title: Simple and accurate high-performance liquid chromatographic method for the measurement of three antiepileptics in therapeutic drug monitoring.
abstract: A high-performance liquid chromatographic method for simultaneous determination of three antiepileptics, phenytoin, phenobarbital, and carbamazepine, in serum for therapeutic drug monitoring is described. The drugs were extracted and injected onto a silica-gel column using a syringe-type minicolumn, Extrashot-Silica, packed with diatomaceous earth granules. We used dichloromethane for extraction-injection and n-hexane containing 0.2% acetic acid, 2% ethanol, and 15% dichloromethane for the mobile phase of a silica-gel HPLC. The eluent was monitored with a UV detector set at 240 nm. Linear relationships between the amount of drug and peak height were confirmed at 1-20 micrograms/ml in serum for carbamazepine and 5-40 micrograms/ml in serum for phenytoin and phenobarbital. When a 5-microliters aliquot of serum was subjected to this method, the observed detection limits of the drugs were far less than therapeutic concentrations. Thus, our method was simple and accurate enough to be used in routine therapeutic drug monitoring and basic pharmacokinetic studies.
authors.affiliation: Bohsei Pharmacy Co., Kanagawa, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kouno
authors.forename: C
authors.initials: C
authors.lastname: Ishikura
authors.forename: M
authors.initials: M
authors.lastname: Homma
authors.forename: K
authors.initials: K
authors.lastname: Oka
mesh_terms: D000927:Anticonvulsants / Q000097:blood*; D002220:Carbamazepine / Q000097:blood; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D016903:Drug Monitoring / Q000379:methods*; D006801:Humans; D007124:Immunoenzyme Techniques; D010634:Phenobarbital / Q000097:blood; D010672:Phenytoin / Q000097:blood
chemical_list: D000927:Anticonvulsants; D002220:Carbamazepine; D010672:Phenytoin; D010634:Phenobarbital