention include, but are not limited to, 3- (3, - dihydroxyphenyl)-L-alanine (also referred to as L-dopa levodopa or 3-hydroxy-L-tyrosine) . Other dopamine precursors include L-tyrosine and L-phenylalanine, although L-dopa is preferred. These and other dopamine precursors will be readily apparent to those skilled in the art, once armed with the present disclosure.

The preparation of L-dopa may be carried out in a number of different fashions, as will be evident to the skilled artisan. Such preparatory methods include, for example, those described in Cannata, et al., U.S. Patent No. 4,962,223, Knowles, et al., U.S. Patent No. 4,005,127, Reinhold, et al., U.S. Patent No. 4,716,246, Kaiser, et al., U.S. Patent No. 3,969,397, Sih, U.S. Patent No. 3,671,397 and Yamada, et al., Chem Pharm,

Bull . , 10:693 (1962), the disclosures of each of which are hereby incorporated herein by reference in their entirety. L-Dopa is available commercially as "Larodopa®", for which the product information, including dosage and administration, is given in

Physicians' Desk Reference. 47th Edition, 1993, pp. 1992-1993; or as "Dopar®", for which the product information, including dosage and administration, is given in Physicians' Desk Reference. 47th Edition, 1993, p. 1932. Means of obtaining or preparing other dopamine precursors are well known, such as the preparation of the amino acid L-tyrosine from the protein casein. (Marshall J. Biol. Chem, 15 85, 1913; Cox & King Org Syn 611 Vol II, 612, 1943) . Aromatic amino acid decarboxylase inhibitors useful in the method, compositions, and pharmaceutical kits of the present invention include, but are not limited to, (-) -L-α-hydrazino-3, 4-dihydroxy-α-methyl-β- 3- (3,4-dihydroxyphenyl)propanoic acid monohydrate (also referred to as carbidopa or (-)-L-α-hydrazino-α- methylhydrocinnamic acid monohydrate) . A synthesis in racemic form is described in Sletzinger et al., J. Med. Chem. , 6:101 (1963). Synthesis of the L-form is described by Karady et al., J. Org. Chem. 36:1946, 1949 (1971) . The use of carbidopa as a potent dopa decarboxylase inhibitor is described in Watanabe et al. , Clin . Pharmacol . Ther. 11:740 (1970). The disclosures of each of these references is hereby incorporated herein by reference in their entirety.

Other amino acid decarboxylase inhibitors include benserazide (N-[DL-seryl]-N' -[2,3,4- trihydroxybenzyl]-hydrazine) , NSD 1015 (m- hydroxybenzylhydrazine) , MK 485 (beta-[3,4- dihydroxyphenyl]-alpha-hydrazino-alpha-methyl propionic acid, and 2-amino-2- (mono- or di-fluoromethyl)-3-(mono- or di-hydroxyphenyl)propionic acids. These and other compounds, and methods of preparation therefor are described, for example, in Al-Damluji, U.S. Patent No. 5,240,930, McDonald, et al., U.S. Patent No. 4,822,812, Stone, U.S. Patent No. 4,051,251, and Belgian Patent Nos. 686,881 and 882,105, the disclosures of each of which are hereby incorporated herein by reference in their entirety. Preferably, the amino acid decarboxylase inhibitor is carbidopa. A combination of the dopamine precursor (component (ii) ) , specifically levodopa, and the aromatic amino acid decarboxylase inhibitor (component (iii) ) , specifically carbidopa, is available in pharmaceutical composition (formulation) commercially known as Sinemet®, or as a sustained-release formulation called Sinemet® CR, for which the product information, including dosage and administration, is given in Physicians' Desk Reference. 47th Edition, 1993, pp. 974- 978. Such a combination is suitable for use in the present invention.

As discussed in U.S. Patent Nos. 4,760,083 and 5,173,489, compounds of the α,α-disubstituted ring systems of Formula (I) represent a new class of neurotransmitter release enhancers which are useful for the treatment of diseases characterized by abnormally low levels of brain neurotransmitter acetylcholine, such as Alzheimer's Disease. In certain instances, the compounds disclosed were also found to enhance the release of dopamine.

In the present invention it has been found that therapeutic agents of component (i), component (ii) and component (iii), described above, when administered in combination, exert a synergistic neurotransmitter releasing effect, particularly enhancing the release of endogenous dopamine. Such combination treatment may allow the use of lowered clinical doses with increase efficacy and a wider safety window.

The neurotransmitter release enhancers of component (i) useful in this invention include α,α- disubstituted ring systems of the Formula (I) :

(I) or a pharmaceutically acceptable salt thereof, wherein X and Y are taken together to form a saturated or unsaturated carbocyclic first ring and the shown carbon in said ring is α to at least one additional carbocyclic aromatic ring fused to the first ring, the total number of carbocyclic fused rings being 3-5, the sole heterocyclic substituents on said fused rings being Hetl and Het^; and one of Het¹ or Het^ is 2, 3, or 4- pyridyl optionally substituted with a halogen atom or trifluoromethyl, or 2, 4, or 5-pyrimidinyl and the other is selected from (a) 2, 3, or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl,

(b) 2, 4, or 5-pyrimidinyl,

(c) 2-pyrazinyl,

(d) 3 or 4-pyridazinyl, (e) 3 or 4-pyrazolyl, (f) 2 or 3-tetrahydrofuranyl, and

(g) 3-thienyl.

Preferred compounds of component (i) useful in the present invention are compounds of Formula (la) :

(la) wherein: p is 0 or 1;

Z is 0 or S;

R is Ci-Cio alkyl, C3-C8 cycloalkyl, 2-pyridyl, 3- pyridyl, 4-pyridyl, or

V, ,X, and Y independently are H, a halogen atom, C₁-C₃ alkyl, OR¹, O2, CF₃, CN or NR1R2_;

R¹ and R² independently are H or C₁-C₃ alkyl; Het¹ and Het² independently are 6-membered heterocyclic aromatic rings containing one or two nitrogen atoms as part of the ring optionally substituted with one substituent selected from the group C₁-C3 alkyl, a halogen atom, OR¹ or NR¹R²; or an N-oxide or pharmaceutically acceptable acid addition salt thereof. Also preferred compounds of component (i) useful in the method of the present invention are compounds of Formula (lb) :

(lb) or a pharmaceutically acceptable salt thereof, wherein:

each J, K, L and M independently are N, CR¹, CR⁵ or CR² with the proviso that when either M₄, M5 or both is N, then B, D or both cannot be R¹ or R²; A is (CH2)n. C(=S), 0, S(0)ι, S(0)₂, S, NR³ , -CH=CH-, -C(=0)-, -CH(OR³)-, C(=NOH)-,

n is 0, 1, 2 or 3;

R¹ and R² independently are H, a halogen atom, alkyl of 2-3 carbon atoms, acetyl, OR³, θ2# CN, NR R^, or fluoroalkyl of 1-3 carbon atoms;

R³ and R⁴ independently are H, alkyl of 1-3 carbon atoms, or acyl;

B, and D independently are R¹ or R² or, when A is (CH2)o» can be taken together to form -CH=CH-, or -CH2-CH2-;

R5 independently is H, or is taken together with R¹ to form a 2,3- or a 3,4-fused benzo ring;

one of Het¹ or Het² is 2, 3, or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl, or 2, 4 or

5-pyrimidinyl and the other is selected from: (a) 2, 3 or 4-pyridinyl, (b) 2, 4, or 5-pyrimidinyl, (c) 2-pyrazinyl, (d) 3 or 4-pyridazinyl,

(e) 3 or 4-pyrazolyl,

(f) 2 or 3-tetrahydrofuranyl, and

(g) 3-thienyl.

