Increased Norfloxacin Skin Permeability for Fatty Alcohol Propylene Glycol (FAPG) Ointment by Optimized Process of Preparation: Behavior of Stearic Acid in Stratum Corneum Lipids

摘要

Preparation of the fatty alcohol propylene glycol (FAPG) ointment base plays an important role in controllj^ the physicochemical properties of ointments. This essay investigates the effects of preparative conditions such " cooling rate and stirring rate on the percutaneous absorption of norfloxacin from FAPG ointment. The influence ^ process-induced variation in enhancing effect of stearic acid which was incorporated into FAPG base was evaluate -in vityo on rat skin. In the permeation experiment, norfloxacin penetration significantly increased with faster coolj rate. This result directly related to the increasing norfloxacin skin-vehicle partition coefficient. Histological a results showed no appreciable exfoliation of the stratum corneum. The differential scanning calorimetry q results show that stearic acid enriched lipid in the stratum corneum resulting from treatment with supercooli^ products may result in more crystalline structure and, hence, preferential partitioning of the norfloxacin into ttie more crystalline regions of the membrane can be observed. A much greater enhancing effect can be achieved whe^, we use stearic acid together with norfloxacin in propylene glycol (PG); but such effect cannot be found if 5 wt% stearic acid/PG suspension is used to pretreat skin before the application of norfloxacin PG solution.