Paralytic shellfish poison

Abstract

The invention concerns a paralytic shellfish poison for the treatment of itching in a human being or another mammal.

Claims

1. A method for treatment of itching in a human being, said method comprising: topically administering to the human being a therapeutically effective amount of a paralytic shellfish poison (PSP), wherein the PSP is saxitoxin or a salt thereof, or a tricyclic 3,4-propinoperhydropurine represented by the following formula (I) or a salt thereof, ##STR00002## wherein R.sub.1 and R.sub.5 are independently selected from the group consisting of H and OH; R.sub.2 and R.sub.3 are independently selected from the group consisting of H, OSO.sub.3.sup. and SO.sub.3; and R.sub.4 is selected from the group consisting of H, OH, OC(O)NH.sub.2, OC(O)NHSO.sub.3.sup. and OC(O)CH.sub.3.

2. The method according to claim 1, wherein the administering is supported physically.

3. The method according to claim 1, wherein the PSP is administered over a period of one to seven days and/or in multiple treatment cycles.

4. A method for treatment of itching in a human being, said method comprising: topically administering to the human being a therapeutically effective amount to treat itching of a pharmaceutical composition, comprising at least one paralytic shellfish poison (PSP); and a pharmacologically acceptable carrier, wherein the PSP is saxitoxin or a salt thereof, or a tricyclic 3,4-propinoperhydropurine represented by the following formula (I) or a salt thereof, ##STR00003## wherein R.sub.1 and R.sub.5 are independently selected from the group consisting of H and OH; R.sub.2 and R.sub.3 are independently selected from the group consisting of H, OSO.sub.3.sup. and SO.sub.3; and R.sub.4 is selected from the group consisting of H, OH, OC(O)NH.sub.2, OC(O)NHSO.sub.3.sup. and OC(O)CH.sub.3.

5. The method according to claim 1, wherein the administering is supported physically by iontophoresis, phonophoresis, sono-macroporation, thermal modulation or magnetic modulation.

6. The method according to claim 1, wherein the PSP is contained in a liposome.

7. The method according to claim 1, wherein the PSP is comprised in a pharmaceutical composition at a concentration of 1 g to 100 g per ml of the pharmaceutical composition.

8. The method according to claim 4, wherein the PSP is contained in a liposome.

9. The method according to claim 4, wherein the PSP is at a concentration of 1 g to 100 g per ml of the pharmaceutical composition.

10. The method according to claim 4, wherein the PSP is in the form of its racemate, pure stereoisomer, enantiomer or diastereomer or in the form of a mixture of stereoisomers, enantiomers or diastereomers, in neutral form, in the form of an acid or base or in the form of a salt, a physiologically acceptable salt, or in the form of a solvate, or a hydrate.

11. The method according to claim 1, wherein the PSP is synthetically synthesized or isolated from a biological source.

12. The method according to claim 1, wherein the PSP is synthetically synthesized or isolated from a biological source selected from the group consisting of cyanobacteria, dinoflagellates and contaminated shellfish.

13. The method according to claim 1, wherein the PSP is isolated from shellfish contaminated with A. catenella.

14. The method according to claim 1, wherein the PSP is used in an amount of 0.01 g/day to 1000 g/day.

15. The method according to claim 1, wherein the PSP is used in an amount of 0.1 to 100 g/day.

16. The method according to claim 1, wherein the PSP is used in an amount of 1 to 10 g/day.

17. The method according to claim 1, wherein the itching is of pruritoceptive nature, of neurogenic nature, of neuropathic nature, of psychogenic nature, due to an inflammatory process, due to an insect bite, due to an inflammatory process, an inflammatory process due to surgery or healing, due to infectious process, an infectious process caused by a virus, bacteria, a fungus or prions, due to circulating pruritogens, due to a systemic pathology, cholelithiasis or acute or chronic renal insufficiency, due to any allergen exposure, due to tobacco exposure, smokeless tobacco exposure, due to chemical exposure, or due to respiratory cause.

18. The method according to claim 1, wherein the PSP is for a single use or for use over a period of one to seven days, for use in multiple treatment cycles, and/or for use in chronic treatment.

19. The method according to claim 1, wherein administration is by topical administration by use of a skin-patch, a cream, an ointment or a spray and/or by use of a physical transdermal delivery method, iontophoresis, phonophoresis, sono-macroporation, thermal modulation or magnetic modulation or by use of a physical device, respiratory device, or a nebulizer.

20. The method according to claim 4, wherein the pharmaceutical composition is prepared for topical administration.

21. The method according to claim 4, wherein the PSP is contained in the pharmaceutical composition in an amount suitable for an administration of 0.01 to 1000 g.

22. The method according to claim 4, wherein the PSP is contained in the pharmaceutical composition in an amount suitable for an administration of 0.01 to 100 g.

23. The method according to claim 4, wherein the PSP is contained in the pharmaceutical composition in an amount suitable for an administration of 1 to 10 g.

24. The method according to claim 4, wherein the pharmaceutical composition is prepared for topical administration and is a skin-patch, a cream, an ointment, or a spray.

