Non-steroidal Anti-inflammatory Drugs Residues Research Articles

Development of a detection method for 10 non-steroidal anti-inflammatory drugs residues in four swine tissues by ultra-performance liquid chromatography with tandem mass spectrometry

The ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) detection method was developed for the residues of 10 NSAIDs (salicylic acid, acetylsalicylic acid, acetaminophen, diclofenac, tolfenamic acid, antipyrine, flunixin meglumine, aminophenazone, meloxicam, metamizole sodium) in swine muscle, liver, kidney, and fat. Swine tissue samples were extracted by phosphorylated acetonitrile with the addition of an appropriate amount of internal standard working solution, defatted with acetonitrile-saturated n-hexane, and purified by Hydrophile-Lipophile Balance (HLB) solid-phase extraction column, then separated by UPLC BEH shield RP18 column with 0.1% formic acid in water/0.1% formic acid in acetonitrile with gradient elution, which was detected in the multiple reaction monitoring (MRM) modes. The correlation coefficient of the standard curve equation is greater than 0.99, and the coefficient of variation within and between batches is less than 14.4%. We evaluated the analytical method using two green assessment tools. The method established in this study met the requirements of NSAID residue analysis and provides analytical tools for determining and confirming NSAIDs in swine tissue samples. This is the first report on the simultaneous determination of 10 NSAIDs in four swine tissues by the UPLC-MS/MS method and accurate quantification using deuterated internal standards.

Solid Phase Extraction and Simultaneous Chromatographic Quantification of some Non-steroidal Anti-inflammatory Drug Residues; an Application in Pharmaceutical Industrial Wastewater Effluent

Two sensitive and selective methods were developed for the simultaneous determination of four commonly used non-steroidal anti-inflammatory drugs (NSAIDs), namely; paracetamol (PCM), diclofenac sodium (DCF), ibuprofen (IBP), and indomethacin (IND) in wastewater effluents. The first method used HPLC for the determination of the studied drugs using a mobile phase consisting of phosphate buffer (pH 3.0) and acetonitrile at a flow rate of 1 mL/min. in gradient elution mode and detection at 220 nm. The separation process was performed on BDS Hypersil Cyano column (250 x 4.6 mm, 5 μm). The second method was a TLC-densitometric one which was performed using n-Hexane: ethyl acetate: acetic acid in the ratio (6:3.5:0.5) as a developing system. The proposed chromatographic methods were successfully applied for the selective determination of the four studied drugs in simulated and real pharmaceutical wastewater samples after their solid-phase extraction.

The analysis of acidic and basic non-steroidal anti-inflammatory drugs in milk and muscle samples: a comprehensive analytical approach using UHPLC-MS/MS

ABSTRACT In animal husbandry for food production, the administration of non-steroidal anti-inflammatory drugs (NSAIDs) as anti-inflammatory, analgesic, and antipyretic agents, has seen an increase due to raised awareness of animal welfare issues. Residues of NSAIDs may be present in animal products that are intended for human consumption, and since some may pose a certain risk to human health, there is a need to monitor NSAID residues at low levels via routine and targeted surveillance. In analytical chemistry, NSAIDs are usually differentiated using their acid-base properties. Within this study, a method for simultaneous analysis of 27 NSAIDs, including both groups, in milk and muscle samples in 12.5 min is described. Sample processing consisted of enzymatic hydrolysis and acetonitrile extraction, followed by a clean-up of the extract by SPE, and measurement by UHPLC-MS/MS. The in-house validation study (alternative approach), covering trueness, precision, sensitivity, decision limit (CCα), detection capability (CCβ) and matrix effect, was designed and evaluated with the help of validation software to meet the demands of regulatory compliance. The method recovery for milk and muscle matrix was in the range of 98.1% to 106.5% and 98.8% to 102.7%, whereas the CCβ as the parameter for screening analysis, ranged from 0.07 to 46.7 µg/kg and 1.19 to 69.7 µg/kg, and the CCα, as the parameter for confirmatory analysis, from 0.11 to 56.7 µg/kg and 1.12 to 518.6 µg/kg, respectively. The occurrence of NSAID residues in milk and muscle samples was assessed using the developed method within the Croatian National Residue Control Plan, revealing quantifiable residues for diclofenac, ketoprofen, and salicylic acid mostly in milk samples. The most abundant NSAID in analysed samples was salicylic acid, which may be introduced into the food chain and be present in various types of matrices due to its natural occurrence in plants as a phytohormone.

