Innovative Development and Characterisation of a Hyaluronic Acid Gelatin-based Injectable Hydrogel Infused with Ranitidine for Periodontal Applications: An In-vitro Study

Introduction: Periodontitis, a chronic inflammatory disease of the periodontium, is driven by bacterial biofilms that disrupt host immune responses and accelerate disease progression. While scaling and root planing remain standard treatments, their limitations in preventing bacterial recolonisation highlight the need for adjunctive therapies. Hydrogels offer a promising solution due to their biocompatibility, ease of application, and sustained drug release, enhancing the effectiveness of conventional periodontal treatment. Aim: To develop and characterise a Hyaluronic Acid (HA) and gelatin-based injectable hydrogel incorporating ranitidine, an H2 receptor antagonist, for periodontal applications. Materials and Methods: This in-vitro study was conducted at Saveetha Dental College, Chennai, Tamil Nadu, India, from February 2024 to May 2024. HA, gelatin, and ranitidine were combined to formulate the hydrogel. The formulation was refined and cross-linked before being stored. To assess the hydrogel’s safety, haemolytic and biocompatibility assays were conducted for both the hydrogel group and the ranitidine plus hydrogel group. Biocompatibility was evaluated using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-Diphenyltetrazolium Bromide (MTT) assay on human periodontal ligament fibroblasts, and haemolysis was detected by spectrophotometry at 545 nm following incubation with Red Blood Cells (RBCs). Fibroblast morphological alterations were observed using phase contrast microscopy. Intergroup comparisons were conducted using ANOVA, and a p-value of ≤0.05 was considered statistically significant. Results: The haemolytic assay indicated minimal haemolysis (<2%) at therapeutic concentrations, comparable to Negative Controls (NC). Biocompatibility tests revealed >90% cell viability in the ranitidine hydrogel group, with no significant morphological alterations in fibroblasts, indicating low cytotoxicity (p≤0.05). Conclusion: The developed ranitidine hydrogel demonstrated excellent biocompatibility and non haemolytic properties, underscoring its potential as a safe and effective intra-pocket delivery system for periodontal therapy.