Automated Sample Preparation in Quality Control of Eye-Drop Formulation

Significance of the topic

Eye-drop formulations containing corticosteroids and antibiotics must undergo precise quality control to guarantee patient safety and therapeutic effectiveness.

Objectives and study overview

This application note presents the use of the Agilent 7696A Sample Prep WorkBench with WeighStation to automate the preparation of calibration standards and sample dilutions for the quantitative analysis of dexamethasone and chloramphenicol in ophthalmic solutions.

Methodology and instrument setup

The automated workflow includes:

• Serial dilution for a four-level calibration series covering 16–64 µg/mL dexamethasone and 80–320 µg/mL chloramphenicol
• Automated taring of vials, manual addition of solid or viscous samples under pause, solvent addition, and post-dilution weighing

Used instrumentation

• Agilent 7696A Sample Prep WorkBench with integrated WeighStation
• Two Agilent 7693A Automated Liquid Samplers (500 µL and 50 µL syringes)
• Agilent 1290 Infinity HPLC System with UV detection at 254 nm
• Poroshell 120 column (2.1 mm × 100 mm, 2.7 µm)

Main results and discussion

• Excellent linearity for both analytes (R² > 0.999)
• Calibration repeatability: RSD 1.5% for chloramphenicol, 2.7% for dexamethasone
• Sample preparation repeatability: RSD < 1%
• No detectable cross-contamination between samples
• Significant reduction in solvent use and elimination of volumetric glassware handling

Benefits and practical applications

Automating sample preparation enhances precision, reduces manual errors and waste, and accelerates routine HPLC-based QC workflows for ophthalmic products.

Future trends and potential applications

Such automated platforms can be extended to other dosage forms, multi-analyte assays, and integrated with laboratory information management systems for real-time process monitoring and data integrity improvements.

Conclusion

The Agilent 7696A Sample Prep WorkBench with WeighStation provides a robust, accurate, and efficient solution for high-throughput, automated preparation of calibration standards and viscous sample dilutions in eye-drop quality control analysis.