Study On The Supramolecular Systems Of Cyclodextrin With Drug And Biomacromolecules And Its Application

The study of supramolecular chemistry is a significant topic in currently chemistry. Molecular recognition is one of the most important field of the study on supramolecular chemistry.Molecular recognition is the process that host molecule binding with guest molecule selectively and product some special function. Host-guest molecular recognition have a promising future in pharmaceutical and biomacromolecule analysis with the merits of its specific, exclusive and highly selective molecular recognition the host compounds have towards the guest molecules. Cyclodextrins as the excellent molecule receptor, CDs have been widely used in pharmaceutical techniques. Drug molecules can demonstrate dramatically different physical and chemical properties through formation of inclusion complexes with CDs. CDs have been proved to be suitable candidates for targeted drug-delivery and release in human bodies, which can promote digestion, absorbance, and therapy effect of drugs. The supramolecular interaction betweenβ-CD with drug and biomacromolecule, showed an enhanced spectral characters. Based on this, a high sensitivity and good selectivity method for determination of drug and biomacromolecule were proposed. In this paper, we have done the following work focusing on the supramolecular inclusions betweenβ-CD as the host molecular and drug and biomacromolecule as the guest molecular.(1) The supramolecular interaction betweenβ-CD and tetracyclines were studied by fluorescence method. The binding radio and the binding constants were determined using double-reciprocal plot method, and the probable structure of inclusion complexes were discussed. The thermodynamics were obtained by relation between binding constant and temperature. It was proposed that the inclusion process was a spontaneous character,and the inclusion action was exothermic. The enthalpy was the dominating force in the formation of inclusion complexes.Based on the enhancement of the fluorescence of tetracyclines produced through inclusion complex formation,a new method for the determination of tetracyclines were also established. Compared with other methods for tetracyclines determination, the present method has broad linear range and high sensitivity. The proposed method were successfully applied to the determination of tetracyclines in pharmaceutical formulations, the recovery is within the range of 95%～105%.(2) The multirecognition interaction betweenβ-CD,MTC and DBS was sdudied by fluorescence method, and the essential reason for the optimization of analysis conditions was revealed. The results show that in pH10.55 Tris-HCl buffer solutionβ-CD,MTC and DBS can form 1:1:1 ternary inclusion complex. And the apparent binding constant obtained by double-reciprocal plot method was 3.24×10³ L²Â·mol^-2,respectively. The ternary system has strong ability of interaction, and the solubility and stability of MTC were improved significantly in comparison withβ-CD-MTC binary inclusion system. The fluorescence intensity of MTC also increased due to the formed ternary inclusion complex. Based on this, a novel fluorescence method for the determination of MTC by synergetic effect ofβ-CD and DBS was developed. Compared withβ-CD-MTC binary inclusion system, the proposed method has broad linear range and high sensitivity. It was applied to the determination of MTC in pharmaceutical formulation, urine and serum samples with satisfactory results, the recovery is within the range of 94%～105%.(3) The supramolecular interaction betweenβ-CD-MTC binary inclusion complex with BSA was studied by fluorescence method.The experimental result indicated that,in pH10.6 Tris-HCl mediumβ-CD,MTC and BSA can form 1:1:2 supramolecular complex. And the binding constant was determined. The fluorescence intensity of MTC also increased due to the formed ternary supramolecular complex. Based on this, a simple and sensitive fluorescence method for the determination of BSA withβ-CD-MTC fluorescence probe was proposed in the first time.Compared with the spectroscopic probe for protein determination,the present method has high sensitivity.The proposed method was used to determine BSA in synsetic sample with satisfactory result, the recovery is within the range of 95%¹05%.