| As is well-known, the quantity of druggery affects people's health and safety directly. And pharmaceutical analsis is an important means to guarantee medicines safe and effective, which has the prominent function in each link of drugs including research, production, usage, circulation, identification, tests and assay. Therefore the whole control of the quantity of the druggery plays an important role in the clinic and medical treatmen. Spectrophotometry, chromatography and spectrophotometry -chromatography, as the most essential methods in the druggery measurements, have been widely used in the determination of pharmic product. In recent years, the research and application of organic photometric analysis are focusing on biology, clinic, druggery and so on along with the development of life sciences. Obviously, sectrophometry is one of the methods in the quantitative determination of drugs in the modern instrumental analysis. In contrast, spectrophometry is simple, widely, high selectivity and accuracy, very sensitive, economical, less interference or easy to eliminate the interference, easy maintenance and so on. It is still the questions to be solved in the analysis of druggery to optimize the analytical condition, improve the selectivity, reduce the detection limit and simplify the procedure.In this paper, two methods have been developed for the determination of thiol-containing(SH-) or phenolic hydroxyl compound. Firstly, under certain conditions, a redox reaction of Cu(Ⅱ) and the target drug will take place. In the course of phase separation, the precipitation was stayed upon the surface of water. According to the amount of residual Cu(Ⅱ) in the solution, the amount of target drugs can be indirectly determined; secondly, According to the redox reaction of Fe(Ⅲ) and the target drug, the resulting Fe(Ⅱ) reacts with potassium ferricyanide to form soluble prussian blue (KFeⅢ[FeⅡ(CN)6]). The absorbance of soluble prussian blue is measured at the absorption maximum of 730 nm, and the spectrophotometric method has been established to determine the assay of drugs. In this paper, a series of studies were carried out, which were simple and convenient method of drug analysis, discussion of reaction mechanism, optimization of reaction conditions, the application of biological sampls and so on.1. Indirect determination of reductive substances with potassium thiocyanide-potassium nitrate-Cu(Ⅱ) systemIn this paper, the reaction conditions and reaction mechanism between Cu(Ⅱ) and ethamsylate, hydroquinone and tiopronin were discussed, respectively. And the effect of different acidity, reaction temperature, standing time, amount of KSCN and potential interference were researched. And the study indicated that ceftriaxone sodium can be degraded into the thiol product in the presence of 0.2 M sodium hydroxide in boiling water bath. The thiol group (-SH) of the degradation product could reduce Cu(Ⅱ) to Cu(I) by redox reaction. And the effect of degradation time, content of sodium hydroxide, different acidity and potential interference were also discussed. The method was high selectivity and sensitivity, wider linear range, quick and simple, and could be used to determine some reductive group of drugs in pharmaceutical and biological samples. Analytical results obtained with this novel method were satisfactory. It is expected that this method will find broad applications in the detection of drugs with simila structure.2. Determination of cefotaxime sodium with the detection system of potassium ferricyanide- Fe(Ⅲ)A novel method for the determination of cefotaxime sodium by the detection system of potassium ferricyanide- Fe(Ⅲ) was described. This cephalosporin could be completely degraded into thiol- containing product in the presence of 0.2 M sodium hydroxide in boiling water bath. In the presence of potassium ferricyanide, Fe(Ⅲ) is reduced to Fe(Ⅱ) by the degradation product of CTX at pH 3.0. The in situ formed Fe(Ⅱ) reacts with potassium ferricyanide in forming soluble prussian blue (KFeⅢ[FeⅡ(CN)6]), which the maximum absorption is 730 nm, and the amount of cefotaxime sodium can be indirectly calculated. A good linear relationship could be obtained between the absorbance and the amont of cefotaxime sodium in the range of 0.04 - 24.0μg mL-1. The linear regression equation is A = 0.05088+0.21663C (μg mL-1) with linear correlation coefficient of 0.9986. The detection limit and relative standard deviation is 0.01μg mL-1 and 1.36%, respectively. And the apparent molar absorption coefficient of indirect determination of cefotaxime sodium is 0.23×106 L mol-1·cm-1. This method has been successfully applied to the determination of cefotaxime sodium in pharmaceutical and serum samples. |
PDF Full Text Request