A Comparative Study of Pharmaceutical and Bio-Equivalence Characteristics of Different Brands of Extended-Release Diclofenac Sodium Marketed in Zambia Using the Mongoloid Dog Model

Abstract

Diclofenac sodium is a non-steroidal anti-inflammatory compound (NSAID) that is used to treat inflammation and manage pain caused by various conditions. In Zambia, numerous generic brands of diclofenac are available on the market, providing prescribers and patients with a wide range of options. This Study compared pharmaceutical and bioequivalence characteristics of three (3) different brands of extended-release diclofenac sodium 100mg tablets marketed in Zambia. An analytical technique was employed to examine physicochemical parameters. The dissolution analysis was conducted using the paddle technique. A randomised, single-dose, two-way crossover design was performed on six Mongoloid female dogs that were fasted. After receiving 100 mg diclofenac sodium tablets orally, the levels of diclofenac in the plasma were determined using UV-Vis spectrophotometry. Pharmacokinetic parameters, including the time taken for maximum drug concentration (T-max), maximum drug concentration in plasma after dosing (C-max), area under the curve from 0 to 10 (AUC 0-10), and area under the curve infinity (AUC ∞), were determined through a non-compartmental procedure. The physicochemical characteristics were subjected to analysis of variance (ANOVA), while Bioequivalence was assessed using the linear-log trapezoidal rule method. The non-aqueous titration showed that the purity of diclofenac ranged from 95.41% to 102.8% w/w. All brands were well absorbed in the gastrointestinal tract, and the parameters were within the acceptable range set by the FDA for Bioequivalence. The 100 mg diclofenac sodium extended-release tablets from three brands had good physical and chemical properties and met the criteria for drug release. However, there were noticeable differences in the AUC0-10hrs between brand A and brands B and C, suggesting that while the brands are chemically similar, they are not equal in terms of biological equivalence.