Comparison of pharmacokinetics of citalopram in healthy Asian Indian and Mexican volunteers

Abstract

Randomized, two-way crossover, bioequivalence studies were conducted separately in healthy Mexican and Asian Indian volunteers. One tablet either of test or of reference product was administered after 10 h of overnight fasting. After dosing, serial blood samples were collected for a period of 72 h and 168 h, respectively, for both the studies. Plasma samples were analyzed for citalopram by a validated liquid chromatographic and mass spectrometric method (LC-MS/MS). The pharmacokinetic parameters AUC0–t, AUC0–72, AUC0–∞, Cmax, and Tmax were determined from plasma concentration-time profiles for both the test and reference formulation of citalopram 20 mg tablets, and were compared statistically to evaluate bioequivalence between the two brands of citalopram. In both the studies, the analysis of variance (ANOVA) did not show any significant difference between the test and reference formulations and 90% confidence intervals (CI) were lying within the acceptable range for bioequivalence. The test and reference formulations exhibited comparable pharmacokinetics profiles and were bioequivalent, but high values of both Cmax (~ 23%) and AUC (~ 34%) were observed in Asian Indian healthy volunteers as compared to the Mexican volunteers. This may be due to the poor metabolism of Citalopram in the Asian population. This difference in the results of pharmacokinetic parameters of Asian Indian and Mexican volunteers may be attributed to ethnic factors.