In-situ mineralization of calcium carbonate in pectin based edible hydrogel for the delivery of protein at colon

Abstract

Protein administration through oral route remains to be an attractive strategy due to lesser pain, greater convenience and increased patient compliance, thus promoting its pharmaceutical research. Oral delivery, however, suffers from high susceptibility to digestive enzymes in the gastrointestinal tract. Hence, developing colon-specific protein delivery systems, especially with high bioavailability, becomes essential. In this study, calcium carbonate microparticles were in-situ mineralized in pectin/poly(ethylene glycol) (PEG) hydrogel blend to protect and release protein drug at the colon site. Further, bovine serum albumin (BSA) as a model drug was loaded during the fabrication of pectin/PEG blend containing in-situ mineralized calcium carbonate particles. The interaction of loaded BSA with calcium carbonate by physical forces was evidenced by FTIR analysis. BSA could also be visualized around the mineralized calcium carbonate by TEM throughout the hydrogel matrix. Rheological studies on the oral delivery vehicle revealed dynamic nature of the hydrogel, an essential property required for drug carriers for its interaction with the target site. In-vitro swelling and protein release studies of pectin based hydrogel indicated the potentiality of the drug carrier in releasing protein at the colon site. The conformational stability of the released BSA from the hydrogel blend (PPCB) was confirmed by SDS-PAGE and CD spectropolarimetry.