Imprinted Polymers in Separation of Pharmaceuticals

Due to the selective and rather specific tendency of MIPs towards the templates, these structures have been used for the separation of different target species through a variety of methods [157-186]. In this section the studies performed on the separation of pharmaceutical species based on MIPs shall be covered [243-292] in some detail with respect to the polymer ingredients and the results obtained. 

Thibert et al. developed an MIP for the extraction of cocaine and its metabolites, i.e. benzoylecgonine and ecgonine methyl ester from urine prior to LC-MS procedure. They used cocaine as the template during the polymerization of methacrylic acid monomers in combination with ethylene glycol dimethacrylate cross-linker. The polymerization reaction was performed in acetonitrile and azo-N,N/-bis-isobutyroni-trile was used as the initiator. The LOQs for cocaine, benzolecgonine, and methyl ester, after separation and preconcetration through the MIPs, were evaluated to be 0.09 ng/ mL, 0.4 ng/mL, and 1.1 ng/mL respectively [243]. 

In another work lacosamide based MIPs of methacrylic acid monomers were used for the solid-phase extraction of the template from rat plasma before LC analysis and the results revealed a recovery of over 98% for the SPE and the LOD and LR of the method were evaluated to be 0.03 pg mL and 0.1-100 pg mL [244]. B. B. Prasad et al. reported the MIP-based SPE of epinephrine and detection of the same through an MIP based sensing device in plasma cerebrospinal fluids. They reported the reaction of functionalized multiwalled carbon nanotubes (MWCNTs-COCl)] as a monomer with N-hydroxy phenylmaleimide and used glycoldimethylacrylate as the cross-linking agent. The LOD of the hyphenated method was reported to be 0.002 ng mL [245]. In another study M. Moein and co-workers developed MIP cartridges to be used in combination with HPLC for facile analysis of human insulin in plasma and urine. They used insulin as the template, in the reaction between meth-acrylicacid monomer and ethylene eglycol dimethacrylate cross-linker. The reaction initiation was achived by 2,2/-azobisisobutyronitrile. The overal results showed LODs of 0.2 ng mL in plasma and 0.03 ng mL in urine with recovery factors over 87% [246]. 

The selective extraction of catecholamines has been the subject of some studies [250,269]. Recently B. Claude et al developed a method for the selective SPE of catecholamines and metanephrines from bovine serum using MIPs, and reported the recovery, RSD and linearity range of the method to be in the orderof64-98%, less than 6% and 0.30-0.90 pM respectively [250]. In another study M. Bouri et al reported the selective extraction of catecholamines from urine using a dopamine MIP coated magnetic molecularly imprinted polymer and capillary electrophoresis. They used methacrylic acid as the monomer, ethylene glycol dimethacrylate as the cross-Unker and coated the MIP on FCjO particles and used 2,2 - azobisisbutyronitrile as the initiator in methanol/water or acetonitrile/water solvents, and reported LOD of 0.04-0.06 pM, RSD of 0.7%-1.4% and a response range of 2.9%-5.5% [269]. 

Acetaminophen and aspirin specific MIPs have also been prepared based on meth-acryhc acid, 4-vinylpyridine and methyl methacrylate as the monomer and ethylene glycol dimethacrylate as the cross-Hnking aganet [251]. MIPs have further been used 

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