The detection of non-steroidal anti-inflammatory drugs in keratinous matrices

The problems of non-steroidal anti-inflammatory drugs (NSAIDs) as environmental contaminants is an area of concern. NSAIDs are heavily relied upon to treat pain and inflammation. With such prevalence, these compounds are now entering the environment via many routes, such as water discharge and contaminated food. This results in subsequent exposure and effects on various animal species. One such example is diclofenac, which was associated with the extinction of Gyps vultures in Asia. The detection of diclofenac was based on post-mortem samples i.e. after a large decline in populations. In this research non-invasive samples i.e hairs and feathers are analysed pre-mortality as a preventive measure for early detection. A simultaneous liquid chromatography-mass spectrometry (LC-MS) method for detection of eighteen compounds, either of known toxicological effects or future threat (NSAIDs - aceclofenac, carprofen, diclofenac, flunixin, ketoprofen, mefenamic acid, meloxicam, nimesulide, phenylbutazone, piroxicam and suxibuzone; metabolites - oxyphenylbutazone, 3-hydroxymethyl mefenamic acid, 4-hydroxydiclofenac, 4-hydroxynimesulide, 5-carboxymeloxicam, 5-hydroxyflunixin and 5-hydroxypiroxicam) has been developed and validated. A newly optimised sample preparation method was applied to hairs/feathers. Precision of the analytical method was within 10% relative standard deviations for the majority of compounds. Recoveries averaged 83% and limits of detection (LOD) ranged 0.01 to 0.2μg/g. For diclofenac, flunixin, mefenamic acid, oxyphenylbutazone, piroxicam and 5-hydroxyflunixin, LODs were lower than previously reported. Various animal hairs/feathers were analysed (n=20) and in two samples piroxicam and phenylbutazone were individually detected, at 1.2μg/g ± 0.002 and 1.8μg/g ± 0.011 respectively. The LC-MS method reported here has been validated for the first time using animal hair/feather samples. This range of NSAIDs and metabolites have never been reported before. LODs and LOQs of metabolites are reported for the first time. The detection of piroxicam and phenylbutazone in feathers highlights the viability of testing keratinous matrices.