Alternative Sampling Strategies for Cytochrome P450 Phenotyping

Area of Science:

• Pharmacogenomics
• Drug Metabolism
• Clinical Chemistry

Background:

• Interindividual variability in cytochrome P (CYP450) enzyme activity influences drug response.
• Genetic, non-genetic, and environmental factors contribute to this variability.
• In vivo phenotyping assesses CYP450 activity by measuring specific enzyme substrates.

Purpose of the Study:

• To review alternative, non- or minimally invasive sampling methods for in vivo CYP450 phenotyping.
• To evaluate the reliability and convenience of these novel techniques compared to traditional matrices.
• To discuss the potential of these methods for clinical implementation.

Main Methods:

• Comprehensive literature review of alternative sampling techniques for CYP450 phenotyping.
• Analysis of methods using dried blood spots (DBS), hair, oral fluid, exhaled breath, and sweat.
• Comparison of phenotyping metrics from alternative matrices to conventional samples (blood, plasma, urine).

Main Results:

• Reliable CYP450 phenotyping protocols exist for oral fluid, breath, and DBS for enzymes like CYP1A2, CYP2C19, and CYP2D6.
• Further research is needed for other CYP450 isoforms, such as CYP3A4.
• The utility of hair analysis for CYP450 phenotyping requires further investigation.

Conclusions:

• Non- or minimally invasive sampling strategies offer convenient and patient-friendly alternatives for CYP450 phenotyping.
• These methods can potentially improve the clinical application of CYP450 phenotyping.
• Wider adoption of these techniques could enhance personalized drug therapy.