Assessment of bioequivalence profile of locally produced flucloxacillin sodium capsules via urinary excretory rates

The assessment of pharmacokinetic parameters constitutes the basic approach to determining bioequivalence of pharmaceutical products in order to ensure safety, efficacy and potency of the administered drug. This study has examined a locally manufactured flucloxacillin (FLUXACIN 500) and the reference product (FLUCLOXACILLIN 500mg CAPSULES) for therapeutic equivalence in a cross–over non–replicate bioequivalence study using urinary excretion data. The study was conducted with twelve consenting healthy male volunteers in a fasting state using single–dose, randomized, two–period, two–treatment cross over study design. A seven-day washout period was allowed between treatments. Urine specimen collected were analysed by means of HPLC with UV detection while pharmacokinetic parameters were analysed using Microsoft Excel Spreadsheet 2013. fFluxacin 500 reached a maximum excretion rate at an average time of 1.42 hours while flucloxacillin 500 mg reached its maximum excretion rate at an average time of 1 hour. There was no statistical significant difference between the two times. The 90% Confidence Interval of the ratio of the Area under the Excretion Rate–time Curve of fluxacin 500 to flucloxacillin 500 mg was 96.20% to 101.24% while those of the Cumulative Amount of flucloxacillin excreted, and the Rate of Maximum Excretion were 102.92% to 116.85% and 72.59% to 94.61% respectively. Fluxacin 500 demonstrated bioequivalence relationship with flucloxacillin for all the four parameters: Maximal Rate of Excretion, Area under Excretion Rate–Time Curve, Cumulative Amount Excreted and the Time for Maximum Excretion. The test and reference drugs are therefore interchangeable.