Development and Characterization of LBG-PVA Interpenetrating Networks Incorporating Gliclazide for Sustained Release

Background: Controlled oral dosage forms have always been preferred for drugs with variable absorption, and short biological half life and frequent dosing. The prime goal with sustained release systems is to maintain uniform therapeutic blood levels for more extended periods of time. Interpenetrating networks (IPNs) have been evidenced as uniform sustained release systems. In the current study, polyvinyl alcohol (PVA) and locust bean gum (LBG) based IPNs were developed for the oral sustained release drug delivery of gliclazide (shows variable absorption). Methods: The IPNs were synthesized by emulsion cross-linking method using glutaraldehyde (GA) as a cross linking agent. Gliclazide is a potential second generation, and short-acting sulfonylurea oral hypoglycemic agent having a short biological half-life (2-4 h), variable absorption and poor oral bioavailability. Various batches of IPNs were formulated by varying LBG: PVA ratio and evaluated for percentage yield, drug entrapment efficiency (DEE), swelling properties and in vitro drug release studies. Further characterizations were done by Fourier Transform Infrared Spectroscopy (FTIR), C13 Solid state NMR, X-Ray diffraction study (XRD), Scanning electron microscopy (SEM), and Differential scanning microscopy (DSC) studies. Results: The percentage yield, drug entrapment and equilibrium swelling were observed to be dependent on PVA-LBG ratio and GA amount. Sustained release of drug was observed in all IPN formulations (approx 59 - 86% in 8 h in various batches) with variable release kinetics. SEM studies revealed the regular structures of IPNs. FTIR, XRD, C13 Solid state NMR and DSC studies proposed that drug was successfully incorporated into the formed IPNs. Conclusion: IPNs of LBG and PVA can be used as a promising carrier with uniform sustained release characteristics.