Microdosing Cocktail Assay Development for Drug-Drug Interaction Studies

Area of Science:

• Pharmacology
• Analytical Chemistry
• Biotechnology

Background:

• Drug transporters and metabolizing enzymes significantly influence drug disposition.
• Understanding these contributions is crucial for predicting and managing drug-drug interactions (DDIs).
• Microdosing studies offer a way to assess these effects in humans.

Purpose of the Study:

• To develop and qualify a sensitive bioanalytical method for analyzing a microdosing drug cocktail.
• To quantify specific drugs (statins, midazolam, dabigatran) in human plasma.
• To support clinical studies evaluating DDIs mediated by drug transporters and CYP3A.

Main Methods:

• Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was employed for detection.
• Reversed-phase or hydrophilic interaction liquid chromatography with gradient elution was used for separation.
• Sensitive assays were developed and qualified for statins, midazolam, and dabigatran in human plasma.

Main Results:

• The method achieved low limits of quantification (LLOQ) for all analytes (e.g., 1 pg/mL for statins, 0.5 pg/mL for midazolam, 10 pg/mL for dabigatran).
• Assays demonstrated excellent linearity, precision, and accuracy within acceptable ranges.
• The developed methodology was successfully applied to analyze plasma samples from a human microdosing study.

Conclusions:

• A robust and sensitive LC-MS/MS methodology was established for analyzing a microdosing cocktail.
• This method enables the simultaneous assessment of drug disposition and DDIs in humans.
• The findings support the use of microdosing strategies to evaluate transporter and enzyme contributions to drug interactions.