Preparation And Characterization Of PEG-modified Polyurethane Pressure-sensitive Adhesives

Preparation and characterization of hydrophilic pressure-sensitive adhesives (PSAs) were studied mainly in this thesis to solve the disadvantages of the PSAs used in the present transdermal drug delivery systems, such as lower water absorbency, worse permeation of water vapor and biocompatibility, and short of the ability of repeating stick. The main contents are as follows:(1) Hydrophilic polyurethane PSAs was prepared from diisocynates, co-polyether and extender by pre-polymerization. According to pharmacopoeia the methods of rolling boll at a slope , peeling at 180 angle and measuring hold power were used to evaluate the mechanical properties including tack, adhesion and cohesion forces. Effects of diisocynates, co-polyether composition, NCO/OH ratio, temperature and chain extender on the reaction and adhesive characters were studied. Directions and process conditions of producing PU-PSAs with good adhesive characters were established: PEG:PPG:PTMG=24:20:56;NCO/OH=2.0~2.2, vacuum dried co-polyether and HDI pre-polymerized under 80℃in butanone with stannous octanoate as catalyzer, then chain extended with 0.045% EG under 65℃in 3～4 hours.(2) The results indicated PEG and PPG domain of PU chain's soft segment endued PU- PSAs excellent hydrophilicity and good adhesive characters respectively. Water absorbency and water-vapor permeation testing validated PU-PSAs could absorb sweat on skin. Its good bio-compatibility testified by skin testing. In conclusion, PU-PSAs prepared in this thesis could satisfy the applicability of different transdermal drug delivery systems.(3) Using thiamazole, ibuprofen and diclofenac sodium as matrix, we studied PU- PSAs'drug compatibility and influence of drug quantity to its adhesive characters. We worked over its drug-release character and in vitro percutaneous permeability. Results showed that PU-PSAs possessed good drug compatibility and drug-load property.PU-PSAs exhibited good controlled-release drug property to different drug. These good properties enable PU-PSAs potential value for transdermal drug delivery systems use. Synthesis of modifying PLA with MAH was researched briefly in this thesis. FTIR result showed that MAH grafted on PLA in two mode and density of MAH grafted on the PLA chain was under expectation.