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.

Capillary electrochromatography of therapeutic peptides on mixed-mode butylmethacrylate monoliths

In this study, a porous mixed-mode n-alkyl methacrylate-based monolith has been used in the separation of therapeutic peptides. While the sulfonic acid (SCX) moiety derived from 2-acrylamido-2-methyl-1-propanesulfonic acid supports the generation of a stable electroosmotic flow (EOF) at both acidic and basic pH values, the butyl ligands provide the nonpolar sites for chromatographic resolution. The performance of the monolith was evaluated regarding the influence of pH on chromatographic resolution of peptides. The suitability of the butylmethacrylate/SCX monolith for the analysis of therapeutic peptides containing basic centres, for example arginine, at moderately high pH 9.5 and the stability to repeat injections of a mixture of peptides was demonstrated. Separations with efficiencies as high as 5.0 x 10(5) plates/m were obtained and the migration behaviour of the peptides at both low (2.8) and high (9.5) pH values could be rationalised based on their charge, molecular mass/shape and relative hydrophobicities.