Skin barrier modulation by Hibiscus rosa-sinensis L. mucilage for transdermal drug delivery

Abstract

Transdermal drug delivery system provides continuous controlled delivery of active ingredients through the human skin and into the bloodstream. Poor penetration of most drugs into the skin has led to numerous studies being conducted to increase their permeability. The present study investigated the ability of Hibiscus rosa-sinensis L. (HRS) leaves mucilage, a novel source of polysaccharide in modifying skin barrier for transdermal drug delivery. Dried-powdered mucilage was extracted from the leaves and was transformed into HRS gels using three concentrations of HRS mucilage, namely 1 (CL1), 1.5 (CL1.5), and 2 (CL2) % (w/w) while caffeine was employed as a model drug. The in vitro drug release and permeation profiles of caffeine were examined using vertical diffusion cells. Physicochemical properties of HRS mucilage were characterized, and the morphological and structural features of skin samples were evaluated using scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, as well as differential scanning calorimetry. The HRS gel of CL2 demonstrated a significantly highest drug permeation when compared to caffeine solution, CL1, and CL1.5 (ANOVA: p < 0.05). HRS mucilage in the form of a gel altered the barrier and permeability of skin by perturbing the lipid and protein structures, acting on the helical keratin filaments as well as through the O–H and/or N–H interactions. These were then reduced the diffusional resistance for drug transport and increased the drug permeation. The optimal concentration of HRS mucilage at 2% (w/w) was deemed useful in facilitating the transdermal delivery of caffeine.