Synthesis, characterization and evaluation of computationally designed nanoparticles of molecular imprinted polymers as drug delivery systems

The aim of the present study was to prepare nanoparticles of molecular imprinted polymers (MIPs) with high loading capacity for naltrexone as template drug. To achieve this goal, a computational protocol was employed to select the most appropriate monomer for MIP preparation. Density functional theory (DFT) method at the B3LYP level of theory in conjugate with the 6-31+G(d) basis set was used to evaluate the extent of interaction between naltrexone and a small library of frequently used vinylic monomers. The results revealed that acrylic acid (AA) and methacrylic acid (MAA) can be considered as suitable monomers. To select the best monomer, two MIPs with AA and MAA monomer were synthesized and their loading capacity, selectivity and release profile were evaluated. The experimental results showed that the MIPs synthesized using AA (MIP-AA) exhibited a surprisingly high loading capacity to naltrexone (75 mg of drug/g of MIP) compared to MIP-MAA (34 mg of drug/g of MIP). In vitro release dynamics of the drug from MIPs was also investigated and modeled. It was found that non-Fickian-type diffusion mechanism was responsible for drug release. The results can lead to the conclusion that MIPs designed by computational approach can be considered as promising candidates for drug delivery systems. (C) 2011 Elsevier B.V. All rights reserved.