Optimization and Formulation of pH - Specific Fecal Microbiota (FM) Microspheres

Abstract

Gut microbiota is composed of a diverse range of microbial populations including bacteria, archaea, protozoans, viruses. Gut microbiota confer health benefits like strengthening the gut integrity, harvesting energy, protection against pathogens, maintaining host immunity, etc. The gut microflora keeps developing throughout the lifespan of a host. Any chaotic shift in the normal composition of gut microflora is referred to as “gut microflora dysbiosis” which is associated with several diseases. In order to restructure the altered gut microflora, probiotics, prebiotics, postbiotics, antibiotics and fecal microbiota transplantation (FMT) can be used. Amongst all of these, FMT is considered to be more efficient since it provides a durable period of time for the gut microflora to colonize and restore. Fecal microbiota transplantation (FMT) is administration of intestinal microflora from a healthy individual into the gastrointestinal (GI) tract of a patient with gut microbiota dysbiosis. In this present study, we have tried to formulate the fecal microbiota in the form of pH-specific microspheres using Eudragit-L-100-55 for its target specific delivery. Eudragit-L-100-55 is a pH sensitive polymer which is responsive to intestinal pH for colon-targeting delivery. It is a derivative of poly methacrylic acid and most widely used for enteric coating of drugs. Fecal samples were collected from healthy rodents and formulated in the form microspheres using two different strategies involving the use of Eudragit-L-100-55 and chitosan along with raw as well as lyophilized fecal samples. Chitosan-FM (Fecal Microbiota) microspheres were then coated with Eudragit-L-100-55 to provide the pH-specificity. Chitosan is a natural biocompatible and biodegradable polymer which has a significant property like muco-adhesion and it also provides better colonization opportunities. After the formulation of pH-specific microspheres, microspheres were characterized by particle size analysis (PSA) and fourier transform-infrared (FT-IR) spectroscopy. PSA was performed to determine the size of formulated microspheres. FT-IR was carried out to analyze the interaction between the functional groups. To determine the solubility of formulated microspheres, they were suspended into phosphate buffer saline (PBS) and sodium phosphate buffer of 6.8 and 7.3 pH. To conclude this study, pH-specific FM microspheres were formulated following the above mentioned strategies. These microspheres can further be applied for in-vivo studies after further optimization