LC-MS/MS Determination of 21 Non-Steroidal Anti-Inflammatory Drugs Residues in Animal Milk and Muscles.

The presented procedure combines experience from two LC-MS/MS methods previously developed by our team for NSAIDs determination in meat and milk. The novelty was a modification of sample preparation and combining LC-MS/MS method for milk and muscle. The clean-up procedure was investigated, leading to a change from SPE to dSPE with C18 bulk sorbent. Unlike most of the existing methods, chromatographic separation was achieved on a C8 chromatographic column. This method was developed and validated under European Commission Decision 2002/657/EC. Recovery for milk samples values between 86.3% to 108%, with the coefficient of variation, varied from 5.51% to 16.2%. The recovery for muscle was calculated to be between 85.0% and 109%, and the coefficient of variation was—4.73% to 16.6%. The validation results prove that the method is suitable for confirmatory purposes in milk and muscle. Of 452 samples tested in 2019 and 2020, two have been identified as non-compliant.

Novel solid-phase extraction filter based on a zirconium meta-organic framework for determination of non-steroidal anti-inflammatory drugs residues

In this study, a zirconium-based metal-organic framework UiO-66-NH2 modified cotton fiber (CF@UiO-66-NH2) was fabricated for the extraction of five common NSAIDs, namely ketoprofen, naproxen, flurbiprofen, diclofenac sodium, and ibuprofen. UiO-66-NH2 was synthesized and immobilized on the surface of cotton fiber using an environmentally friendly aqueous synthesis method. The prepared CF@UiO-66-NH2 composite of 50 mg was loaded into a 13 mm recessed filter for use as a solid-phase extraction (SPE) adsorbent material. The filter was then used to enrich NSAIDs in fish and shrimp muscle tissues followed by ultra-high performance liquid chromatography (UPLC) detection. Several key parameters were evaluated and optimized, including adsorption flow rate, pH value of sample, desorption flow rate, and the formic acid content of the eluent. Under optimized conditions, linear ranges of ketoprofen, naproxen, flurbiprofen, diclofenac sodium, and ibuprofen were 2.0–300.0 ng/mL, 1.4–280.0 ng/mL, 3.0–400.0 ng/mL, 1.0–500.0 ng/mL, and 14.0–560.0 ng/mL, respectively. The detection limits ranged from 0.12 ng/mL to 3.50 ng/mL with recoveries in the range of 72.95–116.99%, RSDs < 9.90%. The results demonstrated that the homemade filters based on CF@UiO-66-NH2 exhibited good reproducibility, stability and adsorption property for the determination of trace-level NSAIDs in complex matrix.

Green method development approach of superheated water liquid chromatography for separation and trace determination of non-steroidal anti-inflammatory compounds in pharmaceutical and water samples and their extraction

Non-steroidal anti-inflammatory drugs (NSAIDs) are pharmaceutical compounds with anti-inflammatory, analgesic, and antipyretic effects. Herein, a simple and rapid high-temperature liquid chromatography and superheated water chromatography method was developed and validated for the trace determination of NSAID residues of ketoprofen, naproxen, sodium diclofenac, and ibuprofen in water samples. The NSAIDs were separated in less than five minutes using buffered distilled water as the mobile phase and ODS Zirconia RP-C18 column as the stationary phase. Linearity was observed in the van’t Hoff plots of the tested drugs by employing a low acetonitrile percentage (20% ACN) in the mobile phase, without any significant changes in their retention mechanisms. However, nonlinear van’t Hoff plots were obtained for the superheated water chromatography data of the tested drugs because of significant changes in their retention factors, transition stage of the stationary phase, or the mobile phase properties. The limits of detection for ketoprofen, naproxen, sodium diclofenac, and ibuprofen were 14, 2, 4.2, and 32 µg L −1 , respectively, and their limits of quantification were 44, 8, 12, and 98 µg L −1 , respectively. The accuracy and precision parameters were determined for selected drugs, where the relative standard deviations were in the range of ± 0.2179–2.6741%. In addition, these conditions were employed for the removal of NSAIDs from the water samples using carbon nanotubes. The proposed system was applied for the separation and analyses of drugs in water and pharmaceutical samples, and acceptable recoveries of 90.48–98.15% for the water samples and 99.9–100.08% for the pharmaceutical samples were obtained.

