[Determination of warfarin in plasma by HPLC and an investigation of monitoring patients after cardiac valve replacement].
OBJECTIVE
A simple HPLC method was established for the determination of warfarin in plasma to investigate the relationship between warfarin concentration and anticoagulant effect.


METHODS
The mixture of dichloromethane and hexane (1:9) was used as extracting solvent for the plasma samples. The chromatographic separation was on C18 column with a mobile phase consisting of methanol and 50 mmol/L ammonium acetate buffer (pH2.5, 70:30).


RESULTS
The calibration curve was linear within 50-2000 ng/ml. The extraction recoveries of warfarin were 78.0%-81.6%. The recoveries of methodology were 103.1%-106.5%. Inter-day and intra-day RSD were 2.33%-5.46% and 5.29%-7.73%, respectively. This method was used for determining warfarin in 70 patients after cardiac valve replacement. The results showed that 44 cases had their INR within the safety range (1.31-2.35) recommended to Chinese, and of them 37(84.1%) cases had a warfarin level at 616.2 +/- 154.8 ng/ml.


CONCLUSIONS
This method is useful in monitoring warfarin concentration during anticoagulant therapy.
Huang
Y
Y
Institute of Clinical Pharmacology, First Affiliated Hospital, WCUMS, Chengdu 610041, China.
Liang
M
M
Dong
L
L
Yu
Q
Q
Qin
Y
Y
Zou
Y
Y
D000925:Anticoagulants / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D006349:Heart Valve Diseases / Q000097:blood* / Q000601:surgery; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D011184:Postoperative Period; D014859:Warfarin / Q000097:blood*
D000925:Anticoagulants; D014859:Warfarin