Preparation and characterization of a sulindac sensor based on PVC/TOA-SUL membrane.

A potentiometric sulindac sensitive sensor based on tetraoctylammonium (Z)-5-fluoro-2-methyl-1-[[p-(methylsulfinyl)phenyl]methylene]-1H-indene-3-acetate (TOA-SUL) was described. The electrode responded with sensitivity of 57.5±1.6mV decade(-1) over the linear range 5×10(-5)-1×10(-2)mol L(-1) at pH6.0-9.0. It had the limit of detection 1.4×10(-5)mol L(-1), a fast response time of 13s and showed clear discrimination of sulindac ions from several inorganic and organic compounds and also amino acids. This electrode did not contain any inner solutions, so it was easy and comfortable to use. The proposed sensor was used to determine sulindac in clear solution and in urine sample solution.

Sulindac selectively inhibits colon tumor cell growth by activating the cGMP/PKG pathway to suppress Wnt/ß-catenin signaling.

Nonsteroidal anti-inflammatory drugs (NSAID) display promising antineoplastic activity for colorectal and other cancers, but toxicity from COX inhibition limits their long-term use for chemoprevention. Previous studies have concluded that the basis for their tumor cell growth inhibitory activity does not require COX inhibition, although the underlying mechanism is poorly understood. Here, we report that the NSAID sulindac sulfide inhibits cyclic guanosine 3',5'-monophosphate phosphodiesterase (cGMP PDE) activity to increase intracellular cGMP levels and activate cGMP-dependent protein kinase (PKG) at concentrations that inhibit proliferation and induce apoptosis of colon tumor cells. Sulindac sulfide did not activate the cGMP/PKG pathway, nor affect proliferation or apoptosis in normal colonocytes. Knockdown of the cGMP-specific PDE5 isozyme by siRNA and PDE5-specific inhibitors tadalafil and sildenafil also selectively inhibited the growth of colon tumor cells that expressed high levels of PDE5 compared with colonocytes. The mechanism by which sulindac sulfide and the cGMP/PKG pathway inhibits colon tumor cell growth involves the transcriptional suppression of ß-catenin to inhibit Wnt/ß-catenin T-cell factor transcriptional activity, leading to downregulation of cyclin D1 and survivin. These observations suggest that safer and more efficacious sulindac derivatives can be developed for colorectal cancer chemoprevention by targeting PDE5 and possibly other cGMP-degrading isozymes.

Optimisation and validation of a fast HPLC method for the quantification of sulindac and its related impurities.

The European Pharmacopoeia describes a liquid chromatography (LC) method for the quantification of sulindac, using a quaternary mobile phase including chloroform and with a rather long run time. In the present study, a new method using a short sub-2 µm column, which can be used on a classical HPLC system, was developed. The new LC conditions (without chloroform) were optimised by means of a new methodology based on design of experiments in order to obtain an optimal separation. Four factors were studied: the duration of the initial isocratic step, the percentage of organic modifier at the beginning of the gradient, the percentage of organic modifier at the end of the gradient and the gradient time. The optimal condition allows the separation of sulindac and of its 3 related impurities in 6 min instead of 18 min. Finally, the method was successfully validated using an accuracy profile approach in order to demonstrate its ability to accurately quantify these compounds.

Functionalized magnetic nanoparticles for small-molecule isolation, identification, and quantification.

Functionalized magnetic nanoparticles (MNPs) were synthesized to serve as laser desorption/ionization elements as well as solid-phase extraction probes for simultaneous enrichment and detection of small molecules in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis. Two laser-absorbing matrices were each conjugated onto MNP to give MNP@matrix which provided high ionization efficiency and background-free detection in MS leading to unambiguous identification of target small molecules in a complex mixture. MNP@matrix was demonstrated to serve as a general matrix-free additive in MALDI-TOF MS analysis of structurally distinct small molecules. Also, MNP@matrix provides a simple, rapid, and reliable quantitative assay for small molecules by mass without either the use of an internal standard or an isotopic labeling tag. Furthermore, the affinity extraction of small molecules from complex biofluid was achieved by probe protein-conjugated MNP@matrix without laborious purification. We demonstrated that a nanoprobe-based assay is a cost-effective, rapid, and accurate platform for robotic screening of small molecules.

Reduction of Sulindac to its active metabolite, sulindac sulfide: assay and role of the methionine sulfoxide reductase system.