Also preferred compounds of component (i) useful in the present invention are compounds of Formula (Ic) :

(Ic) or a pharmaceutically acceptable salt thereof, wherein;

a is a single bond or double bond;

X and Y taken together when a is a single bond is

-CH=CH-CH=CH-;

I I

W Z X and Y taken together when a is a double bond is

-CH2-(CH2-)nCH-CH-;

I I

W Z where n is 1 or 2;

Q when a is a single bond is =0; =S; H2 =N0R¹,

-0(CH2)pO-, -S(CH2)pS-, -(H)F, = NOR¹, F2; (R^ OR³, =CR¹R²;

Q, when a is a double bond is R², OR³ or a halogen atom;

p is 2 or 3;

R¹ is H, alkyl of 1-10 carbon atoms, cycloalkyl of 3-8 carbon atoms, or

R² is R¹, NO2, CN, CO2R¹, C(=0)R¹ or a halogen atom;

R³ is C(=0)R¹ or CR¹;

W, Z independently are H, a halogen atom, alkyl of 1-3 carbon atoms, OR³, O2, CF3, fluoroalkyl, CN, or (R¹)2; and one of Het¹ or Het² is 2, 3, or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl, or 2, 4, or

5-pyrimidinyl and the other is selected from (a) 2, 3, or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl,,

(b) 2, 4, or 5-pyrimidinyl,

(c) 1-pyrazinyl,

(d) 3 or 4-pyridazinyl, (e) 3 or 4-pyrazolyl,

(f) 2 or 3-tetrahydrofuranyl, and

(g) 3-thienyl.

Also preferred compounds of component (i) useful in the present invention are compounds of Formula (Id) :

(Id) or a pharmaceutically acceptable salt thereof, wherein:

a is a single bond or double bond; b is a single bond or double bond, provided one of a or b is a single bond;

X independently when a and b are single bonds is: 0,S, CR^², CQ, CRⁱOR³ or -(CH₂)N- where N is 1-3, N(CH₂)_PR³ where p is 0-1, or NC^OR¹;

X independently when one of a or b is a double bond is CR², COR³, or N;

V independently when b is a single bond is CQ;

V independently when b is a double bond is CR2 or COR3;

1 1 A _sιs a single bond, -(-CR₂-)n~' -X-# -⁽-CR2-⁾n~X/ where n is 1, 2 or 3 and

X is as defined above when a is a single bond;

V and V taken together when A and b are single bonds is

-C=C-CH=CH-; / \ W Z

Y and V taken together when A is a single bond is -CH2- (CH2)m-CH2~ where m is 1 or 2; provided that when Y and V are connected, then V and X are not connected; V and X taken together when b is a double bond is C- CH=CH-CH=CH-C-, or, C- (-CH2-)p-C; provided that when V and X are connected, then Y and V are not connected;

Q when a is a single bond is =0, =S, H2, s OR¹,

-0(CH2)pO-, -S(CH2)pS-, -(H)F, F², (R÷ OR³, =CR¹R ;

Q when a is a double bond is R², OR³ or a halogen atom;

p is 2 or 3;

R¹ is H, alkyl of 1-10 carbon atoms, cycloalkyl of 3-8 - carbon atoms, or

R² is R¹, NO2, CN, CN2 ¹, C(=0)R¹ or a halogen atom;

R³ is R¹ or C(=0)R¹;

, Y, Z independently are H, a halogen atom, alkyl of 1- 3 carbon atoms, OR³, NO2, CF3, fluoroalkyl, CN, or (R¹)2; and one of Het¹ or Het² is 2, 3, or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl, or 2, 4, or 5-pyrimidinyl and the other is selected from

(a) 2 , 3, or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl, ,

(b) 2, 4, or 5-pyrimidinyl,

(c) 2-pyrazinyl, (d) 3, or 4-pyridazinyl,

(e) 3, or 4-pyrazolyl,

(f) 2, or 3-tetrahydrofuranyl, and

(g) 3-thienyl.

More preferred compounds of component (i) useful in the present invention are compounds of Formula (I) wherein:

Het¹ or Het² is 2-, 3-,or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl, or 2-, 4-, or 5-pyrimidinyl and the other is 2-, 3- , or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl, 2-, 4-, or 5- pyrimidinyl, or 2-, or 3-tetrahydrofuranyl.

Most preferred compounds of component (i) useful in the present invention are compounds of Formula (I) wherein: Het¹ and Het² is most preferably selected from:

(a) 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl and 4-pyridazinyl,

(b) 4-pyrimidinyl and 4-pyrimidinyl, (c) 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl and 4-pyrimidinyl,

(d) 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl and 3-tetrahydrofuranyl. Specifically preferred compounds of component (i) useful in the present invention are the compounds of Formula (la) wherein:

p is 0;

Z 'is O;

W, X, Y and Z are hydrogen;

R is methyl, phenyl or m-chlorophenyl; and

Het¹ and Het² are each pyridinyl attached by a ring carbon atom.

The most specifically preferred compounds of component (i) useful in the present invention are the compound of Formula (la) which is 3, 3-Bis(4- pyridinylmethyl) -l-phenylindolin-2-one and selected from: 3, 3-bis (4-pyridinylmethyl) -l-phenylindolin-2-one and 10,10-bis( (2-fluoro-4-pyridinyl)methyl)-9 (10H) anthracenone.

Methods for the preparation of the compounds of Formula (I) are described in great detail in Myers, et al., U.S. Patent No. 4,760,083 and Earl, et al., U.S. Patent No. 5,173,489, and United States Patent Application Serial No. 08/216,881 filed March 28, 1994, all of which are incorporated herein by reference in their entirety. The preferred compound of component (ii) useful in the present invention is the compound (-)-3- (3,4-dihydroxyphenyl)alanine (also referred to as L- dopa) .

The preferred compound of component (iii) useful in the present invention is the compound (-)-L-α- hydrazino-α-methyl-β-(3, 4-dihydroxyphenyl)propanoic acid monohydrate (also referred to as carbidopa) .

Preferred compounds of component (ii) and component (iii) preformulated in a single pharmaceutical composition useful in the present invention are the compound (-)-3- (3,4-dihydroxyphenyl)alanine and (-)-L-α- hydrazino-α-methyl-β-(3,4-dihydroxyphenyl)propanoic acid monohydrate, respectively.

Component (i) of the present invention may also be provided as a pharmaceutical composition comprising an therapeutically effective amount of a compound of Formula (I) (including those of the subformulae la, lb, Ic and Id) and a pharmaceutically acceptable carrier. Component (ii) of the present invention may likewise be presented as a pharmaceutical composition comprising a therapeutically effective amount of a dopamine precursor and a pharmaceutically acceptable carrier. Similarly, component (iii) may be provided as a pharmaceutical composition comprising a therapeutically effective amount of an aromatic amino acid decarboxylate inhibitor and a pharmaceutically acceptable carrier. Mixtures of the components (i), (ii) and (iii), with or without a pharmaceutically acceptable carrier, are also within the ambit of the present invention.

Neurological disorders associated with neurotransmitter deficit include, but are not limited to, Parkinson's Disease and Alzheimer's Disease, as well as other central nervous system disorders or degenerative diseases.

When any variable occurs more than one time in any constituent in formula (I), or any other formula herein, its definition on each occurrence is independent of its definition at every other occurrence. Also, combinations of substituents and/or variables are permissible only if such combinations result in stable compounds.

