Construction and structural characterization of carboxymethyl cellulose-based hydrogels from Rosa roxburghii Tratt pomace for oral drug delivery.

Rosa roxburghii Tratt pomace (RRTP), a by-product generated during the processing of R. roxburghii Tratt fruit, is abundant in cellulose but remains largely underutilized. In this study, the cellulose (RCC) was isolated from RRTP and chemically modified to form its carboxymethyl derivative (RCMC). RCMC was then combined with sodium alginate (SA) at specific ratios (13:0, 6.5:3, 6.5:4, 6.5:5, 6.5:6, w/w) and crosslinked with Ca2+to construct five green hydrogels (RCMCH, RCMC/SA-3, RCMC/SA-4, RCMC/SA-5, RCMC/SA-6). Structural and texture analyses revealed that all hydrogels exhibited a three-dimensional network stabilized by hydrogen and coordination bonds. The RCMC/SA hydrogels displayed a denser structure, with enhanced hardness, springiness, and chewiness compared to RCMCH. Additionally, the RCMC/SA hydrogels demonstrated enhanced swelling and pH-responsive properties. Among these, RCMC/SA-3 and RCMC/SA-4, which exhibited higher swelling degrees, showed better drug loading capacities (389.77 mg/g and 367.81 mg/g, respectively) and encapsulation efficiencies (62.39 % and 58.88 %, respectively) for tea polyphenols. Notably, RCMC/SA-4 demonstrated optimal performance in reducing the release of tea polyphenols in simulated gastric fluid while enabling their targeted delivery to the colonic regions, with a maximum release rate of 93.98 % by the end of the colon phase in vitro. Overall, this study highlights the potential of RCMC-based hydrogels as an effective colon-targeted delivery system, providing a sustainable approach to utilizing RRTP and advancing the development of carboxymethyl cellulose-based hydrogels for oral drug delivery applications.