Monoolein liquid crystalline phases for topical delivery of crocetin.

The present investigation concerns the production and characterization of monoolein-water systems designed for cutaneous administration of crocetin. The different monoolein crystalline phases forming in the presence of crocetin as a function of added water have been investigated by x-ray and polarized light microscopy. Franz cell was employed to compare in vitro the crocetin diffusion from selected monoolein water systems containing 95, 90 or 75% w/w of monoolein, while to investigate the performance of monoolein-water as transdermal delivery systems, in vivo studies, based on tape stripping were performed. The presence of micellar, lamellar and Q230 phases was found in the case of systems containing monoolein 95, 90 and 75% w/w respectively, with a viscosity almost directly proportional to the amount of added water. The higher the amount of water, the longer the crocetin stability, while its diffusion was slower in the case of more viscous systems. Tape stripping results indicated a more rapid depletion of crocetin on stratum corneum in the case of systems characterized by cubic phases, followed by micellar and lamellar ones. This behaviour could be related to a more rapid drug penetration throughout the deeper skin strata.