Fully automated quantification of Meropenem, Tazobactam, Piperacillin and Dexamethasone in plasma

Significance of the Topic

Simultaneous quantification of corticosteroids and antibiotics in plasma is essential for therapeutic monitoring, infection control and personalized treatment strategies. A rapid, robust and fully automated workflow reduces manual errors, increases laboratory throughput and supports timely clinical decision–making, especially in critical settings such as intensive care, sepsis management and COVID-19 treatment.

Study Objectives and Overview

This study aimed to develop and validate a fully automated method for simultaneous determination of dexamethasone, meropenem, piperacillin and tazobactam in human plasma. Key goals included achieving a broad dynamic range (1–100 ng/mL), high repeatability (%RSD < 15%), acceptable accuracy (85–115%), and a total run time of 5 minutes per sample.

Methodology

The workflow integrated automated sample preparation with CLAM–2030 and LC–MS/MS analysis on a Shimadzu LCMS–8060 triple quadrupole. Main steps:

• Spiking plasma with standard solutions and [2H4]–dexamethasone internal standard (10 ng/mL).
• Automated pretreatment by CLAM–2030: addition of isopropanol and acetonitrile, shaking, filtration and transfer to LC vials.
• Chromatographic separation on Shim-pack Scepter C18 (50 × 2.1 mm, 1.9 µm) at 30 °C, flow rate 600 µL/min, 0.1 mM ammonium fluoride in water (A) and methanol (B) gradient over 5 min.
• MRM transitions optimized by FIA; source gases set at 3 L/min nebulizing, 10 L/min drying and heating; interface at 400 °C and heat block at 500 °C.

Used Instrumentation

• Sample preparation: CLAM–2030 fully automated module
• Liquid chromatograph: Shimadzu Nexera X2 with Shim-pack Scepter C18 column
• Mass spectrometer: Shimadzu LCMS–8060 triple quadrupole

Main Results and Discussion

Calibration curves were linear between 0.4 and 100 ng/mL (R² > 0.995). The LOQ for all analytes was set at 1 ng/mL. Accuracy across calibrators ranged from 85% to 115% and precision (%RSD) was below 15%. Between-day reproducibility studies at low (2 ng/mL), medium (20 ng/mL) and high (80 ng/mL) levels confirmed robustness:

• Tazobactam precision ≤ 12.5%, accuracy 87–113%
• Piperacillin precision ≤ 14.5%, accuracy 91–107%
• Meropenem precision ≤ 12.0%, accuracy 89–111%
• Dexamethasone precision ≤ 14.9%, accuracy 91–113%

The 5-minute run time and automated handling allowed high throughput without compromising sensitivity or data quality.

Benefits and Practical Applications

Key advantages of this method include:

• High throughput: up to hundreds of samples per day with minimal operator input
• Comprehensive panel: simultaneous measure of one corticosteroid and three antibiotics in a single assay
• Rapid turnaround: 5 min analysis per sample
• Accuracy and precision meeting regulatory requirements for bioanalysis

This workflow is suitable for clinical pharmacokinetic studies, therapeutic drug monitoring, antibiotic stewardship programs and drug interaction assessments.

Future Trends and Opportunities

Advancements may include:

• Expansion to additional drug classes and biomarkers for multi-analyte panels
• Integration with laboratory information management systems (LIMS) for seamless data flow
• Miniaturized high-throughput platforms to further reduce solvent consumption and costs
• Use of HRMS for untargeted screening alongside targeted assays

Conclusion

The combination of CLAM–2030 and LCMS–8060 provides a robust, fully automated platform for fast, accurate quantification of dexamethasone and three antibiotics in plasma. The method meets stringent bioanalytical criteria and offers significant efficiency gains for high-throughput laboratories.

Reference

1. RECOVERY Collaborative Group. Dexamethasone in Hospitalized Patients with Covid-19. N Engl J Med. 2021;384(8):693–704.
2. NIH COVID-19 Treatment Guidelines. Corticosteroids. https://www.covid19treatmentguidelines.nih.gov/immunomodulators/corticosteroids/