The Effect of Sample Vials on Analyte Stability: Mitigating In-Vial Degradation of Pharmaceuticals During LC Analysis

Significance of the Topic

In pharmaceutical quality control, accurate detection of impurities is critical to ensure product safety and compliance with regulatory standards

Objectives and Study Overview

This study evaluates how different vial types influence in-vial degradation of two lactone-containing small molecule drugs during liquid chromatography analysis

Methodology and Instrumentation

Stock solutions of drospirenone and lovastatin at 1 mg/mL in 70:30 water-acetonitrile were prepared
Forced degradation involved addition of sodium hydroxide and incubation at room temperature for up to 24 hours

• Liquid chromatography system ACQUITY UPLC H-Class PLUS with Quaternary Solvent Manager, Sample Manager Flow Through Needle, Column Manager, PDA detector and QDa mass detector
• Column ACQUITY Premier HSS T3 1.8 micrometer, 2.1 x 50 mm
• Mobile phases 0.1 percent formic acid in water and in acetonitrile with a gradient from 5 to 95 percent organic over five minutes
• Sample temperature 10 °C, column temperature 30 °C, injection volume 1 microliter, flow rate 0.5 mL/min
• Mass spectrometry via ACQUITY QDa in positive and negative electrospray modes monitoring selected ions
• Vial types evaluated polypropylene, standard borosilicate glass, and pH control treated glass

Results and Discussion

Leachable sodium from glass vials caused pH increases up to pH 9, promoting base-catalyzed hydrolysis of lactone rings
Forced degradation confirmed formation of hydrolysis products with distinct retention times and mass spectra
Stability tests over 16 hours showed:

• Standard glass vials produced variable and elevated degradant levels across replicates
• Polypropylene and treated glass vials maintained neutral pH and exhibited minimal degradant formation

Variable outcomes with standard vials risk false out-of-specification results and complex troubleshooting

Benefits and Practical Applications

• Use of pH control treated glass vials or polypropylene vials minimizes undesired in-vial chemical changes
• Consistent impurity profiles improve reliability of QC assays
• Reduction in false OOS events decreases time and cost associated with investigations

Future Trends and Opportunities

Development of vial materials with further reduced leachable species will expand stability across diverse analytes
Integration of vial certification data with laboratory information management systems may enhance traceability
Exploration of surface treatments and coatings to mitigate adsorption and degradation in high-throughput workflows

Conclusion

Vial composition plays a pivotal role in sample stability during LC analysis
Standard glass vials can introduce pH shifts leading to variable hydrolysis of lactone drugs
pH control certified glass vials and polypropylene vials offer reproducible results and mitigate in-vial degradation, ensuring accurate QC outcomes

References

1 Does an Autosampler Glass Vial Influence the pH of Valuable Samples Thermo Scientific Technical Note TN21921 EN 0619S 2019
2 Wallace A How Glass Vial Quality Affects Data Accuracy LabMate Online 2020
3 Arvary R Mangion I The Importance of Vial Composition in HPLC Analysis J Pharm Biomed Anal 134 2017 237 242
4 Jin J Wang Z Lin J et al Ghost peaks of Ezetimibe in Acetonitrile Induced by Alkaline Impurities From Glass Vials J Pharm Biomed Anal 140 2017 281 286
5 Huang Y et al Circumventing Glass Vial and Diluent Effects on Solution Stability J Pharm Biomed Anal 213 2022 114676
6 Gomez Bombarelli R Calle E Casado J Mechanisms of Lactone Hydrolysis J Org Chem 78 14 2013 6868 6879
7 Durivage M FDA Guidance for Investigating OOS Test Results in Pharma Production Pharmaceutical Online June 24 2022