NSAIDs detected in Iberian avian scavengers and carrion after diclofenac registration for veterinary use in Spain

Despite the now well recognised impact of diclofenac on vultures across the Indian subcontinent, this non-steroidal anti-inflammatory drug (NSAID) was registered in 2013 for livestock treatment in Spain, Europe’s main vulture stronghold. We assessed the risk of exposure to diclofenac and nine other NSAIDs in avian scavengers in the Iberian Peninsula (Spain and Portugal) after the onset of diclofenac commercialization. We sampled 228 livestock carcasses from vulture feeding sites, primarily pig (n = 156) and sheep (n = 45). We also sampled tissues of 389 avian scavenger carcasses (306 Eurasian griffon vultures, 15 cinereous vultures, 11 Egyptian vultures, 12 bearded vultures and 45 other facultative scavengers). Samples were analysed by liquid chromatography with mass spectrometry (LCMS). Seven livestock carcasses (3.07%) contained NSAID residues: flunixin (1.75%), ketoprofen, diclofenac and meloxicam (0.44% each). NSAID residues were only detected in sheep (4.44%) and pig (3.21%) carcasses. Fourteen dead avian scavengers (3.60%) had NSAID residues in kidney and liver, specifically flunixin (1.03%) and meloxicam (2.57%). Flunixin was associated with visceral gout and/or kidney damage in three (0.98%) dead Eurasian griffons. To date, diclofenac poisoning has not been observed in Spain and Portugal, however, flunixin would appear to pose an immediate and clear risk. This work supports the need for well managed carrion disposal, alongside appropriate risk labelling on veterinary NSAIDs and other pharmaceuticals potentially toxic to avian scavengers.

Rapid, simple and green solid phase extraction based on polyaniline nanofibers-mat for detecting non-steroidal anti-inflammatory drug residues in animal-origin food

In this study, polyaniline modified polyacrylonitrile nanofibers mat (PANI NFsM) was prepared as a novel adsorbent for the solid-phase extraction (SPE) of non-steroidal anti-inflammatory drug residues in meat or egg samples. The solvent extracts of samples were simply diluted with water to perform the SPE, and then the eluent was directly analyzed. Significant reduction of the matrix effect was obtained after SPE using only 5 mg of PANI NFsM. The entire sample preparation time is 5–10 times lower than the existing methods. The limits of detection of the target analytes ranging from 0.6 to 12.2 µg kg−1 had already met the demand of food safety monitoring by only 1 g sample. The recoveries ranged from 85.18% to 107.31%, with the intra-day and inter-day relative standard deviations of 2.74% to 16.01%, revealing satisfactory accuracy and precision. Finally, real samples analyses were applied to verify the practicability of the method.

Magnetic Graphene Solid-Phase Extraction for the Determination of 47 Kinds of Non-steroidal Anti-inflammatory Drug Residues in Animal Food with Liquid Chromatography Tandem Mass Spectrometry

Based on magnetic graphene (Fe3O4-G), a liquid chromatography with tandem mass spectrometric detection (LC-MS/MS) method coupled with magnetic solid-phase extraction was developed for the simultaneous detection of 47 kinds of nonsteroidal anti-inflammatory drug (NSAID) residues in meat of swine, chicken, and bovine. The samples were extracted with acetonitrile-phosphate, then the extracts were purified by dispersed solid-phase extraction based on magnetic graphene (Fe3O4-G). The linearity range is 0.1–50 μg L−1. Limits of detection were between 0.1 μg kg−1 and 0.5 μg kg−1, and limits of quantification were between 0.5 μg kg−1 and 1.0 μg kg−1. The average recoveries were 72.4–97.1% at spiking levels. The inter-day RSDs varied from 5.3 to 12.6%. Due to the advantages of easy collection of magnetic solid-phase extraction materials, the method was more rapid and efficient for the enrichment and separation without filling columns. The sensitivity, precision, and accuracy method was suitable for simultaneous detection of multi-component residues of nonsteroidal anti-inflammatory drugs.

