Formulation and evaluation of sustained release paracetamol peroral matrix tablets: optimisation and <i>in vitro</i> evaluation

Abstract

An optimised formulation of sustained release paracetamol peroral matrix tablets for a three-times-daily use was prepared with hydroxypropylmethylcellulose (HPMC). The levels of HPMC 4,000, polyethylene glycol (PEG) 6,000 and lactose were varied according to a 2 level 3-factor full factorial experimental design using the release rate of the drug from the matrices as the response variable. From the dissolution data of the eight tablet formulations that resulted from the experimental design, a polynomial regression equation was generated from which an optimum formulation was obtained. Three different batches of granules of the \'optimum formulation\' were compressed into tablets at a compression force of 15 kN with an instrumented EK-0 Korsch eccentric single punch tablet machine. Evaluation of tablet weight variation, crushing strength and friability demonstrated acceptable results. In vitro dissolution tests also revealed sustained release of the drug for an 8-hour period at the end of which almost complete release was achieved (96.22 ± 0.72%, 97.69 ± 0.20% and 98.94 ± 1.17%, respectively, for the three batches).

Keywords: sustained release, paracetamol matrix tablets, hydroxypropylmethylcellulose, in vitro dissolution tests, optimization

Ethiopian Pharmaceutical Journal, vol. 22 (2004): 27-38