Grewia Gum as a Film Coating Agent in Theophylline Tablet Formulation : Properties of Theophylline tablets coated with grewia gum as a film coating agent

Film coating of pharmaceutical dosage forms is a science that has contributed immensely to the advancement of drug delivery. Film coating is the deposition of a thin film of a polymer all over the tablet core surface and it involves low weight increase (2-3%) and it is a single stage process. The main ingredient of film coating formulation is the polymer, which may be synthetic, semisynthetic or natural. The synthetic polymers have often been used as the film coating agents in pharmaceutical formulations to the neglect of the natural polymers, which are readily available, less toxic, ecofriendly and cheaper. The advent of modern equipment has helped in the elucidation of plant materials today more than before and that has better position them for industrial use more than it was possible in the past. Grewia gum is a natural polymeric material that is obtained from the inner stem back of Grewia mollis, and it of the Family Malvaceae, in the expanded sense as proposed by the Angiosperm Phylogeny Group (APG). The physicochemical properties and the potential of the gum as a pharmaceutical excipient have been of interest lately. None of the investigations has reported the use of the gum