Studies On Hydrophilic Polyurethane Press Sensitive Adhesives For Transdermal Drug Delivery Systems

The traditional pressure sensitive adhesives (PSAs), such as natural rubber, polyisobutylene, silicone rubber and polyacrylate, although they get wide application on the transdermal drug delivery systems (TDDS), are difficult to satisfy the need of improving the rate of drug release because of their strong hydrophobic property. Also, the phenomenon of water accumulation will occurred when they paste on the skin, In addition, it is difficult to get rid of the hurt and residue When these PSA are peeled off from skin. Base on the requirement of hydrophilic PSAs in transdermal drug delivery systems (TDDS), the synthesis and properties of the hydrophilic polyurethane PSAs were studied in this thesis.The hydrophilic polyurethane PSA without ionic groups was synthesized by condensation copolymerization of polymer glycol, polyethylene glycol (PEG), diisocyanate and extender. Polyethylene glycol (PEG) was chosen as the hydrophilic segments and has been introduced into the molecular chains of polyurethane PSAs to provide hydrophilicity. Different polymer glycols, diisocyanates and the extenders were selected, and the effects of the temperature, reaction time and the ratios of the materials on the productions were investigated carefully in this work.The methods of infrared spectrum, GPC, X-ray diffraction were used to characterize the product. The methods of rolling boll at a slope, peeling at 180°angle and cohesion test were used to evaluate the mechanical properties including the tack, adhesion and cohesion forces. The air permeability, water absorption and anti moisture ability of the hydrophilic polyurethane PSAs were investigated. The thesis also primarily studied the drug transdermal delivery behavior of the prepared polyurethane PSA and the suitable transdermal enhancers. The studied results indicated that the hydrophilic polyurethane PSAs prepared in this thesis shew good air permeability, water absorption, anti moisture ability and mechanical properties, which suit for the TDDs application when suit transdermal enhancers exist .