Controlled Drug Release from Weakly Crosslinked Molecularly Imprinted Networks: The Benefit of Living Radical Polymerization

Abstract

This work focuses on the complex relationship between molecularly imprinted polymer network formation, network structure, and composition, and template binding and transport. A comprehensive study of template binding and transport is performed using two different reaction schemes (living radical polymerization and conventional free radical polymerization) while altering template concentration, functional monomer concentration, solvent content, crosslinking monomer length, and extent of crosslinking. Imprinted poly(HEMA-co -DEAEMco -PEG200DMA) networks prepared by living radical polymerization (LRP) exhibit enhanced molecular imprinting and have signifi cantly higher template binding affi nities ( ≈ 2 × ), higher binding capacities ( ≈ 2.3 × ), slower template release, and lower template diffusion coeffi cients (1/2 × ) compared with imprinted polymers prepared via free radical polymerization (FRP) with statistically similar parameters for non-imprinted polymers. A synergistic effect between LRP and molecular imprinting is demonstrated. LRP has a profound structural effect on the network leading to reduced free volume and/or increased homogeneity in the mesh structure leading to enhanced macromolecular memory. In addition, by altering reaction parameters, like template and monomer concentrations, the template binding and release characteristics can be tuned. By using an LRP reaction scheme, improved control over release can be achieved enhancing the role the molecular imprinting technique can make in the design and engineering of novel drug delivery materials.

Imprinted Contact Lenses for Sustained Release of Polymyxin B and Related Antimicrobial Peptides

“…Imprinting of small molecules in rigid polymer networks is now well developed and also incipiently proved in swellable hydrogels. 12,14,15 However, preparation of hydrogels imprinted for peptide drugs is still challenging for two main reasons: (1) the peptide has to be soluble in the monomer solution and be able to diffuse through the network during removal and rebinding (which is difficult due to steric hindrance of the network mesh size); and (2) the relatively low cross-linking density of the contact lenses and their swelling in aqueous media (including lachrymal fluid) after polymerization may reduce the stability of the imprinted cavities. 16 Therefore, the imprinting procedure should be designed to yield the optimum network stability and maximum interactions between the drug and the network.…”

Molecularly Imprinted Polymeric Micro- and Nano-Particles for the Targeted Delivery of Active Molecules

“…A systematic study of recognition properties combined to delivery performances were evaluated in the work of Salian et al [127]. In this paper the synergic effect of the synthesis scheme (living radical polymerization vs conventional free radical polymerization) and MI technology was demonstrated.…”

Desorption of 3,3′-diindolylmethane from imprinted particles: An impact of cross-linker structure on binding capacity and selectivity

“…It was found that the increase in the length of cross-linker resulted in the decrease of template binding capacity as well as the increase of the template transport rate in polymer gels, and that the living radical polymerization increased the binding capacity. Tested imprinted material was used for controlled release of diclofenac [15]. In our previous paper, we described the preparation of 3,3′-diindolylmethane (DIM) imprinted polymer and its application to selective separation of the template from biological matrix [16], but usefulness to the controlled release of DIM was not studied.…”