Formulation, release and stability studies of diclofenac topical dosage forms

Abstract

Diclofenac sodium (DS) and diclofenac diethylammonium (DE) were different in microscopic appearance, IR spectra, solubility, stability and the release from topical preparations. The general rank order of drug stability was pH 9 > pH 7 ~ pH 6 >> pH 5. The composition of oil phase in o/w creams, type and percent of gelling agent in hydrophilic gels significantly affected the release of drug. The percent of oil phase in o/w creams and oil-water gels also significantly affected the release. The release of DS from oil phase B cream containing spermaceti, stearic acid and white beeswax was significantly less than of DE but shown the reverse in sodium CMC gel. The general rank order of the release of drug was sodium CMC gel > commercial products (A, B and C) > oil-water gel ~ poloxamer gel > o/w cream.