In the present study, we developed and validated a rapid,
specific,
sensitive, and reproducible liquid chromatography–electrospray
ionization tandem mass spectrometry method for quantifying quercetin
(QT) in rabbit plasma using hydrochlorothiazide as the internal standard.
Animals were orally administered with optimized QT-loaded nanoemulsion
(QTNE) and QT suspension (QTS), equivalent to 30 mg/kg, to the test
and control group, respectively. The blood samples were collected
at pre-determined time points up to 48 h. The linearity range was
from 5 to 5000 ng mL–1 with R
2 = 0.995. Further, we analyzed the various pharmacokinetic
parameters and established the in vitro–in vivo correlation (IVIVC) of QTNE using GastroPlus software.
The method was successfully developed and validated, and when applied
for the determination of QT in rabbit plasma, it exhibited an increase
in C
max from 122.56 ng mL–1 (QTS) to 286.51 ng mL–1 (QTNE) (2.34-fold) and
AUC0–48 from 976 ng h mL–1 (QTS)
to 4249 ng h mL–1 (QTNE) (4.35-fold), indicating
improved oral bioavailability QT when administered as QTNE. Statistical
analysis revealed that the Loo–Riegelman method (two-compartmental
method) best fitted the deconvolution approach (R
2 = 0.998, SEP = 4.537, MAE = 2.759, and AIC = 42.38)
for establishing the IVIVC. In conclusion, the established bioanalytical
method and IVIVC studies revealed that QTNE is a potential carrier
for the effective delivery of QT with enhanced oral bioavailability.