Study design
This was a single center, randomized, open-label, single-dose, two-period crossover bioequivalence study in both fasting and fed conditions. According to pre-test and previous studies, the coefficient of individual variation of lisinopril/amlodipinebesylate FDC product arranged from 20%-30%[13-15]. Under the condition that α=0.05, statistical test efficiency 1-β= 0.9, coefficient of variationwas 0.28, equivalent lower limitwas 0.80, upper limit was1.25 and actual ratiowas1, 35 samples were needed, using the ”equivalence tests for the ratio of two means in a 2x2 cross over design” process insoftwarePower Analysis and Sample Size (PASS,version 15.0).Considering the possibility of shedding, 40 subjects were planned to be selectedin each fasting and fed bioequivalence study. All eligible subjects were randomly assignedaccording to the random table generated by the statistical professionals in the Department of Shanghai Second Military Medical University using SAS9.4. The subjects took the test(T) and reference(R)drugsrespectivelywith 240ml water after an overnight fast of at least 10 hours (fasting study) or after the high-fat breakfast within half an hour before dosing(fed study).The high-fat breakfast contained 929 kcal calories, and consisted of three pork buns with cabbage, spinach mixed with Yuba, and millet gruel. Breakfast composition and energy distribution was showed in Table1. Subjects were forbidden to drink water within 1h before and after taking the drug, and the lunch and dinner were provided at 4 h and 8 h respectively post-drug administration. No other food and beverage intake was permitted except the normal diets provided by the clinical trial center during the study. A washout of 14 days was set between the two administrations, according to the half-life recorded inoriginal drug instructions. 4ml venous blood samples were collected before drug administration and at1,2,3,4,5,6,7,8,9,10,11,12,13,24,36,48,72,96,144,168h after administration. The samples were centrifuged at 1700gear per minute for 10min at 4℃ to separate the plasma, which was divided into two aliquots(drug monitoring at least 800ul and backup) and stored at ﹣80℃until analysis.The study flow chart is presented in Figure 1.