WO2020051644A1

WO2020051644A1 - Treatment of peripheral nervous tissue inflammation

Info

Publication number: WO2020051644A1
Application number: PCT/AU2019/050982
Authority: WO
Inventors: Graham Kelly; Benny EVISON
Original assignee: Norbio No. 2 Pty Ltd
Priority date: 2018-09-13
Filing date: 2019-09-13
Publication date: 2020-03-19

Abstract

The invention relates to treating or minimising inflammation of peripheral neural tissue in an individual requiring said treatment utilising a compound according to general formula (I), (II), (III), (IV) and/or (V) described herein.

Description

Treatment of peripheral nervous tissue inflammation

Field of the invention

The invention relates to treatment of diseases or conditions associated with inflammation of peripheral neural tissue.

Background of the invention

Reference to any prior art in the specification is not an acknowledgment or suggestion that this prior art forms part of the common general knowledge in any jurisdiction or that this prior art could reasonably be expected to be understood, regarded as relevant, and/or combined with other pieces of prior art by a skilled person in the art.

Inflammation is a natural response by the body to tissue damage and infection. It is an essential step in repairing damage. Inflammation is fundamentally a protective cellular response aimed at removing injurious stimuli and initiating the healing process. These stimuli may arise from acute or chronic injury. The inflammatory process involves a complex interplay of multiple components and is tightly regulated by the body so that it responds, repairs and then retreats. Control over the inflammatory process may be disrupted such that the inflammatory process becomes dysfunctional, essentially turning into a disease process itself on top of the original insult. The development of anti- inflammatory drugs has been driven by the need to counteract abnormal over-expression of inflammation.

The body initiates and integrates this complex interplay between the different responding cells and the different stages through a complex system of chemical messengers. There are many different kinds of chemical messengers including, but not limited to, cytokines, interleukins, growth factors and hormones.

An important class of signalling molecule related to inflammation are the eicosanoids, which derive from oxidation of fatty acids such as arachidonic acid. There are multiple families of eicosanoids, including most prominently the prostaglandins, prostacyclins, leukotrienes, and thromboxane A2 (TXA2). The place of these eicosanoid molecules in the inflammatory cascade is summarised in Figure 1 . The prostaglandins include metabolites of arachidonic acid such as PGG2, PGH2, PGE2, PGD2, PGF2, PGA2 and PGB2. The prostacyclins include metabolites such as PG12. The leukotrienes include metabolites such as LTA4, LTB4, LTC4, LTD4 and LTE4. The thromboxanes include the inactive metabolite thromboxane B2 (TXB2). Within each of the first 3 categories (prostaglandins, prostacyclins and leukotrienes) there are different sub- families of metabolites, many of which have diametrically opposed biological functions. This serves to highlight the complex equilibrium that underlies the inflammatory process, which itself serves to highlight the inherent drawbacks of developing drugs to treat chronic inflammation without taking into consideration the effect of inhibiting some pathways on this complex interplay.

There are 3 main classes of anti-inflammatory drugs - corticosteroids, non- steroidal drugs, and specific inhibitors.

Cortisone and prednisone are the body’s natural anti-inflammatory hormones. Synthetic analogs include dexamethasone, hydrocortisone and prednisolone. Steroidal anti-inflammatories are the most effective therapies for most cases of chronic inflammation. They work predominantly by suppressing genes that have been upregulated by proinflam matory transcription factors. These genes encode for the main proinflammatory factors - cytokines, chemokines, adhesion molecules, inflammatory enzymes, receptors and proteins. While it generally is accepted that the corticosteroids provide the most potent and the best form of controlling inflammation in a way that is least likely to disrupt the equilibrium between multiple interrelated aspects of the inflammatory cascade, their use is limited due to a range of side-effects associated with chronic dosing including suppression of the immune system, water retention (oedema), sleeplessness, and mental disorders. These side-effects mean that corticosteroid use generally is limited to short periods of treatment.

The non-steroidal anti-inflammatory drugs (NSAIDs) are the most commonly prescribed anti-inflammatory drugs. Although not as potent as the corticosteroids and less forgiving of the equilibrium between different aspects of the inflammatory cascade, they nevertheless have fewer side-effects compared to the corticosteroids and therefore are suitable for chronic administration. Aspirin, indomethacin, ibuprofen, paracetamol and diclofenac are examples of the most commonly-used NSAIDs. They work by blocking enzymes known as cyclooxygenase 1 and cyclooxygenase 2 (COX 1 and 2 inhibitors), blocking the production of the majority of arachidonic metabolites (prostaglandins, prostacyclins, leukotrienes and thromboxanes). While NSAIDs are without the serious side-effects associated with corticosteroid use, their primary drawback is that they are generally regarded as a blunt instrument, blocking all eicosanoid synthesis regardless of the individual nature of the inflammatory process. This disrupts the equilibrium between opposing eicosanoids, depriving the body of beneficial functions, such as the role of prostacyclins in protecting the lining of the gut from acidic digestive juices.

The third class of anti-inflammatory drugs are those designed to target single pro- inflammatory factors, whether they be eicosanoids or any one of the myriad of non- eicosanoid chemical messengers such as the interleukins. The use of such drugs typically is limited to specific inflammatory conditions where a single chemical factor is known to be prominent. An example is the drug adalimumab (Humira™) which is a specific inhibitor of TNFa and is used in the treatment of inflammation associated with rheumatoid arthritis. Another example includes drugs designed to block the production of thromboxane A2 or to block its ability to bind to its receptor. W02006108212 discloses the use of isoflavonoid compounds for the treatment of systemic inflammatory diseases, particularly inflammatory bowel disease, and demonstrates that the compounds selectively inhibit thromboxane A2 synthase.

Inflammation of neural tissue shares some components of inflammation in the rest of the body, but also has some unique aspects, leading to a growing view that inflammation of neural tissue should be seen as a discrete biology.

Inflammation generally is understood to be a key element in the pathophysiology of a wide range of conditions of the peripheral nervous system (PNS).

Inflammation may accompany acute injury in the form of invasive injury of peripheral neural tissue including external trauma, and ischaemia/reperfusion injury.

Inflammation accompanies bacterial or viral infiltration of peripheral neural tissue.

Inflammation accompanies chronic conditions of the PNS including diabetic peripheral neuropathy, ankylosing spondylitis, Guillain-Barre Syndrome, Sjorgen’s Syndrome, systemic lupus erythematosus, rheumatoid arthritis, gouty arthritis, otitis media, psoriasis, psoriatic arthritis, polymyositis, dermatomyositis, hidradenitis supperativa, intervertebral disc disease, chronic inflammatory demyelinating polyneuropathy, sciatica, necrotizing vasculitis, and chemotherapy-induced peripheral neuropathy.

There are three main challenges to the successful treatment of chronic inflammation of peripheral neural tissue: (i) the uniqueness of inflammation of peripheral neural tissue compared to systemic inflammation; (ii) the likely idiosyncratic nature of the inflammatory process accompanying each specific disease state; and (iii) the blood-nerve barrier (BNB).