As used herein, "alkyl" is intended to include both branched and straight-chain saturated aliphatic hydrocarbon groups having the specified number of carbon atoms. As used herein "alkoxy" represents an alkyl group of indicated number of carbon atoms attached through an oxygen bridge; "cycloalkyl" is intended to include saturated ring groups, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl; and "biycloalkyl" is intended to include saturated bicyclic ring groups such as

[3.3.0]bicyclooctane, [4.3.0]bicyclononane, [4.4.0]bicyclodecane (decalin) , [2.2,2]bicyclooctane, and so forth. "Alkenyl" is intended to include hydrocarbon chains of either a straight or branched configuration and one or more unsaturated carbon-carbon bonds which may occur in any stable point along the chain, such as ethenyl, propenyl, and the like; and "alkynyl" is intended to include hydrocarbon chains of either a straight or branched configuration and one or more triple carbon-carbon bonds which may occur in any stable point along the chain, such as ethynyl, propynyl and the like. "Cycloalkyl-alkyl" is intended to include cycloalkyl attached to alkyl. "halogen" as used herein refers to fluoro, chloro, bromo, and iodo; and "counterion" is used to represent a small, negatively charged species such as chloride, bromide, hydroxide, acetate, sulfate, and the like.

As used herein, "aryl" or "aromatic residue" is intended to mean phenyl or naphthyl; "carbocyclic" is intended to mean any stable 5- to 7- membered monocyclic or bicyclic or 7- to 14-membered bicyclic or tricyclic carbon ring, any of which may be saturated, partially unsaturated, or aromatic, for example, indanyl or tetrahydronaphthyl (tetralin) . As used herein, "aralkyl" is intended to mean any aryl group bearing an alkyl group. The aralkyl group may be attached at any of its carbon atoms.

The term "substituted", as used herein, means that one or more hydrogen on the designated atom is replaced with a selection from the indicated group, provided that the designated atom's normal valency is not exceeded, and that the substitution results in a stable compound.

By "stable compound" or "stable structure" is meant herein a compound that is sufficiently robust to survive isolation to a useful degree of purity from a reaction mixture, and formulation into an efficacious therapeutic agent.

As used herein, "pharmaceutically acceptable salts" refer to derivatives of the disclosed compounds that are modified by making acid or base salts. Examples include, but are not limited to, mineral or organic acid salts of basic residues such as amines; alkali or organic salts of acidic residues such as carboxylic acids. As used herein, "therapeutically effective amount" means the amount capable of achieving the desired clinical effect.

Pharmaceutically acceptable salts of the compounds of the invention can be prepared by reacting the free acid or base forms of these compounds with a stoichiometric amount of the appropriate base or acid in water or in an organic solvent, or in a mixture of the two; generally, nonaqueous media like ether, ethyl acetate, ethanol, isopropanol, or acetonitrile are preferred. Lists of suitable salts are found in

Remington's Pharmaceutical Sciences. 17th ed. , Mack Publishing Company, Easton, PA, 1985, p. 1418, the disclosure of which is hereby incorporated by reference.

Dosaσe and Formulation

The neurotransmitter release enhancer (component (i)), dopamine precursor (component (ii)) and aromatic amino acid decarboxylase inhibitor (component (iii) ) combination treatment of the invention can be administered by any conventional means available for the use in conjunction with pharmaceuticals, either as individual separate dosage units administered simultaneously or concurrently, or in a physical combination of each component therapeutic agent in a single or combined dosage unit. The active agents can be administered alone, but are generally administered with a pharmaceutical carrier selected on the basis of the chosen route of administration and standard pharmaceutical practice.

The dosage administered will, of course vary depending on the use and known factors such as the pharmacodynamic characteristics of the particular agent, and its mode and route of administration; age, health, and weight of the recipient; nature and extent of symptoms, kind of concurrent treatment, frequency of treatment, and the effect desired. The recipient may be any type of mammal, but is preferably a human. For use in the treatment of diseases characterized by abnormally low levels of dopamine, such as Parkinson's disease, by way of general guidance, a daily oral dosage of active ingredient(s) can be about 0.001 to 1000 mg/kg of body weight. Ordinarily a dose of 0.1 to 500 mg/kg per day in divided doses one to four times a day or in sustained release form is effective to obtain the desired results. Dosage forms (compositions) suitable for administration contain about 1 milligram to 100 milligrams of active ingredient per unit. In these pharmaceutical compositions, the active ingredient will ordinarily be present in an amount of about 0.5-95% by weight based on the total weight of the composition. The active ingredient may be administered orally in solid dosage forms, such as capsules, tablets, and powders, or in liquid dosage forms, such as elixirs, syrups, and suspensions. It can also be administered parenterally, in sterile liquid dosage forms.

Gelatin capsules contain the active ingredient and powdered carriers, such as lactose, starch, cellulose derivatives, magnesium stearate, stearic acid, and the like. Similar diluents can be used to make compressed tablets. Both tablets and capsules can be manufactured as sustained release products to provide for continuous release of medication over a period of hours. Compressed tablets can be sugar coated or film coated to mask any unpleasant taste and protect the tablet from the atmosphere, or enteric coated for selective disintegration in the gastrointestinal tract.

Liquid dosage forms for oral administration can contain coloring and flavoring to increase patient acceptance.

In general, water, a suitable oil, saline, aqueous dextrose (glucose) , and related sugar solutions and glycols such as propylene glycol or polyethylene glycols are suitable carriers for parenteral solutions. Solutions for parenteral administration preferably contain a water soluble salt of the active ingredient, suitable stabilizing agents, and if necessary, buffer substances. Antioxidizing agents such as sodium bisulfate, sodium sulfite, or ascorbic acid, either alone or combined, are suitable stabilizing agents. Also used are citric acid and its salts and sodium EDTA. In addition, parenteral solutions can contain preservatives, such as benzalkonium chloride, methyl- or propyl-paraben, and chlorobutanol.

Suitable pharmaceutical carriers and methods of preparing pharmaceutical dosage forms are described in Remington's Pharmaceutical Sciences. Mack Publishing Company, a standard reference text in this field.

Useful pharmaceutical compositions (dosage forms) for administration of the compounds of this invention can be illustrated as follows: Capsules

A large number of unit capsules are prepared by filling standard two-piece hard gelatin capsules each with 100 milligrams of powdered active ingredient, 150 milligrams of lactose, 50 milligrams of cellulose, and 6 milligrams magnesium stearate. Soft Gelatin Capsules A mixture of active ingredient in a digestible oil such as soybean oil, cottonseed oil or olive oil is prepared and injected by means of a positive displacement pump into gelatin to form soft gelatin capsules containing 100 milligrams of the active ingredient. The capsules are washed and dried. Tablets

A large number of tablets are prepared by conventional procedures so that the dosage unit was 100 milligrams of active ingredient, 0.2 milligrams of colloidal silicon dioxide, 5 milligrams of magnesium stearate, 275 milligrams of microcrystalline cellulose, 11 milligrams of starch and 98.8 milligrams of lactose. Appropriate coatings may be applied to increase palatability or delay absorption. Suspension

An aqueous suspension is prepared for oral administration so that each 5 ml contain 25 mg of finely divided active ingredient, 200 mg of sodium carboxymethyl cellulose, 5 mg of sodium benzoate, 1.0 g of sorbitol solution, U.S.P., and 0.025 mg of vanillin.

