Bioequivalence studies of cetirizine tablets using the urine excretion data of healthy Ghanaian male volunteers

BACKGROUND: In the wake of economic challenges, the role of generic medicines has become crucial in meeting the healthcare needs of people. Their use, however, can only be guaranteed if established to be bioequivalent to their corresponding innovator products. AIM: In this study, we assess the suitability of a generic brand of cetirizine hydrochloride tablet to be used in place of the innovator brand on the Ghanaian market through bioequivalence assessment. METHOD: An HPLC bioanalytical method was developed and validated for the detection and quantitation of cetirizine in a urine matrix. This was then used to quantify the amount of cetirizine excreted unchanged in urine samples of 12 healthy male volunteers collected over a 24-h period using a two-way crossover design approach. RESULTS: Chromatographic separation was successfully achieved with an isocratic elution on a reverse-phase column. The mean retention time for cetirizine was 2.890 ± 0.243 min. The mean cumulative amounts of cetirizine in the reference and test drugs excreted were 5.69 ± 0.98 mg and 5.82 ± 1.96 mg respectively. Other pharmacokinetic parameters including mean relative Areas Under Curve (AUC(0-24)) of 13.32 and 13.05 μg/mL, and peak Concentration (Cmax) of 3.378 and 3.043 μg/mL at the times at which Cmax was observed (Tmax) being 7.25 and 7.42 min were established respectively for the reference and test drugs. The relative bioavailability was determined to be 102.28, making the locally manufactured brand bioequivalent to the innovator brand. CONCLUSION: The locally manufactured test Cetirizine drug was found to be bioequivalent with the innovator brand and could serve as a suitable alternative to the latter. Additionally, relevant pharmacokinetic parameters for cetirizine has been established using urinary excretion data.