Optimization studies for encapsulation and controlled release of curcumin drug using Zn⁺² cross-linked alginate and carboxy methylcellulose blend

Biopolymers have attracted significant attention for the development of drug-carrying systems due to their high degree of biocompatibility, nontoxicity, biodegradability, and renewability. The focus of this work is to examine the optimized conditions for maximum encapsulation and release of anti-cancer drug curcumin using modified biopolymer blend beads of sodium alginate (SA) and carboxymethylcellulose (CMC). Biopolymer blend beads were prepared by mixing equal amounts of SA and CMC using normal syringe method followed by crosslinking with ZnCl₂ to improve the stability of the drug carrier. The applicability of the Zn²⁺ Crosslinked SA/CMC for curcumin was evaluated in terms of entrapment efficiency, swelling, in vitro release and drug release kinetics. Further, pseudo-first order and pseudo-second-order kinetics and isotherm models were applied to the encapsulation data and the results demonstrate that the interaction between curcumin and the biopolymers was physio sorption. The developed biopolymer drug carriers were characterized by Fourier transform infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) with and without loading of curcumin to investigate the interactions between the curcumin drug and drug carrier. The obtained results were also analyzed and compared with pristine SA beads. The maximum encapsulation efficiency was found to be 79.75% and 93.07% for SA and SA/CMC blend respectively for the formulations. The in vitro drug release studies were carried out at pH 7.4 in phosphate buffer for 8 h at 37 °C and the results demonstrate the cumulative percentage of curcumin release was increased with increasing carrier concentration. Among several kinetic models of drug release, Korsmeyer-Peppas model exhibited high correlation coefficient (r²) for both the SA and the SA/CMC.