Preparation and structural characterization of thermosensitive natural oils-based organogels

Abstract

Organogels (ORG) are semi-solid systems, where an organic phase is immobilized by a three-dimensional network composed of self-assembled systems, forming the aqueous phase. In general, ORG have advantages over conventional systems (creams, ointments, hydrogels) such as modulation of skin permeation rate, as well as high affinity to the site of administration, according to their composition. The research for bioactive compounds from natural sources associated to low toxic potential promoted the development of new, effective and safer pharmaceutical formulations compared to other conventional components. In particular, the antibacterial, antioxidant, wound healing and anti-inflammatory pharmacological properties of essential oils from Arnica (Arnica montana) and Melaleuca (Melaleuca alternifolia) are resulting from their chemical composition (linoleic acid, flavonoids, caffeic acid, terpenols and pinene). In addition, formulations proposed here have the advantage of not using compounds, such as parabens and organic solvents during the preparation process, contributing to their biocompatibility. On the other hand, there is a lack of information on the characterization of these systems from the structural point of view, considering the diversity of essential oils chemical composition. Another important fact is the ORG skin bioadhesion property, forming a uniform film on stratum corneum, which increases the contact of the formulation with the application site. Taken together, those factors highlight the need for investigations regarding to the ORG physical-chemical characterization and their interactions with the stratum corneum components. In this sense, this project proposes the development (preparation and physico-chemical characterization), the evaluation of the stratum corneum structure and in vitro cytotoxicity, post-treatments with essential oils incorporated into poloxamer-based thermosensitive matrices.