Main - The Object Of Multiple Recognition Mechanism And Its Drug Analysis Applications,

The theory of host-guest molecular recognition is built on the base of studies on thevarious information-delivery in biological bodies and the interactive course betweenenzyme and substrates. It can discover specific, exclusive and highly selective molecularrecognition the host compounds have towards the guest molecules, from which artificialreceptor and artificial enzyme with special function such as cell membrane can be designedand applied in various fields. In recent years, the application of new host compounds, suchas cyclodextrins(CDs) and calixarene, on the recognition and analysis of bio-pertinentsubstances have gradually become the focal point of the present research work. CDs havehollow truncated cone with hydrophobic cavity and hydrophilic wall. They are well knownto have the property of forming inclusion complex with organic and inorganic moleculeswhich possess suitable polarity and dimension. So, as the excellent eazyme model andmolecule receptor, CDs have been widely used in a good many of fields in science andtechnology. The formation of supramolecular complex with CDs can alter thephotochemical and photophysical properties of the guest molecules and considerableattentions have been focused on the luminescence application of CDs. Drug molecules candemonstrate dramatically different physical, chemical and biological properties throughformation of inclusion complexes with CDs, such as the enhancement of the solubility,stability, and bioavailability. CDs have been proved to be suitable candidates for targeteddrug-delivery and release in human bodies, which can promote digestion, absorbance, andtherapy effect of drugs.Surfactants can provide a similar microenvironment like the CDs, which can enhance solubility, stability, and sensitivity of analysis systems. Some chemical and physical properties of surfactants can be changed when they are included in CDs cavity, so the interaction of surfactants with CDs have attracted much attention recently. Stydies about the formation of multirecognition ternary CDs complexes in which two different guests are complexed in a single CD host cavity, have been performed. In a drug:CD:surfactant multirecognition ternary complex, drug molecues can show remarkably different spectralcharacteristics compared to in a binary drug:CD complex, such as very high sensitivity and selectivity, which has very important theoratic and applicative value.Based on the changes in the spectrum characters of drug molecules in micellar medium or produced through ternary inclusion complex with CDs and surfactants, we have carried out three aspects of investigation:First, the mechanism of the influence of various micellar medium on the spectral characters of novel drug, Zaleplon, for the treatment of insomnia, was systematically studied. A simple, rapid, sensitive and selective spectrofluorimetric method has been developed for the directive determination of Zaleplon in aqueous phase based on the sensitizing enhancement effect produced by non-ionic surfactant Triton X-100. The proposed method was successfully applied to the determination of zaleplon in tablets, serum and urine.Second, The mechanism of the supramolecular interaction of broad-spectrum anthelminthic drug and fungicide Thiabendazole(TBZ) and β -cyclodextrin ( β -CD) has been studied and discussed by spectrophotometry. P -CD-TBZ inclusion complex was synthesized and its structure was characterized by 1HNMR and IR. The results show that the phenyl ring of TBZ is included into the β -CD cavity to form a 1:1 host-guest complex. Inclusion complex thermodynamics has also been investigated. The changing trends of the thermodynamics have been researched. Based on the enhancement of the absorbance of TBZ produced through complex formation, a spectrophotometric method for the determination of TBZ in bulk aqueous solution in the presence of β -CD was developed. The proposed method has been successfully applied to the determination of TBZ in fruits.