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