Dissolution Rate and Bioavailability of Spironolactone Tablets: Effect of Various Technological Factors

Abstract

The effects of the magnesium stearate, talc and gelatin contents of spironolactone tablets on dissolution rate and bioavailability of the drug have been evaluated. The dissolution test results for eight formulations corresponding to a 2×2×2 factorial design showed dissolution rates to be chiefly dependent on gelatin content. Testing the bioavailability of the eight formulations using a balanced incomplete block design revealed no evidence of bioinequivalence, but in view of the possibility that the absence of significant differences had been due to the large number of formulations (and consequent lack of sensitivity on the part of experimental design) three representative formulations were re-tested using a 3×3 Latin square design. The results confirmed those of the balanced incomplete block study. Use of the balanced incomplete block design is advocated for bioavailability studies in which a large number of formulations are to be compared.