Imprinted polymers as drug delivery vehicles for metal-based anti-inflammatory drug

A drug delivery system based on metal-chelate imprinting is described for the first time for a metal-based drug, copper salicylate. Metal-chelate embedded polymer (MCEP) material was prepared by adding 2 equiv. of 4-vinyl pyridine, 8 equiv. of 2-hydroxyethyl methacrylate, 32 equiv. of ethyleneglycoldimethacrylate to 1 equiv. of copper salicylate in 10 ml of 2-methoxyethanol and then polymerizing thermally in the presence of 2,2′-azobisisobutyronitrile as initiator. The removal of the embedded copper salicylate from MCEP to prepare metal-chelate imprinted polymer (MCIP) was assessed by X-ray photoelectron spectroscopy (XPS), flame atomic absorption spectroscopy (FAAS) and high performance liquid chromatography (HPLC) techniques. Conventional or non-imprinted polymer material was prepared in a similar manner to MCEP, but without the addition of copper salicylate to the synthesis recipe. The drug release behaviour was examined in vitro with polymer materials having different template to monomer ratio, different crosslinker density and with polymer material loaded with copper salicylate to different extent. Detailed drug release studies with the drug loaded to MCIP and NIP materials unequivocally establish the higher and sustained release of the therapeutic agent over several days in addition to higher drug loading capacity with the former material.