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 . A topical formulation comprising
 about 0.1% to about 2.0% by weight ivermectin,   at least one solubilizer,   at least one suspending agent,   at least one paraben preservative,   at least one non-ionic surfactant, and   about 30% to 40% by weight water.   
     
     
         2 . The topical formulation of  claim 1 , comprising about 0.5% by weight ivermectin. 
     
     
         3 . (canceled) 
     
     
         4 . The topical formulation of  claim 1 , wherein said solubilizer is selected from the group consisting of polysorbate 80, cetyl acetate, acetylated lanolin alcohol and combinations thereof. 
     
     
         5 . The topical formulation of  claim 1 , wherein the preservative is selected from the group consisting of methylparaben, propylparaben, ethylparaben, butylparaben, isobutylparaben, isopropylparaben, or benzylparaben, sodium salts thereof, and combination thereof. 
     
     
         6 . The topical formulation of  claim 1 , wherein said nonionic surfactant is selected from the group consisting of oleyl alcohol, lanolin alcohol, sorbitan tristerate, bees wax, erucyl alcohol, ricinolyl alcohol, arachidyl alcohol, capryl alcohol, capric alcohol, behenyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol, palmitoleyl alcohol, linoleyl alcohol, elaidyl alcohol, elaidolinoleyl alcohol, linolenyl alcohol, elaidolinolenyl alcohol, glycerine, glyceryl triacetate, sorbitol, xylitol, maltitol, polydextrose, quillaia, lactic acid, urea, and combinations thereof. 
     
     
         7 . The topical formulation of  claim 6 , wherein said nonionic surfactant is selected from the group consisting of oleyl alcohol, lanolin alcohol, acetylated lanolin alcohol, sorbitan tristearate, and combinations thereof. 
     
     
         8 . The topical formulation of  claim 1 , further comprising a conditioner. 
     
     
         9 . The topical formulation of  claim 8 , wherein said conditioner is selected from the group consisting of cyclomethicone, dimethicone, hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, dodecamethylpentasiloxane, polydimethylsiloxanes, and combinations thereof. 
     
     
         10 . The topical formulation of  claim 1 , formulated as a cream, gel, or pomade. 
     
     
         11 . The topical formulation of  claim 1  prepared according to a method comprising:
 (a) preparing a first solution by dissolving ivermectin in the at least one solubilizer; and 
 (b) adding to the first solution a second solution comprising the at least one suspending agent, the at least one paraben preservative, and the at least one non-ionic surfactant; and 
 (c) dispersing the mixture of (b) in water. 
 
     
     
         12 . (canceled) 
     
     
         13 . A method of treating a head lice infestation in a human patient comprising topically administering to said patient the topical formulation of  claim 1  in one dosage or multiple dosages. 
     
     
         14 . The method of  claim 13 , wherein said human patient is a child. 
     
     
         15 . The method of  claim 13 , wherein at least about 60 mL of the topical formulation is applied to said human patient. 
     
     
         16 . The method of  claim 13 , wherein about 1 mL to about 100 mL of the topical formulation is applied to said human patient. 
     
     
         17 . The method of  claim 13 , wherein said topical formulation is left on the scalp for about 1 to about 60 minutes. 
     
     
         18 . The method of  claim 17 , wherein said topical formulation is left on the scalp for about 3 minutes, about 5 minutes, or about 10 minutes. 
     
     
         19 . The method of  claim 13  wherein the topical formulation is administered as a single dose. 
     
     
         20 . The method of  claim 13  wherein the topical formulation is administered as an initial dosage with one or two additional dosages. 
     
     
         21 . The topical formulation of  claim 1 , wherein the at least one suspending agent comprises a combination of fatty oils and fats.