AIM:To study the pharmacokinetics and relative bioavailability of 2 domestic
diclofenac sodium sustained release tablets
in 12 normal male volunteers. METHODS: A single oral dose of 100 mg and a multi oral dose were given according to a crossover design. The
diclofenac sodium concentrations in plasma were determined by reversed phase high performance liquid chromatography. RESULTS: The concentration time curves of 2 products fitted to two compartment open model. In the single dose
experiment tablets (A) the AUC , c max , t max , T 1/2α and T 1/2β of the subject were ( 5 753 ±216) (h·ng)/ml, (675 4±141 6) ng/ml, (2 284±0 542) h, ( 0 943 0 ± 0 582 4 ) h, (6 713±2 208) h; the standard tablets (B) were ( 5 150 ± 2 167 ) (h·ng)/ml,( 620 1±187 1) ng/ml, (2 491±0 645) h, ( 1 060 0 ± 0 682 9 ) h, (6 159±2 372) h, respectively. In the multi oral dose experiment the AUC, c max , t max , T 1/2α and T 1/2β were ( 5 915 ± 1 112 ) (h·ng)/ml, (766 5±173 0) ng/ml, (2 670±0 770) h, (1 690±1 060) h, (5 460± 2 070) h; the standard tablets were ( 5 781 ± 1 849 ) (h·ng)/ml, (759 2±216 3) ng/ml, (2 310±0 520) h,(1 200±0 830) h, (6 160±2 210) h, respectively. The relative bioavailability of the subject tablets were 107 9% in the single dose experiment and 102 3% in the multi oral dose experiment. The results obtained from our studies showed no significant difference between 2 products ( P >0 05). CONCLUSION: The 2 preparations are bioequivalent.