The Structural, Crystallinity, and Thermal Properties of pH-responsive Interpenetrating Gelatin/Sodium Alginate-based Polymeric Composites for the Controlled Delivery of Cetirizine HCl.

Objectives: The present work aimed to design and synthesize pH-sensitive cross-linked Ge/SA hydrogels using different ratios of each polymer, and to investigate the effect of each polymer on dynamic, equilibrium swelling, and release pattern of cetirizine hydrochloride, which was selected as a model drug.

Materials And Methods: These gelatin and sodium alginate hydrogels were prepared at room temperature through free radical polymerization using glutaraldehyde as a crosslinker. These polymeric composites were used as model systems to envisage various important characterizations. The release pattern of drug was investigated in three different mediums (phosphate buffer solution of pH 1.2, 5.5, 7.5 whose ionic strength was kept constant). Various structure property relationships that affect its release behavior were determined such as swelling analysis, porosity, sol-gel analysis, average molecular weight between crosslinks (Mc), solvent interaction parameter (χ), volume fraction of polymer () and diffusion coefficient. The structural, crystallinity, and thermal stability were confirmed using FTIR, XRD, and DSC analysis.

Results: These hydrogels showed maximum swelling at pH 1.2. Zero-order, first-order, Higuchi, and Peppas models were applied to demonstrate the release pattern of drug. The release of drug occurred through non-Fickian diffusion or anomalous mechanism. Porosity was found increased with an increase in concentration of both polymers, and porosity decreased when the concentration of the crosslinker was increased. Gel fraction increased with an increase in concentration of SA, Ge, and glutaraldehyde.

Conclusion: The prepared pH sensitive hydrogels can be used as a potential carrier for the sustained delivery of cetirizine hydrochloride.