AIM To study in vitro stereoselective metabolism of mandelic acid (MA) in 3 kinds of laboratory animal tissue fractions and observe the differences of MA biotransformation. METHODS MA enantiomers were incubated with the tissue fractions from rats, mice and rabbits. The phenylglyoxylic acid (PGA) concentrations in incubation mixture were determined by high-performance liquid chromatography. Coenzymes and inhibitors were co-incubated with MA to investigate their effects on MA metabolism. RESULTS Only S-MA showed a unique metabolism in liver and kidneys S9 fractions of rats. No inhibition of the enzyme activity was observed by addition of ethanol or 4-methyl pyrazole. NADPH caused a remarkable increase in S-MA metabolism. CONCLUSION Nonmicrosomal enzymes in kidneys and liver except alcohol dehydrogenase are responsible for the stereoselective metabolism of MA in rats. The MA biotransformation is significantly different between rats and mice or rabbits.

OBJECTIVE:To establish a method for the determination of related substances in anastrozole. METHODS:HPLC was performed on the column of Welch Materials XB C18 with mobile phase of acetonitrile-water(35:65,V/V)at a flow rate of 1.0 mL/min,detection wavelength was 210 nm,column temperature of 25 ℃,and the injection volume was 20 μL. RESULTS:Only one impurity(impurity A)was detected in anastrozole,the linear range was 0.1-1.6 μg/mL(r=0.9996);limit of quantitation was 0.1 μg/mL,limit of detection was 0.02 μg/mL;RSDs of precision,stability and reproducibility tests were lower than 2%;recovery was 98.95%-105.29%(RSD%=1.78%,n=9). CONCLUSIONS:The method is simple,accurate,and can be used for the determination of related substances in anastrozole.

The stereoselective hydrolysis of esmolol in whole blood and in its separated components from rat,rabbit and human was investigated.Blood esterase activities were variable in different species in the order of rat ＞ rabbit ＞ human.Rat plasma showed the high esterase activity and had no stereoselectivity to enantiomers.Rabbit red blood cell (RBC) membrane,RBC cytosol and plasma all hydrolyzed esmolol but with different esterase activity,whereas the hydrolysis in RBC membrane and cytosol showed significant stereoselectivity towards R-(+)-esmolol.Esterase in RBC cytosol from human blood mainly contributed to the esmolol hydrolysis,which was demonstrated with no stereoselctivity.Esterase in human plasma showed a low activity,but a remarkable stereoselectivity with R-(+)-esmolol.In addition,the protein concentration affected the hydrolysis behavior of esmolol in RBC suspension.Protein binding of esmolol enantiomers in human plasma,human serum albumin (HSA) and α1-acid glycoprotein (AGP) revealed that there was a significant difference in bound fractions between two enantiomers,especially for AGP.Our results indicated that the stereoselective protein binding might play a role in the different hydrolysis rates of esmolol enantiomers in human plasma.

OBJECTIVETo establish the quality standards of Linmaoxiang Jiedu pills.

METHODCinobufagin and bufogenin were determined by HPLC simultaneously.

RESULTThe average recoverys of Cinobufagin and bufogenin was 100.5% and 100.3%, their linear range were 48.74-731.10 ng and 49.90-748.50 ng, respectively.

CONCLUSIONThe method for quantification is reproducible and realizable. The method can be used to control quality of Linmaoxiang Jiedu pills as the quality standards.

Bufanolides ; analysis ; Chromatography, High Pressure Liquid ; Drugs, Chinese Herbal ; analysis ; Reproducibility of Results