Short communication
Time-course monitoring of in vitro biotransformation reaction via solid-phase microextraction-ambient mass spectrometry approaches

https://doi.org/10.1016/j.jpha.2021.08.001Get rights and content
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Highlights

Solid-phase microextraction direct mass spectrometry is used for drug biotransformation.

SPME protocol is developed for a rapid time-course analysis of metabolism reactions.

Phosphate prodrug is converted to active form via FBS phosphatases.

Abstract

The solid-phase microextraction technique quantifies analytes without considerably affecting the sample composition. Herein, a proof-of-concept study was conducted to demonstrate the use of coated probe electrospray ionization (coated-PESI) and coated blade spray (CBS) as ambient mass spectrometry approaches for monitoring drug biotransformation. The ability of these methods was investigated for monitoring the dephosphorylation of a prodrug, combretastatin A4 phosphate (CA4P), into its active form, combretastatin A4 (CA4), in a cell culture medium supplemented with fetal bovine serum. The CBS spot analysis was modified to achieve the same extraction efficiency as protein precipitation and obtained results in 7 min. Because coated-PESI performs extraction without consuming any samples, it is the preferred technique in the case of a limited sample volume. Although coated-PESI only extracts small quantities of analytes, it uses the desorption solvent volume of 5–10 pL, resulting in high sensitivity, thus allowing the detection of compounds after only 1 min of extraction. The biotransformation of CA4P into CA4 via phosphatases occurs within the simple matrix, and the proposed sample preparation techniques are suitable for monitoring the biotransformation.

Keywords

Solid-phase microextraction
Coated probe electrospray ionization
Coated blade spray
Combretastatin
Biotransformation
Prodrug activation

Peer review under responsibility of Xi’an Jiaotong University.