LC-MS methods for analyzing anti-inflammatory drugs in animal-food products

Simultaneous determination of 58 glucocorticoid residues in milk by ultra-high performance liquid chromatography-tandem mass spectrometry

Abuse of glucocorticoid veterinary drugs in dairy industry can potentially threat milk safety and consequently influence human health. Here a reliable method for determination of 58 glucocorticoid drug residues in milk was established by combining solid phase extraction with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The analytes were extracted with acetonitrile and cleanup with EMR-Lipid lipid removal column. The analytes were chromatographically separated using Poroshell EC-C18 column and acquired by electrospray ionization with multiple-reaction monitoring (MRM) mode. The limit of quantification (S/N ≥ 10) ranged from 0.2 to 2.0 µg/kg and the limit of detection (S/N ≥ 3) ranged from 0.1 to 1.0 µg/kg. Average recoveries were from 71% to 113%, the relative standard deviations (RSDs) were less than 15%, and the correlation coefficients (R2) of calibration curves exceeded 0.99. The method was applied to detect twenty milk products obtained from local supermarkets including ten pasteurized milk and ten UHT milk. Two endogenous glucocorticoids, i.e. hydrocortisone and cortisone were detected but not exceed the maximum residue limits (MRLs).

Trace analysis of corticosteroids (CSs) in environmental waters by liquid chromatography-tandem mass spectrometry

Natural and synthetic corticosteroids (CSs) are a class of steroid hormones which could potentially disturb the corticosteroid signaling pathways in wildlife and humans. In this study, a sensitive and robust analytical method using solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for simultaneous analysis of sub-ng/L concentrations of 26 CSs in highly complex natural water matrices. The method performance was validated for WWTP influent, effluent, surface water and finished drinking water. Low practical quantification levels (PQLs) were achieved as 0.008-0.16 ng/L in finished drinking water, 0.019-0.50 ng/L in surface water, 0.047-1.5 ng/L in WWTP effluent, and 0.10-3.1 ng/L in WWTP influent, respectively, with the recoveries ranging from 70% to 130%. The cleanup performance and matrix interferences were also evaluated. This method was then applied to the analysis of target CSs in WWTP influent and effluent samples collected from a local WWTP, as well as surface water downstream of the WWTP outfall, detecting an average summed CS concentration of 744 ng/L in influent, 23.4 ng/L in effluent and 10.9 ng/L in surface water. Four synthetic CSs (triamcinolone acetonide, fluocinolone acetonide, clobetasol propionate, and fluticasone propionate) were found poorly removed in the WWTP. The developed method provides a tool to obtain occurrence data of corticosteroids in environmental waters, which will permit assessing their risk to environmental organisms.

Tolfenamic Acid

Tolfenamic acid (TA) is a nonsteroidal antiinflammatory drug and belongs to the group of fenamates. It is used as a potent pain reliever in the treatment of acute migraine attacks, and disorders like dysmenorrhea, rheumatoid, and osteoarthritis. TA has shown excellent in vitro antibacterial activity against certain ATCC strains of bacteria when complexed with bismuth(III). It has also been reported to block pathological processes associated with Alzheimer's disease. In the recent past, TA has also been used as a novel anticancer agent for the treatment of various cancers. In view of the clinical importance of TA, a comprehensive review of the physical and pharmaceutical properties and details of the various analytical methods used for the assay of the drug in pharmaceutical and biological systems has been made. The methods reviewed include identification tests and titrimetric, spectrophotometric, chromatographic, electrochemical, thermal, microscopic, enzymatic, and solid-state techniques. Along with the analytical profile, the stability and degradation of TA, its pharmacology and pharmacokinetics, dosage forms and dose, adverse effects and toxicity, and interactions have been discussed.

Biotransformation of NSAIDs by pig liver microsomes in vitro: Kinetics, metabolites identification and toxicity prediction

Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most frequently used pharmaceuticals in animals. In the current study, the biotransformation of five NSAIDs by pig liver microsomes (PLMs) was studied. The pseudo-first-order kinetics mode was obtained for the metabolization of the studied NSAIDs by PLMs in vitro. The metabolites were identified by high performance liquid chromatography with a high-resolution LTQ-Orbitrap mass spectrometry. The hydroxylation of benzene was confirmed to be the dominating metabolic pathway. Finally, the toxicity of the metabolites was predicted by the Estimation Programs Interface Suite software based on quantitative structure-activity relationships. Decreased toxicity was expected for the most metabolites of the studied NSAIDs except flurbiprofen, whose main metabolite exhibited slightly more toxicity. The present study provided a preliminary foundation to understand the metabolites of some NSAIDs and their toxicity, which was of great significance in animal food safety.

