Development of non-aqueous ethylcellulose gel for topical drug delivery

Abstract

This study reports the development of non-aqueous hydrophilic and lipophilic gels for stabilizing moisture-sensitive drugs and for topical drug delivery. The lipophilic gel, formulated using ethylcellulose and propylene glycol dicaprylate/dicaprate was found to be suitable for the model drug, minocycline hydrochloride (MH). Ethylcellulose gel rheological and mechanical properties, wettability, spreadability, ability to achieve MH stability, in vitro MH release and antimicrobial efficacy were characterized. Wettability and spreadability were characterized using newly developed methods based on dynamic contact angle measurements. Ethylcellulose gel matrices exhibited prominent viscoelasticity, yield stress, thixotropy and lipophilicity. Gel wetting and spreading parameters were linearly correlated to rheological and mechanical properties. Ethylcellulose gel containing MH demonstrated sustained release behavior and high antimicrobial efficacy against two opportunistic pathogens commonly found on human skin. In conclusion, ethylcellulose gel showed desirable rheological and mechanical properties, wettability and spreadability for the ease of topical application, and as reservoir for sustained drug delivery.