Crosslinked Alginate Films as Rate Controlling Membranes for Transdermal Drug Delivery Application

The present investigation was undertaken to prepare and evaluate the crosslinked sodium alginate (SA) films as rate controlling membranes (RCM) for transdermal drug delivery application. The drug free films of SA were prepared by mercury substrate method and evaluated for thickness uniformity, tensile strength and water vapor permeation (WVP). The films were characterized by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Drug diffusion characteristics of the films were studied using diclofenac diethylamine as a model drug. The prepared membranes were thin, flexible and smooth. Tensile strength measurement and DSC analysis suggested that as the crosslink density increases, the tougher membranes were formed. The WVP and drug diffusion were dependent upon the crosslink density and thickness of the films. The permeability was decreased with increasing crosslink density and thickness of the films. The molar mass between the crosslinks and crosslink density were calculated using empirical equations. The primary skin irritation study indicated that the prepared membranes were less irritant and safe for transdermal application.