Extractables and Leachables Detected in Ophthalmic Drug Products

Importance of Topic

Ophthalmic drug products can be contaminated by chemical compounds that migrate from primary and secondary packaging materials, posing potential health risks. Sensitive and selective analytical strategies are essential to detect and identify low-level extractables and leachables against complex drug matrices. High-resolution LC/MS/MS coupled with statistical evaluation offers a reliable solution for comprehensive safety assessments.

Objectives and Overview

This study aimed to develop and validate an analytical workflow for the untargeted detection and identification of extractable and leachable impurities in ophthalmic drug products. By combining high-resolution quadrupole time-of-flight mass spectrometry with statistical comparison and structure elucidation software, the method supports regulatory risk evaluation and ensures drug suitability.

Used Methodology and Instrumentation

Sample Preparation and Analysis Workflow:

• Extractables: Ophthalmic containers were washed, filled with 1:1 methanol–water, and incubated at 55 °C for 72 h. Extracts were injected directly.
• Leachables: Drug formulations were stressed at 60 °C for 24 h (stressed sample) and compared with nonstressed controls.
• Untargeted Screening: Statistical comparison (fold-change > 2x, occurrence > 50 %) against blanks or nonstressed samples using Agilent Mass Profiler Software.
• Accurate Mass Matching: Differential features matched to a custom user-generated PCDL (1,840 compounds) with < 5 ppm mass error.
• Structure Confirmation: Auto MS/MS data processed in MassHunter Qualitative Analysis, and known/unknown structures confirmed or elucidated with Agilent Molecular Structure Correlator.
• Semi-quantitation: External phthalate standard curve (1 pg/µL – 50 ng/µL) provided rough concentration estimates.

Instrumentation:

• Agilent 1290 Infinity II UHPLC System
• Agilent 6540 Q-TOF Mass Spectrometer with Dual Agilent Jet Stream ESI
• Agilent MassHunter Acquisition, Mass Profiler, MassHunter ProFinder, and Molecular Structure Correlator software

Key Results and Discussion

Approximately 50 extractables and leachables were detected per sample. Combining positive and negative ionization analyses yielded 54 unique compounds. Statistical plots highlighted features with 2x and 4x abundance above controls. Major identified compounds included:

• Phthalates: diisononyl phthalate (DINP), n-dioctyl phthalate (DOP/DEHP)
• Plastic additives: erucamide, Irgacure 907, diethylene glycol, isopropyl-9H-thioxanthen-9-one
• Leachable impurities: myristyl dimethylamine oxide, propyl acetate, phthalic anhydride

Unknowns such as N-butyl-9-octadecenamide and 3-oxo-2,3-diphenylpropanal were structurally proposed via MSC. Semiquantitative estimates revealed three leachables exceeding the 1 ppm reporting threshold:

• DINP: 1.4 µg/mL
• DOP/DEHP: 2.5 µg/mL
• Erucamide: 1.7 µg/mL

Benefits and Practical Applications

This integrated workflow offers:

• High sensitivity and selectivity for low-level impurities.
• Rapid untargeted screening complemented by targeted confirmation.
• Automated statistical comparison reduces false positives from blank interferences.
• Structural elucidation without reference standards accelerates unknown identification.
• Regulatory-compliant reporting aligned with FDA and PQRI guidance.

Future Trends and Potential Applications

Emerging directions in E&L analysis may include:

• Application of machine learning for spectral annotation and pattern recognition.
• Expansion of accurate-mass databases with predicted degradants and polymer additives.
• Improved quantitative accuracy using isotope-labeled internal standards.
• Extension of workflows to biologics, complex formulations, and alternative container materials.

Conclusion

The presented HR LC/Q-TOF approach, combined with statistical software and molecular correlator tools, enabled comprehensive detection, identification, and semiquantitation of extractables and leachables in ophthalmic drug products. The method identified ~50 compounds per study, highlighted three leachables above reporting thresholds, and supports robust safety assessments for regulatory compliance.

Reference

• U.S. FDA. Container Closure Systems for Packaging Human Drugs and Biologics; Guidance for Industry; May 1999.
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• Wong, D. M.; Firor, R. L. Analysis of Extractable/Leachable Compounds from Plastic Intravenous Bag Sets Using GC/MSD Systems. Agilent Technologies Application Note 5991-5616EN, 2015.
• Wong, D. M.; Firor, R. L. Analysis of Extractable/Leachable Compounds from Generic Liquid Drug Formulations Using GC/MSD Systems. Agilent Technologies Application Note 5991-5632EN, 2015.
• Norwood, D. L.; et al. HPLC and LC/MS Analysis of Pharmaceutical Container Closure System Leachables and Extractables. J. Liq. Chromatogr. Relat. Technol. 2009, 32, 1768–1827.
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