GB2204243A

GB2204243A - Lousicides

Info

Publication number: GB2204243A
Application number: GB08810161A
Authority: GB
Inventors: Robert Stronach Goldie; Stewart Thomas Leslie; Sandra Therese Antoi Malkowska
Original assignee: Euro Celtique SA
Current assignee: Euro Celtique SA
Priority date: 1987-05-07
Filing date: 1988-04-29
Publication date: 1988-11-09
Anticipated expiration: 2008-04-29
Also published as: GB2204243B; IE881370L; GB8710784D0; IE60936B1; GB8810161D0

Abstract

A method for controlling lice or their ova on human subjects without irritating the skin consists of applying a topical composition containing a lousicide and a C2-C4 alkyl ester of a C10-C20 fatty acid dissolved in an alcoholic solution. Preferably the lousicide is carbaryl, malathion or phenothrin, the alkyl ester is isopropyl myristate and the alcoholic solution is isopropanol.

Description

A METHOD FOR CONTROLLING LICE OR THEIR OVA The present invention relates to a method for controlling lice or their ova on human subjects without irritating the skin of said subjects.

According to the present invention, there is provided a method for controlling lice or their ova on human subjects without irritating the skin of said subjects comprising applying toa human subject a topical, lousicidal composition comprising a lousicidally effective amount of at least one lousicide and at least one C2-C4 alkyl ester of a C10-C20 fatty acid dissolved in an alcoholic solution.

Preferably the topical composition is a pour-on composition such as a lotion. The at least one lousicide must be soluble in the alcoholic solution and must be compatible with the fatty acid ester. It may be, for example, permethrin or a siloxane, but is preferably, carbaryl malathion or phenothrin.

The at least one fatty acid ester must also be soluble in the alcoholic solution ant must be compatible with the lousicide.

It may be, for example, ethyl laurate but is preferably a C3-C4 alkyl ester of a C14-C18 fatty acid, such as butyl stearate, isobutyl stearate, butyl oleate or, which is especially preferred, isopropyl myristate.

The alcoholic solution must dissolve both the at least one lousicide and the at least one fatty acid ester. Together with the at least one lousicide and the at least one fatty acid ester, it must be substantially non-irritant to human skin.

Preferably, the alcoholic solution comprises at least one C2-C4, especially C3-C4, alkyl alcohol, such as n-propanol, tert.butyl alcohol or, which is especially preferred, isopropanol.

The alcoholic solution may also contain a certain proportion, generally up to about 40(v/v), of water.

In addition to the above ingredients, the present topical, composition may also contain further constjtuents, provided they are pharmaceutically acceptable, compatible with the at least one lousicide and the at least one fatty acid ester and soluble in the alcoholic solution. Suitable materials, such as perfumes, will be known to those skilled in the pharmaceutical art.

The amount of the at least one lousicide in the present lousicidal composition must be sufficient, in use, to control lice or their ova on human subjects. In the present specification, an amount sufficient to control lice or their ova is that amount which will cause at least 50% of the lice exposed in the two minute immersion tests described below to die within 24 hours, in the case of adult lice, and within 2 weeks, in the case of their ova.For the preferred lousicides, the preferred concentrations (w/v) in the present composition are Permethnn 0.1 - 1.0%, especially 0.1 - 0.5; Carbaryl 0.25 - 1.25%, especially 0.5 - 1.0% Siloxane 5 - 25%, especially 10 - 20% Malathion 0.25 - 1.25%, especially 0.5 - 1.0% Phenothrin O.i - 0.5%, especially 0.2 - 0.4% The two minute immersion tests referred to above is carried out as follows: Lousicial activity A 50ml beaker is filled with tap water and allowed to come to room temperature (about 20 C). Ten young adult male and ten young adult female lice (Pediculus humanus corporis) of the same age group and from the same stock colony are placed on a 2 x 2cm coarse mesh patch. The sample to be tested, maintained at room temperature, is shaken and placed into a 50ml beaker.The mesh patch is placed into the sample immediately after pouring, allowed to submerge, and after two minutes is removed and immediately plunged into the beaker containing tap water. The patch is vigorously agitated every ten secounds and after one minute the patch is removed and placed on paper toweling. The lice are then transferred to a 4 x 4cm black corduroy cloth patch and this point of time is considered zero hours. Thereafter, the corduroy patch is placed in a petri dish which is covered and stored in a 30"C holding chamber.

Ovicidal activity 15 adult, 5 to 10 day old, female lice (Pediculus humanus corporis) are placed on a 2 x 2cm nylon mesh patch which is placed on a petri dish, covered and maintained in an incubator at.30 C for 24 hours. The adult lice are then removed and the number of plump viable eggs and shriveled non-fertile eggs on the patch are recorded. The sample to be tested, maintained at. room temperature, is shaken and poured into a 50ml beaker.

Immediately after the pouring, the mesh patch is placed into the beaker, allowed to submerge, and after two minutes is removed and immediately plunged into a 50ml beaker containing tap water at room temperature (about 24"C). The patch is vigorously agitated every ten seconds, and after one minute, the patch is removed and placed on paper toweling for one minute. The patch is then placed in a petri dish which is covered and stored in the 30"C incubator.

