Hidrogéis de quitosana como sistemas de liberação transdérmica de nicotina

Abstract

The transdermal delivery systems present several advantages over oral or parenteral drug administration mainly at extend control of drug action. In this context, the formulations chitosan-based, a natural polymer, have shown great potential mainly due to its characteristics of low toxicity, on permeation enhancing properties and control of drug release. Nicotine is a drug that has the most favorable physicochemical characteristics for transdermal administration; however there is the difficulty in obtaining systems that control the transdermal delivery of nicotine over 24 hours. In the present work, chitosan hydrogels crosslinked or uncrosslinked, hydrated or partially dried, were developed and evaluated as transdermal delivery systems of nicotine. All hydrogels evaluated were able to control the in vitro skin permeation of nicotine through pig ear skin for a period of 48 hours following zero order kinetics. The chitosan hydrogel uncrosslinked partially dried released higher amounts of nicotine to the skin. Swelling studies of the partially dried gels showed that the crosslinking decreased the degree of swelling and the diffusion of water into the system and therefore the uncrosslinked gel was able to absorb a larger amount of water, favoring the diffusion of nicotine to the skin. By the thermal analysis was possible to provide for the thermal stability of the hydrogels. The gels were also characterized by infrared spectroscopy that was able to demonstrate the crosslinking of chitosan gel with glutaraldehyde. It was concluded that the partially dried chitosan hydrogels are promising in the control of nicotine permeation in vitro skin, showing great potential as systems for transdermal delivery of nicotine.