Determination of ritodrine in biological fluids of the pregnant sheep by fused-silica capillary gas chromatography using electron-capture detection.
A sensitive and selective gas chromatographic assay method employing splitless injection, fused-silica capillary columns and electron-capture detection is reported for the quantitation of the tocolytic drug, ritodrine, in a variety of biological fluids obtained from the pregnant ewe and fetus. This method has improved sensitivity and selectivity over previously published assay procedures. A 25 m x 0.31 mm I.D., cross-linked 5% phenylmethylsilicone, fused-silica capillary column was employed for all analyses. Linearity of response was observed over the range 2.5-75 ng of ritodrine base per 0.05-0.5 ml of biological fluid, representing approximately 1-75 pg at the detector. The coefficient of variation was less than 10% over the range 2.5-75 ng of added ritodrine. The minimum quantifiable amount is approximately 2.5 ng from a 0.5-ml biological fluid sample. Applicability of this method to biological fluids, obtained from ovine subjects, is demonstrated by the analysis of samples obtained during the course of ritodrine placental transfer studies.
Wright
M R
MR
Division of Biopharmaceutics and Pharmaceutics, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada.
Axelson
J E
JE
Abbott
F S
FS
Riggs
K W
KW
Van der Weyde
M P
MP
Taylor
S M
SM
McMorland
G H
GH
Rurak
D W
DW
D000653:Amniotic Fluid / Q000737:chemistry*; D000818:Animals; D002849:Chromatography, Gas / Q000295:instrumentation / Q000379:methods*; D005260:Female; D005333:Fetus / Q000737:chemistry; D011247:Pregnancy; D012312:Ritodrine / Q000032:analysis* / Q000097:blood; D012756:Sheep; D014132:Trachea / Q000737:chemistry
D012312:Ritodrine