Imprinted polymers for selective adsorption of cholesterol from gastrointestinal fluids

A series of highly cross-linked terpolymers of methacryloylated cholesterol or bile acid methyl esters, methacrylic acid, and ethyleneglycol dimethacr ylate were prepared in the presence or absence of cholesterol acting as a t emplate molecule. The polymers were freed from cholesterol by washing and t he resulting adsorbents tested for cholesterol rebinding in the chromatogra phic mode using methanol-water as mobile phase or in the batch mode using a n intestinal mimicking fluid of concentrated bile acids in water. The polym ers prepared in polar solvents, favoring the apolar association of the temp late and the apolar face of the amphiphilic monomers, exhibited selective r ebinding of cholesterol as compared to a nonimprinted blank polymer prepare d identically but without cholesterol. The strongest rebinding was seen for the polymer prepared using 3 beta-methacryloyl-cholesterol as the function al monomer; Using a physiologically relevant intestinal-mimicking solution of cholesterol(1 mM), these polymers adsorbed ca. 17 mg cholesterol per gra m dry adsorbent, whereas a nonimprinted blank polymer adsorbed ca. 13 mg. T he imprinted polymers showed the highest uptake of cholesterol as compared to other adsorbents (<13 mg/g) that were expected to show high affinity for cholesterol.