Box–Behnken Experimental Design for the Synthesis of Magnetite–Polypyrrole Composite for the Magnetic Solid Phase Extraction of Non-steroidal Anti-inflammatory Drug Residues

ABSTRACTA magnetite–polypyrrole composite adsorbent was synthesized and applied for the magnetic solid phase extraction of three non-steroidal anti-inflammatory drugs in aqueous solution and systematically investigated using Box–Behnken design. The synthesized composite adsorbent was characterized using Fourier-transform infrared spectroscopy, transmission electron microscopy, the Brunauer–Emmett–Teller method, vibrating sample magnetometry, and X-ray diffraction. The material was successfully modeled by Box–Behnken design (R2 = 0.94–0.98, p value: <0.001%) by monitoring the extraction efficiencies of naproxen, diclofenac sodium, and mefenamic acid. The analytes were determined using high-performance liquid chromatography with ultraviolet detection. The polymerization time was found to be the most significant factor, followed by amount of oxidant and monomer in the synthesis of the composite with a fixed Fe3O4 mass. Box–Behnken design was employed for the optimization of four parameters affecting the magnetic solid phase extraction: sample pH, salt addition, adsorption, and desorption time (R2 = 0.88–0.94). The optimized conditions for the procedure were validated, providing low detection limits (0.9–3.5 µg L−1) with good reproducibility (<7.16% relative standard deviation) and excellent recoveries (97.87–100.49%) for tap, river, and wastewater samples. The synthesized adsorbent demonstrated good adsorption efficiency for the simultaneous determination of the non-steroidal anti-inflammatory drug residues.

Magnetic solid phase extraction of non-steroidal anti-inflammatory drugs from water samples using a metal organic framework of type Fe3O4/MIL-101(Cr), and their quantitation by UPLC-MS/MS

The authors describe a method for magnetic solid phase extraction (MSPE) combined with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for the quantitation of eight non-steroidal anti-inflammatory drugs (NSAIDs) in wastewater and environmental water samples. Specifically, the NSAIDs were directly extracted by using a magnetic nanocomposite of type Fe3O4/MIL-101(Cr) (Material Institute Lavoisier, MIL) from 50 mL water samples without any further cleanup. The effects of the amount of adsorbent, pH value, salt concentration, ultrasonic extraction time, desorption solvent nature and volume and desorption time were investigated. Under the optimal conditions, UPLC-MS/MS based detection resulted in the following figures of merit: (a) Linear calibration plots that typically extend from 0.1 (0.2, 0.05, 0.02) to 50 μg·L−1, depending on the compound; (b) detection limits between 3 to 60 ng·L−1; and (c), recoveries varying from 81.2% to 116.8% with relative standard deviations between 0.4% and 10.8%. The adsorption of NSAIDs on Fe3O4/MIL-101(Cr) was characterized by adsorption isotherms, kinetics and thermodynamics studies and provides a deeper insight into the adsorption mechanism. Compared to other method for pretreatment and preconcentration of NSAIDs, the new method is more rapid, sensitive, accurate and eco-friendly. The method was successfully applied to the determination of the NSAID residues in a variety of real environmental and wastewater samples.

Determination of non-steroidal anti-inflammatory drugs in water and urine using selective molecular imprinted polymer extraction and liquid chromatography

A selective solid-phase extraction was employed for the improvement of the determination of non-steroidal anti-inflammatory drugs (NSAIDs) in continental water and urine samples. Ketoprofen, naproxen, diclofenac, and ibuprofen were selected as target analytes due to they are the most frequently administered and consumed NSAIDs. These compounds were extracted using molecular imprinted polymers and determined by liquid chromatography with diode array (DAD), and tandem-mass spectrometry (MS–MS) detectors. Performance of DAD and MS–MS detectors was evaluated throughout this study. The obtained limits of quantification, after a 50-fold preconcentration solid-phase extraction, varied from 20 to 30μgL−1 for DAD, and from 0.007 to 0.017μgL−1 for MS–MS for both types of sample matrixes. Quantitative recoveries were found for blank-samples spiked at different NSAIDs concentration levels, ranging from 0.05 to 10mgL−1 for urine and from 0.5 to 500μgL−1 for water. The proposed methodology was applied for the determination of NSAID residues in urine of prescribed individuals, and continental waters.

