Verapamil drug metabolism studies by automated in-tube solid phase microextraction

Area of Science:

• Pharmacology
• Analytical Chemistry
• Biotechnology

Background:

• Verapamil, a calcium antagonist, possesses antianginal, antihypertensive, and antiarrhythmic properties.
• Verapamil metabolites exhibit pharmacological activity, necessitating robust metabolic screening techniques.
• In-tube solid-phase microextraction (SPME) offers solvent-free sample preparation for bioanalysis.

Purpose of the Study:

• To evaluate in-tube SPME coupled with LC-MS for monitoring verapamil metabolites in biological matrices.
• To establish the utility of this method for drug metabolism studies and pharmacokinetic analyses.
• To develop and validate an efficient analytical method for verapamil and its metabolites.

Main Methods:

• Development of an in-tube SPME method for extracting verapamil and its metabolites from plasma, urine, and cell culture media.
• Coupling of in-tube SPME with liquid chromatography-mass spectrometry (LC-MS) for sensitive detection and quantification.
• Validation of the method for detection limits, precision, and linear dynamic range.

Main Results:

• The in-tube SPME LC-MS method successfully monitored main verapamil metabolites in various biological matrices.
• Detection limits were as low as 5-8 ng/ml using MS detection.
• The method demonstrated good precision (% R.S.D. averaging 3.7-4.3%) and a linear dynamic range of 100-800 ng/ml (UV detection).
• Total sample preparation and analysis time was optimized to 34 minutes.

Conclusions:

• In-tube SPME coupled with LC-MS is a powerful and efficient technique for the bioanalysis of verapamil metabolites.
• This method is suitable for routine pharmacokinetic measurements and drug metabolism screening.
• The solvent-free nature of in-tube SPME enhances its applicability in biological sample analysis.