Formulation and evaluation of vildagliptin loaded in-situ gel for ocular drug delivery: An improved approach towards management of diabetic retinopathy

Most often, diabetic retinopathy (DRP) is caused by diabetes mellitus (DM). DRP’s classification as a microvascular illness has long been established. Vildagliptin (VLD) was one of the medications prescribed to treat DRP. In addition to having hypoglycemic properties, VLD lowers eye inflammation and promotes retinal blood flow in individuals with type 2 diabetes. The aim of the experiment focuses on the development of vildagliptin-loaded in-situ gels, using polymers Carbopol-940 and HPMC K4M as a pH-triggered gelling agent to improve contact time, control drug release, lower the frequency of administration and boost the drug’s therapeutic efficacy. The clarity of all the prepared formulations was found to be satisfactory as the formulations were clear and no particulate matter was present. The FTIR study suggested that there is no interaction between the drug and used excipients. The developed formulations showed excellent gelling capability as they were converted into gel immediately and maintained their consistency for extended periods. The enhanced viscosity due to gel formation increases the drug’s contact time at the site of administration. The pH of all formulations was evaluated and found to be between 6.2 and 7.3, indicating that they have no impact on the eyes, as proved by the Draize test. The isotonicity test was performed under a microscope, confirmed that the prepared in-situ gels are isotonic with blood and the tear fluid. After 360 minutes of the in-vitro drug release, the cumulative drug release of formulations was in the range of 84.01 % to 97.68%. Docking analysis was used to determine all relationship between vildagliptin and its target, dipeptidyl peptidase-4. The study revealed that vildagliptin has a favorable docking score of −6.9 Kcal/mol with dipeptidyl peptidase-4. After six months of accelerated stability study, the study found that no developed formulation deviates significantly from the initial recorded parameters. After completing the research, it was revealed that the optimized formulations showed improved contact time, controlled drug release, lowered frequency of administration and boosted the drug’s therapeutic efficacy.