Analysis of loxoprofen in tablets, patches, and equine urine as tert-butyldimethylsilyl derivative by gas chromatography-mass spectrometry.
Abstract: Loxoprofen is a non-steroidal anti-inflammatory drug of the 2-arylpropionic acid type, which has used to treat musculoskeletal disorders in the horse racing industry. However, it has also used illicitly to mask clinical signs of inflammation and pain in racehorses. Thus, its accurate analysis has become an important issue in horse doping laboratories. In this study, an analytical method of loxoprofen was developed as tert-butyldimethylsilyl (TBDMS) derivative by gas chromatography-mass spectrometry (GC-MS). Characteristic fragment ions of [M-15], [M-57], and [M-139] permitted the accurate and selective detection of loxoprofen. Under optimal conditions, this method showed good linearity (r ≥ 0.999) in the range of 10-500 ng/mL, repeatability (% relative standard deviation = 5.6-8.5), and accuracy (% relative error = - 0.3-0.9) with a detection limit of 1.0 ng. When applied to the analysis of loxoprofen in tablet and patch products, loxoprofen was positively identified as TBDMS derivative by GC-MS. The present method provided rapid and accurate determination of loxoprofen in patch and tablet products. Levels of loxoprofen were highest in equine urine at 0.5 and 1 h after oral administration with single dose (3 mg/kg) to three horses, and then rapidly reduced to below the lower limit of quantification at 24 h. Therefore, the present method will be useful for the pharmacokinetic study and doping tests for loxoprofen and other similar acidic drugs in horses.
Publication Date: 2018-03-23 PubMed ID: 29572683DOI: 10.1007/s12272-018-1023-5Google Scholar: Lookup
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Summary
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This study develops a new method for precisely identifying the presence of an anti-inflammatory drug, loxoprofen, particularly in horse races where it can be used illicitly. The method involves transforming the drug into a specific derivative and using gas chromatography-mass spectrometry for detection.
Introduction and Basic Method
- Loxoprofen, a non-steroidal anti-inflammatory drug, is often used within the horse racing industry to treat musculoskeletal issues. However, it is also utilized to deceptively conceal illness and pain in racehorses.
- To tackle this issue, the research aims to develop a reliable method to detect loxoprofen. This involves creating a tert-butyldimethylsilyl (TBDMS) derivative of loxoprofen and applying gas chromatography-mass spectrometry (GC-MS) to enable its identification.
Theoretical Underpinning and Methodical Precision
- The process of accurately detecting the presence of loxoprofen involves the identification of specific fragment ions of [M-15], [M-57], and [M-139].
- The devised method, under optimal conditions, demonstrated strong linearity (r ≥ 0.999) within the range of 10-500ng/mL, repeatability (% relative standard deviation = 5.6-8.5), and accuracy (% relative error = - 0.3-0.9) with a detection limit of 1.0ng.
Application to Products and Biological Samples
- The application of this method to loxoprofen detection in tablet and patch products confirmed the presence of the drug (as a TBDMS derivative) via GC-MS.
- In addition to products, this developed method was used on equine urine samples. The results indicated peak loxoprofen levels at 0.5 and 1 hour after a single-dose oral administration of the drug (3mg/kg) to three horses. The drug level then quickly fell below the detection limit at the 24-hour mark.
Conclusion and Future Implication
- The newly developed method for loxoprofen detection demonstrates rapid and accurate measurements of the drug in both tablet and patch forms.
- This method can be highly beneficial for both pharmacokinetic studies and doping tests for loxoprofen and similar acidic drugs in horses. Therefore, it has high potential implications for ensuring fair and ethical practices within the horse racing industry.
Cite This Article
APA
Kim Y, Seo C, Oh S, Kwak J, Jung S, Sin E, Kim H, Ji M, Lee HS, Park HJ, Lee G, Yu J, Kim M, Lee W, Paik MJ.
(2018).
Analysis of loxoprofen in tablets, patches, and equine urine as tert-butyldimethylsilyl derivative by gas chromatography-mass spectrometry.
Arch Pharm Res, 41(4), 459-466.
https://doi.org/10.1007/s12272-018-1023-5 Publication
Researcher Affiliations
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, 540-950, Republic of Korea.
- Jeonbuk Branch Institute, Korea Research Institute of Bioscience and Biotechnology, Jeonbuk, 56212, Republic of Korea.
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, 540-950, Republic of Korea.
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, 540-950, Republic of Korea.
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, 540-950, Republic of Korea.
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, 540-950, Republic of Korea.
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, 540-950, Republic of Korea.
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, 540-950, Republic of Korea.
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, 540-950, Republic of Korea.
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, 540-950, Republic of Korea.
- Department of Physiology and Department of Biomedical Sciences, Ajou University School of Medicine, Suwon, 443-749, Republic of Korea.
- Department of Physiology and Department of Biomedical Sciences, Ajou University School of Medicine, Suwon, 443-749, Republic of Korea.
- Racing Laboratory, Korea Racing Authority, Gwacheon, 13822, Republic of Korea.
- Jeonbuk Branch Institute, Korea Research Institute of Bioscience and Biotechnology, Jeonbuk, 56212, Republic of Korea.
- College of Pharmacy, Chosun University, Gwangju, 501-759, Republic of Korea. wlee@chosun.ac.kr.
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, 540-950, Republic of Korea. paik815@sunchon.ac.kr.
MeSH Terms
- Administration, Oral
- Animals
- Anti-Inflammatory Agents, Non-Steroidal / analysis
- Anti-Inflammatory Agents, Non-Steroidal / urine
- Gas Chromatography-Mass Spectrometry / methods
- Horses
- Organosilicon Compounds / analysis
- Phenylpropionates / analysis
- Phenylpropionates / urine
- Tablets / analysis
- Transdermal Patch
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