PURPOSE: The purpose of this study was to test the hypothesis that nonionic liposomes facilitate the topical delivery of peptide drugs into pilosebaceous units. METHODS: The hamster ear was used as a model for human pilosebaceous units. The deposition of a hydrophilic protein, alpha-interferon (alpha-IFN), into pilosebaceous units and other strata of the hamster ear 12 hours after topical in vivo application of three nonionic liposomal formulations, one composed of glyceryl dilaurate/cholesterol/polyoxyethylene-10-stearyl ether (Non-1), the second composed of glyceryl distearate/cholesterol/polyoxyethylene-10-stearyl ether (Non-2) and the third composed of polyoxyethylene-10-stearyl ether/cholesterol (Non-3), a phospholipid-based liposomal formulation (PC) and an aqueous control solution (AQ) was determined. We also determined the deposition of a hydrophobic peptide, cyclosporin-A (CsA), into pilosebaceous units and other strata of the hamster ear after topical in vivo application of these liposomal formulations and a hydroalcoholic control solution (HA). RESULTS: The deposition of alpha-IFN into the pilosebaceous units was in the order: Non-1 >> PC > Non-2 > Non-3 = AQ. The deposition of CsA into the pilosebaceous units was in the order: Non-1 >> HA > PC > Non-2 = Non-3. CONCLUSIONS: Despite differences in the hydrophobicities and size of the drug molecules, deposition into the various ear strata was significantly enhanced by the Non-1 liposomal system.
PURPOSE: The purpose of this study was to test the hypothesis that nonionic liposomes facilitate the topical delivery of peptide drugs into pilosebaceous units. METHODS: The hamster ear was used as a model for human pilosebaceous units. The deposition of a hydrophilic protein, alpha-interferon (alpha-IFN), into pilosebaceous units and other strata of the hamster ear 12 hours after topical in vivo application of three nonionic liposomal formulations, one composed of glyceryl dilaurate/cholesterol/polyoxyethylene-10-stearyl ether (Non-1), the second composed of glyceryl distearate/cholesterol/polyoxyethylene-10-stearyl ether (Non-2) and the third composed of polyoxyethylene-10-stearyl ether/cholesterol (Non-3), a phospholipid-based liposomal formulation (PC) and an aqueous control solution (AQ) was determined. We also determined the deposition of a hydrophobic peptide, cyclosporin-A (CsA), into pilosebaceous units and other strata of the hamster ear after topical in vivo application of these liposomal formulations and a hydroalcoholic control solution (HA). RESULTS: The deposition of alpha-IFN into the pilosebaceous units was in the order: Non-1 >> PC > Non-2 > Non-3 = AQ. The deposition of CsA into the pilosebaceous units was in the order: Non-1 >> HA > PC > Non-2 = Non-3. CONCLUSIONS: Despite differences in the hydrophobicities and size of the drug molecules, deposition into the various ear strata was significantly enhanced by the Non-1 liposomal system.