Formulation and in vivo evaluation of probiotics-encapsulated pellets with hydroxypropyl methylcellulose acetate succinate (HPMCAS)

Abstract

The aim of this study was to formulate probiotics-encapsulated pellets with hydroxypropyl methylcellulose acetate succinate (HPMCAS) using a dry powder coating technique to improve the storage stability, acid resistance, and intestinal adherence of viable bacteria (Lactobacillus acidophilus and Bifidobacteria animalis ssp. Lactis). Dry coated pellet (DCP) loaded with probiotics was optimized with respect to the quantity of the HPMCAS, an enteric coating polymer (108mg), and the kinds and amounts of plasticizer (triethyl citrate, 15.7mg; acetylated monoglyceride, 6.8mg), by evaluating the survival rate of the bacteria during preparation process and in an acidic medium. Dry coating process allows the whole survivals of living bacteria during preparation process. The DCP formulation exhibited markedly higher acid tolerability and storage stability compared to uncoated viable bacteria. In an in vivo mucosal adherence study in rats, a profound colonization of viable bacteria in the small and large intestine was observed in rats receiving DCP system (p<0.05) compared to rats receiving uncoated probiotics. Moreover, we found that the repeated DCP administration noticeably inhibited intestinal penetration of endotoxin, a potent inflammatory stimulant, from intestinal mucus. The novel DCP system may be an alternative approach for improving bacterial viability in the preparation process and in an acidic medium, and to promote mucosal colonization of probiotic bacteria in the human gut.