DEVELOPMENT AND BIOPHARMACEUTICAL EVALUATIONS OF A NEW PRESS-COATED PROLONGED-RELEASE SALBUTAMOL SULFATE TABLET IN MAN

The aim of the study described was to develop prolonged-release press- coated tablets of salbutamol sulphate from which drug release would in crease with time. The bioavailability of the formulation considered be st was then studied in man. The tablets, each consisting of a core and a coat, were prepared using a compression-coating technique. Salbutam ol sulphate was divided between the core and the coat in the ratio 2:1 or 1:2. Different viscosity grades and amounts of hydroxypropylmethyl cellulose (HPMC) were used in the coat. When HPMC K100 was used, relea se of salbutamol sulphate from tablets with 2/3 of the drug in the cor e increased with time. The release patterns obtained with 1/3 of the d rug in the core were biphasic. With other HPMC grades, the release pat terns were best described by zero-order kinetics with 2/3 of the drug in the core and square-root-of-time kinetics with 1/3 of the drug in t he core. For all formulations, an increase in the amount of HPMC decre ased drug release rate. In man the only statistically significant diff erence in bioavailability parameters between the test formulation and the commercial reference preparation related to C-max values.