25. The method according to claim 4, wherein the pharmaceutical composition further comprises at least one antipruritic compound, an antihistaminic compound, chlorphenamine, loratadine or desloratadin, a corticosteroid, betamethasone, clobetasol or mometasone, or a non-steroidal anti-inflammatory drug, ibuprofen, ketoprofen or diclofenac.

26. The method according to claim 4, wherein the PSP is contained in a liposome or a microemulsion and/or wherein the pharmaceutical composition further comprises at least one substance facilitating the transport of the PSP through the skin, in particular a substance selected from the group consisting of: alcohols, amines, amides, amino acids, amino acid esters, 1-substituted azacycloheptan-2-ones, pyrrolidones, terpenes, fatty acids, fatty acid esters, macrocyclic compounds, tensides, sulfoxides, liposomes, transferomes, lecithin vesicles, ethosomes, anionic, cationic and non-ionic surfactants, polyols, essential oils, dimethylsulfoxide, decylmethylsulfoxide, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, sodium laurate, sodium lauryl sulfate, cetyltrimethylammonium bromide, benzalkonium chloride, a poloxamer, polysorbate 20 (polyoxyethylene sorbitan monolaurate), polysorbate 40 (polyoxyethylene sorbitan monopalmitate), polysorbate 60 (polyoxyethylene sorbitan monostearate), polysorbate 80 (polyoxyethylene sorbitan monooleate), lecithin, 1-n-dodecylcyclazacycloheptan-2-one, ethanol, propanol, octanol, benzyl alcohol, lauric acid, oleic acid, valeric acid, isopropyl myristate, isopropyl palmitate, methylpropionate, ethyl oleate, sorbitan sesquioleate, propylene glycol, ethylene glycol, glycerol, butanediol, polyethylene glycol, polyethylene glycol monolaurate, urea, dimethylacetamide, dimethylformamide, 2-pyrrolidone, 1-methyl-2-pyrrolidone, ethanol amine, diethanol amine, triethanolamine, alkanones, salicylic acid, salicylates, citric acid and succinic acid.

27. The method according to claim 1, wherein the PSP is a tricyclic 3,4-propinoperhydropurine represented by formula (I) or a salt thereof, wherein R.sub.1 is H and R.sub.5 is OH; R.sub.2 is H and R.sub.3 is OSO.sub.3.sup. or R.sub.2 is OSO.sub.3.sup. and R.sub.3 is H; and R.sub.4 is OC(O)NH.sub.2.

28. The method according to claim 4, wherein the PSP is a tricyclic 3,4-propinoperhydropurine represented by formula (I) or a salt thereof, wherein R.sub.1 is H and R.sub.5 is OH; R.sub.2 is H and R.sub.3 is OSO.sub.3.sup. or R.sub.2 is +OSO.sub.3.sup. and R.sub.3 is H; and R.sub.4 is OC(O)NH.sub.2.

Description

EMBODIMENTS

(1) To design a study where the effects of the PSP toxin on itching can be assessed, the two most commonly used itching models in rats were compared; subcutaneous injections of serotonin or histamine. Such injections have been reported to induce increased scratching in the injected zone.

(2) The following preparations were used for animal tests: a) Serotonin-Solution: Serotonin hydrochloride 2.5 mg/Kg (Enzo Life Sciences) dissolved in saline (0.9% NaCl). b) Gel test formulation v1 234: GTX 2/3 (Cetiol SB-45, Panalene L-14-E, Ceteary Alc-Ceteareth 20, Glucamate SS, Glucamate SSE 20, Propylparaben, Methylparaben, Carbopol 2020, Glycerine, water, Trietanolamine, Silicone DC 345, Microcare PM5, Sepigel 305. c) 110214 PB GTX: GTX 2/3 in Saline (0.9% NaCl). d) Three GTX toxin preparations: GTX 2/3+liposome (water, Persea Gratissima Oil, Propylene Glycol, Squalane, Petrolatum, Dimethicone, PEG-20 Methyl Glucose Sesquistearate, Cetyl Acetate (y) Acetylated Lanolin Alcohol, Diazolinidyl Urea (y) Methylparaben (y), Propylparaben (y) Propylene Glycol, Glyceryl Stearate, Methyl Glucose, Sesquistearate, Triethanolamine, Ozokerite, Carbomer Acrylates/C 10-30 Alkyl Acrylate Crosspolymer, Tocopherol (y) ascorbyl Palmitate (y) Lecithin, (y) Glyceryl Stearate (y) Glyceryl Oleate (y) Citric Acid). Composition as described before with GTX 2/3 5, 10 and 20 g/g of cream. e) Vehicle: As d, but without GTX 2/3 (Placebo). f) Lidocaine gel 4%: Lidocaine Hydrochloride LCH Gel 4%+excipients
1. Effects of the Toxin in Subcutaneous Serotonin-Induced Itching

(3) Rationale: The objective was to test the effects of the toxin in subcutaneous serotonin (5-HT)-induced itching, which is the most commonly used and effective method to attain itching in rats. As the toxin cream preparation shows only cutaneous effects, we decided to test the effects of the cream preparation on the skin and subcutaneous co injection of serotonin with the toxin.

