Preparation and evaluation of enteric granules of aspirin prepared by acylglycerols

Abstract

The pH-independent enteric granule containing aspirin prepared using a monoacylglycerol preparation (Poemu S100V ®) commercially available as glyceryl monostearate and a triacylglycerol, glyceryl trilaurate (GTL), digested by lipase and bile salts in intestinal juice was investigated. The preparation processes consisted of a two-step dry mixing method using a centrifugal rotating mixer (Mechano-mill ®). When aspirin was m powder form (80–100 mesh), it was aggregated by melted Poemu S100V; the aspirin-Poemu S100V mass was formed in the first step of the preparation process. During the subsequent step, the crushed aspirin-Poemu S100V mass was coated with melted GTL. Finally, an enteric granule (5.5–12 mesh) was obtained. In the dissolution test in vitro, the dissolution percentages of aspirin from the granule over a 2 h period at pH 1.2 were very low (~ 10%), while aspirin from the granule in pH 6.4 phosphate buffer solution (PBS) containing lipase and cholic acid was well dissolved (~ 90%). Aspirin was insufficiently dissolved (~ 40%) from the crushed aspirin-Poemu S100V mass without the GTL coating in PBS containing lipase and cholic acid. When aspirin was in crystalline form (12–42 mesh), the surfaces of individual crystals of aspirin were coated with Poemu S100V in the first step of the preparation process. However, a low dissolution percentage of aspirin from this product was not obtained at pH 1.2. The results obtained in human subjects suggested that the prepared granule of aspirin had the property of pH-independent dissolution.