Topical Avermectin Formulations and Methods For Elimination and Prophylaxis of Susceptible and Treatment Resistant Strains of Head Lice

Abstract

An avermectin-based topical formulation is disclosed which is useful for prevention and treatment of head lice (Pediculus humanus capitis). This topical formulation may be formulated as a shampoo-condition which comprises an effective amount of avermectin, solubilizers, suspending agents, preservatives, nonionic surfactants, humectants, a silicone compound, and water. Also disclosed are methods of using the topical formulations disclosed within this specification to treat either a susceptible or treatment-resistant strain of lice, as well as uses in the manufacture of a medicament for treating or preventing a lice infestation from a susceptible or treatment-resistant strain in a human patient.

1 .- 20 . (canceled) 
     
     
         21 . A method for treatment or prophylaxis of a lice infestation, the method comprising:
 (a) applying a pediculicidal formulation to a human scalp infested with lice; wherein the pediculicidal formulation comprises:
 about 0.1% to about 2.0% by weight ivermectin; 
 less than about 30% of a pharmaceutically acceptable glycol; 
 at least one suspending agent; 
 about 10 to about 35% of at least one non-iononic surfactant; and 
 water, 
   (b) maintaining the topical pediculicidal formulation on the scalp for about 1 to about 60 minutes to provide treated lice; and   (c) removing the pediculicidal formulation from the scalp,   wherein the treated lice have a faster mortality response than lice treated with unformulated 0.5% ivermectin.   
     
     
         22 . The method of  claim 21 , wherein the pediculicidal formulation is packaged as a single dose. 
     
     
         23 . The method of  claim 21 , wherein the pediculicidal formulation comprises about 0.5% by weight ivermectin. 
     
     
         24 . The method of  claim 21 , wherein the at least one suspending agent is selected from the group consisting of fatty oils, fats and combinations thereof. 
     
     
         25 . The method of  claim 21 , wherein the pediculicidal formulation comprises at least two suspending agents, wherein the at least two suspending agents comprise a fatty oil and a fat. 
     
     
         26 . The method of  claim 25 , wherein the fatty oil is olive oil. 
     
     
         27 . The method of claim  5 , wherein the fat is shea butter. 
     
     
         28 . The method of  claim 21 , wherein the pediculicidal formulation comprises at least two non-ionic surfactants. 
     
     
         29 . The method of  claim 28 , wherein the at least two non-ionic surfactants are selected from the group consisting of fatty alcohols, sorbitan tristearate and combinations thereof. 
     
     
         30 . The method of  claim 29 , wherein the fatty alcohol is selected from the group consisting of oleyl alcohol, lanolin alcohol and combinations thereof. 
     
     
         31 . The method of claim  1 , wherein the pediculicidal formulation comprises less than about 25% of a pharmaceutically acceptable glycol. 
     
     
         32 . The method of  claim 21 , wherein the pediculicidal formulation comprises less than about 20% of a pharmaceutically acceptable glycol. 
     
     
         33 . The method of  claim 21 , wherein the pediculicidal formulation comprises less than about 15% of a pharmaceutically acceptable glycol. 
     
     
         34 . The method of  claim 21 , wherein the pediculicidal formulation comprises less than about 10% of a pharmaceutically acceptable glycol. 
     
     
         35 . The method of  claim 21 , wherein the pediculicidal formulation has the texture of a gel or shampoo-conditioner. 
     
     
         36 . The method of  claim 21 , wherein the pediculicidal formulation has the texture of a lotion. 
     
     
         37 . The method of  claim 21 , wherein the non-ionic surfactant is selected from stearyl acetate, oleyl acetate and combinations thereof. 
     
     
         38 . The method of  claim 21 , wherein the pediculicidal formulation is maintained on the scalp for about 3 to about 60 minutes. 
     
     
         39 . The method of  claim 21 , wherein the pediculicidal formulation is maintained on the scalp for about 10 minutes. 
     
     
         40 . The method of  claim 21 , further comprising (d) removing the pediculicidal formulation from the scalp by rinsing.