In terms of the uniqueness of inflammation of peripheral neural tissue, peripheral neural tissue is comprised of unique cellular networks, which modulate pro- and anti- inflammatory mediators specific to the PNS system. In peripheral neural tissue, proinflam matory mediators are initially produced by Schwann cells which are unique to the nervous system and suggest pro- and anti- inflammatory mechanisms of action that are specific to peripheral neural tissue.

One of the challenges with treating inflammation of peripheral neural tissue, as compared to non-neural inflammation, is that some eicosanoids have been observed to have pro-inflammatory effect in some neural tissue and anti-inflammatory effect in non- neural tissue. Prostaglandin E 2 (PGE2) is one example [Cudaback E. et. al. 2014 Biochem Pharmacol 88(4):565-572; Howes L G et al. 2007 Expert Opin. Investiq. Druqs

16(8): 1255-1266] It is believed that these effects are in part a consequence of the multiple receptor types that can be bound by a specific eicosanoid ligand, and the cells on which those receptors are expressed.

In terms of the ability of the drug to gain access to peripheral neural tissue, another challenge with treating inflammation of peripheral neural tissue as compared to non- neural inflammation is that for drug targets in the PNS, the BNB can be problematic because of the potential to restrict or prevent drugs from reaching their site of action. Tight junctions between endothelial cells that line the surface of blood vessels at the BNB interface restrict the passage of solutes from the circulatory system to the nervous system. The BNB is comprised of tight junctions between endothelial cells that line the surface of blood vessels in the PNS which isolate the perineurium from the blood. NSAIDs, for example, are restricted from entering the PNS by the BNB and therefore have insufficient efficacy in treating severe pain. Alternative treatments for peripheral neuropathy in particular, such as opioids, antidepressants, anticonvulsants, and topical agents, manage symptoms not the underlying pathology.

There is therefore a need for improved treatments of diseases or conditions associated with inflammation of peripheral neural tissue by addressing one or more of the following matters:

• The ability of the drug to access the PNS at levels that are therapeutically relevant.

• The ability to target the key components of the inflammatory process in the specific PNS disorder and to do so with reduced disruption to the homeostasis of the PNS.

• The ability to successfully treat the inflammatory process in peripheral neural tissue with reduced disruption to the homeostasis of the rest of the body.

Summary of the invention

In one embodiment there is provided a method for treating or minimising inflammation of peripheral neural tissue in an individual requiring said treatment including:

(i) providing an individual for whom treatment or minimisation of inflammation of peripheral neural tissue is required;

(ii) administering a therapeutically effective amount of a compound of general formula (I) to the individual

wherein D is halo;

Ri is H, C1-10 alkyl, aryl, arylalkyl or RACO where RA is C1-10 alkyl or an amino acid; R2 is H, OH or OR6; R3 is H, OH, or RB where RB is an amino acid or CORA where RA is as previously defined;

A and B together with the atoms between them form a six membered ring selected from the group

or A is -ORe and B is

wherein R4 is H, CORD where RD is H, OH, C1-10 alkyl or an amino acid, CO2RC where Rc is C1-10 alkyl, CORE where RE is H, C1-10 alkyl or an amino acid, COOH, CORc where Rc is as previously defined, or CONHRE where RE is as previously defined;

R5 is H, CO2RC where Rc is as previously defined, or CORCORE where Rc and RE are as previously defined, and where the two R5 groups are attached to the same group they are the same or different, or

R5 is substituted or unsubstituted aryl or substituted or unsubstituted heteroaryl; R6 is C1-10 alkyl, aryl or arylalkyl;

X is 0, N or S;

Y is

where RZA and RZB are each independently H, OH or OR7; with the proviso that at least one of R7A and R7B is OH or OR7; wherein R7 is C1-10 alkyl, aryl or arylalkyl; and “ =====” represents either a single bond or a double bond; wherein said administration minimises or treats inflammation of peripheral neural tissue in the individual.

In one embodiment there is provided a method for treating or minimising inflammation of peripheral neural tissue in an individual requiring said treatment including: (i) providing an individual for whom treatment or minimisation of inflammation of peripheral neural tissue is required;

(ii) administering a therapeutically effective amount of a compound of general formula (II) to the individual:

wherein D is halo; Ri is H, or RACO where RA is C1-10 alkyl or an amino acid;

R2 is H, OH, or RB where RB is an amino acid or CORA where RA is as previously defined;

A and B together with the atoms between them form the group:

wherein

R4 is H, CORD where RD is H, OH, C1-10 alkyl or an amino acid, CO2RC where Rc is C1-10 alkyl, CORE where RE is H, C1-10 alkyl or an amino acid, COOH, CORc where Rc is as previously defined, or CONHRE where RE is as previously defined;

R5 is substituted or unsubstituted aryl or substituted or unsubstituted heteroaryl;

X is 0, N or S;

Y is

where R7 is H, or C1-10 alkyl; and

“ =====” represents either a single bond or a double bond; wherein said administration minimises or treats inflammation of peripheral neural tissue in the individual.

(i) providing an individual for whom treatment or minimisation of inflammation of peripheral neural tissue is required; (ii) administering a therapeutically effective amount of a compound of general formula (III) to the individual:

wherein

D is halo;

“ =====” represents either a single bond or a double bond;

R1 is H, C1-10 alkyl, aryl, arylalkyl or RACO where RA is C1-10 alkyl or an amino acid; R5 is O when is a double bond, or R5 is hydrogen or hydroxyl when is a single bond;

Y is

where RZA and RZB are each independently H, OH or OR7; with the proviso that at least one of R7A and R7B is OH or OR7; and wherein R7 is C1-10 alkyl, aryl or arylalkyl; wherein said administration minimises or treats inflammation of peripheral neural tissue in the individual.

(ii) administering a therapeutically effective amount of a compound of general formula (IV) to the individual:

wherein

D is halo, and wherein said administration minimises or treats inflammation of peripheral neural tissue in the individual. In one embodiment there is provided a method for treating or minimising inflammation of peripheral neural tissue in an individual requiring said treatment including:

(i) providing an individual for whom treatment or minimisation of inflammation of peripheral neural tissue is required; (ii) administering a therapeutically effective amount of a compound of general formula (V) to the individual:

wherein

D is halo, and wherein said administration minimises or treats inflammation of peripheral neural tissue in the individual.

In one embodiment, the compound is compound (1 ):

In some aspects of the present invention, the compounds may be present as racemic mixtures. In other aspects, specific enantiomers will be favoured. In one embodiment, therefore, the present invention utilises one of the following enantiomers:

In one embodiment, the compound of the present invention is

In another embodiment, the compound of the present invention is

In another embodiment there is provided a compound of any one of general formula (I), (II), (III), (IV) and/or (V), preferably compound (1 ), for use in a method of minimising or treating inflammation of peripheral neural tissue in an individual.

