Influence of nonionic liposomal composition on topical delivery of peptide drugs into pilosebaceous units: an in vivo study using the hamster ear model.

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.