Photoprotection and skin irritation effect of hydrogels containing hydroalcoholic extract of red propolis: A natural pathway against skin cancer

Abstract

The use of natural products in sunscreen formulations as a prophylactic measure against skin cancer is receiving special attention attributed to the photoprotective and antioxidant properties of their chemical components. In this work, we describe the development of topical hydrogel formulations containing hydroalcoholic extract of red propolis (HERP), and the evaluation of the dermal sensitizing effect of the developed products. Sunscreen formulations composed of HERP in different concentrations (1.5, 2.5 or 3.5% w/w) alone or in combination with a chemical (octyl methoxycinnamate) and/or physical (titanium dioxide) filters were developed using poloxamer 407 as gel basis. The preliminary and accelerated stability tests, texture analysis and spreadability tests were performed. All formulations revealed to be stable in preliminary stability assessment. The formulations containing HERP 1.5 and 2.5% alone or associated with the filters showed intense modifications during accelerated stability test, which were confirmed by rheological analyses. The incorporation of HERP and filters in the poloxamer hydrogel decreased the toughness of product (p < 0.05) and the formulation containing HERP alone presented the lowest adhesivity (p < 0.001). The incorporation of HERP in the hydrogel decreased the poloxamer transition temperature, showing different rheological behavior with the increase of HERP concentration. The developed formulations were stable, exhibited non-Newtonian and pseudoplastic behavior, showing in vivo skin compatibility and no skin irritancy.

Use of sisal industrial waste (Agave sisalana Perrine) in sustainable and multifunctional cosmetic products

“…The results obtained in this work corroborate those presented by Tomazelli et al., Rosado et al., and Batista et al. [68–70], who evaluated the safety of rutin, caffeine, and red propolis, respectively, associated with a photoprotective formulation.…”

“…The photoprotective emulsion with sisal extract did not induce skin irritation and sensitization during the study period and, therefore, supports the claim "Dermatologically tested". The results obtained in this work corroborate those presented by Tomazelli et al, Rosado et al, and Batista et al [68][69][70], who evaluated the safety of rutin, caffeine, and red propolis, respectively, associated with a photoprotective formulation. Sunscreens of natural origin, when absorbing solar energy, can produce singlet oxygen, which is phototoxic to membrane proteins and lipids and to DNA.…”

Gel Formulations for Topical Treatment of Skin Cancer: A Review

“…Batista and team investigated the stability of a poloxamer 407 gel in the case of incorporation of hydroalcoholic extract. Evidently, the gelling agent is compatible with ethanol in comparison to HEC-based gel [106]. Nevertheless, poloxamer 407 gels possess some disadvantages such as low mechanical strength, low durability, and very fast drug release [107].…”

“…pH Gel sample is diluted in purified water to obtain a concentration of 10% w/v. A potentiometric measurement of the pH could be used to elucidate skin tolerability and possible stability issues [106].…”

“…The method allows evaluation of various parameters such as cohesiveness, adhesiveness, hardness, and extrudability [106,175]. They determine the ability to spread on the skin, the bioadhesion, and the ability to be evacuated from the packaging [106].…”