title: Development of enzyme-linked immunosorbent assay for therapeutic drug monitoring of mexiletine.
abstract: This paper reports a sensitive and specific enzyme-linked immunosorbent assay for determination of the antiarrhythmic drug mexiletine in human serum. Anti-mexiletine antibody was obtained by immunizing rabbits with an antigen conjugated with mercaptosuccinyl bovine serum albumin using N-(epsilon-maleimidocaproyloxy)succinimide as a heterobifunctional coupling agent. Enzyme labeling of mexiletine with beta-D-galactosidase was performed using glutaraldehyde. In this assay, the mexiletine to be quantified is chemically modified by acetic anhydride allowed to compete with a mexiletine-beta-D-galactosidase conjugate for binding to a limited amount of an anti-mexiletine antibody which was used to coat the wells of a microtiter plate. Mexiletine concentrations lower than 80 ng/ml were measurable reproducibly by the enzyme-linked immunosorbent assay. This assay was specific for mexiletine and showed very slight cross-reactivity with its major metabolite, 2-hydroxymethylmexiletine (1.5%), but none with p-hydroxymexiletine. The values of serum mexiletine levels from 15 patients by this enzyme-linked immunosorbent assay were comparable with those measured by HPLC. There was a good correlation between the values determined by the two methods. The enzyme-linked immunosorbent assay should be a valuable tool in therapeutic drug monitoring and pharmacokinetic studies of mexiletine.
authors.affiliation: Faculty of Hospital Pharmacy, Saga Medical School, 5-1-1 Nabeshima, Saga 849-8501, Japan. saita@post-saga-med.ac.jp
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Saita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fujito
authors.forename: Masato
authors.initials: M
authors.lastname: Mori
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology*; D000918:Antibody Specificity / Q000276:immunology*; D001667:Binding, Competitive; D002851:Chromatography, High Pressure Liquid; D016903:Drug Monitoring / Q000379:methods; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D008801:Mexiletine / Q000097:blood* / Q000737:chemistry / Q000276:immunology; D011817:Rabbits; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D001616:beta-Galactosidase / Q000737:chemistry
chemical_list: D000911:Antibodies, Monoclonal; D008801:Mexiletine; D001616:beta-Galactosidase