Iniectable

A parenteral composition suitable for administration by injection is prepared by stirring 1.5% by weight of active ingredient in 10% by volume propylene glycol and water. The solution is sterilized by commonly used techniques. Each therapeutic agent component of this invention can independently be in any dosage form, such as those described above, and can also be administered in various ways, as described above. The component (i), (ii) and (iii) of the invention may be formulated together, in a single dosage unit (that is, combined together in one capsule, tablet, powder, or liquid, etc.) as a composition (combination product). More preferably, the dopamine precursor (component (i)) and the aromatic amino acid decarboxylase inhibitor (component (ii)) are formulated together as a composition. When component (i), (ii) and (iii) are not formulated together in a single dosage unit, the neurotransmitter release enhancer component (i) may be administered at the same time as the dopamine precursor component (ii) and aromatic amino acid decarboxylase component (iii), or in any order. For example, component (i) of this invention may be administered first, followed by administration of components (ii), (iii) , or they may be administered in the reverse order. When not administered at the same time, preferably the administration of component (i) and components (ii) , (iii) of this invention occurs less than about one hour apart. Preferably, the route of administration of component (i) and component (ii) , (iii) of the invention is oral. The terms oral agent, oral release enhancer, oral compound, or the like, as used herein, denote compounds which may be orally administered. Although it is preferable that component (i), (ii), and (iii) of the invention are both administered by the same route (that is, for example, both orally) or in the same dosage form (that is, for example, as a tablet), if desired, they may each be administered by different routes (that is, > for example, one component of the combination product may be administered orally, and another component may be administered intravenously) or in different dosage forms (that is, for example, one component as a tablet and another as a liquid) .

As will be appreciated by a medical practitioner skilled in the art, the dosage of the combination therapy of the invention may vary depending upon various factors such as the pharmacodynamic characteristics of the particular agent and its mode and route of administration, the age, health and weight of the recipient, the nature and extent of the symptoms, the kind of concurrent treatment, the frequency of treatment, and the effect desired, as described above. The proper dosage of component (i), component (ii) and component (iii) in this invention will be readily ascertainable by a medical practitioner skilled in the art, based upon the present disclosure. By way of general guidance, typically a daily dosage may be about 100 milligrams to about 1.5 grams of each component. By way of general guidance, when the compounds of component (i) and component (ii) are administered in combination, the dosage amount of each component may be reduced by about 70-80% relative to the usual dosage of the component when it is administered alone as a single agent for the treatment of abnormalities associated with low dopamine levels, in view of the synergistic effect of the combination.

The combination products of this invention may be formulated such that, although the active ingredients are combined in a single dosage unit, the physical contact between the active ingredients is minimized. In order to minimize contact, for example, where the product is orally administered, one or more of the active ingredients may be enteric coated. By enteric coating one of the active ingredients, it is possible not only to minimize the contact between the combined active ingredients, but also, it is possible to control the release of one of these components in the gastrointestinal tract such that one of these components is not released in the stomach but rather is released in the intestines. Another embodiment of this invention where oral administration is desired provides for a combination product wherein one or more of the active ingredients is coated with a sustained-release material which effects a sustained-release throughout the gastrointestinal tract and also serves to minimize physical contact between the combined active ingredients. Furthermore, the sustained-released component can be additionally enteric coated such that the release of this component occurs only in the intestine. Still another approach would involve the formulation of a combination product in which the one or more components is coated with a sustained and/or enteric release polymer, and the other(s) component is also coated with a polymer such as a low viscosity grade of hydroxypropyl methylcellulose or other appropriate materials as known in the art, in order to further separate the active components. The polymer coating serves to form an additional barrier to interaction with the other component.

Dosage forms of the combination products of the present invention wherein one active ingredient is enteric coated can be in the form of tablets such that the enteric coated component and the other active ingredients are blended together and then compressed into a tablet or such that the enteric coated component is compressed into one tablet layer and the other active ingredient is compressed into an additional layer. Optionally, in order to further separate the two layers, one or more placebo layers may be present such that the placebo layer is between the layers of active ingredients. In addition, dosage forms of the present invention can be in the form of capsules wherein one active ingredient is compressed into a tablet or in the form of a plurality of microtablets, particles, granules or non-perils, which are then enteric coated. These enteric coated microtablets, particles, granules or non-perils are then placed into a capsule or compressed into a capsule along with a granulation of the other active ingredient.

These as well as other ways of minimizing contact between the components of combination products of the present invention, whether administered in a single dosage form or administered in separate forms but at the same time or concurrently by the same manner, will be readily apparent to those skilled in the art, based on the present disclosure.

Pharmaceutical kits useful for the treatment of abnormal dopamine levels, which comprise a therapeutically effective amount of a compound of component (i), a compound of component (ii), and a compound of component (iii) in one or more containers, are also within the ambit of the present invention. Sterilization of the container may be carried out using conventional sterilization methodology well known to those skilled in the art. Component (i), component (ii) and component (iii) may be in the same container or in separate containers. The containers of materials may comprise separate containers, or one or more multi-part containers, as desired. Component (i), component (ii) , and component (iii) may be separate, or physically combined into a single dosage form or unit as described above. A single dosage combination of the present invention is the combination of component (ii) and component (iii) . Such kits may further include, if desired, one or more of various conventional pharmaceutical kit components, such as for example, one or more pharmaceutically acceptable carriers, additional vials for mixing the components, etc., as will be readily apparent to those skilled in the art. Instructions, either as inserts or as labels, indicating quantities of the components to be administered, guidelines for administration, and/or guidelines for mixing the components, may also be included in the kit.

, Examples

The examples described below may be used to demonstrate the synergistic endogenous dopamine releasing effect of a neurotransmitter release enhancer of Formula (I) administered in combination with a dopamine precursor. The tests and the results described below demonstrate that a representative neurotransmitter release enhancer of Formula (I), 3,3-bis(4- pyridinylmethyl)-l-phenylindolin-2-one, acts synergistically with a representative dopamine precursor, L-dopa, to effect release of endogenous dopamine. The compound 3,3-bis(4-pyridinylmethyl)-1- phenylindolin-2-one, is described in Earl, et al. , U.S. Patent No. 5,173,489 as Example Number 4, and as Example Number 4 in Myers, et al., U.S. Patent No. 4,760,083, and is herein referred to as "linopirdine" . The compound 10,10-bis( (2-fluoro-4-pyridinyl)methyl)-9(10H) anthracenone may be prepared as described in copending patent application U.S. Serial Number 08/216,881 filed March 28, 1994. The above cited patents and patent application also teach the preparation of the other neurotransmitter release enhancers useful in the present invention. Accordingly, the above cited patents and patent application are incorporated herein by reference in their entirety.

