Hemostatic and Wound Healing Nonisocyanate Polyhydroxyurethanes (NIPHUs) Dressings from Soybean Oil: In Vivo Characterization

Abstract

Wound healing is a dynamic process that consists of four stages: hemostasis, inflammation, proliferation, and remodeling. Some alterations in this process can lead to fatal adverse effects such as bleeding or chronic wound formation. Thus, the use of appropriate dressings is necessary to allow for hemostasis and healing to take place properly. Nonisocyanate polyhydroxyurethanes (NIPHUs) have emerged as a more sustainable alternative for biomaterials. Thus, the aim was to evaluate the wound healing capacity of four new NIPHUs with different ratios of amines used. The water vapor transmission rate (WVTR), in vivo hemostatic capability in the mouse tail model, skin irritation, and wound healing assays were performed. Results showed new formulations of NIPHUs with different WVTRs (95.6 g/m2/day to 593.3 g/m2/day). The amount of blood loss was lower when NIPHU 50/50 was applied than in wounds without any treatment. NIPHUs that were nonirritating dressings were used in the healing process assays. On day 14, all of the wounds were closed, including controls. The healed zone in animals treated with any NIPHUs was smaller and thinner, while an elongated and thick scab was still observed in the healed skin of the control groups (wounds without any treatment and wounds treated with a commercial patch). In accordance with the macroscopic observations, in all treatments, the histologic observations showed that the healing zone was epithelialized, and below it was occupied by residual granulation tissue. In NIPHU 100/0, NIPHU 67/33, and controls, no hypodermis was identified, but in the case of NIPHU 50/50, below this epithelium, several regions could be recognized: connective tissue with active fibroblasts was observed, and there were some newly formed adipocytes, neoformation of pilosebaceous units, and the muscle layer was complete. In conclusion, as a preliminary study, NIPHU 50/50 exhibited hemostatic activity and allowed the wounds to be in the remodeling phase in 14 days, making it suitable for use as a dressing.