Pineapple-Derived Sodium Carboxymethylcellulose: Physicochemical Basis for Hydrogel Formulation

The synthesis of sodium carboxymethylcellulose (NaCMC) from lignocellulosic pineapple stubble provides a renewable alternative to conventional cellulose sources for pharmaceutical applications. This study aimed to obtain NaCMC from pineapple biomass, characterize it according to pharmacopoeial specifications, and formulate hydrogels as a physicochemical proof-of-concept for future drug delivery and tissue regeneration applications. NaCMC was successfully synthesized and met the requirements of the Mexican Pharmacopoeia. Hydrogels were prepared by blending NaCMC with gelatin and crosslinking with citric acid. Spectroscopic, morphological, and thermal analyses confirmed the structural equivalence between pineapple-derived NaCMC (NaCMC-Pi) and commercial NaCMC (NaCMC-Co). Swelling and gel fraction studies showed that NaCMC-Pi hydrogels exhibited a higher gel fraction, indicating a more crosslinked network, which corresponded to lower swelling capacity but higher thermal stability compared to NaCMC-Co hydrogels. Overall, these results demonstrate that pineapple stubble is a viable source of pharmaceutical-grade NaCMC and that the resulting hydrogels provide a robust physicochemical basis for future biomedical validation. The use of agro-industrial residues additionally offers a complementary sustainability benefit without compromising pharmaceutical performance.