Coating potential of a new modified starch coating for immediate release oral tablets

Film coating of tablets is the application of a thin layer of coating material to improve the tablet properties. Different coating materials like hydroxypropyl methylcellulose (HPMC) and polyvinyl alcohol (PVA) have been widely used in tablet coatings for immediate release of the active pharmaceutical ingredient. A new immediate release film coating formula that contains modified corn starch as the coating polymer was investigated, and it shows improved physiochemical properties over conventional film coating material (HPMC and PVA). The purpose of this study is to investigate the potential of the new modified starch coating as a coating material in comparison with HPMC- and PVA-based formulas. Evaluation was done on a coating powder dispersion of 20% w/w by measuring the viscosity, sedimentation, foaming behavior, and microbial stability. Free films were prepared from each coating formula and tested for water vapor permeability and morphology. The coating process was then executed on the model tablets (levofloxacin 500 mg) after optimizing the coating parameters. Characterization of modified starch film-coated tablets was done by testing morphology, hardness, friability, thickness, disintegration, and drug release profiles. It was concluded that the new modified starch coating is superior to HPMC and PVA formulations in terms of free film and applied coated tablet esthetics, inner structure composition, preparation and coating process parameters. Additionally, the modified starch coating showed similar release profiles to HPMC- and PVA-based coating formulas.