Selective adsorption mechanisms of antilipidemic and non-steroidal anti-inflammatory drug residues on functionalized silica-based porous materials in a mixed solute

The selective adsorption mechanisms of naproxen (NAP), acetaminophen (ACT), and clofibric acid (CFA) on silica-based porous materials were examined by single and mixed-batch adsorption. Effects of the types and densities of surface functional groups on adsorption capacities were determined, including the role of hydrophobic and hydrophilic dissolved organic matters (DOMs). Hexagonal mesoporous silica (HMS), superparamagnetic HMS (HMS-SP) and SBA-15 were functionalized and applied as adsorbents. Compared with powdered activated carbon (PAC), amine-functionalized HMS had a better adsorption capacity for CFA, but PAC possessed a higher adsorption capacity for the other pharmaceuticals than HMS and its two derivatives. In contrast to PAC, the adsorption capacity of the mesoporous silicas varied with the solution pH, being highest at pH 5. Electrostatic interactions and hydrogen bonding were found to be the main mechanisms. Increase in grafted amine group density on silica surfaces can enhance the CFA adsorption capacity. Further, hydrophilic DOM can decrease CFA adsorption capacities on amino-grafted adsorbents by adsorption site competition, while hydrophobic DOM can interfere with CFA adsorption by the interaction between hydrophobic DOM and CFA. Finally, in a competitive adsorption study, the adsorption capacity of hydrophilic adsorbents for acidic pharmaceuticals varied with their pKa values.

Non-Steroidal Anti-Inflammatory Drugs in Food Producing Animals

Providing adequate food supply to meet the demands of a growing population is a challenge for this century. The food producing animals bred in optimized conditions supply a large amount of food derivatives. At the same time, society has become progressively more concerned about animal suffering and aware of the need of pain prevention and treatments. One of the measures aimed at improving animals welfare is pain management a rational and controlled use of the anti-inflammatory drugs such as Non-Steroidal Anti-Inflammatory Drugs (NSAIDs). However, NSAIDs residues in biological matrices are still an issue. In addition veterinary pharmacology still has a reduced drug armamentarium if compared with human medicine. In order to address these shortfalls investigations on new NSAIDs (off label drug) in food producing animals are needed.

Development of a simple method for simultaneous determination of nine subclasses of non-steroidal anti-inflammatory drugs in milk and dairy products by ultra-performance liquid chromatography with tandem mass spectrometry

A multi-residue analysis method for simultaneous determination of nine subclasses of non-steroidal anti-inflammatory drugs (NSAIDs) in milk and dairy products by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been established. The sample was initially extracted and deproteinized with ascorbic acid buffer (0.01M, pH 3) and acetonitrile-ethyl acetate mixture, followed by centrifugation and evaporation, then reconstituted with acetonitrile-0.1% formic acid (1+1, v/v). After removal of lipid material by n-hexane, the sample was analyzed by UPLC-MS/MS with electro-spray ionization (ESI) interface in Multiple Reaction Monitoring (MRM) mode. The range of limits of detection (LODs) and limits of quantification (LOQs) were 0.03-0.30μg/kg and 0.10-1.00μg/kg, respectively. The recoveries in milk, milk powder, yogurt, processed cheese and milk beverage ranged from 61.7% to 117%, and the relative standard deviations (RSDs) were less than 17.9% at three spiked levels (1, 10 and 100 times of the LOQ). Matrix effects were also investigated and it was determined the signals of the analytes were suppressed from 9.4% to 76.6% in processed cheese. The proposed method was also applied to incurred sample analysis. The results proved that this method was suitable for the simultaneous determination of nine subclasses of NSAIDs residues in milk and dairy products.

Ion Exchange Solid Phase Extraction Coupled with Liquid Chromatography Tandem Mass Spectrometry for Determination of 8 Classes of Non-steroidal Anti-inflammatory Drugs Residues in Animal Tissues

An ultraperformance liquid chromatography tandem mass spectrometric(UPLC-MS/MS) method was established for the simultaneous determination of residues of 8 classes of 14 non-steroidal anti-inflammatory drugs(NSAIDs) in animal tissues.The samples were extracted with acetonitrile-ethyl acetate(1 ∶ 1,V/V),defatted with n-hexane,and then purified by MCX solid phase extraction(SPE) cartridge.Analysis was carried out on UPLC-ESI-MS/MS working with multiple reaction monitoring mode with polarity switching.Limits of detection were between 3.0 μg/kg and 10.0 μg/kg,and limits of quantification were between 10.0 μg/kg and 25.0 μg/kg.At spiked levels of 10.0-1000.0 μg/kg,in bovine and swine muscle the recoveries were 62.9%-108.4% and 63.4%-117.0%,respectively,and relative standard deviations(RSD) of the method were less than 10% and 9%,respectively.