Protocol

Neurotransmitter Release Assay _s Dopamine release studies were performed using rat striatal slices. Male Wistar rats (200-250 g) were decapitated and striatum was dissected out and cut into prisms of 0.25 mm x 0.25 mm x tissue thickness. Aliquots of the slices (approximately 100 mg) were transferred to perfusion chambers of a Brandel SF-20 superfusion apparatus. The tissue was superfused at 0.5 ml/min. with normal Kreb's solution consisting of 116 mM NaCl, 3 mM KC1, 1.0 mM CaCl2, 1.2 mM MgCl2, 1.2 mM KH2PO4, 1.2 mM Na2P04, 25 mM NaHC03, and 11 mM glucose. There was 100 mg/ml of sodium metabisulfite was added to the superfusate to reduce oxidation of catecholamines. Serial 4 min. fractions were collected into vials containing 0.2 ml of IN HCl. Slices were stimulated with 20 mM KCl in fractions 4 (SI) and 8 (S2) . There was an isomolar reduction in NaCl to compensate for the high KCl in fractions 4 and 8. Compounds of the Formula (I), or for purposes of the following experiment, linopirdine, and/or neurotransmitter precursor was added during fractions 5-8. Dopamine Measurement

Dopamine and DOPAC (3,4-dihydroxyphenylacetic acid; a dopamine metabolite) concentrations were measured from 40 μl of the superfusate by HPLC-EC. After the collection of fractions was ended, the εuperfusion chambers were emptied and the tissue was sonicated in 1.0 ml of 0.12 M εodium acetate (pH adjuεted to 5.0 with IN HCl), centrifuged (45,000 x g for 15 min. ) , and 20 μl of the resulting supernatant was analyzed by HPLC-EC to determine remaining tissue levels of dopamine. Peak height was used to quantitate biogenic amine concentration. Dopamine was separated on a 15 cm reverse phase HPLC column (Resolve C18, Waterε Assoc, Milford, MA) using a mobile phase consisting of 0.1 M sodium acetate, 0.1 M citric acid, 1.8 mM 1-octanesulfonic acid sodium salt, 0.15 mM EDTA, 1 mM dibutylamine, and 5% methanol (V/V) , pH 3.7 at a flow rate of 1.0 ml/min.

Dopamine was detected using a Waterε 460 electrochemical detector equipped with a glassy-carbon working electrode at a potential of 0.75 V vs. Ag/AgCl reference. Statistics

The data for each experimental group are from 3-7 separate studies. Statistics were performed using ANOVA followed by one tailed Dunnett's test. Synergism was tested using a two-way ANOVA analysis of interaction between L-dopa and linopirdine. Regultg Stimulation of striatal slices by 20 mM K⁺ led to short pulεeε of dopamine release which coincided with the stimulation with %S2/S1 for control = 88.6 ± 7.0%. In the presence of 10 μM linopirdine, K⁺-stimulated dopamine release was 393% of control (*** p < .001 compared to control) . Adding the dopamine precursor L- dopa (10 μM) resulted in greater than a 2-fold increase in K⁺-stimulated dopamine release, when L-dopa and linopirdine were combined, dopamine release was increased 12-fold over control (p < .001 compared to control ***). Since L-dopa alone led to a 2-fold increase and linopirdine alone led to a 4-fold increase (additivity = 5.57 fold), the effect of the combination of the two drugs was synergistic (+++ P < .001 interaction of L-dopa and linopirdine) . Dopamine Release (% of control) control 100 ± 8

L-dopa 224 ± 55 linopirdine 433 ± 37***

L-dopa + linopirdine 1201 ±

173- ^r+++

The measurement of endogenous dopamine release allowed determination of the effect of a combination of dopamine precursor loading and linopirdine on K⁺- εtimulated dopamine release. The ability of L-dopa to enhance basal and stimulated (K⁺ or electrical) release of dopamine has been previously established by Ng, et al., Science 170:76-77 (1970); Tyce and Rorie, Life Sci . 37:2439-2448 (1985); and Snyder and Zigmond, Brain Res. 508:181-187 (1990). The resultε of the preεent study are consiεtent with theεe previouε findingε. It was found that the presence of 10 μM l-dopa led to an increaεe in K⁺-εtimulated releaεe of more than two-fold. It was also found that the combination of l-dopa preloading and linopirdine was synergistic in enhancing dopamine release from εtriatal εlices.

The synergistic enhancement of εtriatal dopamine release by linopirdine and L-dopa suggeεtε that a combination therapy of Sinemet^® (L-dopa/carbidopa) or Sinemet^® CR, with a compound of Formula (I) , by example with linopirdine, iε eεpecially beneficial in treating Parkinεon's Diseaεe. Therefore, the combined effects of linopirdine or other dopamine release enhancers and Sinemet^® may prove more useful in partial restoration of neurotransmisεion in Parkinson's disease than each therapy alone. In addition, the cognitive enhancing properties of linopirdine, as described by Cook et al., Drug Devel . Res . 19:301-314 (1990) and Brioni et al., Pharmacol . Biochem. Behav. 44:37-43 (1990), may ameliorate some of the cognitive deficits associated with late stage Parkinson's diseaεe.

The disclosureε of all of the referenceε cited herein are hereby incorporated herein by reference in their entirety. - Variouε modificationε of the invention in addition to thoεe εhown and deεcribed herein will be apparent to thoεe εkilled in the art from the foregoing deεcription. Such modificationε are alεo intended to fall within the εcope of the appended claimε.

Claims

WHAT IS CLAIMED IS:

1. A method of treating a neurological disorder associated with a neurotransmitter deficit in a mammal compriεing administering to a mammal a therapeutically effective amount of a combination of: (i) at least one neurotransmitter release enhancer; (ii) at least one dopamine precursor; and (iii) at least one aromatic amino acid decarboxylase inhibitor.

2. A method of Claim 1 wherein said neurotransmitter release enhancer is a compound of the formula :

. '

(I) or a pharmaceutically acceptable salt thereof, wherein: X and Y are taken together to form a saturated or unsaturated carbocyclic first ring and the shown carbon in said ring iε α to at leaεt one additional carbocyclic aromatic ring fuεed to the firεt ring, the total number of carbocyclic fuεed ringε being 3-5, the sole heterocyclic substituents on said fused rings being Het¹ and Het²; and one of Het¹ or Het² is 2, 3, or 4-pyridinyl optionally subεtituted with a halogen atom or trifluoromethyl, or 2, 4, or 5-pyrimidinyl and the other iε selected from

(a) 2, 3, or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl,

(b) 2, 4, or 5-pyrimidinyl, (c) 2-pyrazinyl,

(d) 3 or 4-pyridezinyl,

(e) 3 or 4-pyrazolyl,

(f) 2 or 3-tetrahydrofuranyl, and

(g) 3-thienyl.

3. A method of Claim 2 wherein said neurotransmitter release enhancer iε a compound of the formula:

(la) wherein: p is 0 or 1;

Z iε 0 or S;

R is Ci-Cio alkyl, C3-C₈ cycloalkyl, 2-pyridyl, 3- pyridyl, 4-pyridyl, or

_;

V,W,X, and Y independently are H, a halogen atom, C₁-C₃ alkyl, OR¹, N0₂, CF₃, CN or NRⁱR²;

R¹ and R² independently are H or C₁-C₃ alkyl;

Het¹ and Het² independently are 6-membered heterocyclic aromatic rings containing one or two nitrogen atoms as part of the ring optionally subεtituted with one εubεtituent εelected from the group C₁-C₃ alkyl, a halogen atom, OR¹ or NR¹R²; or an N-oxide or pharmaceutically acceptable acid addition εalt thereof. 4. A method of Claim 2 wherein εaid neurotranεmitter release enhancer is a compound of the formula:

( lb) or a pharmaceutically acceptable salt thereof, wherein:

each J, K, L and M independently are N, CR¹, CR5 or CR² with the proviso that when either M₄, M₅ or both is N, then B, D or both cannot be R¹ or R²;

A is (CH2)n. C(=S), O, S(0)ι, S(0)₂, S, NR³, -CH=CH-, -C(=0)-, -CH(OR³)-, C(=NOH)-,

-CH-CH- o'^C\> s % \ / -/ , \_J or CH₂; n is 0, 1, 2 or 3; R¹ and R² independently are H, a halogen atom, alkyl of 2-3 carbon atoms, acetyl, OR³, NO2, CN, NR³R⁴, or fluoroalkyl of 1-3 carbon atoms;

