Comparative Bioavailability Studies of Indomethacin from Two-Controlled Release Formulations in Healthy Albino Sheep

The objective of the study was to obtain the pharmacokinetic data of two controlled release formulations of (75 mg) indomethacin and to compare the relative bioavailability of the test formulation (product B cetostearyl alcohol microspheres) with standard formulation (product A–MicrocidSR 75 mg capsule). A single dose randomized (4×2) complete cross over study of the indomethacin (75 mg) was carried out on 8 healthy albino sheep. The study was carried out on two separate occasions with a washout period of 2 weeks. Blood samples were collected at pre­ determined time intervals. Plasma indomethacin concentrations and other pharmacokinetic parameters obtained were statistically analyzed. The results of the paired t-test for the comparison of pharmacokinetic data showed that there was no significant variation between the products A and B. Products did not show any significant difference between them with regard to the T max , C max , AUC O-24 , AUC O-∞, MRT, Ka, Kel , K1/2, 3.0 h, 2054 ± 55.78 ng/ml, 9637 ± 132.87 ng h/ml, 9870 ± 129.22 ng h/ml, 4.76 ± 0.10 h, 0.3812 ± 0.002 h, 0.2713 ± 0.004 h, 2.55 ± 0.03 h, respectively for product A and 3.5 h, 1929 ± 20.32 ng/ml, 8343 ± 40.04 ng h/ml, 8617 ± 46.88 ng h/ml, 4.98 ± 0.02 h, 0.3648 ± 0.002 h, 0.2427 ± 0.010 h, 2.86 ± 0.20 h for product B. From the dissolution studies and in vivo bioavailability studies, it was concluded that the products A and B are bioequivalent.