Lipid based liquid-crystalline stabilized formulations for the sustained release of bioactive hydrophilic molecules.

Lipid based formulations, endowed of long term stability as a result of the formation of lamellar liquid crystals, were prepared using the natural lipids lecithin and glycerol trioleate in water, and characterized using optical microscopy, SAXRD and NMR. The formulations, designed as possible carriers for lysozyme and caffeine, were evaluated for structural features and stability after the loading of the guest molecules. Release experiments were performed at 37 °C using the PBS medium. No burst release was observed either for lysozyme or caffeine. Although lysozyme released from the lipid formulations does not fully retain its biological activity, the investigated liquid crystal stabilized formulations display a promising potential as drug and cosmetic carriers for topical applications, due to their high biocompatibility.