In Vitro Investigation On The Interaction Of Keratin And Chitosan Oligomers/D-glucosamine

Transdermal drug delivery system (TDDS) has much more advantages than other traditional modes, the application of which is an area of growing potential and development in pharmaceutical industry. However, the skin barrier limits the development of many drugs in TDDS. Chitosan oligomers(CS) and its relative derivatives, for its safe and effective properties, have been shown having the ability to aid the drugs delivery through skin. In this thesis, keratin from human hair(KH) and mouse stratum corneum(SC) were chose as in vitro models to research the effects and mechanism of CS, D-glucosamine (DG), DGP and DGH in the TDDS.The project of dissolving KH with the mixed solvent system of reducer, denature reagent and surfactants was firstly confirmed, which containedβ-mercaptoethanol, Urea and SDS, respectively. The results showed that when the hair was reduced with the mixture respectively being 3.5%, 7mol/L and 2% at 45°C for 12h, a steady keratin solution was gained while of a higher hair reducing ratio. Keratin membrane was obtained insoluble in normal organic solvent, such as THF, DMF, DMSO, could slightly swell in hot water(80°C), but easily dissolved inβ-mercaptoethanol solution (≥0.2%). Both of the KH membrane and keratin from Sigma were dense and homogeneous. 13C NMR researched on KH showed that which had resemble structure of mouse SC and collagen. So KH can be used as a model in vitro for researching on the effects of CS and its relative derivatives in TDDS.Meanwhile, SEM, FTIR, DSC and EIS were used to study the mechanism of transdermal enhancers in the vitro models. Both CS and DG with the concentration of 1% changed the dense and homogeneous on keratin surface, while the secondary structure ofα-helix clearly shifted toβ-sheet in relation to the untreated keratin sample. The enhancers with the concentration of 5% decreased the melting of a-form crystallites in KH while the endothermal peak temperature reduced from 201°C to 189°C and 165°C, respectively. The EIS values of Mouse SC reduced from 3.79E6?·cm2 to 8.379E5?·cm2, 1.001E5 ?·cm2 and 1.772E5 ?·cm2 after treatment with CS, DGP and DGH, respectively. The results showed that the application of CS and its relative derivatives to confluent keratin monolayers can result in reduction of trans-epithelial electrical resistance(TEER) indicating an effect on tight junctions, thus the enhancers aid the drug permeation into the SC.