Determination of exogenous epigallocatechin gallate peracetate in mouse plasma using liquid chromatography with quadrupole time‐of‐flight mass spectrometry

A robust method for the quantitation of epigallocatechin gallate peracetate in plasma for pharmacokinetic studies is lacking. We have developed a validated method to quantify this compound using liquid chromatography with quadrupole time‐of‐flight mass spectrometry with isopropanol and tert‐butyl methyl ether (3:10) extraction and thin‐layer chromatography purification. The epigallocatechin gallate peracetate‐1‐¹³C₈ isotope was used as an internal standard. The linear range (r² > 0.9950) was from 0.05 to 100.00 μg/mL. The lower limit of quantification of the method was 0.05 μg/mL. Reproducibility, coefficient of variation, was between 0.7 and 12.6% (n = 6), accuracy between 83.7 and 104.6% (n = 5), and recovery ranged from 82.4 to 109.0% (n = 4). Ion suppression was approximately 40%. No mass spectral peaks were found to interfere between the standard and internal standard or the blank plasma extracts. Epigallocatechin gallate peracetate in plasma was stably stored at –80°C over three months even after three freeze–thaw cycles. Extracts were stable in the sampler at 4°C for over 48 h. Plasma levels were maintained at 1.36 μg/mL for 360 min after intraorbital intravenous injection at 50 mg/kg in mice. This method can be used to reliably measure epigallocatechin gallate peracetate in plasma for pharmacokinetic studies.