Cyclodextrin-functionalized polyethylene and polypropylene as biocompatible materials for diclofenac delivery

Polyethylene (PE) and polypropylene (PP) were surface functionalized with β-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) with the aim of providing PE and PP with the capability of behaving as drug delivery systems. Functionalization was carried out according to a two-step procedure: (i) glycidyl methacrylate (GMA) was grafted by means of gamma radiation and (ii) the epoxy groups of GMA reacted with the hydroxyl groups of CDs forming ether bonds. For a fix radiation dose and GMA concentration, grafting yield (ranging from 1 to 100 μmol GMA cm−2) depended on the time during which the preirradiated PE and PP films and slabs were immersed in the GMA solution. CD grafting (from 0.013 to 0.734 μmol cm−2) was confirmed by infrared analysis, DSC and the organic compound approach (using 3-methylbenzoic acid as a probe). Functionalization with CDs rendered as highly cytocompatible materials as the starting ones, did not cause relevant changes in the water contact angle and the friction coefficient of PE and PP, but remarkably improved their capability to uptake diclofenac through formation of inclusion complexes with the CDs. Furthermore, the functionalized materials released the drug for 1 h, which could be useful for management of initial pain, inflammation at the insertion site as well as adhesion of certain microorganisms if these materials are used as medicated medical devices.