Biodegradable photo-crosslinked poly(ether-ester) networks for lubricious coatings

Biodegradable poly(ether-ester) networks were synthesized by UV photopolymerization and their lubrication performances were evaluated. Polyethers such as poly(ethylene glycol) (PEG), poly(propylene glycol) (PPG), and poly(tetramethylene glycol) (PTMG) were copolymerized with oligomers of D,L-lactic acid and terminated with acrylate groups to form photopolymerizable macromers. H-1 NMR and IR spectra confirmed the chemical structures of copolymers and diacrylated macromers. Crosslinked polymer networks were formed upon UV-initiated free-radical polymerization. Gel contents, water contents, and contact angles were measured to characterize the crosslinked networks. In vitro degradation times of the crosslinked networks at 37 degrees C in 1 N NaOH varied from 20 min to 7 days depending on the crosslinking density (molecular weight of macromer) and the hydrophilic susceptibility (types of polyethers). The crosslinked polymers were coated on stainless-steel needles to investigate the lubrication properties by measuring penetration and drag forces through rubber stoppers. The maximum improvement in penetration force over control was 41% in the needle coated with PPG-based polymer networks (molecular weight of PPG = 4000). These materials can potentially be used as biodegradable lubricants for coating various medical products to replace the existing non-degradable silicone-based materials currently used. (C) 1999 Elsevier Science Ltd. All rights reserved.