Determination of the anticoagulant phenprocoumon in human plasma and urine by high-performance liquid chromatography

The determination of the anticoagulant phenprocoumon in plasma, after acidification and extraction with 1,2-dichloroethane was effected through isocratic high-performance liquid chromatography; a C18 reversed-phase column was used as stationary phase using aqueous acetonitrile as eluent and UV detection at 313 nm; p-chlorophenprocoumon was used as internal standard. A high proportion of phenprocoumon in urine is eliminated as the glucuronide and must be hydrolyzed enzymatically before extraction; the same column and detector as for plasma were used, but with gradient elution. The method was used in the range 0.1-5 mg/1, the sensitivity was 0.1 mg/1 for plasma and 0.02 mg/1 for urine, the precision was in the range 3-5% and the absence of interference due to other anticoagulants, drugs or endogenous compounds allows the specific determination of phenprocoumon in plasma and urine from patients and volunteers in clinical relevant cases, drug interaction, compliance, toxicological and pharmacokinetic studies.