Dermal Application of Chloramphenicol - The Effect of Liposomes and Chitosan Hydrogel Formulations on ex vivo Permeation and Antimicrobial Activity

Abstract

Liposomes solubilize lipophilic drugs in the phospholipid membrane, and entrap hydrophilic drugs in its aqueous core. These vesicles provide a sustained- and targeted- drug release, and protect from degradation. Liposomes retain the drug onto/in the skin and improve skin drug deposition. Due to their liquid nature, a secondary vehicle, such as a hydrogel, is needed to obtain a necessary retention and bioadhesion onto the skin surface. Chloramphenicol (CAM) is an antimicrobial drug that, due to its bone marrow toxicity, is mainly applied in the treatment of eye and ear infections. When applied dermally to treat skin infections, systemic absorption should be avoided. The chitosan (CS) hydrogel with inherent antimicrobial activity might improve the antimicrobial activity. In this study, we investigated the effect of both the liposomal carrier and the CS-hydrogel on the retention and permeation of CAM through pig skin ex vivo. Four different formulations were compared; CAM aqueous solution (CAM-Sol), CAM in a liposome dispersion (CAM-Lip), CAM dissolved in chitosan hydrogel (CAM-CS) and CAM in a liposome-in-hydrogel formulation (CS-CAM-Lip). Finally, the antimicrobial activity of CSCAM-Lip and CAM-Sol was compared.