Simultaneous determination of thirty non-steroidal anti-inflammatory drug residues in swine muscle by ultra-high-performance liquid chromatography with tandem mass spectrometry

An ultra-high-performance liquid chromatography with tandem mass spectrometric detection (UHPLC-MS/MS) method was established for the simultaneous determination of residues of thirty non-steroidal anti-inflammatory drugs (NSAIDs) in swine muscle. The samples were extracted with acetonitrile and phosphoric acid. The extracts were defatted with n-hexane, and then purified by HLB solid-phase extraction cartridge. Analysis was carried out on UHPLC-ESI-MS/MS working with multiple reaction monitoring mode with polarity switching. Limits of detection were between 0.4 μg/kg and 2.0 μg/kg, and limits of quantification were between 1.0 μg/kg and 5.0 μg/kg. The recoveries of NSAIDs were between 61.7% and 125.7% at spiked levels of 1.0-500 μg/kg. The repeatability was less than 8% and the within-laboratory reproducibility was not more than 12.3%. The method was reliable, convenient and sensitive.

Analyses of Non-steroidal Anti-inflammatory Drugs in Environmental Water Samples with Microemulsion Electrokinetic Chromatography

In this study, a microemulsion electrokinetic chromatography (MEEKC) was used to analyze ten non-steroidal anti-inflammatory drugs (NSAIDs) in water samples. The type and ratio of organic modifiers were found to be the predominant influences on the NSAIDs separation. Subsequently, field-amplified sample injection was coupled with this MEEKC method in order to enhance the detection sensitivity. When both the acid plug (3 s) and water plug (5 s) were placed at the front of the capillary, and the acetonitrile (ACN) solvent was added to the water plug (10% ACN) and the sample matrix (15% ACN), the separation time was shortened to 15 min, as well as the limit of detection (LOD) of these NSAIDs was reduced to the range of 0.03 to 0.3 microg/L, which provided about a 1400-fold to 6100-fold enhancement in LOD. Finally, the proposed on-line concentration MEEKC method also successfully determined the NSAIDs residues in water samples after solid-phase extraction.

Determination of non-steroidal anti-inflammatory drugs residues in animal muscles by liquid chromatography–tandem mass spectrometry

A confirmatory method for the determination of residues of nine non-steroidal anti-inflammatory drugs and one metabolite in animal muscles has been developed. After enzymatic hydrolysis samples were extracted with acetonitrile and cleaned up using alumina and C 18 SPE cartridges. Liquid chromatography–tandem mass spectrometry was used for the separation and determination of analytes. The method was validated in bovine muscles, according to the Commission Decision 2002/657/EC criteria. Applicability of the method in the analysis of swine, horse and chicken muscles was checked by precision and recovery experiment. The influence of matrix effect on the quantification of non-steroidal anti-inflammatory drugs residues was investigated. The method was used for the confirmation of phenylbutazone and oxyphenbutazone in horse muscle sample.

Multi-Residue Determination of Non-Steroidal Anti-Inflammatory Drug Residues in Animal Serum and Plasma by HPLC and Photo-Diode Array Detection

The European Union regulated the use of non-steroidal anti-inflammatory drugs (NSAIDs) in animal production and set the official analytical controls to detect their residues in plasma, serum, and milk within the frame of national monitoring programs in each member state. In this work, a multi-residue reversed-phase high-performance liquid chromatography with diode array detector (DAD) method is described for the simultaneous determination of 13 NSAIDs in serum and plasma of farm animals. Chromatographic separation by a C12 stationary phase column with a linear gradient is able to resolve all the compounds considered: salicylic acid, ketoprofen, flurbiprofen, phenylbutazone and its metabolite (oxyphenbutazone), carprofen, ibuprofen, naproxen, niflumic acid, suxibutazone, diclofenac, mefenamic acid, and tolfenamic acid. These compounds are chosen as the most representative of the different NSAID chemical sub-classes. The DAD analysis allows the confirmation of all drugs on the basis of their own UV-vis spectrum, according to the requirements of the European Council Decision 2002/657/EC. Moreover, the method is in-house validated, evaluating mean recoveries, specificity, repeatability, and within-laboratory reproducibility as the performance parameters required by the Decision. The results of this study indicate the method is specific and repeatable, with the mean percentage recoveries of the drugs ranging between 72.5% and 104.5%. Only salicylic acid has poor recovery, with results ranging between 36.3% and 54.9%.