In another embodiment there is provided use of a compound of any one of general formula (I), (II), (III), (IV) and/or (V), preferably compound (1 ), in the manufacture of a medicament for minimising or treating inflammation of peripheral neural tissue in an individual.

In the above described embodiments, the inflammation of peripheral neural tissue may be associated with diabetic peripheral neuropathy, ankylosing spondylitis, Guillain- Barre Syndrome, Sjorgen’s Syndrome, systemic lupus erythematosus, rheumatoid arthritis, gouty arthritis, otitis media, psoriasis, psoriatic arthritis, polymyositis, dermatomyositis, hidradenitis supperativa, intervertebral disc disease, chronic inflammatory demyelinating polyneuropathy, sciatica, necrotizing vasculitis, and chemotherapy-induced peripheral neuropathy. In a preferred embodiment, the inflammation of peripheral neural tissue is associated with diabetic peripheral neuropathy. In the above described embodiments, the inflammation of peripheral neural tissue may be associated with ischemia or reperfusion injury.

In a preferred embodiment, in the above described embodiments, the compound may be administered rectally.

In another embodiment there is provided a composition including:

- an oleaginous base for use in a device for rectal, vaginal or urethral application;

- a compound of general formula (I), (II), (III), (IV) or (V).

Brief description of the figures

Figure 1 : (1a): Comparison of the concentration time profile of Compound (1 ) in plasma and the sciatic nerve following rectal administration at 100mg/kg (API) in male SD rats (N=3/arm) and oral administration at 100mg/kg (API) in male SD rats (N=3/arm). (1 b): The comparison of Figure 1 a depicted with a discontinuous concentration-axis. (1c): The comparison of Figure 1 a depicting only the sciatic nerve concentration over time.

Figure 2: Mean plasma, sciatic nerve, and rectum concentration-time profile of compound (1 ) after rectal dosing of compound (1 ) at 100mg/kg (API) in male SD rats (N=3/arm).

Figure 3: Mean plasma concentration-time profile of compound (1 ) and its glucuronide metabolite following rectal administration of compound (1 ) at 10Omg/kg (API) in male SD rats (N=3/arm).

Detailed description of the embodiments

Reference will now be made in detail to certain embodiments of the invention. While the invention will be described in conjunction with the embodiments, it will be understood that the intention is not to limit the invention to those embodiments. On the contrary, the invention is intended to cover all alternatives, modifications, and equivalents, which may be included within the scope of the present invention as defined by the claims.

One skilled in the art will recognize many methods and materials similar or equivalent to those described herein, which could be used in the practice of the present invention. The present invention is in no way limited to the methods and materials described.

It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text. All of these different combinations constitute various alternative aspects of the invention.

As used herein, except where the context requires otherwise, the term "comprise" and variations of the term, such as "comprising", "comprises" and "comprised", are not intended to exclude further additives, components, integers or steps. A. Compounds & synthetic methods

As discussed above, in one aspect, the invention provides for uses of isoflavonoid compounds for minimising or treating inflammation of peripheral neural tissue. These compounds and relevant synthetic methods are described below.

In one embodiment, the compound for use in the method of minimising or treating inflammation of peripheral neural tissue is a compound of general formula (I)

wherein

D is halo;

Ri is H, C1-10 alkyl, aryl, arylalkyl or RACO where RA is C1-10 alkyl or an amino acid;

R2 is H, OH or OR6; R3 is H, OH, or RB where RB is an amino acid or CORA where RA is as previously defined;

or A is -ORe and B is:

wherein

R5 is H, CO2RC where Rc is as previously defined, or CORCORE where Rc and RE are as previously defined, and where the two R5 groups are attached to the same group they are the same or different, or R5 is substituted or unsubstituted aryl or substituted or unsubstituted heteroaryl; R6 is C1-10 alkyl, aryl or arylalkyl;

X is 0, N or S; Y is

where R7A and R7B are each independently H, OH or OR7; with the proviso that at least one of R7A and R7B is OH or OR7; wherein R7 is C1-10 alkyl, aryl or arylalkyl; and

“ ==” represents either a single bond or a double bond.

In one particularly preferred embodiment of general formula (I), D is bromo.

In one embodiment, A and B together with the atoms between them form the six membered ring:

In one embodiment, Ri is H.

In one embodiment, R2 is H. In one embodiment, R3 is H.

In one embodiment, R₄ is H.

In one preferred embodiment, RZA is H and RZB is OH. In one embodiment, the compound for use in the method of minimising or treating inflammation of peripheral neural tissue is a compound of general formula (II)

wherein

D is halo;

Ri is H, or RACO where RA is C1-10 alkyl or an amino acid;

A and B together with the atoms between them form the group:

wherein

R4 is H, CORD where RD is H, OH, C1-10 alkyl or an amino acid, CO2RC where Rc is Rc is C1-10 alkyl, CORE where RE is H, C1-10 alkyl or an amino acid, COOH, CORc where Rc is as previously defined, or CONHRE where RE is as previously defined;

X is 0, N or S; Y is

where R7 is H, or C1-10 alkyl; and

“ =====” represents either a single bond or a double bond. In one particularly preferred embodiment, D is bromo.

In one embodiment, R2 is H.

In one embodiment, R₄ is H.

In one embodiment, R7 is H.

In another embodiment, the compound for use in the method of minimising or treating inflammation of peripheral neural tissue is a compound of general formula (III)

- a compound of general formula (III):

wherein

D is halo;

“ =====” represents either a single bond or a double bond; R1 is H, C1-10 alkyl, aryl, arylalkyl or RACO where RA is C1-10 alkyl or an amino acid;

R5 is 0 when ===== is a double bond, or R5 is hydrogen or hydroxyl when ===== is a single bond;

Y is

where RZA and RZB are each independently H, OH or OR7; with the proviso that at least one of R7A and R7B is OH or OR7; and wherein R7 is C1-10 alkyl, aryl or arylalkyl.

In one particularly preferred embodiment, D is bromo. In one embodiment, D is in the 8-position as shown below:

In one embodiment, R1 is H.

In one preferred embodiment, ===== is a double bond and Rs is 0.

In one preferred embodiment, R7A is H and R7B is OH.

In one embodiment, there is provided a method for treating or minimising inflammation of peripheral neural tissue in an individual requiring said treatment including: (i) providing an individual for whom treatment or minimisation of inflammation of peripheral neural tissue is required;

wherein

Preferably, D is bromo.

(ii) administering a therapeutically effective amount of a compound of general formula (V) to the individual:

wherein

Preferably, D is bromo.

In one particularly preferred embodiment, the compound is compound (1 ):

(1 ).

As used herein the term "alkyl" refers to a straight or branched chain hydrocarbon radical having from one to ten carbon atoms, or any range between, i.e. it contains 1 , 2, 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms. The alkyl group is optionally substituted with substituents, multiple degrees of substitution being allowed. Examples of "alkyl" as used herein include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, isopentyl, and the like.