R³ and R⁴ independently are H, alkyl of 1-3 carbon atoms, or acyl;

B and D independently are R¹ or R² or, when A is (CH2)o/ can be taken together to form -CH=CH-, or -CH2-CH2-;

R5 independently is H, or is taken together with R¹ to form a 2,3- or a 3,4-fused benzo ring;

one of Het¹ or Het² iε 2, 3, or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl, or 2, 4 or 5-pyrimidinyl and the other is selected from:

(a) 2, 3 or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl,

(b) 2, 4, or 5-pyrimidinyl, (c) 2-pyrazinyl,

(d) 3 or 4-pyridazinyl,

(e) 3 or 4-pyrazolyl,

(f) 2 or 3-tetrahydrofuranyl, and

(g) 3-thienyl. 5. A method of Claim 2 wherein said neurotransmitter release enhancer is a compound of the formula:

(IC) or a pharmaceutically acceptable salt thereof, wherein;

a iε a εingle bond or double bond;

X and Y taken together when a is a single bond is

-CH=CH-CH=CH-;

I I

W Z X and Y taken together when a is a double bond is

-CH2- (CH2-)nCH-CH-;

W

where n is 1 or 2;

Q when a is a εingle bond iε =0; =S; H2, sNOR¹,

-0(CH2)pO-, -S(CH2)pS-, -(H)F, = NOR¹, F2; (R÷MOR³, iCRiR²; Q, when a is a double bond is R², OR³ or a halogen atom;

p is 2 or 3;

R¹ is H, alkyl of 1-10 carbon atoms, cycloalkyl of 3-8 carbon atoms, or

_R2 i_{s R}l_{f Nθ2( CNf} CO2R¹, C(=0)R¹ or a halogen atom;

R³ iε C(=0)R¹ or CR¹;

W, Z independently are H, a halogen atom, alkyl of 1-3 carbon atoms, OR³, NO2, CF3, fluoroalkyl, CN, or N(R¹>2; and

one of Het¹ or Het² is 2, 3, or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl, or 2,

4, or

5-pyrimidinyl and the other is εelected from (a) 2, 3, or 4-pyridinyl optionally εubεtituted with a halogen atom or trifluoromethyl, , (b) 2, 4, or 5-pyrimidinyl,

(c) 1-pyrazinyl,

(d) 3 or 4-pyridazinyl,

(e) 3 or 4-pyrazolyl,

(f) 2 or 3-tetrahydrofuranyl, and

(g) 3-thienyl.

6. A method of Claim 2 wherein said neurotransmitter release enhancer is a compound of the formula:

(Id) or a pharmaceutically acceptable salt thereof, wherein:

a is a εingle bond or double bond;

b iε a εingle bond or double bond, provided one of a or b is a εingle bond;

X independently when a and b are single bonds is: 0,S, CRⁱR², CQ, CRⁱOR³ or -(CH₂)N- where N is 1-3, N(CH₂)_PR³ where p is 0-1, or NC(=0)R¹;

X independently when one of a or b is a double bond is CR², COR³, or N;

V independently when b is a single bond is CQ;

V independently when b is a double bond is CR2 or COR3;

1 1

A is a single bond, -(-CR₂-⁾ _n ^~' ^_x~' ~⁽-CR₂-)_n-X, where n is 1, 2 or 3 and

X is aε defined above when a is a single bond;

Y >and V taken together when A and b are single bonds is

-C=C-CH=CH-; / \ W Z

V and V taken together when A is a εingle bond iε -CH2-

(CH2)m-CH2~ where m iε 1 or 2; provided that when Y and V are connected, then V and X are not connected;

V and X taken together when b is a double bond is C- CH=CH-CH=CH-C-, or, C- (-CH2-)p-C; provided that when V and X are connected, then Y and V are not connected;

Q when a is a single bond is =0, =S, H2, =NOR¹, -0(CH2)pO-, -S(CH2)pS-, -(H)F, F², (R^OR³, =CR¹R²;

Q when a is a double bond is R², OR³ or a halogen atom;

p is 2 or 3;

R¹ is H, alkyl of 1-10 carbon atoms, cycloalkyl of 3-8 carbon atoms, or

R² is R¹, NO2, CN, CN2R¹, C(=0)R¹ or a halogen atom;

R³ is R¹ or C(=0)R¹;

W, Y, Z independently are H, a halogen atom, alkyl of 1- 3 carbon atoms, OR³, NO2, CF3, fluoroalkyl, CN, or

N(R¹)2; and one of Het¹ or Het² is 2, 3, or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl, or 2, 4, or 5-pyrimidinyl and the other is εelected from (a) 2, 3, or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl,,

(b) 2, 4, or 5-pyrimidinyl,

(c) 2-pyrazinyl,

(d) 3, or 4-pyridazinyl, (e) 3, or 4-pyrazolyl,

(f) 2, or 3-tetrahydrofuranyl, and

(g) 3-thienyl.

7. A method of Claim 2 wherein: Het¹ or Het² is 2-, 3-,or 4-pyridinyl or 2-, 4-, or 5- pyrimidinyl and the other iε 2-, 3-, or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl, 2-, 4-, or 5-pyrimidinyl, or 2-, or 3-tetrahydrofuranyl.

8. A method of Claim 2 wherein: Het¹ and Het² is selected from:

(a) 4-pyridinyl optionally εubεtituted with a halogen atom or trifluoromethyl and 4-pyridinyl optionally εubstituted with a halogen atom or trifluoromethyl,

(b) 4-pyrimidinyl and 4-pyrimidinyl,

(c) 4-pyridinyl optionally subεtituted with a halogen atom or trifluoromethyl and 4-pyrimidinyl,

(d) 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl and 3-tetrahydrofuranyl.

9. A method of Claim 3 wherein: p is 0;

Z is O;

W, X, Y and Z are hydrogen;

R iε methyl, phenyl or m-chlorophenyl; and

Het¹ and Het² is each pyridinyl attached by a ring carbon atom.

10. A method of Claim 2 wherein εaid neurotranεmitter release enhancer is εelected from: 3,3- biε (4-pyridinylmethyl) -l-phenylindolin-2-one and 10,10- biε ( (2-fluoro-4-pyridinyl)methyl) -9 (10H) anthracenone.

11. A method of Claim 1 wherein said dopamine precursor is 3- (3,4-dihydroxyphenyl) -L-alanine.

12. A method of Claim 2 wherein εaid dopamine precurεor iε 3-(3,4-dihydroxyphenyl)-L-alanine.

13. A method of Claim 1 wherein said aromatic amino acid decarboxylate inhibitor is (-)-L-α-hydrazino- α -methyl-β-(3,4-dihydroxyphenyl)propanoic acid monohydrate.

14. A method of Claim 2 wherein said aromatic amino acid decarboxylate inhibitor iε (-)-L-α-hydrazino- α-methyl-β- (3,4-dihydroxyphenyl)propanoic acid monohydrate.

15. A method of Claim 1 wherein said dopamine precursor iε 3- (3,4-dihydroxyphenyl)-L-alanine and said aromatic amino acid decarboxylate inhibitor is (-)-L-α- hydrazino-α-methyl-β- (3,4-dihydroxyphenyl)propanoic acid monohydrate.

16. A method of Claim 2 wherein said dopamine precursor is 3- (3,4-dihydroxyphenyl) -L-alanine and said aromatic amino acid decarboxylate inhibitor is (-)-L-α- hydrazino-α-methyl-β- (3,4-dihydroxyphenyl)propanoic acid monohydrate.

