Journal of Bioequivalence & Bioavailability

Abstract

Bioequivalence Study of Two Loperamide Hydrochloride 2 mg Formulations: An Open-Label, Randomized, Single-Dose, Two-Way Crossover Study in Healthy Volunteers under Fasting Conditions

Wen Yao Mak, Yi Lin Lee, Siew Siew Tan, Jia Woei Wong, Siaw Kuen Chin, Ai Boey Lim, Ean Peng Soon, Irene Looi and Kah Hay Yuen

The objective of this study was to compare the rate and extent of drug absorption of the test product (Colodium 2 mg Capsule, Hovid Bhd.) against the reference product (Imodium® 2 mg Capsule, Janssen Cilag S.A.) in twentythree healthy male volunteers under fasting condition in order to evaluate bioequivalence. A single dose of 8 mg (4 capsules of 2 mg each) of test and reference products were given to volunteers during two periods of the study respectively. There was a 7 day washout period between the two study periods. Blood samples were taken at pre-dose and at 13 time points up till 48 h post dosing. Plasma levels of loperamide were determined by liquid chromatography-tandem mass spectrometry. The plasma concentration-time data was used to estimate the pharmacokinetic parameters, namely, Cmax, Tmax, AUC0-t and AUC0-∞. Analysis of variance (ANOVA) procedure was used to analyze the values of Cmax, AUC0-t, AUC0-∞ and ke obtained from the two preparations. For the analysis of Tmax values, the Wilcoxon Signed Rank Test for paired samples was used. In this study, the 90% confidence interval for the ratio of the AUC0-t, AUC0-∞ and Cmax were calculated to be between 0.8730-1.0181, 0.8852-0.9891 and 0.8023- 0.9559 respectively. All of the values were within the acceptable bioequivalence requirement of 0.8000-1.2500. No drug-related adverse event was reported throughout the study. Thus, the two preparations could be concluded to be bioequivalent and interchangeable.