As used herein, the term "C1-10 alkyl" refers to an alkyl group, as defined above, containing at least 1 , and at most 10 carbon atoms respectively, or any range in between (e.g. alkyl groups containing 2-5 carbon atoms are also within the range of C1-10).

Preferably the alkyl groups contain from 1 to 5 carbons and more preferably are methyl, ethyl or propyl.

As used herein, the term "aryl" refers to an optionally substituted benzene ring. The aryl group is optionally substituted with substituents, multiple degrees of substitution being allowed.

As used herein, the term "heteroaryl" refers to a monocyclic five, six or seven membered aromatic ring containing one or more nitrogen, sulphur, and/or oxygen heteroatoms, where N-oxides and sulphur oxides and dioxides are permissible heteroatom substitutions and may be optionally substituted with up to three members. Examples of "heteroaryl" groups used herein include furanyl, thiophenyl, pyrrolyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, thiazolyl, oxazolyl, isoxazolyl, oxadiazolyl, oxo- pyridyl, thiadiazolyl, isothiazolyl, pyridyl, pyridazyl, pyrazinyl, pyrimidyl and substituted versions thereof.

A "substituent" as used herein, refers to a molecular moiety that is covalently bonded to an atom within a molecule of interest. For example, a "ring substituent" may be a moiety such as a halogen, alkyl group, or other substituent described herein that is covalently bonded to an atom, preferably a carbon or nitrogen atom, that is a ring member. The term "substituted," as used herein, means that any one or more hydrogens on the designated atom is replaced with a selection from the indicated substituents, provided that the designated atom's normal valence is not exceeded, and that the substitution results in a stable compound, i.e. , a compound that can be isolated, characterised and tested for biological activity.

The terms "optionally substituted" or“may be substituted” and the like, as used throughout the specification, denotes that the group may or may not be further substituted, with one or more non-hydrogen substituent groups. Suitable chemically viable substituents for a particular functional group will be apparent to those skilled in the art.

Examples of substituents include but are not limited to:

C1-C6 alkyl, C1-C6 haloalkyl, C1-C6 haloalkoxy, C1-C6 hydroxyalkyl, C3-C7 heterocyclyl, C3-C7 cycloalkyl, C1-C6 alkoxy, C1-C6 alkylsulfanyl, C1-C6 alkylsulfenyl, C1- C6 alkylsulfonyl, C1-C6 alkylsulfonylamino, arylsulfonoamino, alkylcarboxy, alkylcarboxyamide, oxo, hydroxy, mercapto, amino, acyl, carboxy, carbamoyl, aminosulfonyl, acyloxy, alkoxycarbonyl, nitro, cyano or halogen.

The term "isoflavonoid" as used herein is to be taken broadly and includes isoflavones, isoflavenes, isoflavans, isoflavanones, isoflavanols and similar or related compounds. Some non-limiting examples of isoflavonoid core structures are shown below:

wherein“ ” represents either a single bond or a double bond.

Methods for synthesis of isoflavonoid type compounds are described in W01998/008503 and W02005/049008 and references cited therein towards the synthesis, the contents of which are incorporated herein by reference in entirety.

Methods for the synthesis of the compound below and related compounds can be found in W02006108212.

The compounds include all salts, such as acid addition salts, anionic salts and zwitterionic salts, and in particular include pharmaceutically acceptable salts as would be known to those skilled in the art. The term "pharmaceutically acceptable salt" refers to an organic or inorganic moiety that carries a charge and that can be administered in association with a pharmaceutical agent, for example, as a counter-cation or counter- anion in a salt. Pharmaceutically acceptable cations are known to those of skilled in the art, and include but are not limited to sodium, potassium, calcium, zinc and quaternary amine. Pharmaceutically acceptable anions are known to those of skill in the art, and include but are not limited to chloride, acetate, tosylate, citrate, bicarbonate and carbonate. Pharmaceutically acceptable salts include those formed from: acetic, ascorbic, aspartic, benzoic, benzenesulphonic, citric, cinnamic, ethanesulphonic, fumaric, glutamic, glutaric, gluconic, hydrochloric, hydrobromic, lactic, maleic, malic, methanesulphonic, naphthoic, hydroxynaphthoic, naphthalenesulphonic, naphthalenedisulphonic, naphthaleneacrylic, oleic, oxalic, oxaloacetic, phosphoric, pyruvic, para-toluenesulphonic, tartaric, trifluoroacetic, triphenylacetic, tricarballylic, salicylic, sulphuric, sulphamic, sulphanilic and succinic acid.

The term "pharmaceutically acceptable derivative" or "prodrug" refers to a derivative of the active compound that upon administration to the recipient is capable of providing directly or indirectly, the parent compound or metabolite, or that exhibits activity itself and includes for example phosphate derivatives and sulphonate derivatives. Thus, derivatives include solvates, pharmaceutically active esters, prodrugs or the like.

The preferred compounds of the present invention also include all derivatives with physiologically cleavable leaving groups that can be cleaved in vivo to provide the compounds of the invention or their active moiety. The leaving groups may include acyl, phosphate, sulfate, sulfonate, and preferably are mono-, di- and per-acyl oxy-substituted compounds, where one or more of the pendant hydroxy groups are protected by an acyl group, preferably an acetyl group. Typically, acyloxy substituted compounds of the invention are readily cleavable to the corresponding hydroxy substituted compounds.

B. Formulations

The compounds of any one of general formula (I), (II), (III), (IV) and/or (V) may be provided in the form of a pharmaceutical composition including at least one pharmaceutically acceptable excipient, especially for use in treatment or in the manufacture of a medicament, for example, for the minimising or treating inflammation of peripheral neural tissue.

In the context of this application substantially pure is intended to mean 90% purity or greater such as 95% purity, particularly 98% purity, especially 99% purity, for example as assessed by HPLC analysis.

The invention also extends to employing at least two compounds of general formula (I), (II), (III), (IV) and/or (V) in the various aspects of the invention described herein.

Pharmaceutical formulations include those suitable for oral, parenteral (including subcutaneous, intradermal, intramuscular, intravenous, and intra-articular), inhalation (including use of metered dose pressurised aerosols, nebulisers or insufflators), intranasal, rectal and topical (including dermal, buccal, sublingual and intraocular) administration. The most suitable route may depend upon for example the condition and disorder of the recipient. The formulations may conveniently be presented in unit dosage form and may be prepared by any of the methods well known in the art of pharmacy. All methods include the step of bringing the active ingredient into association with the carrier which constitutes one or more accessory ingredients. In general, the formulations are prepared by uniformly and intimately bringing into association the active ingredient with liquid carrier or finely divided solid carriers or both and then, if necessary, shaping the product into the desired formulation.

