[Determination of enantiomeric impurity of timolol maleate in bulk substances and eye drops].
To determine the enantiomeric impurity contents of domestic timolol maleate in bulk drugs and eye drops.



Enantiomer impurity of timolol was assayed by chiral high performance liquid chromatography. The chromatographic conditions were as follows:chiralcel OD chiral column (4.6 mm ×150 mm, 5μm), detection wavelength:297 nm, mobile phase:hexane-isopropanol-diethylamine (480:20:1), column temperature:25 ℃, flow rate:1.0 ml/min, sample injection volume:5 μl.



The resolution between R- and S-timolol was more than 4. The enantiomeric impurity contents were less than 0.67% on average in two batches of timolol maleate bulk drugs, and 0.31% on average in three batches of timolol maleate eye drops.



Enantiomeric impurity contents in each batch of products all meet European Pharmacopoeia criteria, which can be used as references in Chinese Pharmacopoeia criteria.
Laboratory of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences; Zhejiang Province Key Laboratory of Anti-Cancer Drug Research,Zhejiang University, Hangzhou 310058, China.
Qian-ying
QY
Zhu
Laboratory of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences; Zhejiang Province Key Laboratory of Anti-Cancer Drug Research,Zhejiang University, Hangzhou 310058, China.
Lu-shan
LS
Yu
Zhejiang Institute for Food and Drug Quality Control, Hangzhou 310004, China; 3. Zhejiang Center for Drug Evaluation, Hangzhou 310012, China.
Guo-gang
GG
Zheng
Zhejiang Institute for Food and Drug Quality Control, Hangzhou 310004, China; 3. Zhejiang Center for Drug Evaluation, Hangzhou 310012, China.
Shen-gu
SG
Xie
Zhejiang Institute for Food and Drug Quality Control, Hangzhou 310004, China; 3. Zhejiang Center for Drug Evaluation, Hangzhou 310012, China.
Qiao-feng
QF
Tao
D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004340:Drug Contamination; D009883:Ophthalmic Solutions / Q000032:analysis* / Q000592:standards; D013237:Stereoisomerism; D013999:Timolol / Q000032:analysis* / Q000592:standards
D009883:Ophthalmic Solutions; D013999:Timolol