Fabrication and characterization of calcium phosphate-reinforced alginate/gelatin composite hydrogels with pH-dependent ciprofloxacin release behavior

Abstract

Controlled drug delivery systems have been developed to overcome the challenges associated with conventional delivery systems. Among all drug carriers, hydrogels are considered one of the most promising due to their ease of fabrication and their structural similarity to the body’s extracellular matrix. In this work, a sodium alginate/gelatin (Alg/Gel)-based hydrogel composite system was developed by incorporating hydroxyapatite (HA) and monetite (Mon) as fillers to improve its biological and mechanical properties. A comparative analysis of both composites was performed to evaluate the pH-dependent drug release of ciprofloxacin (CP). The characterization of the prepared composite was performed using Fourier transform infrared spectroscopy, which confirmed that the presence of physical and non-covalent interactions within the composite. Scanning electron microscopy (SEM) analysis of the prepared composites showed that the pristine hydrogel membrane surface was smooth, while the surface roughness increased with increasing filler concentration. A significant improvement in mechanical strength, hydrophilicity, and swelling ability was observed after the addition of HA and Mon to the Alg/Gel system. Both composite systems showed a slow and gradual release of the drug at different pH values (2, 7.4, and 10). The two polymer composites (Alg/Gel/HA/100 mg CP and Alg/Gel/Mon/100 mg CP) exhibited almost the same percentage drug release at pH 2 (acidic) and pH 10 (alkaline). However, Alg/Gel/HA/100 mg CP has the highest percentage drug release at pH 7.4 (physiological). The results suggest that the prepared hydrogel system could be used for a gradual, pH-dependent drug delivery.