Formulations of the present invention suitable for oral administration may be presented as discrete units such as capsules such as gelatine or hydroxypropyl methylcellulose (HPMC) capsules, cachets or tablets each containing a predetermined amount of the active ingredient; as a powder or granules; as a solution or a suspension in an aqueous liquid or a non-aqueous liquid; or as an oil-in-water liquid emulsion or a water-in-oil liquid emulsion. The active ingredient may also be presented as a paste.

When compounds of general formula (I), (II), (III), (IV) and/or (V) are formulated as capsules preferably the compound is formulated with one or more pharmaceutically acceptable carrier such as starch, lactose, microcrystalline cellulose, silicon dioxide and/or a cyclic oligosaccharide such as cyclodextrin.

Additional ingredients may include lubricants such as magnesium stearate and/or calcium stearate.

Suitable cyclodextrins include a-cyclodextrin, b-cyclodextrin, y-cyclodextrin, dimethyl-p-cyclodextrin, 2-hydroxyethyl-p-cyclodextrin, 2-hyroxypropyl-cyclodextrin, 3- hydroxypropyl-p-cyclodextrin and tri-methyl-p-cyclodextrin. More preferably the cyclodextrin is hydroxypropyl-p-cyclodextrin.

Tablets may be prepared by compression or moulding, optionally with one or more accessory ingredients. Compressed tablets may be prepared by compressing in a suitable machine the active ingredient in a free-flowing form such as a powder or granules, optionally mixed with a binder, lubricant such as magnesium stearate or calcium stearate, inert diluent or a surface active/dispersing agent. Moulded tablets may be made by moulding a mixture of the powdered compound moistened with an inert liquid diluent, in a suitable machine. The tablets may optionally be coated, for example, with an enteric coating and may be formulated so as to provide slow or controlled release of the active ingredient therein.

Formulations for parenteral administration include aqueous and non-aqueous sterile injection solutions which may contain antioxidants, buffers, bacteriostats and solutes which render the formulation isotonic with the blood of the intended recipient and which may include suspending agents and thickening agents. Preferably a parenteral formulation will comprise a cyclic oligosaccharide such as hydroxypropyl-p-cyclodextrin. The formulations may be presented in unit-dose or multi-dose containers, for example sealed ampoules and vials, and may be stored in a freeze-dried (lyophilised) condition requiring only the addition of the sterile liquid carrier, for example saline or water-for- injection (WFI), immediately prior to use. Extemporaneous injection solutions and suspensions may be prepared from sterile powders, granules and tablets of the kind previously described.

Dry powder compositions for topical delivery to the lung by inhalation may, for example, be presented in capsules and cartridges of for example gelatine, or blisters of for example laminated aluminium foil, for use in an inhaler or insufflator. Formulations generally contain a powder mix for inhalation of the one or more compounds of the invention and a suitable powder base (carrier substance) such as lactose or starch. Use of lactose is preferred. Each capsule or cartridge may generally contain between 20pg- 10mg of the compound formula (I) optionally in combination with another therapeutically active ingredient. Alternatively, the compound or compounds of the invention may be presented without excipients. Packaging of the formulation may be for unit dose or multi- dose delivery.

Spray compositions for topical delivery to the lung by inhalation may, for example be formulated as aqueous solutions or suspensions or as aerosols suspensions or solutions delivered from pressurised packs, such as a metered dose inhaler, with the use of a suitable liquefied propellant. Suitable propellants include a fluorocarbon or a hydrogen-containing chlorofluorocarbon or mixtures thereof, particularly hydrofluoroalkanes, e.g. dichlorodifluoromethane, trichlorofluoromethane, dichlorotetra- fluoroethane, especially 1 , 1 , 1 ,2-tetrafluoroethane 1 , 1 , 1 ,2,3,3,3-heptafluoro-n-propane or a mixture thereof. Carbon dioxide or other suitable gas may also be used as propellant. The aerosol composition may be excipient free or may optionally contain additional formulation excipients well known in the art such as surfactants e.g. oleic acid or lecithin and cosolvents e.g. ethanol. Pressurised formulations will generally be retained in a canister (e.g. an aluminium canister) closed with a valve (e.g. a metering valve) and fitted into an actuator provided with a mouthpiece.

Medicaments for administration by inhalation desirably have a controlled particle size. The optimum particle size for inhalation into the bronchial system is usually 1 -1 Opm, preferably 2-5pm. Particles having a size above 20pm are generally too large when inhaled to reach the small airways. When the excipient is lactose it will typically be present as milled lactose, wherein not more than 85% of lactose particles will have a MMD of 60- 90pm and not less than 15% will have a MMD of less than 15pm.

Formulations for intranasal administration include mucoadhesive nano-emulsions. Preferably, an intranasal formulation will comprise a mucoadhesive polymer such as Chitosan, and may optionally include additives such as an oil, surfactant, cosurfactant, and combinations thereof. Suitable oils include oleic acid, which enhance transmembrane delivery. Suitable surfactants and cosurfactants include Tween 80, PEG, Labrasol, Carbitol, Tanscutol HP, Cremophore EL, Tween 20, Span 20, ethyl alcohol. Intranasal formulations may be prepared as a sterile powder or suspension of the kind previously described and may contain a preservative.

Medicaments for intranasal administration desirably have a controlled particle size. The optimum particle size for intranasal delivery is usually less than about 1 pm, preferably less than about 500 nm, more preferably less than about 200nm.

It should be understood that in addition to the ingredients particularly mentioned above, the formulations of this invention may include other agents conventional in the art having regard to the type of formulation in question, for example those suitable for oral administration may include flavouring agents.

The compounds and pharmaceutical formulations according to the invention may be used in combination with or include one or more other therapeutic agents, for example anti-inflammatory agents for minimisation or treatment of inflammation of peripheral neural tissue. Examples may include corticosteroids and NSAIDs. Suitable corticosteroids, which may be used in combination with the compounds of the invention are those oral and inhaled corticosteroids and their pro-drugs which have anti- inflammatory activity. Examples include methyl prednisolone, prednisolone, dexamethasone, fluticasone propionate, 6a,9a-difluoro-17a-[(2-furanylcarbonyl)oxy]-l 1 b-hydroxy-l 6a-methyl-3-oxo-androsta-l,4-diene-17p-carbothioic acid S-fluoromethyl ester, 6a,9a-difluoro~l ip-hydroxy-16a-methyl-3-oxo-l 7a-propionyloxy-androsta-l ,4- diene-l 7p-carbothioic acid 5"-(2-OXo-tetrahydro-furan-3S-yl) ester, beclomethasone esters (e.g. the 17-propionate ester or the 17,21 -dipropionate ester), budesonide, flunisolide, mometasone esters (e.g. the furoate ester), triamcinolone acetonide, rofleponide, ciclesonide and butixocort propionate. Preferred corticosteroids include fluticasone propionate, and 6a,9a-difluoro-17a-[(2-furanylcarbonyl)oxy] - 1 1 b-hydroxy- 16a-methyl-3 -oxo-androsta- 1 ,4-diene- 17b-q3 >oίIiίoίo acid S-fluoromethyl ester, more preferably 6a,9a-difluoro-17a-[(2-furanylcarbonyl)oxy]-l ^-hydroxy-16a-methyl-3 -oxo- androsta- I,4^ίbhb-17b-q3^3qίΐΊίoίo acid S-fluoromethyl ester.

