Stability of nonsteroidal anti-inflammatory drugs in urine and solution: effects of degradation on analytical assessment: supplementary materials

Aims: Knowledge of optimal storage conditions of drugs is crucial for properly interpreting analytical
assessments. Materials & methods: The current study aimed to investigate the stability of some
nonsteroidal anti-inflammatory drugs using a validated method by gas chromatography (GC)–MS. For this
propose, long-term, short-term and solution stability were investigated. Results: The analytes remained
stable in the sample, similar to the working solution. The most affected substance over time in both
matrix and working solution was phenylbutazone. The freeze–thaw cycle affected flunixin and carprofen,
but diclofenac and vedaprofen changed only in the third cycle. In short-term stability, high-temperature
conditions changed carprofen. Conclusion: The present study is a comprehensive assay for nonsteroidal
anti-inflammatory drug stability and can be used as a reference for results assessment.