Preparation and study of tramadol imprinted micro-and nanoparticles by precipitation polymerization: microwave irradiation and conventional heating method.

In the present work a series of tramadole imprinted micro- and nanoparticles were prepared and study their recognition properties. Methacrylic acid (MAA), as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linker and different solvents (chloroform, toluene and acetonitrile (ACN)) were used for the preparation of molecularly imprinted polymers (MIPs) and non-imprinted polymers (NIPs). Several factors such as template/monomer molar ratio, volume of polymerization solvent, total monomers/solvent volume ratio, polymerization condition (heating or microwave irradiation) were also investigated. Particle size of the polymers, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), rebinding, selectivity tests and release study were applied for evaluation of the polymers. The optimized polymers with smaller particle size and superior binding properties were obtained in acetonitrile under heating method. MIPA4 with a size of 42.6 nm and a binding factor (BF) of 6.79 was selected for selectivity and release tests. The polymerization was not successful in acetonitrile and toluene under microwave irradiation. The MIPA4 could selectively adsorb tramadol, compared to imipramine, naltrexone and gabapentin. The data showed that tramadol release from MIPA4 was significantly slower than that of its non-imprinted polymer. Therefore, MIP nanoparticles with high selectivity, binding capacity and ability to control tramadol release could be obtained in precipitation polymerization with optimized condition.