Abstract

DEVELOPMENT, DESIGN AND EFFECTS OF FORMULATION AND PROCESSING PARAMETERS ON DRUG RELEASE OF FLOATING MATRIX TABLETS USING LOW DENSITY POWDER

Abstract

Recent approaches to increase the gastric residence time of drug delivery systems include bioadhesive devices, systems that rapidly increase in size upon swallowing and low density devices that float on the gastric contents. To provide good floating behavior in the stomach, the density of the device should be less than that of the gastric contents (approximately 1.004 g/cm3). The objectives of the present study were to develop a single unit, floating drug delivery system consisting of low density polypropylene foam powder, matrix-forming polymer(s), drug, and filler (optional), and to study the effect of important formulation and processing parameters on the floating and drug release behavior of these systems. The highly porous foam powder provided low density and, thus, excellent in vitro floating behavior of the tablets. All foam powdercontaining tablets remained floating for at least 8 h in 0.1 N HCl at 370C. Different types of matrix-forming polymers were studied. The tablets eroded upon contact with the release medium, and the relative importance of drug diffusion, polymer swelling and tablet erosion for the resulting release patterns varied significantly with the type of matrix former. The release rate could effectively be modified by varying the matrixforming polymer/foam powder ratio, the initial drug loading, the tablet geometry , the type of matrix-forming polymer, the use of polymer blends and the addition of water-soluble or water-insoluble fillers (such as lactose or microcrystalline cellulose). The floating behavior of the low density drug delivery systems could successfully be combined with accurate control of the drug release patterns.

Keywords: Floating drug delivery, matrix tablets, in vitro evaluations.