Guar acetate, a hydrophobic derivative of guar gum was synthesized by esterification with acetic anhydride and acetic acid using acid catalysts and evaluated for physicochemical properties. Plasticized and nonplasticized free films prepared by solvent evaporation method were tested for surface morphology, water vapour transmission and mechanical properties (tensile strength, percent elongation and modulus of elasticity). The films showed low tensile strength and high percent elongation values achieving smooth and uniform surface. Guar acetate was further characterized for film coating by evaluating the release of a model drug (diclofenac sodium) from pellets coated with guar acetate as retarding membrane. Drug release was sustained up to 8 h due to 20% w/w coat built up. Increase in coat-built-up further facilitated sustained release from coated forms. Film coating could be achieved without agglomeration of the pellets within a reasonable operating time. The present study proposes novel film forming materials with potential use in sustained drug delivery.
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