title: [Selective and sensitive determination of an antiallergic agent, emedastine difumarate (KG-2413), in human plasma by the radioreceptor assay combined with a high-performance liquid chromatography].
abstract: The selective and sensitive method for the determination of a new antiallergic agent, 1-(2-ethoxyethyl)-2-(hexahydro-4-methyl-1H-1,4-diazepin-1-yl)-1H-b enzimidazole difumarate (emedastine difumarate, KG-2413), in the human plasma has been developed. Emedastine was determined by the receptor assay after the separation from its metabolites by the use of high-performance liquid chromatography (HPLC). This combined method (HPLC-radioreceptor assay (RRA) method) allowed us the quantification only of 0.3 ng/ml of emedastine in the human plasma. The intra-assay coefficients of variation for the determination were below 12%. Furthermore, the total pharmacologically active metabolites, including unchanged emedastine, was determined by the extraction of the unconjugated metabolites in the human plasma with chloroform followed by the receptor assay (RRA method). The human plasma concentrations measured by the HPLC-RRA method were in good agreement with those by the RRA method. These results suggested that in human pharmacological activities occurred by unchanged emedastine itself.
authors.forename: T
authors.initials: T
authors.lastname: Hamada
authors.forename: T
authors.initials: T
authors.lastname: Kawashima
authors.forename: N
authors.initials: N
authors.lastname: Awata
mesh_terms: D000328:Adult; D000818:Animals; D001562:Benzimidazoles / Q000097:blood* / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006168:Guinea Pigs; D006634:Histamine H1 Antagonists / Q000097:blood* / Q000494:pharmacology; D006801:Humans; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D011869:Radioligand Assay / Q000379:methods
chemical_list: D001562:Benzimidazoles; D006634:Histamine H1 Antagonists; C043345:emedastine