Fourteen days followiny treatment, the number of hatched eggs and the number of shriveled or unhatched eggs is noted.

In both two minute immersion tests, controls are run in identical manner to that described with room temperature (24or) tap water substituted for the sample to be tested.

The amount of the at least one fatty acid ester in the present composition will depend, amongst other factors, on the fatty acid ester used, and the choice of lousicide and alcoholic solution. Preferably, the composition contains between 5 and 20% (v/v), especially between 5 and 15% (v/v), of the fatty acid ester.

The amount of the alcoholic solution in the present composition must be sufficient to dissolve both the at least one lousicide and the at least one fatty acid ester.

Preferably, the composition contains between 70 and 95% (v/v), especially between 80 and 95% (v/v) of the alcoholic solution.

The present topical, lousicidal composition must be substantially non-irritant to human skin. In the present specification, the phrases "without irritating the skin of said (human) subjects" and "substantially non-irritant to human skin" means that more than 80, preferably more than 9U, patients out of every 100 patients show no reaction to the topical, lousicidal composition.

The present composition is used to control lice or their ova in humans, by applying the composition to a site of infestation or to a site believed to be infested.

Alternatively, the composition may be used prophylactically to prevent infestation.

In a further aspect of the present invention, there is provided a topical, lousicidal composition for controlling lice or their ova comprising a lousicidally effective amount of at least one lousicide selected from carbaryl, malathion or phenothrin and 5 to 20% (v/v) of at least one C2-C4 alkyl ester of a C10-C20 fatty acid dissolved in 70-95% (v/v) of an alcoholic solution, the composition being substantially non-irritant to human skin.

In a still further aspect of the present invention there is provided a process for the preparation of a topical, lousicidal composition that is substantially non-irritant to human skin comprising dissolving a lousicidally effective amount of at least one lousicide selected from carbaryl, malathion or phenothrin and 5 to 20% (v/v) of at least one C2-C4 alkyl ester of a C10-C20 fatty acid in 70-95% (v/v) of an alcoholic solution.

The present topical, lousicidal composition and processes for its preparation will now be described by way-of Example only.

Example 1 (Malathion Lotion) A solution was prepared by mixing isopropyl myristate (1O()ml), golden delicious perfume P15498 (5ml) and isopropanol (678ml).

To this solution was added malathion (5.0gm) and the whole was mixed until homogeneous. A further aliquot of isopropanol was then added to bring the volume of the composition to 1000ml and the whole was again mixed until homogeneous.

Example 2 (Phenothrin Lotion) The procedure of Example 1 was followed except that phenothrin (2.0gm) replaced malathion and herbal green bouquet (5.0ml) replaced golden delicious perfume P15498.

Comparative Example (Malathion Lotion) A lotion having the following formulation was prepared, Malathion 0.525% (w/v) Terpineol 11.0 (v/v) Dipentene 10.0 (v/v) Perfume 07676 0.25 (v/v) Isopropanol to 100.0 (v/v) Irritancy Test Malathion lotions (Example 1 and Comparative Example) were tested using a routine repeat insult schedule of applications with assessment over a 24 day period.

The procedure was as follows: Day 1 Apply materials under occlusion Day. 3 Remove, wait 15 minutes, assess, re-apply Day 5 Remove, wait 15 minutes, assess, re-apply Day 8 Remove, wait 15 minutes, assess, re-apply Day 10 Remove, wait 15 minutes, assess, re-apply Day 12 Remove, wait 15 minutes, assess, re-apply Day 15 Remove, wait 15 minutes, assess, Day 22 Apply materials under occlusion Day 24 Remove, wait 15 minutes, assess re-application This technique of repeat insult supplied a maximal cutaneous stimulus which was designed to reveal low order of irritancy and sensitisation potential.

At each assessment time the sites were graded on a 0-6 scale, as follows: 0 = No reaction 1 = Slight erythema 2 = Moderate erythema 3 = Strong erythema with some swelling 4 = Erythema, swelling and vesiculation 5 = Marked erythema, spreading outside patch 6 = Severe reaction with erosion All repeat applications were of the same materials to the same sites, but no re-application was made to any site showing a reaction at any time that was graded "2" or more on the above scale of assessment.

After the sixth grading (day 15) the sites were left untreated for a seven day period. On day 22 the materials were re-applied to new sites, occluded as before, and a final assessment was made on day 24 to check for any delayed hypersensitivity.

Fifty-two patients were treated with "Comparative Example" lotion and 100 patients were treated with the "Example 1" lotion.

A summary of the results is presented in the following table.

Irritancy scores / Sensitisation scores Lotion 2 1 0 2 1 0 Comparative 50 0 2 - - Example I Example 1 1 1 0 99 1 2 5 93 1 - Product not re-applied in these subjects Efficacy Trial A study was conducted using phenothrin lotion (Example 2) in 23 patients.

Patient's scalps were examined for evidence of the live lice and/or viable eggs (Visit 1). This was recorded together with details of the patient's age and sex. Each patient was issued with a bottle of phenothrin lotion (Example 2).

