Dermatological compositions comprising avermectin nanocapsules

1. A composition comprising lipid nanocapsules, said lipid nanocapsules comprising:

(a) an oily inner phase consisting of diisopropyl adipate and at least one physically and chemically stable avermectin compound solubilized in said diisopropyl adipate; and

(b) a surfactant comprising soybean and/or egg lecithin(s) having a hydrogenated phosphatidylcholine content of greater than 70% by weight, said surfactant being lipophilic, solid at room temperature and coating said oily inner phase;

said lipid nanocapsules being dispersed in a continuous hydrophilic phase;

said composition being devoid of any surfactant(s) other than said lecithin(s);

said composition being devoid of any organic solvent(s) other than said diisopropyl adipate;

said composition being devoid of propenetrating agents;

said composition being physically stable at 4° C., ambient temperature and 40° C., for a period of two months;

said avermectin compound being chemically stable in said composition at 4° C., ambient temperature and 40° C., for a period of three months.

2. The composition as defined by claim 1 , said at least one avermectin compound being selected from the group consisting of ivermectin, invermectin, avermectin, abamectin, doramectin, eprinomectin and selamectin.

3. The composition as defined by claim 1 , said lecithin(s) comprising between 0.1 and 10% by weight relative to the total weight thereof.

4. The composition as defined by claim 1 , formulated for topical administration.

5. The composition as defined by claim 1 , said composition being in the form of a nanoemulsion.

6. The composition as defined by claim 1 , formulated for oral administration.

7. The composition as defined by claim 4 , formulated as a cream, milk, ointment, impregnated pad, syndet, wipe, gel, spray, foam, lotion, stick, shampoo or cleansing base.

8. The composition as defined by claim 6 , formulated as gelatin capsules, sugar-coated tablets or syrups.

9. A composition comprising lipid nanocapsules, said lipid nanocapsules comprising:

(a) an oily inner phase consisting of diisopropyl adipate and at least one physically and chemically stable avermectin compound solubilized in said diisopropyl adipate; and

(b) a surfactant comprising soybean and/or egg lecithin(s) having a hydrogenated phosphatidylcholine content of greater than 70% by weight, said surfactant being lipophilic, solid at room temperature and coating said oily inner phase;

said lipid nanocapsules being dispersed in a continuous hydrophilic phase; and

said composition further comprising a gelling agent which is a cellulose derivative selected from the group consisting of methylcellulose, ethylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, hydroxymethylcellulose and hydroxypropylcellulose, and mixtures thereof;

said composition being devoid of any surfactant(s) other than said lecithin(s);

said composition being devoid of any organic solvent(s) other than said diisopropyl adipate;

said composition being devoid of propenetrating agents;

said composition being physically stable at 4° C., ambient temperature and 40° C., for a period of nine months;

said avermectin compound being chemically stable in said composition at 4° C., ambient temperature and 40° C., for a period of three months.

10. The composition as defined by claim 9 , said lecithin(s) comprising from 0.1 to 10% by weight relative to the total weight thereof.

11. The composition as defined by claim 9 , comprising by weight relative to the total weight thereof:

(a) 0.1 to 5% of lecithin(s);

(b) 1 to 20% of diisopropyl adipate;

(c) 0.1 to 5% of avermectin compound; and

(d) up to 2% of cellulose derivative.

12. The composition as defined by claim 9 , formulated for topical administration.

13. The composition as defined by claim 9 , formulated for oral administration.

14. The composition as defined by claim 12 , formulated as a cream, milk, ointment, impregnated pad, syndet, wipe, gel, spray, foam, lotion, stick, shampoo or cleansing base.

15. The composition as defined by claim 13 , formulated as gelatin capsules, sugar-coated tablets or syrups.

16. A composition comprising lipid nanocapsules, said lipid nanocapsules comprising:

(a) an oily inner phase consisting of diisopropyl adipate and an avermectin compound solubilized in said diisopropyl adipate; and

(b) a surfactant comprising soybean and/or egg lecithin(s) having a hydrogenated phosphatidylcholine content of greater than 70% by weight, said surfactant being lipophilic, solid at room temperature and coating said oily inner phase;

said lipid nanocapsules being dispersed in a continuous hydrophilic phase;

said composition being devoid of any surfactant(s) other than said lecithin(s);

said composition being devoid of any organic solvent(s) other than said diisopropyl adipate;

said composition being devoid of propenetrating agents;

said composition being physically and chemically stable at 4° C., ambient temperature and 40° C., for a period of at least two months.

17. A composition comprising lipid nanocapsules, said lipid nanocapsules comprising:

(a) an oily inner phase consisting of diisopropyl adipate and an avermectin compound solubilized in said diisopropyl adipate; and

(b) a surfactant comprising soybean and/or egg lecithin(s) having a hydrogenated phosphatidylcholine content of greater than 70% by weight, said surfactant being lipophilic, solid at room temperature and coating said oily inner phase;

said lipid nanocapsules being dispersed in a continuous hydrophilic phase; and

said composition further comprising a gelling agent which is a cellulose derivative selected from the group consisting of methylcellulose, ethylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, hydroxymethylcellulose and hydroxypropylcellulose, and mixtures thereof;

said composition being devoid of any surfactant(s) other than said lecithin(s);

said composition being devoid of any organic solvent(s) other than said diisopropyl adipate;

said composition being devoid of propenetrating agents;

said composition being physically and chemically stable at 4° C., ambient temperature and 40° C., for a period of at least three months.

18. A method for the treatment of rosacea, comprising administering to an individual in need of such treatment an effective amount of the composition as defined by claim 1 .

19. A method for preparing the composition as defined by claim 1 , comprising the following steps:

(i) solubilizing at least one avermectin compound in diisopropyl adipate to obtain the oily phase;

(ii) mixing hydrophilic compounds to obtain the hydrophilic phase;

(iii) dispersing the lecithin(s) in the oily phase obtained in (i) or in the hydrophilic phase obtained in (ii);

(iv) mixing the oily phase with the hydrophilic phase;

(v) introducing the mixture obtained in (iv) into a High-Pressure Homogenizer, to obtain a nanoemulsion.

20. A method as defined by claim 19 , comprising a step (vi) of adding a gelling agent to the nanoemulsion obtained in (v).