Long-term monitoring of opioid, sedative and anti-inflammatory drugs in horse hair using a selective and sensitive LC-MS/MS procedure

Abstract

BackgroundCompared to blood or urine, drugs can be detected for much longer periods in the long hair of horses. The aim of this study was to establish and validate a highly sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the detection and quantification of frequently prescribed opioids, sedatives and non-steroidal anti-inflammatory agents in the mane and tail hair of horses. Based on an average growth rate of about 2 cm per month, times of administration reported by horse owners or veterinary physicians were related to drug localizations in hair. Hair samples were collected from ten horses that received drug treatments and analyzed in segments of 2, 4 or 6 cm in length. Hair segments were decontaminated, cut into fragments and methanol-extracted under sonication. The extracts were analyzed by LC-MS/MS for 13 commonly used drugs using the validated procedure. Deuterated analogs were included as internal standards.ResultsAnalytes were detected in hair samples with a length of up to 70 cm. Fourteen out of 16 hair samples were positive for at least one of the tested drugs. Segmentation allowed for time-resolved monitoring of periods of 1 to 3 months of drug administration. Concentrations in dark hair reached a maximum of 4.0 pg/mg for butorphanol, 6.0 pg/mg for tramadol, 1.4 pg/mg for morphine, 1.8 pg/mg for detomidine, 1.2 pg/mg for acepromazine, 39 pg/mg for flunixin, 5.0 pg/mg for firocoxib, and 3’600 pg/mg for phenylbutazone. Only trace amounts of meloxicam were detected. Drug detection correlated well with the reported period of medical treatment. No analytes were detected in the light-colored mane and tail hair samples from one horse despite preceding administrations of acepromazine and phenylbutazone.ConclusionThis study describes a sensitive and selective technique suitable for the validated detection and quantification of frequently prescribed veterinary drugs in horse hair. The segmental method can be applied for time-resolved long-term retrospective drug monitoring, for example in prepurchase examinations of horses as drug detection in hair can prove preceding medical treatments.

Different localizations of drugs simultaneously administered in a strand of hair by micro‐segmental analysis

“…In conventional segmental analysis, multiple strands of hair are typically cut at intervals of several centimeters, and then the strands of hair from the same segment are lumped together to obtain sufficient detection sensitivity on analytical instruments. Therefore, the estimated drug intake time can include error margins at the level of several months . In certain cases, such as sexual assault, segmental hair analysis has been established to be useful in understanding the context surrounding a case .…”

“…Therefore, the estimated drug intake time can include error margins at the level of several months. 4,5 In certain cases, such as sexual assault, segmental hair analysis has been established to be useful in understanding the context surrounding a case. [6][7][8][9] For example, detection of a sleeping drug at only a specific hair segment of a victim can become objective evidence indicating that a drug was present in the victim's body at the time of a case.…”

Liquid-liquid extraction by low-temperature partition and high-performance liquid chromatography for determination of flunixin and phenylbutazone in horse hair

“…A página da Revista Agrária Acadêmica no ERIH pode ser acessada no link erihplus/periodical/agrariacad. rates of the analytes (MADRY et al, 2016;RICHARDS et al, 2011), limiting measurement comparison of the efficiency of the method. Table 3 shows some references that deal with either the analytes or the matrix treated in this work and can be useful for some considerations.…”

“…Drug analysis for horses using hair as a sample, regardless of the target analytes, is still growing (SCHLUPP et al, 2004;COMIN et al, 2012;STEGELMEIER;HALL, 2014;GRAY et al, 2013). In addition, few studies have been performed on nonsteroidal anti-inflammatory drugs (NSAID) frequently prescribed for horses MADRY et al, 2016).…”

Challenges in detecting substances for equine anti‐doping

“…The detection of these emerging substances and their metabolites has been achieved with the development of various techniques including LC-MS/MS and/or GC-MS. To the best of the authors' knowledge, there is no information for the use of these new synthetic opioids in horses, except the press release recently reported by ARCI in order to notify all racing regulatory agencies worldwide about the detection of AH-7921 in post-race samples taken recently from horses. [89] Furthermore, according to a study that describes a sensitive and selective technique for the validated detection and quantification of frequently prescribed veterinary drugs in horse hair, [90] time-resolved long-term retrospective drug monitoring in horse hair may be feasible for drug detection in the future.…”