Allopurinol: a comparative study of the bioavailability and effect on plasma uric acid of two products in tablet form

A comparative bioavailability study was carried out with two allopurinol products, i.e. Allopurinol tablets 100 mg, DAK, and Apurin tablets 100 mg, Gea. Eleven healthy volunteers participated and were given a single dose of 200 mg of each product according to the cross-over principle. The bioavailability was evaluated with respect to the maximum plasma concentration, the peak time, and the area under the plasma concentration-time curve for allopurinol and the major metabolite oxipurinol. The elimination half-life of oxipurinol was also estimated. None of the parameters showed statistically significant differences (p greater than 0.10) between the two products. Furthermore, the pharmacodynamic effect of the two products was examined with respect to the reduction of plasma uric acid within 24 hours after administration of 200 mg allopurinol. The two products did not differ significantly (p greater than 0.10) in this respect. It is concluded that the two tablet products are bioequivalent.