Carboxymethylation of Locust Bean Gum: Application in Interpenetrating Polymer Network Microspheres for Controlled Drug Delivery

For hydrophilic modification, the sodium carboxymethyl ether of locust bean gum was developed by Williamson synthesis using monochloroacetic acid as the etherifying agent. The modification reaction was optimized in terms of concentration of monochloroacetic acid and sodium hydroxide. The modified gum was evaluated for its degree of substitution, elemental analysis, viscosity, swelling, and contact angle. The etherification of locust bean gum was further confirmed by FTIR, 13C NMR, DSC, and XRD techniques. Acute oral toxicity and biodegradability studies showed that the modified gum was safe enough for internal use. This carboxymethylated gum with poly(vinyl alcohol) was utilized to prepare the interpenetrating polymer network microspheres of buflomedil hydrochloride for controlled drug delivery. The microspheres were evaluated for their drug entrapment efficiency, swelling, and particle size. The microspheres were further characterized by FTIR, 13C NMR, and XRD techniques. The in vitro release study of microspheres showed retarded drug release up to 12 h.