Studies of permeation through the hair follicle of topical formulations containing caffeic acid

Abstract

Caffeic acid (CA) is a polyphenol that can be found in many dietary sources of plant. The CA has a remarkable antioxidant potential and in vitro studies demonstrated the antimicrobial action. The emulsions, especially O / W, are widely used as systems for the release of active substances, since they have so many advantages. The challenge of dermal application is to overcome the anatomical and physiological barriers and to provide the effective concentration of the active site. Therefore, one should invest in alternative routes such as transfollicular. For penetration studies, pig ear skin was evaluated as a valuable in vitro model and is known as the "gold standard", since, among many anatomically advantageous: hair follicles (HFs) of human and porcine offspring are similar in several aspects. The development of micro and nanostructured systems come to meet with the main objective of the trans- follicular route, which is to make the asset available in the tissue for an extended period, since it aims to facilitate the delivery of compounds to their targets. The objective of this project is to investigate the potential of transfollicular delivery and obtain the permeation profile through the skin layers of a topical emulsion containing CA. Emulsions containing CA will be produced on a laboratory scale, one of which will contain free CA and the other microencapsulated CA. The first step will involve the application of the CA formulation over a predetermined area in the outer auricle of the pig's ear. After the predetermined incubation time under constant temperature conditions, will be realized the tape stripping technique to remove the SC. To analyze the extent of follicular drug penetration, cyanoacrylate glue is applied over the pretreated skin area followed by subsequent removal of the skin surface. Cryosection of the skin will be used to obtain analogous information from the deeper layers of the skin (viable epidermis and dermis). Quantification of CA content will be performed by HPLC. (AU)