B. Streel et al., Determination of fenofibric acid in human plasma using automated solid-phase extraction coupled to liquid chromatography, J CHROMAT B, 742(2), 2000, pp. 391-400
The pharmacokinetic studies of fenofibrate require a rapid, selective and r
obust method to allow the determination of fenofibric acid, its active meta
bolite, in different biological matrixes (such as plasma, serum or urine).
A new fully automated method for the determination of fenofibric acid in pl
asma has been developed, which involves the solid-phase extraction (SPE) of
the analyte from plasma on disposable extraction cartridges (DECs) and rev
ersed-phase HPLC with UV detection. The SPE operations were performed autom
atically by means of a sample processor equipped with a robotic arm (ASPEC
system). The DEC filled with octadecyl silica was first conditioned with me
thanol and pH 7.4 phosphate buffer. A 0.8-ml volume of diluted plasma sampl
e containing the internal standard (sulindac) was then applied on the DEC.
The washing step was performed with the same buffer (pH 7.4). Finally, the
analytes were successively eluted with methanol (1.0 ml) and 0.04 M phospho
ric acid (1.0 mi). After a mixing step, 100 mu l of the resultant extract w
as directly introduced into the HPLC system. The liquid chromatographic (LC
) separation of the analytes was achieved on a Nucleosil RP-8 stationary ph
ase (5 mu m) The mobile phase consisted of a mixture of methanol and 0.04 M
phosphoric acid (60.40, v/v). The analyte was monitored photometrically at
288 nm. The method developed was validated. In these conditions, the absol
ute recovery of fenofibric acid was close to 100% and a linear calibration
curve was obtained in the concentration range from 0.25 to 20 mu g/ml. The
mean RSD values for repeatability and intermediate precision were 1.7 and 3
.9% for fenofibric acid. The method developed was successfully used to inve
stigate the bioequivalence between a micronized fenofibrate capsule formula
tion and a fenofibrate Lidose(TM) formulation. (C) 2000 Elsevier Science B.
V. All rights reserved.