Study Of Sulfa-drugs Molecular Imprinted Systems By Computer Molecular Simulation

Sulfonamides are the earliest antibiotic agent drugs which have remarkableeffectiveness in the treatment of the epidemic cerebrospinal meningitis, plague andother diseases. They were frequently used as a feed additive in livestock breedingindustry, because of their obvious effect, low price. However, excessive use of sulfadrugs or food containing sulfonamides residues will cause serious harm to humanbody. The detection and separation of sulfonamides plays a very important role onquality control in medicine and food industry. The development of molecularimprinting technology provides a new path for the detection and separation of sulfadrugs. But further widespread application and development of molecular imprintingtechnique are limited by the selection of functional monomer, solvent selection andmolecular imprinting mechanism.In this paper, the molecular imprinted polymers of sulfanilamide,sulfisoxazole and sulfadimidine were researched by quantum chemistry. The mainresearch works are presented as follows:1. Molecular imprinted polymer of sulfadimidine was studied by densityfunctionaltheory (DFT) and Semi-empirical method (PM3). Based on DFT//B31YP/6-311++G**, the conformation of sulfadimidine and functional monomer wereoptimized, then the polymers were formed by analysing the Mulliken charges of theatoms in SM2. Used PM3, the progress of molecular imprinted polymer wassimulated, and the appropriate functional monomers were selected by means ofcomparison of the binding energy (ΔE) of the template and functional monomers. Theresults showed that the stability of polymer formed by TFMAA and SM2was themost powerful, the second was MAA, and then AA, AM was the last.2. The comparison researches for MIP with sulfanilamide were developed bydensity functional theory and semi-empirical method. The interactions betweendifferent functional monomers and the same template monomer, the stability ofmolecular imprinted polymers were calculated by quantum chemistry. There was no difference in the stability of the complexes by DFT or PM3. Calculating the solventenergy of the SMN and AM in the solvents with different dielectric constants byputting the pre-assembly system into PCM, the results indicated that the solvationenergies of sulfonamide and acrylic acid were related to their dielectric constants.3. Using sulfafurazole(SIZ) as the template, the methacrylic acid(MAA),acrylamide(AM), acrylic acid(AA) as the functional monomers, the molecularimprinted systems including those chemicals were studied. The binding energy of thefunctional monomers and the template as well as the solvation energy of the systemwas calculate by quantum chemistry method in the basis of MP2，which were used asthe basis of selection of functional monomers and solvents. We studied the1:1ratio ofthe template and the functional monomer by the Frontier Molecular Orbitals, whichwas considered as the basis of the strength for binding point.