Sulindac is a known anti-inflammatory drug that functions by inhibition of cyclooxygenases 1 and 2 (COX). There has been recent interest in Sulindac and other non-steroidal anti-inflammatory drugs (NSAID) because of their anti-tumor activity against colorectal cancer. Studies with sulindac have indicated that it may also function as an anti-tumor agent by stimulating apoptosis. Sulindac is a pro-drug, containing a methyl sulfoxide group, that must be reduced to sulindac sulfide to be active as a COX inhibitor. In the present studies we have developed a simple assay to measure sulindac reduction and tested sulindac as a substrate for 6 known members of the methionine sulfoxide reductase (Msr) family that have been identified in Escherichia coli. Only MsrA and a membrane associated Msr can reduce sulindac to the active sulfide. The reduction of sulindac also has been demonstrated in extracts of calf liver, kidney, and brain. Sulindac reductase activity is also present in mitochondria and microsomes.

Drug-associated cholelithiasis: a case of sulindac stone formation and the incorporation of sulindac metabolites into the gallstones.

A case of drug-associated cholelithiasis (sulindac chlecystohepatolithiasis) in a 63-yr-old woman is reported. The patient was admitted to our hospital to undergo treatment for rheumatoid arthritis of 20 yr duration. She was treated with nonsteroidal anti-inflammatory drugs (NSAID: sulindac). Two months later, she presented with right upper quadrant pain. Diagnostic studies including ultrasonography (US), computed tomography (CT) and endoscopic retrograde cholangiography (ERC), led to the diagnosis of cholecystohepatolithiasis. She underwent cholecystectomy and choledochotomy with an extraction of intrahepatic stones. The intrahepatic stones were light yellow in color with a claylike appearance. Unexpectedly, an infrared spectroscopic analysis of the stone showed it to consist of sulindac metabolites. In addition, the dilated segment of the intrahepatic bile duct naturally returned to its normal size after the discontinuation of the drug administration. This is the first reported case of sulindac stone formation in the bile duct. No similar problems with other NSAIDs have been reported previously.

Determination of sulindac and its metabolites in human serum by reversed-phase high-performance liquid chromatography using on-line post-column ultraviolet irradiation and fluorescence detection.

On irradiation with ultraviolet light, the antiinflammatory agent sulindac and its two metabolites sulindac sulfone and sulindac sulfide form highly fluorescent derivatives. This reaction was exploited for the sensitive and selective detection of these compounds in serum using reversed-phase high-performance liquid chromatography on a Ultrasphere octylsilane column (150 x 4.6 mm I.D.) at ambient temperature with a flow-rate of 0.5 ml/min. The analytes of interest were isolated from serum using a Bond-Elut C2 column with satisfactory recovery and selectivity. The detection limits were 10 ng/ml for each of the three analytes using 1 ml of serum and the limit of quantitation was 50 ng/ml. Linear calibration curves from 50 to 1000 ng/ml for all three analytes show coefficients of determination of 0.9999. The post-column ultraviolet irradiation was optimized and the effect of irradiation time on the fluorescence response was determined for all three analytes. Precision and accuracy of the method were 0.4-5.6 and 1.6-4.5% for sulindac, 2.3-5.6 and 1.4-5.3% for sulindac sulfone and 2.5-4.3 and 0.8-2.8% for sulindac sulfide, respectively.

Quantitative analysis of non-steroidal anti-inflammatory drugs by capillary zone electrophoresis.

The potential utility of capillary zone electrophoresis (CZE) for the separation and quantitative determination of some non-steroidal anti-inflammatory drugs (NSAIDs) was investigated. The influence of different parameters on migration times, peak symmetry, efficiency and resolution was studied; these parameters included the nature and concentration of the anionic and cationic components of the separation buffer. A buffer consisting of 75 mM glycine adjusted to pH 9.1 with triethanolamine was found to provide a very efficient and stable electrophoretic system for the CZE analysis of NSAIDs, giving RSD values of about 0.1 and 0.5% for the within-day reproducibility of migration times and peak areas, respectively at a concentration of 25 micrograms ml-1 (n = 5). Response was linear from 2-100 micrograms ml-1 for both sulindac and tiaprofenic acid, for which the LOQ values were 2.8 and 1.9 micrograms ml-1, respectively, using UV detection at 280 nm. Accuracy for each drug was 102-103%.

Avaliaçäo das atividades antiexsudativa e antiproliferativa dos antiinflamatórios näo esteróides Naproxen, Ibuprofen, Sulindac e Glucametacina em modelos inflamatórios produzidos pela inoculaçäo subcutânea de fragmentos de parede celular de microorganismos da placa dental / Evaluation of antiexsudative and antiproliferative activities of non-steroidal antiinflammatory Naproxen, Ibuprofen, Sulindac and Glucamethacin in inflammatory models produced by subcutaneous inoculation of cell wall fragments of dental plaque microo

A inflamaçäo aguda constitui-se em uma resposta tecidual inicial a todas as formas de agressäo, qualquer que seja o agente etiológico, sendo as suas principais características a exsudaçäo de líquidos e de proteínas plasmáticas do sangue para o interstício e a transmigraçäo de células, principalmente de leucócitos polimorfonucleares neutrófilos. A cura do processo inflamatório ocorre após a eliminaçäo do agente etiológico através do processo de reparo. Entretanto, quando certos agentes nocivos näo podem ser destruídos ou eliminados, a inflamaçäo persiste e tenta isolá-los do organismo formando o granuloma. Existem muitas condiçöes inflamatórias de origem ainda desconhecida, como a artrite reumatóide, onde se manifestam tanto os fenômenos exsudativos como os proliferativos da inflamaçäo, que determinam alteraçöes funcionais e deformidades articulares irreversíveis, em geral acompanhadas de notáveis manifestaçöes sistêmicas. Embora as drogas antiinflamatórias sejam utilizadas para modificar a resposta inflamatória nas doenças de etiologia desconhecida, a terapêutica näo é curativa, pois muitas vezes estäo envolvidos mecanismos etiopatogenéticos complexos e ainda obscuros da doença, o que torna a droga inespecífica. O seu efeito acha-se fundamentalmente dirigido ao tratamento sintomático da inflamaçäo, ou seja, diminuindo ou bloqueando os sinais e sintomas locais e sistêmicos dessa inflamaçäo. Os antiinflamatórios näo esteróides säo também analgésicos e antipiréticos e, recentemente, tem-se observado também atividade antimitótica. Entretanto, como a sua atividade antimitótica näo tem sido estudada de modo sistêmico, propusemo-nos a determinar in vivo, além da atividade antiinflamatória, também a sua atividade antimitótica em quatro drogas antiinflamatórias näo esteróides, bem como estabelecer a correlaçäo existente entre os dois efeitos (antiinflamatório e antimitótico). As drogas testadas foram: naproxen, ibuprofen, sulindac e glucametacina. Neste estudo foram utilizados 321 ratos adultos, da linhagem Wistar (Rattus novergicus, var. albino), com peso médio de 250 gramas, cujos animais experimentais foram medicados com doses diárias de 33,34mg/kg de naproxen, 80mg/kg de ibuprofen, 13,34mg/kg de sulindac e 14mg de glucametacina. Os animais controles receberam apenas água destilada em substituiçäo às drogas. A administraçäo das drogas ou da água destilada foi feita por intubaçäo gástrica...

Effects of phenylbutazone and oxyphenbutazone on acidic drug detection in high performance thin layer chromatographic systems.

Interference or "masking" in thin layer chromatography occurs when the presence of one drug on a thin layer plate physically obscures or interferes with the detection of another drug. We investigated the ability of phenylbutazone and oxyphenbutazone to mask or interfere with the detection of acidic drugs of high performance thin layer chromatography. Of 20 acidic drugs called "positive" since 1981 by laboratories affiliated with the Association of Official Racing Chemists, 16 did not comigrate with phenylbutazone or oxyphenbutazone and could not, therefore, be masked by these agents. Three medications (diclofenac, fenoprofen, ibuprofen) were potentially masked by phenylbutazone and one (sulindac) was potentially masked by oxyphenbutazone. These agents were therefore administered to horses to determine whether or not their metabolites would allow their detection. In each case, metabolites of these agents were detectable for at least 24 hr after drug administration and detection was not interfered with by phenylbutazone or oxyphenbutazone. These results suggest that these 20 acidic drugs should be readily detectable in postrace urines of horses in the presence of phenylbutazone either as the parent drug or by virtue of the easily distinguishable metabolites that each agent possesses. There is, therefore, no reason to believe that the agents tested in this study can be effectively masked or interfered with by phenylbutazone or its metabolites in equine urine.

Analytical methods for the determination of sulindac and metabolites in plasma, urine, bile, and gastric fluid by liquid chromatography using ultraviolet detection.

A high-performance liquid chromatographic method using a linear elution gradient has been developed for the analysis of sulindac, sulindac sulfone, and sulindac sulfide in plasma, urine, bile, and gastric fluid. The methodology uses reverse-phase, radial compression chromatography with gradient elution, and UV detection. Sulindac and its metabolites in plasma can be quantitated at 0.25 microgram/mL with a mean CV of 6.0 +/- 2.9%; urine, bile, and gastric fluid (0.5 microgram/mL) yield a mean CV of 5.5 +/- 1.9%.