Sensitive determination of methotrexate in monkey plasma by high-performance liquid chromatography using on-line...

Area of Science:

• Analytical Chemistry
• Pharmacokinetics
• Biochemistry

Background:

• Accurate quantification of drugs in biological matrices is crucial for pharmacokinetic studies.
• Methotrexate (MTX) is a vital chemotherapeutic agent requiring precise monitoring.
• Existing methods for MTX determination in plasma may lack sensitivity or require extensive sample preparation.

Purpose of the Study:

• To develop and validate a sensitive high-performance liquid chromatographic (HPLC) method for MTX determination in monkey plasma.
• To establish a robust analytical technique suitable for pharmacokinetic investigations of MTX.

Main Methods:

• Development of a direct injection HPLC method coupled with on-line solid-phase extraction (SPE).
• Utilized a column-switching technique for efficient separation and analysis.
• Employed ion-pair chromatography with tetrabutylammonium bromide for MTX detection.

Main Results:

• The method demonstrated high sensitivity with a quantitation limit of 5 ng/ml.
• Excellent accuracy, precision, and linearity were achieved across a wide concentration range (5-1000 ng/ml).
• The SPE pre-treatment column supported over 50 injections, indicating good durability.

Conclusions:

• The developed HPLC-SPE method provides a sensitive, accurate, and reproducible means for MTX quantification in monkey plasma.
• This method is well-suited for supporting pharmacokinetic studies, enabling reliable drug monitoring.