Suitable NSAIDs include sodium cromoglycate, nedocromil sodium, phosphodiesterase (PDE) inhibitors (e.g. theophylline, PDE4 inhibitors or mixed PDE3/PDE4 inhibitors), leukotriene antagonists, inhibitors of leukotriene synthesis, iNOS inhibitors, tryptase and elastase inhibitors, beta-2 integrin antagonists and adenosine receptor agonists or antagonists (e.g. adenosine 2a agonists), cytokine antagonists (e.g. chemokine antagonists) or inhibitors or cytokine synthesis.

The co-administration of active ingredients may be simultaneous or sequential. Simultaneous administration may be effected by the compounds being in the same unit dose, or in individual and discrete unit doses administered at the same or similar time. Sequential administration may be in any order as required and typically will require an ongoing physiological effect of the first or initial active agent to be current when the second or later active agent is administered, especially where a cumulative or synergistic effect is desired.

In one embodiment the formulation is an oral formulation, more preferably a capsule formulation.

Preferably the capsule formulation will comprise consist essentially of or consist of a compound of general formula (I), (II), (III), (IV) and/or (V) and silicon dioxide. Preferably the capsule will be a HPMC capsule.

In a preferred embodiment the formulation is a suppository or enema, which can be used to direct the active ingredient more closely to the disease affected area of the body.

Formulations for rectal administration may be presented as a suppository with carriers such as hydrogenated vegetable oil, cocoa butter or polyethylene glycol, or as an enema wherein the carrier is an isotonic liquid such as saline. Additional components of the formulation may include one or more surfactants, such as PEG or PEG-8 distearate, buffer salts or acid or alkali to adjust the pH, isotonicity adjusting agents and/or anti-oxidants.

In one particularly preferred embodiment, the compound of general formula (I), (II), (III), (IV) and/or (V) is provided in the form of a suppository, pessary or intra urethral device in a composition that includes an oleaginous suppository base. In this embodiment, the base is formulated so as to ensure that the bulk of the compound of general formula (I), (II), (III), (IV) and/or (V) does not partition from the base.

Generally, the base has a solvent power for the compound of general formula (I), (II), (III), (IV) and/or (V) enabling at least partial, preferably complete dispersion of the isoflavonoid in the base.

The base may be comprised of, or consist of, an oil or fat. Preferably the base comprises hydrogenated vegetable oil.

In one embodiment, the base includes hydrogenated vegetable oil in an amount of about 50% w/w base. The base may comprise additives including PEG, PEG monoesters, PEG monostearate, PEG diesters, PEG distearate, polysorbate esters, and combinations thereof. Preferably, the base comprises PEG distearate, more preferably PEG-8 distearate in an amount of about 50% w/w base.

In one embodiment the base includes saturated fatty acids in an amount of 50 to 65% w/w base. Stearic acid may be included in an amount of 25 to 40% w/w base. Palmitic acid in an amount of 25 to 30% w/w base. Longer chain saturated fatty acids such as myristic, arachidic and lauric acid may be included in an amount of <2% w/w base. In one embodiment, oleaginous bases that include unsaturated fatty acids in an amount of 35 to 50% w/w base are preferred. Monounsaturated fatty acid may be included in an amount of 30 to 45% w/w base. Oleic acid may be included in an amount of 30 to 40% w/w base. Polyunsaturated fatty acids such as linoleic and alpha linolenic acid may be included in an amount of 0 to 5% w/w base.

Theobroma oil (cocoa butter) has been a traditional base in a suppository because of: (a) its non-toxic and non-irritant nature, and (b) its low melting point, meaning that it readily dissolves at body temperature when placed within a bodily cavity, However, it is increasingly being replaced for a number of reasons. One reason is its variability in composition, a consequence of its natural origins; theobroma oil also is polymorphic, meaning it has the ability to exist in more than one crystal form. Another is that the formulated product needs to be kept refrigerated because of its low melting point, rendering it unsuitable in tropical regions. This has led to a number of substitute products offering a range of advantages over theobroma oil such as greater consistency, decreased potential for rancidity, and greater ability to tailor phase transitions (melting and solidification) to specific formulation, processing, and storage requirements.

Nevertheless, theobroma oil or a fatty base with similar composition and physicochemical properties has been found to be a preferred embodiment of the invention.

Typically, the oleaginous base comprises a predominance of (>45% w/w base) of saturated fatty acids. Preferably the oleaginous base is Theobroma oil (cocoa butter) or an oil fraction or derivative or synthetic version thereof having a saturated fatty acid profile substantially the same as, or identical to the fatty acid profile of Theobroma oil.

Other examples of oils that may be used to provide or obtain fatty acids useful as bases include those obtainable from natural sources such as canola oil, palm oil, soya bean oil, vegetable oil, and castor oil. Oils derived from these sources may be fractionated to obtain oil fractions containing saturated fatty acids.

The base may be formed or derived from a hard fat, butter or tallow.

The base may comprise esterified or non-esterified fatty acid chains. The fatty acid chains may be in the form of mono, di and triglycerides, preferably of saturated fatty acid chains of C9-20 chain length. In a preferred embodiment, the base may comprise triglycerides. The base may comprise additives including PEG, PEG monoesters, PEG monostearate, PEG diesters, PEG distearate, polysorbate esters, and combinations thereof.

A suppository base may be formed from synthetic oils or fats, examples including Fattibase, Wecobee, Witepsol (IOI Oleo GmbH, Germany), Suppocire (Gattefosse, France), Hydrokote, Subanal (Dott. Bonapace, Italy) and Dehydag.

The proportion of the oleaginous suppository base in the final product is a function of the dosage of active pharmaceutical ingredient and the presence of other pharmaceutical or inert ingredient (if any) but may be provided by way of example in an amount of about 1 to 99% w/w formulation.

The compositions for rectal, vaginal or urethral application may be prepared as follows. The compound of general formula (I), (II), (III), (IV) and/or (V) is contacted with a suppository base (as described above) in molten form in conditions enabling at least partial, preferably complete or substantially complete dispersion of the compound of general formula (I), (II), (III), (IV) and/or (V) in the base. This suspension is then poured into a suitable mould, such as a PVC, polyethylene, or aluminium mould. For example, the compound of general formula (I), (II), (III), (IV) and/or (V) may be contacted with the base at a temperature of from about 35° C to about 50° C and preferably from about 40° C to about 44° C. The compound of general formula (I), (II), (III), (IV) and/or (V) can be milled or sieved prior to contact with the base. In one embodiment, the conditions provided for manufacture, and formulation or device formed from same, enable at least, or provide at least, 50%, preferably 60%, preferably 70%, preferably 80%, preferably 90%, preferably 95% of the isoflavonoid for a given dosage unit to be dispersed in the dosage unit. In these embodiments, no more than 50% of the isoflavonoid for a given dosage unit, preferably no more than 40%, preferably no more than 30%, preferably no more than 20%, preferably no more than 10%, preferably no more than 5% of isoflavonoid for a given dosage unit may be in admixture with, (i.e. undissolved in) the suppository base of the dosage unit.

