Hydrogel Formulations for Topical Insulin Application: Preparation, Characterization and In Vitro Permeation across the Strat-M(®) Membrane

Insulin has shown efficacy in the treatment of hard-to-heal wounds, which is mainly due to its role in regulating oxidative stress and inflammatory reactions. The aim of this study was to develop an insulin–hydrogel carrier based on Sepineo™ P 600 and Sepineo™ PHD 100 for application to lesional skin. Preformulation studies of the developed formulations were performed in terms of analysis of the pharmaceutical availability of insulin from the hydrogels through the Strat-M(®) membrane, and rheological and texture measurements. Insulin is released in a prolonged manner; after a time of 6.5 h, 4.01 IU/cm(2) (53.36%) and 3.69 IU/cm(2) (47.4%) of the hormone were released from the hydrogel based on Sepineo™ P 600 and Sepineo™ PHD 100, respectively. Rheological analysis showed that the hydrogels tested belong to non-Newtonian, shear-thinning systems with yield stress. The insulin–hydrogel based on Sepineo™ P 600 and Sepineo™ PHD 100 shows optimal application properties. The results obtained provide a basis for further preclinical and clinical studies.