Bovine Carboxylesterases: Evidence for Two CES1 and Five Families of CES Genes on Chromosome 18

Predicted bovine carboxylesterase (CES) protein and gene sequences were derived from bovine (Bos taurus) genomic sequence data. Two bovine CES1 genes (CES1.1 and CES1.2) were located on chromosome 18 encoding amino acid sequences that were 81% identical. Two forms of CES1.2 were also observed apparently caused by an indel polymorphism encoded at the C-terminus end. Two CES gene clusters were observed on chromosome 18: CES5-CES1.1-CES1.2 and CES2-CES3-CES6. Bovine CES1, CES2, CES3, CES5 and CES6 shared 39-45% identity with each other, but showed 71-76% identity with each of the five corresponding human CES family members. Phylogeny studies indicated that bovine CES genes originated from five ancestral gene duplication events which predated the eutherian mammalian common ancestor. In addition, a subsequent CES1 gene duplication event is proposed during mammalian evolution prior to the appearance of the Bovidae common ancestor ~ 20 MY ago.

Development and validation of a methodology to qualitatively screening veterinary drugs in porcine muscle via an innovative extraction/clean-up procedure and LC-MS/MS analysis

A qualitative multiresidue method that facilitates rapid monitoring of veterinary drugs in porcine muscle is described. The method comprises the application of an innovative extraction/clean-up procedure, namely liquid-liquid extraction with partition at very low temperature (LLE-FPVLT), and analysis by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Besides the high selectivity, sensitivity and specificity, this high-throughput method proved to be quite general as 34 veterinary drugs (from six distinct classes: tetracyclines, sulfonamides, penicillins, quinolones, macrolides and benzimidazoles) could be successfully detected. The whole screening procedure was validated according to the directives from European Commission Decision 2002/657/EC and guidelines for the validation of screening methods. Acceptable values for the evaluation parameters were achieved for all analytes (except for ampicillin, clindamycin and erythromycin). Finally, these very promising results have strengthened the possibility of inclusion of such a methodology as an integral part of the National Residue Control Plan scope of the Ministry of Agriculture, Livestock and Food Supply of Brazil.

Detection and characterization of synthetic steroidal and non-steroidal anti-inflammatory drugs in Indian ayurvedic/herbal products using LC-MS/TOF

It is claimed that ayurvedic/herbal healthcare products (AHPs) are safe because of their natural origin. However, several reports exist of adulteration of AHPs with synthetic drugs. In this study, a generalized strategy was developed using LC-MS/TOF for the detection and verification of steroidal and anti-inflammatory drugs in 58 AHPs collected from various parts of India. The strategy involved recording of mass spectral information for standard drugs-including ionization mode (ESI/APCI - ve or + ve), mass spectrum, accurate mass, identification of qualifier fragments (two), extracted ion chromatograms (EICs), isotopic pattern and determination of UV max (nm)-through UV-PDA studies. Adulteration was then detected in AHPs primarily through comparison of EICs at accurate m/z for molecular ion peaks and R(T) matching with the standard. It was confirmed by spiking with the standards, and matching mass spectrum, accurate mass, R(T) of qualifier fragments, isotopic pattern and UV spectrum of the standards with the adulterant peaks in AHPs. Dexamethasone and diclofenac were detected as adulterants in ten AHPs whereas one AHP tested positive for piroxicam and another for dexamethasone. All the adulterated products were sold by the healthcare practitioners, while no product marketed by manufacturers or chemist shops had this problem. The study showed that LC-MS/TOF-based screening could be used as a rapid approach to monitor adulteration of steroids and anti-inflammatory drugs in AHPs.

Preparation and chromatographic performance of calix[4]crown-5 macrocycle-bonded silica stationary phase

A new calix[4]crown-5 macrocycle-bonded silica stationary phase (CL-CIMS) was prepared and applied at the same time to develop a chromatographic procedure to separate aromatic amines, phenols and drugs in this study. The chromatographic behaviors of the prepared stationary phase for these analytes were studied and compared with those of ODS (octadecylsilane). The effect of organic modifier content and pH of the mobile phase on retention and selectivity of these compounds were investigated. Some aromatic amines, phenols or drugs on CL-CIMS were successfully separated. The results show that CL-CIMS exhibits high selectivities for the above analytes in high aqueous mobile phases and a bright prospect in routine, fast separation of aromatic amines, phenols and drug compounds. From chromatographic data, it can be concluded that hydrophobic interaction is mainly responsible for the retention behavior as well as hydrogen-bonding interaction, π-π and dipole-dipole interaction.