Quantitative Analysis of Favipiravir Spiked in Plasma Using by HPLC

Significance of the Topic

Favipiravir has emerged as a key antiviral agent in response to the COVID-19 pandemic and influenza infections. Accurate quantification of its plasma concentration supports therapeutic drug monitoring, dosage optimization, and safety assessment without relying on mass spectrometry.

Objectives and Overview of the Study

The study aimed to establish and validate a high-performance liquid chromatography (HPLC) method with fluorescence detection for sensitive, quantitative analysis of favipiravir in human plasma. This approach leverages standard HPLC equipment to facilitate implementation in routine laboratories.

Methodology and Instrumentation

Sample Preparation:

• Mix 25 µL plasma with 100 µL methanol for protein precipitation.
• Centrifuge and collect supernatant.
• Dilute supernatant 15-fold with mobile phase prior to injection.

HPLC Conditions:

• System: Shimadzu Nexera XR.
• Column: Shim-pack Scepter C18-120 (150 × 4.6 mm, 5 µm) with guard.
• Mobile Phase A: 10 mmol/L sodium phosphate buffer, pH 6.9; B: methanol.
• Gradient program: 0–2.5 min (100% A), 2.5–7.5 min (100→30% A), 7.5–9.5 min (30% A), 9.51 min return to 100% A.
• Flow rate: 1.0 mL/min; column temperature: 30 °C; injection volume: 1 µL.
• Detection: fluorescence (Ex. 360 nm, Em. 433 nm).

Main Results and Discussion

The calibration curve (1–100 µg/mL) demonstrated excellent linearity (R2 = 0.999, 1/C weighting). Intra-assay precision (%RSD) ranged 0.21–0.31% with accuracy between 92.1–106%. Quality control validation at 2, 45, and 90 µg/mL yielded precision of 0.18–0.35% and accuracy of 96.5–100%, meeting acceptance criteria.

Benefits and Practical Applications

This HPLC-fluorescence method offers:

• High sensitivity and specificity without mass spectrometry.
• Rapid turnaround suitable for clinical and research labs.
• Cost-effective monitoring of favipiravir therapy and pharmacokinetic studies.

Future Trends and Potential Applications

Advancements may include automation of sample preparation, expansion to multiplex assays for simultaneous drug panels, miniaturized or point-of-care HPLC systems, and integration with data analytics for real-time therapeutic guidance.

Conclusion

The developed HPLC method with fluorescence detection delivers robust, precise, and accurate quantitation of favipiravir in plasma. Its simplicity and performance facilitate broad adoption in drug monitoring and pharmacology research.

Reference

• Gowen BB, et al. Alterations in favipiravir (T-705) pharmacokinetics and biodistribution in a hamster model of viral hemorrhagic fever. Antiviral Res. 2015.
• Takashita E, et al. Antiviral susceptibility of influenza viruses isolated from patients pre- and post-administration of favipiravir. Antiviral Res. 2016.
• Shiraki K, et al. Favipiravir, an anti-influenza drug against life-threatening RNA virus infections. Pharmacol Ther. 2020.