ABSTRACT
Polyurethanes have been widely used in several industries due to their versatile properties.1 On account of their biodegradability, some of them are very useful for several medical applications. Biodegradability of the polymers depends on various factors such as chemical structure, molecular weight, degree of crystallinity and morphology.2 Functional groups such as ether, ester, amide, urethane and so on in backbone of polymeric structures make them biodegradable.3 It has been reported that microbial degradation of polyurethanes depends on diisocyanate and diol used (4). One important aspect regarding biodegradability of polyurethane is the ratio of
soft and hard segment.2,5 Incorporation of hydrophilic polyethylene glycol (PEG) may enhance biodegradability of polyurethane.6 In the stability of polyether urethane (PEU), molecular weight of PEG plays a significant role.7 As reported, a good polymeric coating matrix should have proper balance between hydrophobicity and hydrophilicity.8 Controlled release of drug from the matrix is also an important aspect for medical application apart from biodegradability.9 The release of drug from the matrix and the degradation rate should be controlled to achieve effective drug release for a long period.6 As most of the major complications with implant devices arise from bacterial infection and biofilm formation, the best strategy could be coating of implant material, which is biodegradable, biocompatible and has the ability of releasing drug in controlled fashion.10
