Studies And Applications Of Charge Transfer Spectrophotometry In Pharmaceutical Analysis

Charge transfer reaction belongs to that kind of reaction in which charge transfer complex is formed by charge transfering between electron donor and electron acceptor. After formed charge- transfer complex, substance presents its own character. The dissolution, the distribution, the figure of crystal, the colour of solution has changed a lot. A lot of drugs that are abundant in electrons are used as electron donors. Charge transfer spectrophotometry that is used in pharmaceutical analysis is brief, fast and exact. So it has good far forward.In this paper, UV-Vis spectrophotometry was used to study the charge transfer reaction between medicine and alizarin red or alizar as electron donors. The studies are as follows:One is that aciclovir can react with alizarin red to form 1:1 complex after being placed in the 30℃water bath for 75 minutes, which gives a maximum absorption peak at 520 nm. The molar absorptivity of the complex was 1.03×104L·mol^-1·cm^-1 and the linear range was 1.0×10-6～2.5×10-4 mol/L.The linear equation was A=0.02200+0.3873C (10-4mol/L), R=0.9995, and RSD was 0.80% (n=8). If used in the determination of aciclovir for injection, the recoveriey was between 96.44% and 100.2%.The second is that aciclovir can react with alizarin to form 1:1 complex in the presence of alcohol-water solution after being placed in the 40℃water bath for 60 minutes, which gives a maximum absorption peak at 537 nm. The molar absorptivity of the complex was 7.94×103 L·mol^-1·cm^-1 and the linear range was 5.0×10-6～2.0×10-4 mol/L. The linear equation was A=0.08805+0.1779C (10-4mol/L), R=0.9990, and RSD was 0.62% (n=7). If used in the determination of aciclovir troche, the recovery was between 97.78% and 106.2%.The third is that cefradine can react with alizarin red to form 1:1 complex in the presence of water at room temperature, which gives a maximum absorption peak at 520 nm. The molar absorptivity of the complex was 4.70×103 L·mol^-1·cm^-1 and the linear range was 5.0×10-6～5.0×10-4 mol/L. The linear equation was A=0.03570+0.2042C (10-4mol/L), R=0.9999. RSD was 0.60% (n=6). If used in the determination of cefradine for injection, the recovery was between 97.00% and 99.29%. The forth is that cefradine can react with alizarin to form 1:1 complex in the presence of acohol-water solution after being placed in the 30℃water bath for 75 minutes, which gives a maximum absorption peak at 524nm. The molar absorptivity of the complex was 2.01×104 L·mol^-1·cm^-1 and the linear range was 2.5×10-6～2.5×10-4 mol/L. The linear equation was A=0.1629+0.1920C (10-4 mol/L), R=0.9990. RSD was 1.1% (n=7). If used in the determination of cefradine capsule, the recovery was between 91.40% and 103.6%.