Sensitive method for plasma and tumor Ko143 quantification using reversed-phase high-performance liquid...

Area of Science:

• Pharmacology and Toxicology
• Analytical Chemistry
• Biochemistry

Background:

• The fumitremorgin C analogue Ko143 is a key inhibitor of the ATP-binding cassette transporter ABCG2.
• Accurate quantification of Ko143 is crucial for in vivo studies investigating ABCG2-mediated drug resistance.

Purpose of the Study:

• To develop a sensitive and selective bioanalytical method for quantifying Ko143 in plasma and tumor matrices.
• To validate the method for accuracy, precision, and stability, supporting its use in pharmacokinetic and resistance studies.

Main Methods:

• Liquid-liquid extraction using diethyl ether for sample pretreatment.
• Reversed-phase high-performance liquid chromatography (RP-HPLC) with fluorescence detection (295nm excitation/350nm emission).
• Quantification using fumitremorgin C as the internal standard, with matrix-matched calibration curves for tumor samples.

Main Results:

• The method achieved recoveries of 50% in human/mouse plasma and 40% in mouse tumor tissue.
• Linear dynamic range was 2-500 ng/mL with accuracy and precision within ±15% for both matrices.
• Ko143 demonstrated stability in human plasma but rapid degradation in mouse plasma at room temperature, mitigated by using sodium fluoride tubes and cold processing.

Conclusions:

• A validated, sensitive, and selective HPLC-fluorescence method for Ko143 quantification in plasma and tumor homogenates has been established.
• The assay is suitable for supporting in vivo ABCG2 resistance studies, including preliminary pharmacokinetic assessments in mice.
• Consideration of sample handling is critical for accurate Ko143 measurement in mouse plasma due to esterase activity.