Brazilian Journal of Analytical Chemistry - BRJAC - Brazilian Journal ...

spiking it with the analyte at the LOQ concentration.
There was no difference observed in the signal for the
solution and for the spiked plasma extract at the LOQ
concentration and the signal observed in blank plasma
was below 20% of the analyte signal at the LOQ concentration.
The recovery for sample preparation, which involved
a liquid-liquid extraction with hexane/ethyl acetate (1:1,
v/v), was calculated by comparing the peak area ratios
of flunarizine in plasma samples with the peak area ratios
of solvent samples, and it was estimated at control
levels of analyte.
There have also been several other reports on analytical
techniques to measure flunarizine in human plasma.
In this study an analytical method of flunarizine determination
using LC–MS-MS has been developed. This
new technique presented some advantages over others
previously described, such as: simple sample preparation
(liquid-liquid extraction), small sample volume of
300 µL, low limit of quantification (0.3 ng/mL) and
short run time allowing the analysis of a large number
of samples per day. Moreover, this new method has an
analytical frequency very suitable for large numbers of
samples such as demanded by bioequivalence analysis,
and the quantification limit is better.
Co n C l u s i o n
The described method has proven to be rapid and
robust, with each sample requiring less than 2.5 min of
run time. This assay method is also highly specific due
to the inherent selectivity of tandem mass spectrometry.
The technique possesses significant advantages
over others previously described for the measurement
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determination o f f l u n a r i z i n e in plasma by liquid
C h ro m a t o g r a p h y-eleCtrospray t a n d e m m a s s speCtrometry
of flunarizine in biological fluids while the detectivity
of the assay is sufficient to accurately follow this drug’s
pharmacokinetics.
aC k n o w l E d g m E n t s
Gilvan Vieira do Carmo received a fellowship from
UNIFAG. The authors also thank UNIFAG for the financial
support.
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