Comparative bioavailability study of capecitabine tablets of 500 mg in metastatic breast cancer and colorectal cancer patients under fed condition

Capecitabine (oral prodrug of 5-fluorouracil) is the first-line treatment for the metastatic breast and colorectal cancer. The objective of the study was to determine the bioequivalence between the test product (capecitabine tablets 500 mg) of Dr. Reddy’s Laboratories Limited relative to that of reference product XELODA® (capecitabine) 500 mg tablets of Roche Registration Inc. in patients of metastatic breast or colorectal cancer stabilized with twice daily dosing of capecitabine monotherapy. This was an open-label, randomized, single dose, two-way cross-over bioequivalence study under fed conditions. The subjects received either of the treatments (test or reference) 30 min after consumption of a high fat, high calorie breakfast as a single morning dose of 2000 mg on two separate days (days 1 and 2) based on their body surface area. Blood samples were collected up to 10 h post-dose and analyzed for capecitabine using the validated liquid chromatographic mass spectrometric (LC-MS/MS) method. The least square mean ratio and 90% confidence intervals of Cmax, AUC0–t and AUC0–∞ were within the regulatory acceptance criteria of 80.00–125.00% and considered as bioequivalent.