A comparative study of the pharmacokinetics of conventional and sustained-release tablet formulations of aceclofenac in healthy male subjects

Purpose: To examine the pharmacokinetics of a formulated aceclofenac sustained release tablet formulation and determine if it is bioequivalent to a commercial brand of aceclofenac immediate release tablet (Zerodol® 100 mg). Methods: Each of two groups of twelve fasting volunteers received either the reference standard (Zerodol 100 mg tablets) or the test formulation (200 mg aceclofenac) orally once, using a cross-over design with a one week wash-out period. Their blood samples were obtained at regular time intervals over 24 h and analyzed by high performance liquid chromatography (HPLC). Using the non-compartmental approach, plasma levels of aceclofenac were employed to compute their individual disposition kinetics, including peak plasma concentration (C max ), peak time (T max ), area under the plasma level-time curve (AUC 0-t ), elimination rate constant (K el ) and elimination half life ( t 1/2 ). Results: The C max values of 11043 ± 3073 ng/ml and 12301 ± 3000 ng /ml were attained in 2.58 ± 1.22 h and 1.29 ± 0.75 h for the test and reference products, respectively, while AUC O-∞ was 45996 ± 10427 and 50253 ± 8283 ng.h/ml, respectively. At 90% confidence interval, the C max , AUC 0-t and AUC 0-∞ values of the test preparation were 96.4 - 101.3, 100.2 -101.9 and 98.5 - 99.8%, respectively, of the values for the reference. The t ½ values were found to be 4.50 ± 1.25 and 2.20 ± 2.59 h for the reference and test products. Conclusion: On the basis of the pharmacokinetic data, it can be said that the test aceclofenac sustained release formulation and the reference product were bioequivalent in some respects. However, the test formulation exhibited a longer elimination half-life (t1/2 ), thus demonstrating sustained release properties, unlike the reference