title: Liquid chromatographic determination of plasma ropivacaine for assessing pharmacokinetics of the viscous preparation.
abstract: We developed assay method for determination of plasma ropivacaine by using reversed-phase high performance liquid chromatography (HPLC) equipped with ordinary octadecylsilyl silica-gel (ODS) column. Plasma samples spiked with internal standard (bupivacaine) were treated by ethylacetate to extract ropivacaine and internal standard. The ropivacaine and internal standard separated on ODS column were detected by an ultra violet (UV) detector set at 215 nm. The mobile phase solvent consisted of acetonitrile, methanol and 0.05 M phosphate buffer adjusted to pH 4.0 (10 : 30 : 60, v/v) was pumped at a flow rate of 0.8 ml/min. The calibration curve of ropivacaine was linear at the concentration of 25-1,000 ng/ml (r=0.9998). The recoveries of ropivacaine from plasma were greater than 87.9% with the coefficient of variations (CVs) less than 6.1%. The CVs for intra- and inter-day assay of ropivacaine were 2.0-12.0% and 1.7-14.8%, respectively. This HPLC method was applied to determining plasma ropivacaine in two healthy subjects after receiving 0.5% ropivacaine viscous preparation, which was prepared in our hospital. Our preliminary pharmacokinetic data showed that ropivacaine viscous could be used safely based on the plasma ropivacaine concentrations (C(max): 89-125 ng/ml) for pain relief in oral mucosa.
authors.affiliation: Department of Pharmaceutical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Ten-nodai, Ibaraki 305-0295, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kawata
authors.forename: Masato
authors.initials: M
authors.lastname: Homma
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kakiuchi
authors.forename: Shinichi
authors.initials: S
authors.lastname: Inomata
authors.forename: Masayuki
authors.initials: M
authors.lastname: Miyabe
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kobayashi
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Morimoto
authors.forename: Yukinao
authors.initials: Y
authors.lastname: Kohda
mesh_terms: D000328:Adult; D000577:Amides / Q000097:blood* / Q000493:pharmacokinetics*; D000779:Anesthetics, Local / Q000097:blood* / Q000493:pharmacokinetics*; D019540:Area Under Curve; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006207:Half-Life; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077212:Ropivacaine; D014783:Viscosity
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine