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Abstract This study aims to use a static-based solubility method for measuring the solubility of lumiracoxib at a temperature of 308–338 K and pressure of 120–400 bar for the first time. The obtained solubility data for lumiracoxib is between 4.74 × 10−5 and 3.46 × 10−4 (mole fraction) for the studied ranges of pressure and temperature. The solubility values reveal that the lumiracoxib experiences a crossover pressure of about 160 bar. Moreover, the measured solubility data of these two drugs are correlated with density-based semi-empirical correlations namely Bartle et al., Mendez-Santiago-Teja, Kumar and Johnstone, Chrastil and modified Chrastil models with an average absolute relative deviation of 10.7%, 9.5%, 9.8%, 7.8%, and 8.7% respectively for lumiracoxib. According to these findings, it is obvious that all of the examined models are rather accurate and there is no superiority between these models for both examined drugs although the Chrastil model is slightly better in the overall view.

Lumiracoxib is a selective cyclooxygenase‐2 inhibitor, which has been reported to cause rare but severe liver injury. Considering that lumiracoxib has a carboxylic group in the molecule, glucuronidation to form acylglucuronide would be one of the possible mechanisms of lumiracoxib‐induced liver injury. The aim of this study was to identify the metabolites of lumiracoxib that were formed via acyl‐glucuronidation in human liver microsomes using glutathione (GSH) and N‐acetyl‐lysine (NAL) as trapping agents by liquid chromatography combined with high resolution mass spectrometry. The structures of the detected metabolites were identified by their accurate masses, fragment ions, and retention times. Under the current conditions, eight lumiracoxib associated metabolites were identified. With the presence of UDPGA, lumiracoxib was biotransformed into lumiracoxib‐1‐O‐acylglucuronide (M1) and 4′‐hydroxyl‐lumiracoxib‐1‐O‐acylglucuronide (M2), both of which were reactive and prone to react with GSH to form drug‐S‐acyl‐GSH adducts (M3 and M4) through transacylation. In addition to reaction with GSH, the formed 1‐O‐acylglucuronides were chemically unstable (T1/2 = 1.5 h in phosphate buffer) and rearranged to 2‐, 3‐, and/or 4‐isomers, which further underwent ring‐opening to form aldehyde derivatives and then reacted with NAL to yield Schiff base derivatives (M5–M8). The present study provides a clear bioactivation profile of lumiracoxib through acyl glucuronidation, which would be one of the mechanisms attributed to liver injury caused by lumiracoxib. [ABSTRACT FROM AUTHOR]

The new compound 1-(2-chloro-6-fluorophenyl)-5-methylindolin-2-one (1), designed using the prodrug approach, was easily obtained in 85% yield and characterized by nuclear magnetic resonance, elemental analysis, mass spectrometry and infrared spectroscopy. The lactam 1 showed anti-inflammatory and analgesic activity comparable to that of the COX-2 inhibitor lumiracoxib, without gastro-ulceration effects. Stability studies demonstrated that the lactam function was stable and did not hydrolyze in pH 1.2 or 7.4. Furthermore, using a thioglycollate-induced peritonitis model, compound 1 was shown to inhibit cell migration by 50.4%, while lumiracoxib inhibited it by 18%. This compound represents a new non-ulcerogenic prototype for the treatment of chronic inflammatory diseases.

In this study, two methods, based on highperformance liquid chromatography (HPLC) and UV spectrophotometry, were developed and validated for the quantitative determination of lumiracoxib in tablets. The HPLC was carried out on a column of propylsulfonic acid bonded to silica gel (250 x 4.6 mm; 5 μm), with a mobile phase of phosphate buffer (pH 7.4; 10 mM)-water-acetonitrile (10:40:50, v/v/v) fl owing at 1.0 mL/min and detection of the drug at 278 nm. The UV method was based on absorbance at 275 nm, with ethanol as solvent. Both assays were linear over the concentration range of 2–30 μg/mL (R≈0.999), as well as accurate and precise, with recoveries between 98 and 100% and relative standard deviation (%RSD) < 2.0%. The proposed methods are highly sensitive, precise and accurate and were successfully applied to the quantitation of lumiracoxib in the commercial formulation. The spectrophotometric method is a simple, cheap and less time-consuming method. However, the chromatographic method is selective for the determination of the degradation products of lumiracoxib. Keywords: lumiracoxib; tablets; HPLC; UV spectrophotometry; pharmaceutical analyses.

Celecoxib (CB) and lumiracoxib (LM) are potent COX-2 inhibitors widely marketed for the treatment of rheumatoid arthritis and osteoarthritis. Nevertheless, it is difficult to obtain because it are protected under patents. The aim of this work was to develop an extraction method of drugs, CB and LM, in order to obtain the drug with a purity degree appropriated for use in research projects. The developed method showed to be effective of both drugs, becoming interesting due to its low cost, easy and speed of execution, application to different dosage forms (capsules and tablets) and drugs with different physicochemical properties.

2-Phenylaminophenylacetic acid is a widely-exploited chemical scaffold whereby notable NSAIDs such as diclofenac and lumiracoxib were derived. Yet, their clinical usage has been associated with toxicities in the liver. While some studies have attributed toxicities to the bioactivation of both drugs to reactive intermediates, the structural predisposition for toxicity, as well as relationship between this toxicity and COX inhibitory activity has not been elucidated. In this study, we aimed to address their intricate link by synthesizing compounds that possess the 2-phenylaminophenylacetic acid backbone with varying alkyl and halogen substituents at three positions critical to the COX inhibitory pharmacophore. These compounds were subjected to cytotoxicity testing on two liver cell lines of contrasting metabolic competencies. We observed higher toxicity in the more metabolically competent cell line, supporting the role of bioactivation as a prerequisite for toxicity. We have also shown that structural changes on the chemical scaffold exerted pronounced effect on liver cytotoxicity. The most lipophilic and brominated compound ( 24 ) was identified as the most cytotoxic of all the compounds. A concurrent determination of their pharmacological activity using COX inhibition assays allowed us to derive a safety profile, which showed that selectivity towards COX-2 negatively affected activity and toxicity. [ABSTRACT FROM AUTHOR]

In this study, two methods, based on highperformance liquid chromatography (HPLC) and UV spectrophotometry, were developed and validated for the quantitative determination of lumiracoxib in tablets. The HPLC was carried out on a column of propylsulfonic acid bonded to silica gel (250 x 4.6 mm; 5 μm), with a mobile phase of phosphate buffer (pH 7.4; 10 mM)-water-acetonitrile (10:40:50, v/v/v) flowing at 1.0 mL/min and detection of the drug at 278 nm. The UV method was based on absorbance at 275 nm, with ethanol as solvent. Both assays were linear over the concentration range of 2–30 μg/mL (R≈0.999), as well as accurate and precise, with recoveries between 98 and 100% and relative standard deviation (%RSD) < 2.0%. The proposed methods are highly sensitive, precise and accurate and were successfully applied to the quantitation of lumiracoxib in the commercial formulation. The spectrophotometric method is a simple, cheap and less time-consuming method. However, the chromatographic method is selective for the determination of the degradation products of lumiracoxib.

Abstract: Lumiracoxib is a substrate-selective inhibitor of endocannabinoid oxygenation by cyclooxygenase-2 (COX-2). We assayed a series of lumiracoxib derivatives to identify the structural determinants of substrate-selective inhibition. The hydrogen-bonding potential of the substituents at the ortho positions of the aniline ring dictated the potency and substrate selectivity of the inhibitors. The presence of a 5′-methyl group on the phenylacetic acid ring increased the potency of molecules with a single ortho substituent. Des-fluorolumiracoxib (2) was the most potent and selective inhibitor of endocannabinoid oxygenation. The positioning of critical substituents in the binding site was identified from a 2.35Å crystal structure of lumiracoxib bound to COX-2. [Copyright &y& Elsevier]

Purpose: To re-evaluate the cardiovascular risk of lumiracoxib compared with other non-steroidal anti-inflammatory drugs (NSAIDs) or placebo in patients with osteoarthritis. Methods: We conducted a meta-analysis of randomised controlled trials of lumiracoxib versus placebo or other NSAIDs in patients with osteoarthritis reported up to January 2010. Both published and unpublished trials were included. PubMed searches using predefined search criteria (lumiracoxib AND osteoarthritis, limits: none; COX-189 AND osteoarthritis, limits: none) were used to obtain the relevant published trials. Novartis granted explicit access to their company studies and the right to use these study reports for the purposes of publication in peer reviewed journals. Endpoints were the Antiplatelet Trialists' Collaboration (APTC) endpoint and individual cardiovascular endpoints. Results: Meta-analysis of 6 trials of lumiracoxib versus placebo revealed no difference in cardiovascular outcomes. Meta-analysis of 12 trials of lumiracoxib versus other NSAIDs also revealed no difference. The pooled odds ratios were: 1.16 (95% CI 0.82, 1.63); 1.66 (95% CI 0.84, 3.29); 0.95 (95% CI 0.52, 1.76) and 1.04 (95% CI 0.60, 1.80) for the APTC endpoint, myocardial infarction, stroke and cardiovascular death respectively. Conclusions: The results suggest that there were no significant differences in cardiovascular outcomes between lumiracoxib and placebo or between lumiracoxib and other NSAIDs in patients with osteoarthritis. Wide confidence intervals mean that further research is needed in this area to confirm these findings. [ABSTRACT FROM AUTHOR]

The model-based approach was undertaken to characterize the interaction between the peripheral and central antinociceptive effects exerted by lumiracoxib. The effects of intraplantar and intrathecal administrations and of fixed ratio combinations of lumiracoxib simultaneously administered by these two routes were evaluated using the formalin test in rats. Pain-related behavior data, quantified as the number of flinches of the injected paw, were analyzed using a population approach with NONMEM 7. The pain response during the first phase of the formalin test, which was insensitive to lumiracoxib, was modeled using a monoexponential decay. The second phase, which was sensitive to lumiracoxib, was described incorporating synthesis and degradation processes of pain mediators that were recruited locally after tissue injury. Upregulation at the local level and in the central nervous system (CNS) was set to be proportional to the predicted levels of pain mediators in the local (injured) compartment. Results suggest a greater role of upregulated COX-2Local in generating the pain response compared to COX-2CNS. Drug effects were described as inhibition of upregulated COX-2. The model adequately described the time course of nociception after formalin injection in the absence or presence of lumiracoxib administered locally and/or spinally. Data suggest that the overall response is the additive outcome of drug effects at the peripheral and central compartments, with predominance of peripheral mechanisms. Application of modeling opens new perspectives for understanding the overall mechanism of action of analgesic drugs. [ABSTRACT FROM AUTHOR]

Abstract: There is evidence that systemic sulfonylureas block diclofenac-induced antinociception in normal rat, suggesting that diclofenac activates ATP-sensitive K+ channels. However, there is no evidence for the systemic interaction between different non-steroidal anti-inflammatory drugs (NSAIDs) and sulfonylureas in streptozotocin (STZ)-diabetic rats. Therefore, this work was undertaken to determine whether two sulfonylureas, glibenclamide and glipizide, have any effect on the systemic antinociception that is induced by diclofenac (30mg/kg), lumiracoxib (56mg/kg), meloxicam (30mg/kg), metamizol (56mg/kg) and indomethacin (30mg/kg) using the non-diabetic and STZ-diabetic rat formalin test. Systemic injections of NSAIDs produced dose-dependent antinociception during the second phase of the test in both non-diabetic and STZ-diabetic rats. Systemic pretreatment with glibenclamide (10mg/kg) and glipizide (10mg/kg) blocked diclofenac-induced systemic antinociception in the second phase of the test (P <0.05) in both non-diabetic and STZ-diabetic rats. In contrast, pretreatment with glibenclamide or glipizide did not block lumiracoxib-, meloxicam-, metamizol-, and indomethacin-induced systemic antinociception (P>0.05) in both groups. Results showed that systemic NSAIDs are able to produce antinociception in STZ-diabetic rats. Likewise, data suggest that diclofenac, but not other NSAIDs, activated K+ channels to induce its systemic antinociceptive effect in the non-diabetic and STZ-diabetic rat formalin test. [Copyright &y& Elsevier]