Gum Copal and Gum Damar: Novel Matrix Forming Materials for Sustained Drug Delivery

This study concerns the evaluation of natural gum copal and gum damar as novel sustained release matrix forming materials in tablet formulation. Along with the physicochemical properties, gum copal and gum damar were characterized for molecular weight, polydispersity index and glass transition temperature. Matrix tablets were prepared by wet granulation technique using isopropyl alcohol as a granulating agent. Diclofenac sodium was used as a model drug. Tablet weight (250 mg) and diameter (9 mm) was kept constant. Tablets were evaluated for pharmacotechnical properties, drug content uniformity and in vitro drug release kinetics. Effect of gum concentration (10, 20 and 30% w/w with respect to total tablet weight) on in vitro drug release profile was examined. Both the gums produced matrix tablets with good strength and acceptable pharmacotechnical properties. Matrix tablets with 30% w/w gum copal and gum damar showed sustained drug delivery beyond 10 h. Drug release from gum copal matrix tablets followed zero order kinetics while gum damar (10 and 20% w/w) was found suitable to formulate the insoluble plastic matrix that releases the drug by diffusion. It is concluded that both gums possess substantial matrix forming property that could be used for sustained drug delivery.