Instructions were issued that the lotion should be applied on one occasion to all parts of the hair and scalp, and that it should be left on the hair for 2 hours. Patients were requested to return for re-inspection after 24 hours (Visit 2). At this second visit a record was again made of any live lice and/or viable eggs.

Patients returned three weeks after treatment (Visit 3), when a final inspection for live or viable eggs was carried out.

RESULTS (i) Patients A total of 23 patients were entered into the study, 7 male and 16 female.

(ii) Infestation prior to treatment (Visit 1) All 23 patients had evidence of live lice, viable eggs or both no entry to the study.

(iii) Infestation following treatment (Visit 2) Patients were requested to attend for re-inspection approximately 24 hours following treatment. At this second visit, no patients had evidence of live lice, although 6 had viable eggs.

(iv) Infestation at final follow-up (Visit 3) Patients were requested to return for final inspection 3 weeks following treatment. At this final inspection, no patients showed any evidence of live lice or viable eggs.

Details of head infestation over the study period are given in the Table.

Table - Infestation of each of the 3 visits

I I Live Lice Viable Eggs Both Visit 1 10(n=23) 23 9 (n=23) (pre-treatment) Visit 2 (24 hrs I O(n=22) 1 6(n=22) | 0(n=22) I post-treatement) Visit 3 (21 days 0(n=21) 0(n=21) 0(n=21) post-treatment)

Claims

CLAIMS 1. A method for controlling lice or their ova on human subjects without irritating the skin of said subjects comprising applying to a human subject a topical, lousicidal composition comprising a lousicidally effective amount of at least one lousicide and at least one C2-C4 alkyl ester of a C10-C20 fatty acid dissolved in an alcoholic solution.
2. A method according to claim 1 wherein the at least one lousicide comprises carbaryl, malathion or phenothrin.
3. A method according to claim 2 wherein the at least one lousicide comprises 0.25% to 1.25% (w/v) carbaryl, 0.25% - 1.25% (w/v) malathion or 0.1%-0.5% (w/v) phenothrin.
4. A method according to claim 3 wherein the at least one lousicide comprises 0.5% to 1.0% (w/v) carbaryl, 0.5% - 1.Ut (w/v) malathion or 0.2% - 0.4% (w/v) phenothrin.
5. A method according to any one of claims 1 to 4 wherein the at least one alkyl ester comprises a C3-C4 alkyl ester of a C14-C18 fatty acid.
6. A method according to claim 5 wherein the at least one alkyl ester comprises butyl stearate, isobutyl stearate, butyl oleate or isopropyl myristate
7. A method according to claim 6 wherein the at least one alkyl ester comprises isopropyl myristate.
8. A method according to any one of claims 1 to 7 wherein the composition comprises 5-20% (v/v) of the at least one alkyl ester.
9. A method according to claim 8 wherein the composition comprises 5-15% (v/v) of the at least one alkyl ester.
10. A method according to any one of claims 1 to 9 wherein the alcoholic solution comprises at least one C2-C4 alkyl alcohol.
11. A method according to claim 10 wherein the alcoholic solution comprises at least one C3-C4 alkyl alcohol.
12. A method according to claim 11 wnerein the alcoholic solution comprises n-propanol, isopropanol or tert.butyl alcohol.
13. A method according to claim 12 wherein the alcoholic solution comprises isopropanol.
14. A method according to claim 13 wherein the composition comprises 70-95% (v/v) of the alcoholic solution.
15. A method according to claim 14 wherein the composition comprises 80-95% (v/v) of the alconolic solution.
16. A method for controlling lice or their ova on human subjects without irritating the skin of said subjects substantially as hereinbefore described.
17. A topical, lousicidal composition for controlling lice or their ova comprising a lousicidally effective amount of at least one lousicide selected from carbaryl, malathion or phenothrin and 5-20% (v/v) of at least one C2-C4 alkyl ester - of a C10-C20 fatty acid dissolved in 70-95; (v/v) of an alcoholic solution, the composition being substantially non-irritant to human skin.
18. A composition according to claim 17 wherein the at least one lousicide comprises 0.5 - 1.0% (w/v) carbaryl, 0.5% - 1.0% (w/v) malathion or 0.2% - 0.4% (w/v) phenothrin.
19. A composition according to either claim 17 or claim 18 wherein the alkyl ester comprises isopropyl myristate.
20. A composition according to any one of claims 17 to 19 wherein the alcoholic solution comprises isopropanol.
21. A topical, lousicidal composition for controlling lice or their ova according to claim 17 substantially as hereinbefore described with particular reference to either Example 1 or Example 2.
22. A process for the preparation of a topical, lousicidal composition that is substantially non-irritant to human skin comprising dissolving a lousicidally effective amount of at least one lousicide selected from carbaryl, malathion or phenothrin and 5-20% (v/v) of at least one C2-C4 alkyl ester of a C10-C20 fatty acid in 70-95% (v/v) of an alcoholic solution.
23. A process for the preparation of a topical, lousicidal composition according to claim 22 substantially as hereinbefore described with particular reference to either Example 1 or Example 2.