(4) Methods: After acclimation and trimming male rats were divided into 3 groups. The first group was injected subcutaneously with serotonin (50 l of 5HT (2.5 mg/kg). The second group had the gel test formulation v1 234 applied (between 80-100 mg) to the trimmed region 1 hour before subcutaneous injection of serotonin (same dose as above). The third group was co injected with a mixture of the toxin (10 g/kg 110214 PB GTX) and serotonin (2.5 mg/kg in 50 l). Animal behaviour was measured for 30 minutes since the subcutaneous injections.

(5) Results: Subcutaneous injection of serotonin in the neck induced an increase in scratches (5HT) which was mildly ameliorated by co injection of the toxin and serotonin (5HT-toxin). The application of the toxin gel induced a non significant increase in scratches.

(6) Conclusions: The data suggest that the toxin co injected subcutaneously with serotonin has an effect in itching.

(7) 2. Effects of the Toxin in Cutaneous Serotonin-Induced Itching

(8) Rationale: The objective was to test the effects of the toxin in cutaneous serotonin (5-HT)-induced itching.

(9) Methods: After acclimation and trimming (see above) male rats had the gel test formulation v1 234 applied (between 80-100 mg) to the trimmed region 1 hour before cutaneous application of serotonin (same dose as above).

(10) Results: A significant reduction of the scratching behaviour in the animals is observed after cutaneous toxin application.

(11) Conclusions: GTX in gel induces an over 60% reduction of itching in cutaneous serotonin-induced itching in rats.

(12) 3. Comparison with Lidocaine

(13) Methods: Male Sprague Dawley rats weighing between 250-300 grams were handled once a day for 5 days. On the test day rats were trimmed on a 22 cm region of their right side of the neck. Animals were divided into 6 groups (N=8 each). The first 4 groups were treated cutaneously by rubbing 80-100 mg on the bare skin either with GTX toxin preparations or the vehicle one hour before serotonin application. One group of rats was treated cutaneously with lidocaine gel 4% (80-100 mg) 5 minutes before serotonin application. The last group did not receive any cutaneous treatment. Serotonin (100 l, 2.5 mg/kg) was applied cutaneously to all animals. Rats were then placed in their individual homecages, and animal behaviour was recorded as the number of scratches within 30 minutes from serotonin application. Two consecutive scratches were considered different if a 1 second interval was present between them.

(14) Results: As can be seen in the figure, the three concentrations of GTX (5, 10 and 20 g/g of cream) produced significant decreases in serotonin-induced scratching behaviour (over 50% decrease for 20 g/g cream; p<0.01). Neither the vehicle nor lidocaine gel had significant effects on serotonin-induced pruritus.

(15) 4. Therapeutic Applications

(16) The following cream composition was used for all therapeutic applications described below:

(17) TABLE-US-00002 Ingredient Concentration Aqua 70.400 Persea Gratissima Oil 6.000 Propylene Glycol 5.000 Squalane 3.500 Mixture of the epimers GTX-2 and GTX-3 1.000 Petrolatum 3.500 Dimethicone 3.000 PEG-20 Methyl Glucose Sesquistearate 2.500 Cetyl Acetate and Acetylated Lanolin 2.000 (total Alcohol concentration of the mentioned ingredients) Diazolinidyl Urea and Methylparaben and 1.500 (total Propylparaben and Propylene Glycol concentration of the mentioned ingredients) Glyceryl Stearate 1.000 Methyl Glucose Sesquistearate 0.500 Triethanolamine 0.300 Ozokerite 0.300 Carbomer 0.050 Acrylate(s) 0.200 Perfume 0.150 Tocopherol and Ascorbyl Palmitate and 0.100 Lecithin and Glyceryl Stearate and Glyceryl Oleate and Citric Acid

(18) The acrylate(s) may be C 10-30 alkyl acrylate crosspolymer(s).

(19) A sixty year old man presented with a mosquito bite in his neck. He locally applied the cream composition with a relief of the itching within 10 to 15 minutes. He referred that he did not need further application.

(20) A seventy year old man presented with a skin allergic reaction on both his legs with intense itching and mild to moderate swelling. He locally applied the cream composition with relief of the symptoms within about half an hour. He referred that he has applied the GTX preparation two to three times during 24 hours to obtain a complete relief of the symptoms.

(21) A 79 years old woman with severe itching due to prurigo Hyde had immediate relief from itching from VAS-analogue scale 8 to 2 by application of the cream composition.

(22) Severely itching of a 57 years old man with dyshidrotic hand eczema had been classified VAS-analogue scale 5. After one application of the cream composition the itching was down to zero. The effect lasted almost exactly for 24 h.

(23) A 40 year old woman had an extremely itching angry brown patch on the back. After the first application the itching was gone. This effect lasted under once daily application for 24 h. The itching recurred after the cream was no longer applied.