Reverse hexagonal phase nanodispersion of monoolein and oleic acid for topical delivery of peptides: in vitro and in vivo skin penetration of cyclosporin A.

Purpose: To obtain and characterize reverse hexagonal phase nanodispersions of monoolein and oleic acid, and to evaluate the ability of such system to improve the skin penetration of a model peptide (cyclosporin A, CysA) without causing skin irritation.

Methods: The nanodispersion was prepared by mixing monoolein, oleic acid, poloxamer, and water. CysA was added to the lipid mixture to obtain a final concentration of 0.

Cryo-TEM investigation of phase behaviour and aggregate structure in dilute dispersions of monoolein and oleic acid.

Cryo-transmission electron microscopy (cryo-TEM) was used to image the microstructure in dilute sonicated dispersions of monoolein and oleic acid. The aim of the study was to explore how different experimental parameters, such as sample composition, total lipid concentration, pH, and ageing affect the phase behaviour and aggregate structure. Our investigations show that a rich variety of lamellar and non-lamellar structures, including liposomes and particles of cubic and inverted hexagonal phase, may form depending on the experimental conditions.