Abstract: Copolymer of N,N-dimethylacrylamide and N,N′-ethylene bisacrylamide was partially hydrolyzed to introduce the carboxyl groups onto the copolymer. Amino acids were introduced onto the carboxyl group-containing copolymer by coupling the methyl ester of the amino acids with the copolymer and then saponifying the ester. In this way, three analogues(—Gly, —Gly-D-Ala, —Gly—D-Ala—D-Ala) of the cell wall mucopeptide of Gram-positive bacteria were introduced onto the copolymer and three affinity adsorbents (Adsorbents Ⅰ, Ⅱ and Ⅲ) for vancomycin group of antibiotics were synthesized. The results showed that the adsorption capacities of adsorbents Ⅱ and Ⅲ for N-demethylvancomycin were 0. 80 and 0.86 mmol/g, respectively. The optimal pHfor the adsorption was about 6. The effect of the salt(NaCl) concentration in the solution on the adsorption capacities of adsorbents Ⅰ and Ⅱ indicated that the capacity of adsorbent Ⅰ decreased markedly with increasing the salt concentration, while the effect of the salt concentration on the capacity of adsorbent Ⅱ was relatively slight. The result suggested that the affinity interaction contributed to the adsorption of adsorbent Ⅱ was greater than that of adsorbent Ⅰ. The adsorbed N-demethylvancomycin was completely desorbed by 0.4 mol/L Na₂CO₃(pH9.5)/CH₃CN(7/3 in volume ratio).

Key words: Affinity, Vancomycin, N-Demethylvancomycin, Adsorbent