Mechanisms of drug release control by osmotic additives from multiple w/o/w emulsions containing diclofenac sodium

Mechanisms by which the release of drug could be controlled by certain osmotic additives from multiple w/o/w emulsions were studied Multiple emulsions containing diclofenac sodium in the innermost aqueous phase were prepared by the two step emulsification technique. The efect of osmotic additives like glucose, ascorbic acid, sodium chloride, glycerin, lactose and sodium citrate were studied in two different concentrations, 1% and 3% for their effect of drug release. It was found that the extent of release was lower for all the additives at both the concentration except 3% ascorbic acid, which gave higher release than the control emulsion, which did not contain any additive. Diffusion coefficients of the drug were calculated for all the emulsions.