Carboxymethylation of pectin: Optimization, characterization and in-vitro drug release studies

The sequential optimization of carboxymethylation of pectin by Plackett-Burman (PB) design and response surface methodology (RSM) was reported in this study. PB design was employed to screen the six process variables (ethanol concentration, liquid-polymer ratio, NaOH concentration, CAA concentration, temperature and time). Central composite design (CCD) was used to study the interaction effects of ethanol concentration, NaOH concentration, CAA concentration and time on degree of substitution (DS) in carboxymethylated pectin (CMP). Maximum DS value of 0.496 was predicted at ethanol concentration (80%), NaOH concentration (38%), CAA concentration (8.5%) and time (60 min). The synthesized CMP was characterized by FT-IR, XRD, TGA and viscometer. Results of FTIR, XRD and TGA confirmed the modification made in the pectin polymer and highly methylated. Faster release of 5-FU drug was observed with CMP-chitosan nanoparticles as compared to pectin-chitosan nanoparticles and the drug release followed zero order kinetics model.