*2.7. LC-MS*/*MS Analysis*

The chromatographic analysis was performed using an Agilent 1260 series (Agilent, Germany) HPLC system. Chromatographic separation was achieved from the Phoroshell ® column (C18, 3.0 × 50 mm, 2.7 μm). The mobile phase consisted of 5-mM ammonium formate (pH 4) in water (A) and acetonitrile (B). A gradient method was applied at a flow rate of 0.3 mL/min and, kept on the column temperature at 25 ◦C. The injection volume was 2 μL. An Agilent 6460 triple-quadruple mass spectrometer (Agilent Technologies, Singapore) with an electrospray ionization (ESI) source was used to detect the signal. It was operated in positive ion mode on multiple reaction monitoring (MRM). The monitored ions of fexofenadine and internal standard (terfenadine) were *m*/*z* 502 →466 and *m*/*z* 472 →436 [30,31], respectively. The collision energy and fragmentor of the ions were 25 V and 175 V for fexofenadine, and 25 V and 130 V for terfenadine, respectively. The data were acquired and processed using Mass Hunter Workstation B.06.00 software (Agilent Technologies, Singapore).

### *2.8. Animal Study*
