title: Determination of antihyperglycemic biguanides in serum and urine using an ion-pair solid-phase extraction technique followed by HPLC-UV on a pentafluorophenylpropyl column and on an octadecyl column.
abstract: An HPLC-UV method was established for the determination of metformin and buformin in biological fluids. Metformin was not retained on particles packed in conventional solid-phase extraction cartridges; in contrast, buformin was retained too firmly and not eluted with a solvent for recovery. However, both drugs were retained on particles that had been treated with an ion-pair reagent of heptanesulfonate or dodecylsulfate and recovered almost completely. The recovered fraction was subjected to HPLC on a pentafluorophenylpropyl column which was suitable for the determination of both biguanides in serum and in urine. Limits of quantitation were low enough for clinical use, and reproducibility was high with an RSD of 0.9-2.3%. HPLC on a conventional octadecyl column was suitable only for the determination of buformin in serum since interfering peaks appeared on the chromatograms of urine samples. The method was applied to analysis of some clinical specimens.
authors.affiliation: Kyoritsu University of Pharmacy, 1-5-30, Shibakoen, Minato-ku, Tokyo 105-8512, Japan.
authors.forename: Kayoko
authors.initials: K
authors.lastname: Tahara
authors.forename: Ayumi
authors.initials: A
authors.lastname: Yonemoto
authors.forename: Yuji
authors.initials: Y
authors.lastname: Yoshiyama
authors.forename: Toshiya
authors.initials: T
authors.lastname: Nakamura
authors.forename: Masaaki
authors.initials: M
authors.lastname: Aizawa
authors.forename: Yoshikuni
authors.initials: Y
authors.lastname: Fujita
authors.forename: Takashi
authors.initials: T
authors.lastname: Nishikawa
mesh_terms: D000473:Alkanes; D053000:Analytic Sample Preparation Methods; D002026:Buformin / Q000097:blood* / Q000652:urine*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D007004:Hypoglycemic Agents / Q000097:blood* / Q000652:urine*; D008687:Metformin / Q000097:blood* / Q000652:urine*; D052616:Solid Phase Extraction / Q000379:methods*; D014466:Ultraviolet Rays
chemical_list: D000473:Alkanes; D007004:Hypoglycemic Agents; D008687:Metformin; C022883:octadecane; D002026:Buformin