Development of high speed CYP cocktail inhibition assay using UHPLC-MS/MS

Importance of the Topic

Understanding drug–drug interactions mediated by cytochrome P450 enzymes is critical for assessing the safety of new chemical entities (NCEs). A rapid and reliable assay to evaluate CYP inhibition can prevent adverse effects in patients and streamline drug development workflows.

Objectives and Overview

This study aimed to develop an ultra-fast CYP cocktail inhibition assay using an advanced UHPLC-MS/MS platform (Shimadzu Nexera UHPLC coupled to LCMS-8080) and to compare its performance against a conventional 7-minute HPLC method. Key goals included reducing analysis time without compromising sensitivity, linearity, or repeatability.

Methodology and Instrumentation

Sample Preparation:

• Human liver microsomes (0.1 mg/mL) in phosphate buffer (pH 7.4) with MgCl₂, isocitric acid/ dehydrogenase, and substrate near Km concentrations.
• Pre-incubation at 37 °C (10 min), followed by NADPH addition and further incubation (10 min).
• Reaction quenching with acetonitrile, centrifugation, and collection of supernatant.

UHPLC Conditions (Nexera UHPLC):

• Column: Shim-pack XR-ODSII (30 × 1.5 mm I.D., 2.2 µm).
• Mobile phase: A – 0.05% formic acid in water; B – acetonitrile.
• Gradient: 5% B (0 min) → 35% B (0.50 min) → 80% B (0.51–0.60 min) → 5% B (0.61–1.00 min).
• Flow rate: 0.8 mL/min; Column temperature: 50 °C.

MS/MS Conditions (LCMS-8080):

• Ionization: ESI in positive/negative mode.
• MRM transitions were optimized for five substrates and their metabolites: resorufin, 1′-hydroxy-bufuralol, 4′-hydroxy-mephenytoin, oxidized nifedipine, and hydroxy-tolbutamide.

Results and Discussion

Throughput:

• The UHPLC-MS/MS method achieved a total cycle time of 1 minute, a seven-fold improvement over the 7 minute conventional HPLC method.

Calibration and Sensitivity:

• Dynamic ranges: 0.6–300 nmol/L (typical) up to 0.6–1000 nmol/L for nifedipine.
• Linearity coefficients (r2) exceeded 0.996 for all analytes.
• Repeatability at LOQ showed %RSD ≤ 9.97% across six replicates.

Application to Real Samples:

• Quantification of metabolites produced in microsomal incubations matched expected concentrations, demonstrating accuracy and robustness.

Benefits and Practical Applications

• Significantly higher sample throughput enables large-scale screening during lead optimization and preclinical studies.
• Maintains high sensitivity and precision, ensuring reliable DDI risk assessment.
• Reduces solvent consumption and instrument occupancy, lowering operational costs.

Future Trends and Possibilities

Integration of multiplexed assays with automated sample preparation and data processing can further accelerate CYP profiling. Emerging high-resolution MS technologies may allow simultaneous detection of additional metabolites, expanding the assay’s scope. AI-driven data analysis could enhance understanding of enzyme kinetics and interaction networks.

Conclusion

This work demonstrates that the Shimadzu Nexera UHPLC–LCMS-8080 platform can perform CYP cocktail inhibition assays in just 1 minute per sample without sacrificing analytical quality. The method offers a powerful tool for rapid, reliable assessment of drug–drug interaction potential in drug discovery and development.

References

• Hirano I, Kawashima M, Asano N, Arakawa K, Hayakawa Y. Development of high speed CYP cocktail inhibition assay using UHPLC-MS/MS. ASMS 2013, W02-040.