17. A method of Claim 1 wherein εaid neurotransmitter release enhancer is selected from: 3,3- biε(4-pyridinylmethyl) -l-phenylindolin-2-one and 10,10- biε( (2-fluoro-4-pyridinyl)methyl)-9 (10H) anthracenone, εaid dopamine precursor is 3- (3,4-dihydroxyphenyl)-L- alanine, and said aromatic amino acid decarboxylate inhibitor is (-)-L-α-hydrazino-α -methyl-β- (3,4- dihydroxyphenyl)propanoic acid monohydrate.

18. A method of Claim 1 wherein εaid neurotransmitter deficit is dopamine.

19. A method of Claim 2 wherein said neurotransmitter deficit is dopamine.

20. A method of Claim 1 wherein said neurological diεorder iε Parkinεon'ε Diεease.

21. A method of Claim 2 wherein said neurological disorder is Parkinson'ε Disease.

22. A method of Claim 1 wherein said mammal is a human.

23 A method of Claim 2 wherein εaid mammal is a human.

24. A method of Claim 1 wherein said administration iε oral.

25. A method of Claim 2 wherein said administration is oral.

26. A pharmaceutical composition comprising a therapeutically effective amount of a combination of: (i) at leaεt one neurotranεmitter releaεe enhancer; (ii) at least one dopamine precursor; and (iii) at least one aromatic amino acid decarboxylase inhibitor.

27. A composition of Claim 26 wherein said neurotransmitter release enhancer is a compound of the formula:

(I) or a pharmaceutically acceptable salt thereof, wherein:

X and Y are taken together to form a saturated or unsaturated carbocyclic first ring and the shown carbon in εaid ring iε α to at leaεt one additional carbocyclic aromatic ring fuεed to the firεt ring, the total number of carbocyclic fuεed rings being 3-5, the sole heterocyclic subεtituents on said fused rings being Het¹ and Het²; and one of Het¹ or Het² is 2, 3, or 4-pyridinyl optionally εubstituted with a halogen atom or trifluoromethyl, or 2, 4, or 5-pyrimidinyl and the other is selected from (a) 2, 3, or 4-pyridinyl optionally εubεtituted with a halogen atom or trifluoromethyl,

(b) 2, 4, or 5-pyrimidinyl,

(c) 2-pyrazinyl, (d) 3 or 4-pyridazinyl,

(e) 3 or 4-pyrazolyl,

(f) 2 or 3-tetrahydrofuranyl, and

(g) 3-thienyl.

28. A composition of Claim 27 wherein said neurotransmitter release enhancer iε a compound of the formula:

[la) wherein: p is 0 or 1;

Z iε O or S; R iε Ci-Cio alkyl, C3-C₈ cycloalkyl, 2-pyridyl, 3- pyridy1, 4-pyridyl, or

V,W,X, and Y independently are H, a halogen atom, C₁-C₃ alkyl, OR¹, N0₂, CF3, CN or NRiR²;

R¹ and R² independently are H or C₁-C₃ alkyl;

Het¹ and Het² independently are 6-membered heterocyclic aromatic ringε containing one or two nitrogen atomε as part of the ring optionally substituted with one subεtituent selected from the group C₁-C₃ alkyl, a halogen atom, OR¹ or NR^-R²; or an N-oxide or pharmaceutically acceptable acid addition salt thereof.

29. A compoεition of Claim 27 wherein εaid neurotranεmitter releaεe enhancer iε a compound of the formula:

(lb) or a pharmaceutically acceptable salt thereof , wherein:

each J, K, L and M independently are N, CR¹, CR^ or CR² with the proviso that when either M₄, M₅ or both is N, then B, D or both cannot be R¹ or R²;

A is (CH2)n» C(=S), 0, S(0)ι, S(0)₂, S, NR³, -CH=CH-, -C(=0)-, -CH(OR³)-, C(=NOH)-,

-CH-CH-

\ /

\_/ . \_ or CH₂; n is 0, 1, 2 or 3;

R¹ and R² independently are H, a halogen atom, alkyl of 2-3 carbon atomε, acetyl, OR³, NO2, CN, NR³R⁴, or fluoroalkyl of 1-3 carbon atomε; R³ and R⁴ independently are H, alkyl of 1-3 carbon atomε, or acyl;

B and D independently are R¹ or R² or, when A is (CH2)o can be taken together to form -CH=CH-, or -CH2-CH2-;

R^ independently is H, or is taken together with R¹ to form a 2,3- or a 3, 4-fused benzo ring;

one of Het¹ or Het² is 2, 3, or 4-pyridinyl optionally εubεtituted with a halogen atom or trifluoromethyl, or 2, 4 or

5-pyrimidinyl and the other iε εelected from: (a) 2, 3 or 4-pyridinyl, _λ (b) 2, 4, or 5-pyrimidinyl,

(c) 2-pyrazinyl,

(d) 3 or 4-pyridazinyl,

(e) 3 or 4-pyrazolyl,

(f) 2 or 3-tetrahydrofuranyl, and (g) 3-thienyl.

30. A compoεition of Claim 27 wherein said neurotransmitter release enhancer iε a compound of the formula:

( IC ) or a pharmaceutically acceptable salt thereof, wherein;

a iε a single bond or double bond;

X and Y taken together when a is a single bond iε

-CH=CH-CH=CH-;

W Z X and Y taken together when a iε a double bond iε

-CH2-(CH2-)_nCH-CH-;

W

where n is 1 or 2;

Q when a is a εingle bond iε =0; =S; H2, =NOR¹,

-0(CH2)pO-, -S(CH2)pS-, -(H)F, = NOR¹, F2; (R^OR³, =CR¹R²;

Q, when a iε a double bond iε R², OR³ or a halogen atom; p is 2 or 3 ;

R¹ is H, alkyl of 1-10 carbon atoms, cycloalkyl of 3-8 carbon atoms, or

R² is R¹, NO2, CN, CO2R¹, C(=0)R¹ or a halogen atom;

R³ is C(=0)R¹ or CR¹;

W, Z independently are H, a halogen atom, alkyl of 1-3 carbon atoms, OR³, O2, CF3, fluoroalkyl, CN, or N(R¹)2; and

one of Het¹ or Het² is 2, 3, or 4-pyridinyl optionally subεtituted with a halogen atom or trifluoromethyl, or 2, 4, or

5-pyrimidinyl and the other iε εelected from

(a) 2, 3, or 4-pyridinyl optionally εubstituted with a halogen atom or trifluoromethyl, ,

(b) 2, 4, or 5-pyrimidinyl, (c) 1-pyrazinyl, (d) 3 or 4-pyridazinyl,

(e) 3 or 4-pyrazolyl,

(f) 2 or 3-tetrahydrofuranyl, and

(g) 3-thienyl.

