Insulin for topical use in wound healing: opportunities and limitations

Aims: The role of insulin in the regulation of energy metabolism, protein synthesis, proliferation, migration, secretion by keratinocytes, endothelial cells, and fibroblasts suggests that its presence is essential for wound healing (WH). The present study aims to explore the opportunities and limitations of topical insulin (TI) formulations. Methods: To obtain a complete picture of the challenges of the local insulin formulation a chronological review of previous publications in electronic databases was performed, applying data collection and selection criteria. Results: The opportunity of topically applied insulin has shown active interest over time. According to studies, regular insulin and isophane are suitable for local use, but currently there is no consensus on the appropriate concentration. Insulin can be incorporated into cutaneous liquid, semisolid, and solid dosage forms, either by itself, or by prior nano-or microencapsulation methods. The most important limiting factors to be evaluated are the stability of the peptide and the sterility of the obtained products. Conclusion: Examination of the balance of opportunities and limitations of TI formulations, it can be concluded that the range of  applicable technological methods is wide. A high-quality, safe, and efficacious form of TI would have great value from a socio-economic point of view.