Stable Pexiganan Formulation

Abstract

The invention provides chemically and physically stable topical formulations of pexiganan, and methods of preparing the same.

What is claimed is: 
     
         1 . A topical formulation comprising pexiganan or an acid addition salt thereof comprising a first hydrophilic surfactant having an HLB value between about 12 and about 17 and a second hydrophobic surfactant having an HLB value between about 3.5 and about 5.5, wherein the first hydrophilic and second hydrophobic surfactants comprise from about 1.5% w/w to about 5.0% w/w of the formulation and the weight ratio of the first to second surfactants is such that the blended HLB is between 12.5 and about 14.5. 
     
     
         2 . The topical formulation of  claim 1 , wherein the HLB value of the first hydrophilic surfactant is between about 13 and about 16. 
     
     
         3 . The topical formulation of  claim 1 , wherein the HLB value of the first hydrophilic surfactant is 14.9. 
     
     
         4 . The topical formulation of  claim 1 , wherein the HLB value of the second hydrophobic surfactant is between about 3.5 and about 5.5. 
     
     
         5 . The topical formulation of  claim 1 , wherein the HLB value of the second hydrophilic surfactant is 4.7. 
     
     
         6 . The topical formulation of  claim 1 , wherein the first hydrophilic and second hydrophobic surfactants comprise from about 2% w/w to about 4.5% w/w of the formulation. 
     
     
         7 . The topical formulation of  claim 1 , wherein the first hydrophilic and second hydrophobic surfactants comprise about 3.5% w/w of the formulation. 
     
     
         8 . The topical formulation of  claim 1 , wherein the blended HLB of the first hydrophilic and second hydrophobic surfactants is between about 12.5 and about 14.5. 
     
     
         9 . The topical formulation of  claim 1 , wherein the blended HLB of the first hydrophilic and second hydrophobic surfactants is 13.6. 
     
     
         10 . The topical formulation of  claim 1 , wherein the first hydrophilic surfactant is Tween 60 and the second hydrophobic surfactant is Span 60. 
     
     
         11 . A stable topical formulation comprising:
 (i) 1.05 (% w/w) pexiganan acetate   (ii) 20.0 (% w/w) propylene glycol   (iii) 0.1 (% w/w) EDTA   (iv) 7.5 (% w/w) stearyl alcohol   (v) 2.0 (% w/w) cetyl alcohol   (vi) 1.0 (% w/w) isopropyl myristate   (vii) 0.1 (% w/w) BHT   (viii) 0.43 (% w/w) Span 60   (ix) 3.07 (% w/w) Tween 60   (x) 0.1 (% w/w) Tween 80 and   (xi) (q.s.a.d.) sodium acetate buffer.   
     
     
         12 . A stable topical formulation comprising:
 (i) 1.05 (% w/w) pexiganan acetate   (ii) 20.0 (% w/w) propylene glycol   (iii) 0.1 (% w/w) EDTA   (iv) 6.0 (% w/w) stearyl alcohol   (v) 2.0 (% w/w) cetyl alcohol   (vi) 3.0 (% w/w) isopropyl myristate   (vii) 0.1 (% w/w) BHT   (viii) 0.17 (% w/w) Span 60   (ix) 3.33 (% w/w) Tween 60   (x) 0.1 (% w/w) Tween 80 and   (xi) (q.s.a.d.) sodium acetate buffer.   
     
     
         14 . A method of treating a skin or wound infection comprising topically applying to a patient in need thereof at the site of infection an effective amount of a topical formulation of  claim 1 .