Optionally the suppositories, pessaries or intra-urethra I devices may be coated, prior to packing, for example with cetyl alcohol, macrogol or polyvinyl alcohol and polysorbates to increase disintegration time or lubrication or to reduce adhesion on storage.

One or more sample suppositories, pessaries, or intra-urethral devices from each batch produced are preferably tested by the dissolution method of the present invention for quality control. According to a preferred embodiment, a sample from each batch is tested to determine whether at least about 75 or 80% by weight of the base dissolves within 2 hours.

Typically, the suppository, pessary or like device according to the invention is substantially hydrophobic or lipophilic throughout and does not contain a hydrophilic substance such as hydrophilic carrier or pharmaceutical active, or hydrophilic foci or region formed from the ligation or complexing of the isoflavonoid to or with another pharmaceutical compound, carrier or excipient.

The total weight of the suppository preferably ranges from about 1500 mg to about 3000 mg, preferably 1750 mg to about 2500 mg. In another embodiment the total weight of the suppository preferably ranges from about 2250 mg to about 2700 mg, and more preferably from about 2250 to about 2500 mg. According to one embodiment, the suppository has a total weight ranging from about 2300 mg to about 2500 mg.

The suppository or pessary is preferably smooth torpedo-shaped.

The melting point of the suppository or pessary is generally sufficient to melt in the patient's body, and is typically no more than about 37° C.

In one particularly preferred embodiment there is provided:

- a kit including: a plurality of suppositories sufficient in number to provide an individual with a suppository once daily, or twice daily, for a period of 30 to 90 days, preferably 30 to 60 days, preferably 30 days each suppository including:

400mg, 600 mg, 800mg, or 1 ,200mg of compound (1 );

a suppository base in the form of hydrogenated vegetable oil comprising PEG-8 distearate; wherein the suppository base in provided an amount of 1 -99% w/w of the suppository,

- the kit further including: written instructions to provide the suppository once daily, or twice daily for a period of 30 to 90 days, preferably 30 to 60 days, preferably 30 days.

C. Indications & treatment methods

The term "inflammation" unless otherwise indicated herein, refers to inflammation of peripheral neural tissue.

“Peripheral neural tissue” comprises tissue of the peripheral nervous system. Peripheral neural tissue includes, but is not limited to, nerve axons, neurons, neuroglial cells and connective tissue of the PNS. Neurons of the PNS include sensory afferent neurons. Neuroglial cells of the PNS include Schwann cells and satellite glial cells. Connective tissue of the PNS includes the endoneurium, perineurium and epineurium.

In some embodiments, peripheral neural tissue refers to all elements of the peripheral nervous system. In other embodiments, peripheral neural tissue refers to elements of the peripheral nervous system within the BNB, including tissue within the endoneurium and perineurium. In yet another embodiment, peripheral neural tissue refers to nerve axons.

Inflammation of peripheral neural tissue can be caused by any means, including but not limited to diseases, disorders, infection, toxic metabolites, ischaemia/reperfusion injury or autoimmunity. In certain instances, a compromised blood-nerve barrier (BNB) contributes to or is the result of inflammation of peripheral neural tissue. Inflammation of peripheral neural tissue can be acute, chronic, or both. Acute inflammation of peripheral neural tissue can, in certain instances, be caused by any means, such as a disease, a disorder, a result of injury including ischaemia/reperfusion injury, or induced peripheral stimuli. Acute inflammation of peripheral neural tissue can, for example, result in platelet deposition, tissue oedema, endothelial cell activation, or an increase in certain inflammatory-related molecules (e.g., chemokines or cytokines). Chronic inflammation of peripheral neural tissue can, in certain instances, be caused by any means, such as a disease, a disorder, a result of one or more of prolonged oxidative stress associated with hyperglycaemia (high blood sugar) (e.g., diabetes), aging, autoimmunity, viruses, microbes (e.g., bacteria or yeast), traumatic injury, toxic metabolites, or induced peripheral stimuli.

In some forms of inflammation of peripheral neural tissue, cytokines (e.g., chemokines) can be released by Schwann cells, upregulated or down regulated by Schwann cells or have an increased or decreased level in peripheral neural tissue. In certain aspects, the level of proinflam matory cytokines is increased or up-regulated. In other aspects, the level of anti-inflammatory cytokines is decreased or down-regulated.

The term "minimising inflammation of peripheral neural tissue", unless otherwise indicated herein, refers to diminishing one or more causes of, manifestations of, or results of inflammation of peripheral neural tissue (acute or chronic), such as but not limited to compromised BNB, increased levels of proinflammatory cytokines (e.g., chemokines), or decreased levels of anti-inflammatory cytokines.

The term "preventing inflammation of peripheral neural tissue", unless otherwise indicated herein, refers to stopping or diminishing the potential onset of one or more causes of manifestations, or results of inflammation of peripheral neural tissue (acute or chronic), such as but not limited to compromised BNB, increased levels of pro- inflammatory cytokines (e.g., chemokines), or decreased levels of anti-inflammatory cytokines.

The term "treating inflammation of peripheral neural tissue," unless otherwise indicated herein, refers to reducing inflammation of peripheral neural tissue, ameliorating at least one symptom resulting from inflammation of peripheral neural tissue (such as a symptom of a disease or disorder that could cause inflammation of peripheral neural tissue), or both.

In a particularly preferred embodiment, there is provided a method of minimising or treating acute inflammation of peripheral neural tissue arising from or associated with reperfusion/ischaemia related injury. The method includes the step of administering a compound according to any one of Formula I to V, preferably compound 1 , to an individual requiring the treatment. Generally, the compound is administered immediately post injury, preferably within 48 hours, preferably within 24 or 12 hours, most preferably within 6 hours or less post injury. The compound may be given intravenously. Alternatively, the compound may be given intra ventricularly. The compound may be given in an amount of about 15 to 30 mg per kg per day or less, for example, 10 to 20 mg per kg per day, such as 1 to 10 mg per kg per day of the body weight of the patient. Typically, the compound is given for a period of no longer than about 10 days, preferably 5 to 7 days or less.