31. A composition of Claim 27 wherein said neurotransmitter release enhancer is a compound of the formula:

(Id) or a pharmaceutically acceptable salt thereof, wherein:

a is a εingle bond or double bond;

b iε a single bond or double bond, provided one of a or b iε a εingle bond;

X independently when a and b are εingle bondε is:

0,S, CRiR², CQ, CRiOR³ or -(CH₂)N- where N is 1-3, N(CH₂)_pR³ where p is 0-1, or NC(=0)R¹; X independently when one of a or b is a double bond is CR², COR³, or N;

V independently when b is a single bond is CQ;

V independently when b is a double bond is CR2 or C0R3;

1 1

A is a single bond, -(-CR₂-)_n-, -X-, -(-CR₂-)_n-X/ where

n is 1, 2 or 3 and

X is aε defined above when a iε a εingle bond;

Y and V taken together when A and b are εingle bonds is

-C=C-CH=CH-; / \ W Z

Y and V taken together when A is a single bond is -CH2- (CH2)m-CH2~ where m is 1 or 2; provided that when Y and V are connected, then V and X are not connected;

V and X taken together when b is a double bond is C-

CH=CH-CH=CH-C-, or, C- (-CH2-)p-C; provided that when V and X are connected, then Y and V are not connected; Q when a iε a εingle bond iε =0, =S, H2, =NOR¹,

-0(CH2)pO-, -S(CH2)pS-, -(H)F, F², (R^-JOR³, =CR¹R²;

Q when a is a double bond is R², OR³ or a halogen atom;

p is 2 or 3;

R¹ iε H, alkyl of 1-10 carbon atoms, cycloalkyl of 3-8 carbon atoms, or

R² is R¹, O2, CN, CN2R¹, C(=0)R¹ or a halogen atom;

R³ is R¹ or C(=0)R¹;

W, Y, Z independently are H, a halogen atom, alkyl of 1- 3 carbon atoms, OR³, NO2/ CF3, fluoroalkyl, CN, or N(R¹)2; and

one of Het¹ or Het² is 2, 3, or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl, or 2, 4, or 5-pyrimidinyl and the other is selected from (a) 2, 3, or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl,,

(b) 2, 4, or 5-pyrimidinyl,

(c) 2-pyrazinyl, (d) 3, or 4-pyridazinyl,

(e) 3, or 4-pyrazolyl,

(f) 2, or 3-tetrahydrofuranyl, and

(g) 3-thienyl.

32. A composition of Claim 27 wherein: Het¹ or Het² is 2-, 3-,or 4-pyridinyl or 2-, 4-, or 5- pyrimidinyl and the other is 2-, 3-, or 4- ^' pyridinyl, 2-, 4-, or 5-pyrimidinyl, or 2-, or 3- tetrahydrofuranyl.

33. A composition of Claim 27 wherein: Het¹ and Het² iε εelected from:

(a) 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl and 4-pyridinyl optionally subεtituted with a halogen atom or trifluoromethyl, (b) 4-pyrimidinyl and 4-pyrimidinyl,

(c) 4-pyridinyl optionally εubεtituted with a halogen atom or trifluoromethyl and 4-pyrimidinyl, (d) 4-pyridinyl optionally subεtituted with a halogen atom or trifluoromethyl and 3-tetrahydrofuranyl.

34. A compoεition of Claim 28 wherein: p iε 0;

Z is 0;

W, X, Y and Z are hydrogen;

R iε methyl, phenyl or m-chlorophenyl; and

Het¹ and Het² iε each pyridinyl attached by a ring , carbon atom.

35. A compoεition of Claim 28 wherein εaid neurotransmitter release enhancer is selected from: 3,3- bis(4-pyridinylmethyl)-l-phenylindolin-2-one and 10,10- biε( (2-fluoro-4-pyridinyl)methyl)-9 (10H) anthracenone.

36. A compoεition of Claim 26 wherein said dopamine precursor is 3- (3,4-dihydroxyphenyl)-L-alanine.

37. A compoεition of Claim 27 wherein said dopamine precursor iε 3- (3,4-dihydroxyphenyl)-L-alanine.

38. A compoεition of Claim 26 wherein said aromatic amino acid decarboxylate inhibitor is (-)-L-α- hydrazino-α-methyl-β- (3,4-dihydroxyphenyl)propanoic acid monohydrate.

39. A composition of Claim 27 wherein said aromatic amino acid decarboxylate inhibitor iε (-)-L-α- hydrazino-α -methyl-β- (3, -dihydroxyphenyl)propanoic acid monohydrate.

40. A compoεition of Claim 26 wherein said dopamine precursor is 3- (3,4-dihydroxyphenyl)-L-alanine and the aromatic amino acid decarboxylate inhibitor is (-) -L-α-hydrazino-α-methyl-β-(3,4- dihydroxybenzene)propanoic acid monohydrate.

41. A composition of Claim 27 wherein εaid dopamine precurεor iε 3- (3,4-dihydroxyphenyl)-L-alanine and εaid aromatic amino acid decarboxylate inhibitor iε (-) -L-α-hydrazino-α -methyl-β- (3,4- dihydroxyphenyl)propanoic acid monohydrate.

42. A composition of Claim 26 wherein said neurotransmitter release enhancer iε εelected from: 3,3- biε (4-pyridinylmethyl) -l-phenylindolin-2-one and 10,10- biε ( (2-fluoro-4-pyridinyl)methyl) -9 (10H) anthracenone, said dopamine precursor is 3- (3, 4-dihydroxyphenyl) -L- alanine, and said aromatic amino acid decarboxylate inhibitor is (-) -L-α-hydrazino-α -methyl-β- (3, 4- dihydroxyphenyl)propanoic acid monohydrate.

^v 43. A pharmaceutical kit comprising: (i) at least one neurotransmitter release enhancer; (ii) at least one dopamine precursor; and (iii) at least one aromatic amino acid decarboxylaεe inhibitor.

44. A pharmaceutical kit of Claim 43 wherein said neurotransmitter release enhancer iε a compound of the formula

(I) or a pharmaceutically acceptable εalt thereof, wherein:

X and Y are taken together to form a saturated or unsaturated carbocyclic first ring and the shown carbon in said ring is α to at least one additional carbocyclic aromatic ring fused to the first ring, the total number of carbocyclic fused rings being 3-5, the sole heterocyclic εubεtituentε on εaid fuεed ringε being Het¹ and Het²; and one of Het¹ or Het² is 2, 3, or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl, or 2, 4, or 5-pyrimidinyl and the other is selected from ^' (a) 2, 3, or 4-pyridinyl optionally substituted with a halogen atom or trifluoromethyl,

(b) 2, 4, or 5-pyrimidinyl,

(c) 2-pyrazinyl,

(d) 3 or 4-pyridazinyl, (e) 3 or 4-pyrazolyl,

(f) 2 or 3-tetrahydrofuranyl, and

(g) 3-thienyl.

45. A pharmaceutical kit of Claim 44 wherein said neurotranεmitter release enhancer iε εelected from: 3,3- biε(4-pyridinylmethyl) -l-phenylindolin-2-one and 10,10- biε( (2-fluoro-4-pyridinyl)methyl)-9 (10H) anthracenone.

46. A pharmaceutical kit of Claim 43 wherein said dopamine precursor is 3-(3,4-dihydroxyphenyl)-L-alanine.

47. A pharmaceutical kit of Claim 43 wherein said aromatic amino acid decarboxylate inhibitor is (-) -L-α- hydrazino-α-methyl-β- (3,4-dihydroxyphenyl)propanoic acid monohydrate.

^' 48. A pharmaceutical kit of Claim 43 wherein εaid neurotraεmitter release enhancer is selected from: 3,3- biε(4-pyridinylmethyl)-l-phenylindolin-2-one and 10,10- biε( (2-fluoro-4-pyridinyl)methyl)-9 (10H) anthracenone, εaid dopamine precursor is 3- (3,4-dihydroxyphenyl)-L- alinine, and said aromatic amino acid decarboxylate inhibitor is (-)-L-α-hydrazino-α-methyl-β- (3,4- dihydroxyphenyle)propanoic acid monohydrate.

49. A pharmaceutical kit of Claim 43 further comprising conventional kit components.

50. A pharmaceutical kit of Claim 48 further comprising conventional kit components.