Assessment of hectorite/spring water hydrogels as wound healing products

Wound healing treatments continue to be a medical challenge, since complications usually lead to chronicization and comorbidities. Natural inorganic ingredients such as clays have demonstrated to exert useful activities in this regard [1–3]. Hectorite is a smectite clay with desirable rheology due to its layered structure and remarkable swelling capacity. These properties make it appropriate excipient for semisolid systems. Nonetheless, the biocompatibility of natural hectorite has been scarcely addressed, the majority of studies centred in synthetic or functionalized hectorites [4–10].

The aim of this study was to prepare and characterize a hectorite/spring water hydrogel. The hectorite clay mineral was subjected to a solid-state characterization, while the hydrogel (HTgel@10) was evaluated in terms of rheology, pH and in vitro biocompatibility and wound healing.

Results demonstrated that the hectorite possessed a remarkable purity (84% w/w of hectorite), very similar to that of similar pharmaceutical excipients [11]. HTgel@10 showed a non-Newtonian, viscoplastic to pseudoplastic profile and a stable pH for 12 months. In vitro tests reported that the hectorite and the HTgel@10 were biocompatible (cellular viability ≥ 70%). Specifically, the hectorite used in this study was more biocompatible toward fibroblasts than Veegum^® HS [12]. The in vitro wound healing test revealed that HTgel@10 was able to favour the wound closure. Therefore, hectorite/spring water hydrogels could be considered as potential wound healing formulations with remarkable stability and safety.