BIOPHARMACEUTICAL EVALUATION OF NEW PROLONGED-RELEASE PRESS-COATED IBUPROFEN TABLETS CONTAINING SODIUM ALGINATE TO ADJUST DRUG-RELEASE

The aim of the study described here was to develop prolonged-release p ress-coated tablets containing ibuprofen. The drug dose was divided be tween the core and the coat in the ratio 2:1. Different chemical types , viscosity grades and amounts of sodium alginate were used in the coa t to control drug release. Each of the variables studied affected the drug release rate. The in vitro release profiles were biphasic. The in itial release rate was slow and in most cases increased with time. The terminal phase obeyed zero-order kinetics. The in vivo absorption pro files were also biphasic but both the initial and the terminal phases were markedly more rapid than in the in vitro dissolution studies. It was concluded that with different sodium alginates it is possible to p repare press-coated tablets from which the absorption rate can be cont rolled over a fairly wide range from an immediate release formulation via slow release formulations even to an extended-release formulation.