Advanced delivery system for skin and burns therapy : mupirocin as an antibacterial model drug

Abstract

Trauma to the skin in the form of severe wound, particularly burns, can facilitate colonization of potentially life threatening bacterial infections. To prevent infections of the wounded area, antimicrobial agents are recommended as standard treatment. Topical administration of antimicrobial agents, such as mupirocin, can provide local therapy, while avoiding the risks of systemic administration. Mupirocin-in-liposomes-in hydrogels were proposed as advanced delivery system for this purpose. Up to now, no liposomal mupirocin for topical administration has been reported. Chitosan was selected as hydrogel matrix due to its biodegradability and in-built antimicrobial and wound healing potentials. Phosphatidylcholine liposomes containing mupirocin, namely non-sonicated and sonicated liposomes, were characterized for vesicle size and size distributions. Non-sonicated vesicles entrapped in average 74 and sonicated 49 % of mupirocin calcium, respectively. Sonication reduced the original vesicle size from around 1 micron down to 135 nm. Liposomes (10 %, w/w) were incorporated in chitosan hydrogels and liposomal hydrogels evaluated for their textural properties. Hydrogels were found to exhibit satisfactory adhesiveness and cohesiveness, with corresponding stability profile. Microbiological assessment confirmed antibacterial properties of liposomally entrapped mupirocin incorporated in hydrogels. In vitro and ex vivo (on pig skin) drug release profiles of various formulations containing mupirocin were performed on Franz diffusion cells. Liposomal hydrogels were compared with marketed mupirocin product, Bactroban® cream. The release studies showed that liposomal size affects the release of the incorporated drug. Liposomal hydrogels were shown to provide sustained release of incorporated mupirocin. In conclusion, liposomal hydrogels developed for mupirocin offer the potential to increase retention time and provide sustained release of a drug, which are important parameters for improved treatment of wounds, including burns.