Simulated gastric fluid (SGF) was preparedaccording to Lian et al. [23] with slight modifications. Briefly, pepsin (3 g/L) was suspended in sterile NaCl solution(0.5%w/v).The pH of the solution was adjusted to pH 2.0 with 12 M HCl, and filtered through a 0.22-μm filter membrane (Pall Corporation, USA). SIF was prepared according to US Pharmacopeia [24]. Briefly, 6.8 g of monobasic potassium phosphate (Sigma, St. Louis, MO, USA) was dissolved in 250 mL of distilled water, followed by addition of 77 mL of 0.2MNaOH,and500mLofdistilledwater.Thesolutionwas vortexed for 30 min and 10 g of pancreatin was added and mixed. pH of the solution was adjusted to 6.8 with 0.2 M NaOH or 0.2 M HCl. The total volume of the solution was madeupto1000mL,followedbyfiltrationthrougha0.45μm filter membrane to remove particulate material, and then filter sterilized through a 0.22-μm filter membrane.