Zafirlukast in Human Plasma Using Retain AX and Accucore RP-MS Column

Significance of the topic

Zafirlukast is a leukotriene receptor antagonist widely used in chronic asthma management. Precise and rapid quantification of this drug in human plasma supports pharmacokinetic studies, therapeutic monitoring and quality control in drug development. An optimized analytical workflow enhances laboratory throughput and data reliability in clinical and industrial bioanalysis.

Objectives and overview of the study

This application note aims to establish a fast, sensitive and reproducible method for extracting and quantifying zafirlukast from human plasma. The approach integrates a high-capacity Retain AX solid-phase extraction (SPE) plate with a core-shell Accucore RP-MS HPLC column, coupled to triple quadrupole mass spectrometry for a total run time under three minutes.

Methodology and instrumentation

• Sample preparation: 30 mg Retain AX 96-well SPE plate; conditioning with acetonitrile and water; load 200 µL plasma spiked with zafirlukast and glybenclamide (internal standard); wash steps; elution with acidified acetonitrile; drying and reconstitution in 200 µL LC-MS grade acetonitrile.
• Chromatography: Thermo Scientific Accela 600 system; Accucore RP-MS (2.6 µm, 50×2.1 mm) with guard column; gradient elution from 35% aqueous (0.1% formic acid) to 100% methanol (0.1% formic acid) within two minutes; flow rate 0.6 mL/min; column temperature 25 °C; injection volume 5 µL.
• Mass spectrometry: Thermo Scientific TSQ Vantage triple quadrupole; heated electrospray ionization (HESI) in positive mode; MRM transitions m/z 574.32→462.24 for zafirlukast and 492.24→367.15 for glybenclamide; optimized source parameters (spray voltage 3500 V, vaporizer 450 °C, capillary 270 °C).

Main results and discussion

The method demonstrated linear response over 50–500 ng/mL with correlation coefficient (r2) of 0.9903. At a mid-level QC (200 ng/mL), precision (n=5) was 4.2% RSD and accuracy was within ±11%. Absolute recovery of zafirlukast from plasma was approximately 85%. Chromatograms showed sharp, well-resolved peaks with no significant carry-over.

Benefits and practical applications

• Rapid analysis time (<3 min) increases sample throughput in bioanalytical laboratories.
• Core-shell RP-MS column enables high efficiency with moderate backpressure, reducing instrument wear.
• High-capacity Retain AX SPE ensures consistent extraction recovery and effective removal of endogenous interferences.
• Sensitivity and robustness support pharmacokinetic profiling, therapeutic drug monitoring and quality control in pharmaceutical research.

Future trends and potential applications

Emerging developments may include further miniaturization using microflow LC, automated SPE workflows, and coupling with high-resolution mass spectrometry for metabolite identification. Integration into clinical diagnostic platforms and expansion to multi-analyte panels could enhance personalized therapy monitoring.

Conclusion

The combined Retain AX SPE and Accucore RP-MS HPLC–MS/MS method provides a fast, accurate and reliable protocol for quantifying zafirlukast in human plasma. Its speed, precision and high recovery make it suitable for routine bioanalysis in both research and clinical settings.

References

1. Drug Information. http://www.drugs.com/mtm/zafirlukast.html. Accessed 24 November 2011.
2. The Internet Drug Index. http://www.rxlist.com/accolate-drug.htm. Accessed 24 November 2011.
3. FDA, US Food and Drug Administration. Safety Alerts for Human Medical Products. http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm166246.htm. Accessed 29 November 2011.