Enhancing Therapeutic Loading and Delaying Transport via Molecular Imprinting and Living/Controlled Polymerization

This work demonstrates for the first time molecular imprinting using a living/controlled polymerization (LCP) strategy to enhance template loading/affinity and delay release in weakly crosslinked gels. Two gel systems were studied: poly(DEAEM-co-HEMA-co-PEG200DMA) gels imprinted for diclofenac sodium and poly(MAA-co-EGDMA) gels imprinted for ethyl adenine-9-acetate. Experimental evidence confirms that template diffusion coefficients within imprinted gels can be heavily influenced by template binding affinity. Recognition studies revealed significant increases in template loading/affinity with large increases in loading for LCP, and dynamic template release studies showed that imprinting via LCP extends the template release profile by twofold over that of imprinting via conventional free-radical polymerization techniques and fourfold over the control network (less Fickian and toward zero-order release with a profile coefficient of 0.70). Analysis of reaction kinetics indicated that LCP with reversible termination events increases the chemically controlled chain propagation mechanism, and that binding sites are formed during this phase of the polymerization. (C) 2009 American Institute of Chemical Engineers AIChE J, 56: 268-279, 2010