| The application of fluorescence spectrometry in pharmaceutical analysis was summarized in this paper. And on the basis of previous work, using the characteristics of the drugs that are abundant in containing protonated tert-ammonium ions which can react with the fluorescence quencher of fluorescence quenching system, made the fluorescent substances release, enhanced the fluorescence intensity of the system. Or using the characteristics of the drugs containing N with a lone pair of electrons, which can destroy the electronic distribution structure of the fluorescence quenching system to prevent the fluorescence quenching occur, enhanced the fluorescence intensity of the system. There was a linear relationship between the fluorescence signal enhancement degree and the concentration of drugs. According to these, series of new methods for determination of drugs were established by anti-fluorescence quenching method and used for the actual sample analysis. At the same time, possible reaction mechanisms were discussed. The studies were as follows:1. The sodium tetraphenylborate has the fluorescence quenching effect on rhodamine B, making the fluorescence signal intensity weaken or even disappear. But cetirizine dihydrochloride which can react with the sodium tetraphenylborate to form a more stable hydrophobic ion-association complex had the anti-quenching effect on rhodamine B-sodium tetraphenylborate system, enhanced the fluorescence intensity of the system. There was a linear relationship between the fluorescence signal enhancement degree and the concentration of cetirizine dihydrochloride. Based on this, a novel method for determination of cetirizine dihydrochloride was established by anti-fluorescence quenching. The linear regression equation of this analysis method was△F=0.63S9ρCTZz+0.9999, correlation coefficient was0.9964, the linear range was3.50～32.3mg·-L-1, the detection limit was1.05mg·L-1and RSD was1.29%. The method was used to determine the cetirizine dihydrochloride tablets and cetirizine dihydrochloride capaules, the measured values were basically in line with the labeled amount of drugs, the recoveries were in the range of90.3106%.2. K+can react with sodium tetraphenylborate to form a more stable ion-association complex precipitation, had the anti-quenching effect on rhodamine B-sodium tetraphenylborate system. In the rhodamine B-sodium tetraphenylborate system of pH6.0, when K+was added, the fluorescence intensity of the system was increased. The solution’s fluorescence intensity F1was measured with375nm for excitation wavelength and640nm for emission wavelength. The fluorescence intensity of blank solution F0was measured under the same conditions. It was found that the different value△F=F1-F0increased linearly with the concentration of K+. Based on this, a simple and sensitive method for determination of K+was developed. Under the optimized conditions, the linear range was2.14～43.0mg·L-1, the detection limit for K+was0.642mg·L-1, and the RSD was1.32%. This method had good selection, can be used for determination of trace potassium in concentration salt solution and has been successfully applied to determination of K+in common salt and compound sodium chloride injection with satisfactory results. The recoveries were95.4～105%. Compared with the Pharmacopoeia method (gravimetric method), there were no significant difference between the two methods. But this method is more simple and fast. Meanwhile, the method solved the interference of matrix elements in atomic spectrometry for determination of similar samples.3. Venlafaxine hydrochloride also had the anti-quenching effect on rhodamine B-sodium tetraphenylborate system, mainly due to venlafaxine hydrochloride containing protonated tert-ammonium ion which can react with the sodium tetraphenylborate to form association complexes, so that rhodamine B was released, and the fluorescence intensity of system was enhanced. The fluorescence signal enhancement degree△F was proportional to the amount of venlafaxine hydrochloride. According to this, a new method for determination of venlafaxine hydrochloride was established by anti-fluorescence quenching on rhodamine B-sodium tetraphenylborate system. The linear range of the method was2.42～43.9mg·L-1. The linear regression equation was△F=0.5206ρVLX +2.4372with correlation coefficient of0.9972. The detection limit was0.727mg·L-1, the RSD was0.87%, the recoveries were between94.9-104%. The method showed high sensitivity, without using any toxic solvent, and was successfully applied in the actual sample analysis with satisfactory results.4. Galanthamine hydrobromide is a kind of new drug for the treatment of Alzheimer’s disease, and its molecular structure contains protonated tert-ammonium ion which could react with sodium tetraphenylborate to form a electrically neutral ion-association complex. When galanthamine hydrobromide was added into the fluorescence quenching system of rhodamine B-sodium tetraphenylborate, rhodamine B was released, and the fluorescence signal of the system was enhanced. The fluorescence difference△F between blank solution and the solution’s fluorescence intensity increased linearly with increasing the concentration of galanthamine hydrobromide. Based on this, a new method has been established for indirect determination of galanthamine hydrobromide by anti-fluorescence quenching method. Under the optimized experimental conditions, the linear range of the method was4.63～64.5mg·L-1, the detection limit was1.39mg·L-1, the RSD was1.82%. Galantamine hydrobromide injection of different batches were determined by this method with satisfactory results which were in accordance with the designated content, and the recoveries were95.1-103%.5. It was found that the effective energy transfer could occur between the acridine orange(AO) and alizarin red(AR) in KH2PO4-Na2HPO4buffer solution at pH=6.8. Then adding venlafaxine hydrochloride, in near-neutral conditions it changed to venlafaxine whicn molecular structure contains N that is abundant in electrons was used as electron donor. And alizarin red was used as electron acceptor, they reacted to form charge transfer complex with the1:1composition ratio. This inhibited the energy transfer between AO and AR, and made the fluorescence intensity of the system enhanced. The fluorescence signal strength difference between blank solution and test solution showed good linear relationship with concentration of venlafaxine hydrochloride. Accordingly, a novel method for indirect determination of venlafaxine hydrochloride by anti-fluorescence quenching method on acridine orange-alizarin red system has been established. Under the optimum conditions, the linear range of the method was3.49～31.4mg·L-1, the detection limit was1.65mg·L-1. The RSD was1.16%. The method was used to determine the venlafaxine hydrochloride in commercial venlafaxine hydrochloride sustained-release tablets and venlafaxine hydrochloride sustained-release capsules with a good precision and accuracy, the recoveries were in the range of95.5～105%. |
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