In another embodiment, there is provided a method of minimising or treating acute inflammation of peripheral neural tissue arising from or associated with surgery. In one embodiment, the inflammation is associated with the PNS arising from or associated with general surgery. According to the method, a compound of any one of Formula I to V, preferably compound 1 , is administered directly to peripheral nervous tissue during or at the completion of surgery thereby reducing inflammation associated with such surgery. This method may include administration directly to the tissue wherein the surgery is general surgery, preferably in a unit dose of between about 400 mg to about 800 mg. The compound may be given in an amount of about 15 to 30 mg per kg per day or less, for example, 10 to 20 mg per kg per day, such as 1 to 10 mg per kg per day of the body weight of the patient.

In a particularly preferred embodiment, there is provided a method of minimising or treating peripheral neuropathy arising from or associated with diabetes. The method includes the step of administering a compound according to any one of Formula I to V, preferably compound 1 , to an individual requiring the treatment. The compound may be given as a suppository in a form described herein. The compound may be given in an amount of about 15 to 30 mg per kg per day or less, for example, 10 to 20 mg per kg per day, such as 1 to 10 mg per kg per day of the body weight of the patient. Typically, the compound is given chronically. Ultimately, the dose prescribed and intervals at which the prescribed dose is taken will be at the discretion of the physician with responsibility for the patient.

Example 1 : Suppository Formulation

To formulate the suppository, one part compound (1 ) to four parts MBK base was used. 1000 mg of compound (1 ) powder was added to 4000 mg MBK solid base. Alternatively, to prepare a 1 g suppository, 200 mg of compound (1 ) powder was added to 800 mg MBK solid base. The tube was vortexed to ensure that the drug compound (1 ) was mixed well with the solid base. The tube was incubated in a water bath set at 45 °C until the base melted. The melted base was vortexed with the drug vigorously for 30 seconds followed by warming in the 45 °C water bath again for 20 seconds. This process was repeated until no clumps or undissolved particles of the drug were visible. To achieve thorough mixing of the drug in the base a 19G needle and 2 ml_ syringe were used to repeatedly mix the drug by drawing it up and expelling out rapidly. The container with the base and drug were kept in a warm water bath (at 45 °C) to prevent it from solidifying. The molten base containing the drug was filled into a plastic Pasteur pipette and allowed to solidify at room temperature. This solid mass was then extruded out of the pipette and cylindrical ribbons formed. The extrusion step was conducted to obtain suitable size suppositories for the animals used in the laboratory scale experiment.

Example 2:

Pharmacokinetics of Compound (1) and its Glucuronide Metabolite following rectal administration in male SD rats

For a 400 g rat, a 200 mg mass of a 1 g suppository was dosed into the rectum by placing the tip of a 3 cm plastic mouse oral gavage device attached to a 1 ml_ plastic syringe 1 cm into the rectum to deliver a dose of 100 mg/kg.

For plasma samples: an aliquot of 30pL sample was added with 200pL IS (Propranolol, 40ng/ml_) in ACN. The mixture was vortexed for 5 min and centrifuged at 5800 rpm for 10 min. The 5 pL mixture was injected into LC-MS/MS.

For rectum samples: tissue, taken post perfusion with saline, was homogenized for 2 min with 3 volumes (v/w) of homogenizing solution (PBS, pH 7.4). An aliquot of 30mI_ sample was added with 200 pL IS (Propranolol, 40 ng/mL) in ACN. The mixture was vortexed for 5 min and centrifuged at 5800 rpm for 10 min. The 5pL mixture was injected into LC-MS/MS.

For sciatic nerve samples: tissue, taken post perfusion with saline, was homogenized for 2 min with 5 volumes (v/w) of homogenizing solution (PBS, pH 7.4). An aliquot of 30pl_ sample was added with 200mI_ IS (Propranolol, 40ng/ml_) in ACN. The mixture was vortexed for 5min and centrifuged at 5800 rpm for 10 min. The 5mI_ mixture was injected into LC-MS/MS.

For faeces samples: tissue was homogenized for 2 min with 5 volumes (v/w) of homogenizing solution (Me0H/H20=1 : 1 ). An aliquot of 30 mI_ sample was added with 200 mI_ IS (Propranolol, 40ng/ml_) in ACN. The mixture was vortexed for 5 min and centrifuged at 5800 rpm for 10 min. The 5mI_ mixture was injected into LC-MS/MS.

For 10-times diluted samples: An aliquot of 6 pL sample was added with 54pL blank to obtain the diluted samples, and the sample dilution factor is 10. The extraction procedure for diluted samples was the same as those for non-diluted samples.

For 100-times diluted samples: An aliquot of 10pL sample was added with 90pL blank to obtain the diluted samples, and the sample dilution factor is 10. Then take 6pL sample, added with 54pL blank to obtain the diluted samples, and the sample dilution factor is 100. The extraction procedure for diluted samples was the same as those for non-diluted samples.

Results

Table 1 : Individual and mean plasma concentration-time data of

Compound (1) after rectal dose of 100 mg/kg (API) in male SD rats

Table 2: Individual and mean sciatic nerve concentration-time data of Compound (1) after rectal administration of 100 mg/kg (API) in male SD rats

Table 3: Individual and mean rectum concentration-time data of Compound (1) after rectal administration of 100 mg/kg (API) in male SD rats

Table 4: Compound (1) concentration data in faeces after rectal administration of 100 mg/kg (API) in male SD rats

Table 5: Individual and mean plasma concentration-time data of glucuronides (metabolite) after rectal administration of Compound (1) at 100 mg/kg (API) in male SD rats

It has surprisingly been found that a compound of general formula (I), (II), (III), (IV) and/or (V), preferably wherein the compound is compound (1 ), may be delivered to peripheral neural tissue (sciatic nerve) wherein the compound is administered as a rectal formulation.

Example 3: Pharmacokinetics of oral administration; and comparing it with the pharmacokinetics of rectal administration

The pharmacokinetics of oral administration (PO) of Compound (1 ) was studied in rats, using the conditions detailed below.

Study Design

_

The pharmacokinetics of oral versus rectal administration was compared (see Figure 1 a-c). Rectal administration of Compound (1 ) delivered more of the drug to the sciatic nerve versus oral administration (PO). A compound of general formula (I), (II), (III), (IV) and/or (V), preferably compound

(1 ), may be advantageously used to treat or minimise inflammation of peripheral neural tissue, or a disease associated with inflammation of peripheral neural tissue.

Claims

1. A method for treating or minimising inflammation of peripheral neural tissue in an individual requiring said treatment including: (i) providing an individual for whom treatment or minimisation of inflammation of peripheral neural tissue is required;

(ii) administering a therapeutically effective amount of a compound of general formula (I), (II), (III), (IV) and/or (V) as described herein to the individual, wherein administration of the compound of general formula (I), (II), (III), (IV) and/or (V) minimises or treats inflammation of peripheral neural tissue in the individual.

2. The method of claim 1 , wherein the compound is compound 1 as described herein, with the structure

3. The method of claim 1 or 2, wherein the individual has peripheral neuropathy.

4. The method of claim 3, wherein the peripheral neuropathy is diabetic peripheral neuropathy.

5. The method of any one of the preceding claims, wherein the compound is administered rectally.