Bioavailability of Acetazolamide Tablets

Plasma acetazolamide levels were measured by an enzymatic assay following single 250-mg oral tablet doses to 20 healthy volunteers; five different lots of acetazolamide tablets from a single manufacturer were used in a balanced incomplete block design. From the measured plasma levels, estimates of the bioavailability parameters (area under the plasma concentration uersus time curve, time to peak plasma concentration, and peak plasma concentration) were obtained by leastsquares digital computer fitting. No significant differences among the tablets were observed (α=0.05) for the analysis of variance of the area under the curve or time to peak parameters. Two tablets, however, provided statistically higher peak plasma concentrations than the other three. Thus, lot-to-lot bioinequivalence of acetazolamide tablets was observed. Some in uitro tests employed showed general trends for correlation with the in uiuo data. However, considerable refinement of these techniques appears necessary for in uitro prediction of the observed lot-to-lot bioinequivalence.