Carboxymethyl Cellulose-Xylan Hydrogel: Synthesis, Characterization, and in Vitro Release of Vitamin B₁₂

The current work reports the synthesis of carboxymethyl cellulose (CMC) and xylan-based homopolymerized as well as copolymerized hydrogels using an ethylene glycol diglycidyl ether cross-linker in alkaline medium. The hydrogels are physically characterized by the swelling ratio and gel fraction. The morphological observation of hydrogels reveals the porous structure for the copolymerized gels. The rheological behavior of the gels elaborates that the copolymerized CMC-xylan gel synthesized in a 1:1 molar ratio has superior strain-bearing ability and possesses the shortest gelation temperature and time. Vitamin B₁₂ here is used as the model vitamin to be loaded in the hydrogels and subsequent studies involving the in vitro release in artificial gastric fluid (AGF, pH = 1.2), artificial intestinal fluid (AIF, pH = 6.8), and phosphate-buffered saline (PBS, pH = 7.4). The synthesized gels show a cumulative release of 19-28% in AGF, 80-88% in AIF, and 93-98% in PBS, independently. Further, the highest cumulative release of 93-99% is recorded for all gels when in vitro release is performed in successive buffers, that is, first in AGF, followed by AIF and PBS.