Application Of Spectroscopic On The Interaction Of β-cyclodextrinwith Fluorescent Reagent

As the second generation of supramolecular host compound, β-cyclodextrins because of its structure characteristics with hydrophile exterior and hydrophobic central cavity has a promising inclusion prospect to guest molecules. So it can changes the spectral properties and physico-chemical property of guest molecules. Meanwhile it has a good application prospect in the fields of medicine, sewage treatment and so on.The inclusion of β-cyclodextrins with guest molecules become an effective and important ways of new analytical methods for certain pharmaceutical formulations to be determined, in order to improve the system analysis determination of sensitivity and detection limit. By using spectrophotometric and to analyze, probe and verify the inclusion mechanism of β-cyclodextrins supramolecular system. According to the theory of supermolecular chemistry, the following four aspects are summarized in this paper:1、A new simple, rapid competitive fluorescence inclusion method is established for the determination of propranolole hydrochloride. At pH8.4, NR has a weak fluorescence intensity, after adding right amount of β-cyclodextrin, the fluorescence intensity of neutral red is largely enhanced because of the inclusion reaction. The addition of propranolole hydrochloride could reduce the fluorescence intensity of the system. Through an indirect way, propranolole hydrochloride can be determined by measuring the fluorescence intensity of the system. The linear range, detection limit and relative standard deviation are 0.1~20 mg/L, 0.006mg/L and 0.5%, respectively. The common coexisting ions do not interfere in the determination. This method has been applied to determinate propranolole hydrochloride in practical samples.2、A new, accurate and sensitive fluorescence method is proposed for the determination of ranitidine hydrochloride in pharmaceutical formulation. The method is based on the enhancement of ranitidine hydrochloride on the fluorescence intensity of the product yielded in the redox reaction between N-bromosuccinimide and methylene blue in hydrochloric acidic medium, in which β-cyclodextrin acts as a sensitizing effect reagent. The fluorescence intensity of the complex is also enhanced greatly. Through an indirect way, ranitidine hydrochloride can be determined by measuring the fluorescence intensity of the methylene blue. Its maximum excitation wavelength is at 647 nm, and the maximum emission wavelength is at 683 nm. The linear range detection limit and relative standard deviation are 0.05~1.55mg/L, 0.007mg/L and 0.20 %, respectively. The method was successfully applied to the assay of ranitidine hydrochloride in capsule forms and the results were statistically compared with those of the reference method.3、New sensitive and rapid spectrophotometric method for the determination of famotidine in pharmaceutical formulation was developed and optimized. The proposed method includes the interaction of N-bromosuccinimide with famotidine and the subsequent interaction of N-bromosuccinimide with neutral red which was followed determined by its reaction with β-cyclodextrin in pH8.6. The fluorescence intensity of the complex was also enhanced greatly. Through an indirect way, famotidine can be determined by measuring the fluorescence intensity of the neutral red.Its maximum excitation wavelength is 464 nm, and the maximum emission wavelength is 580 nm. In this method, the amount of N-bromosuccinimide reacted corresponds to the amount of the drug. The limits of detection and quantification were also reported for the method. The method was successfully applied to the assay of the drug in the pharmaceutical formulation. No interference was observed from common additives and the validity of the method was tested.4、A simple, sensitive, validated and selective spectrofluorimetric method has been developed for the determination of cimetidne in pharmaceutical formulation. The proposed method involves the addition of a measured excess of N-bromosuccinimide and β-cyclodextrin, followed by determination of unreacted N-bromosuccinimide by reacting with a fixed amount of methylene blue and measuring the fluorescence intensity of surplus methylene blue at a maximum emission wavelength 652 nm, upon maximum excitation wavelength at 682 nm.β-cyclodextrin was found to react with the methylene blue to form a stable complex. The fluorescence intensity of the complex was also enhanced greatly. Accordingly, a new fluorescence method for the determination of the studied drugs was established. The different experimental parameters affecting the fluorescence intensity were studied carefully. Moreover, the cimetidne has been calculated using the proposed method. The method was statistically compared to the official method with no significant difference in performance.