Theophylline crystal imprinted polymem capable of inducing theophylline crystallization in aqueous media were prepared by a photo-initiating approach with methacrylic acid (MAA) as the functional monomer and ethylene glycol dimethacrylate (EDMA) as the cross-linker．SEM studies showed that the surface of the theophylline-imprinted polymer

after a thoroughly washing procedure with 0.1 mol/L HCl solutions

could well induce theophyiline crystallization process

when it was immersed in a saturated theophyHine solution for 24 h．On the contrary

the caffeine-imprinted polymer failed to show the same result under the given conditions．The subtle distinction in their molecular structures related to the imidazole ring might be one of the major reasons responsible to the observed results．The theophylline molecule could interact with the carboxyl of methacrylie acid via its imidazole ring as well as the neighboring carbonyl group in its pyrimidine part by hydrogen bonding and/or electrostatic interactions

while the caffeine molecule could not form the same bonds with the methacrylic acid due to the existence of its methyl displaced imidazole ring．