Liquid chromatographic determination of plasma ropivacaine for assessing pharmacokinetics of the viscous preparation.
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.
Kawata
Takeshi
T
Department of Pharmaceutical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Ten-nodai, Ibaraki 305-0295, Japan.
Homma
Masato
M
Kakiuchi
Yoshihiro
Y
Inomata
Shinichi
S
Miyabe
Masayuki
M
Kobayashi
Daisuke
D
Morimoto
Yasunori
Y
Kohda
Yukinao
Y
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
D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine