A Simple UPLC-MS/MS Assay of Rifampin in a Small Volume of Human Plasma
Takuya Sano1, Takuho Ishii1,2, Koichiro Hotta3
1DMPK & Bioanalysis Unit, Tsukuba Division, Sunplanet Co., Ltd., Tokodai 5-1-3, Tsukuba, Ibaraki 300-2635, Japan.
Abstract:
Rifampin (RIF) is a typical cytochrome P450 (CYP) 3A inducer and inhibitor of organic anion transporting polypeptide (OATP) 1B1 to assess drug-drug interaction (DDI) via CYP3A or OATP1B1 in clinical settings. To ensure sufficient exposure of RIF in DDI studies, it is important to determine plasma RIF concentrations. In this study, we developed a simple RIF assay in a small volume of human plasma by ultraperformance liquid chromatography with tandem mass spectrometry. RIF in 0.02 mL of plasma was extracted using protein precipitation and separated on a reverse phase column under gradient elution of three mobile phases, where the mobile phase C containing 1% formic acid was exclusively used to reduce the carryover of RIF. RIF and the internal standard were detected by multiple reaction monitoring in positive-ion electrospray ionization. RIF was quantifiable at 0.025-10 μg/mL without the carryover issue. The intra- and inter-run assays confirmed the reproducibility of the assay. Stability assessments ensured that RIF in human plasma was stable for 6 h at room temperature and for 409 days at -15 °C or below. The assay was successfully applied to a pharmacokinetic study with successful incurred sample reanalysis.
Insights
A new assay accurately measures rifampin (RIF) in human plasma, crucial for drug-drug interaction studies. This method ensures reliable RIF concentrations, improving clinical assessments of interactions involving CYP3A and OATP1B1.
Area of Science:
- Pharmacology
- Analytical Chemistry
- Clinical Pharmacology
Background:
- Rifampin (RIF) is a key probe drug for assessing drug-drug interactions (DDIs) involving cytochrome P450 (CYP3A) and organic anion transporting polypeptide (OATP) 1B1.
- Accurate quantification of plasma RIF concentrations is essential for reliable DDI studies in clinical settings.
Purpose of the Study:
- To develop and validate a sensitive and robust assay for measuring rifampin in human plasma.
- To ensure sufficient drug exposure data for pharmacokinetic and DDI assessments.
Main Methods:
- Ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) was employed.
- A small plasma volume (0.02 mL) was used with protein precipitation for sample preparation.
- A specialized mobile phase composition was utilized to minimize carryover, and positive-ion electrospray ionization with multiple reaction monitoring was used for detection.
Main Results:
- The assay demonstrated quantification of RIF from 0.025 to 10 μg/mL without carryover issues.
- High reproducibility was confirmed through intra- and inter-run assays.
- RIF stability was established in plasma under various storage conditions, including 6 hours at room temperature and 409 days at or below -15 °C.
Conclusions:
- A simple, reproducible, and sensitive UPLC-MS/MS assay for plasma rifampin was successfully developed.
- The assay is suitable for pharmacokinetic studies and incurred sample reanalysis, supporting DDI research.
More Related Videos
09:58Spatial Quantification of Drugs in Pulmonary Tuberculosis Lesions by Laser Capture Microdissection Liquid Chromatography Mass Spectrometry LCM-LC/MS
Published on: April 18, 2018
08:54Validated LC-MS/MS Panel for Quantifying 11 Drug-Resistant TB Medications in Small Hair Samples
Published on: May 19, 2020
