Effect of matrix granulation and wax coating on the dissolution rates of paracetamol granules

Abstract

The study was carried out to investigate the release profile of matrix (non-disintegrating) granules consisting of paracetamol (drug) and acrylatemethacrylate copolymer, a matrix forming material. The
effect of coating the matrix granules with wax on the drug release profiles was also investigated. The objective was to produce drug particles of different release profiles for application as multi-unit dosage
forms. The matrix granules were formed by massing paracetamol powder with a concentrated ethanolic solution of the acrylatemethacrylate copolymer (40%, w/v) followed by drying and screening. Wax
coating was achieved by mixing the matrix granules with a melt of carnuba wax. Conventional granules of paracetamol were made by granulation with starch mucilage (20%, w/v); this served as reference samples for comparison. The granules were subjected to size analysis, packing/flow property, friability and dissolution tests. All the granules (i.e. conventional, matrix as well as the coated matrix granules) flowed readily and were also compressible upon tapping. The compressibility index values were
conventional granules (39±2.2%), matrix granules (27±1.8%) and coated matrix granules (24±1.9%). The friability values were conventional granules (1.96±0.02), matrix granules (0.78±0.01) and coated matrix
granules (0.63±0.03), indicating that matrix granulation increased the cohesive strength of the granules. The dissolution rates were conventional granules (16% h-1), matrix granules (9.4% h-1) and coated matrix
granules (4.4% h-1). Thus, matrix granulation and wax coating of the matrix granules are approaches for retarding drug release and hence prolonging the biologic action of drugs with short biologic half live