Progesterone solubilization within reverse hexagonal mesophase

Abstract

The present work reports on the preparation and characterization of progesterone-loaded reverse hexagonal (HII) mesophase based on a glycerol monooleate (GMO)/tricaprylin (TAG)/water mixture for transdermal application.Several compositions into which progesterone was quantitatively solubilized were selected and used in the present study in order to evaluate the effect of the hormone on structural transitions and characteristics.A GMO/TAG of 90:1wt ratio with 20wt% water was found to form HII mesophases with relative high solubilization capacity of 4wt% progesterone and a shelf life of over one year. The structures were identified by cross-polarized light microscopy (CPLM). Structural confirmations were obtained from small-angle X-ray scattering (SAXS) measurements. The hormone is solubilized at the interface of the HII mesophase as confirmed by SAXS, rheology, FTIR, and DSC. The progesterone, which is loaded onto reverse hexagonal cylinders, leads to strengthening the hydrogen bonding and to better packing of the HII mesophase, suggesting that progesterone is a kosmotropic agent.The reverse hexagonal mesophase seems to be a promising carrier for solubilization of progesterone.