Mechanism-based risk assessment strategy for drug-induced cholestasis using the transcriptional benchmark dose derived by toxicogenomics.

Cholestasis is one of the major causes of drug-induced liver injury (DILI), which can result in withdrawal of approved drugs from the market. Early identification of cholestatic drugs is difficult due to the complex mechanisms involved. In order to develop a strategy for mechanism-based risk assessment of cholestatic drugs, we analyzed gene expression data obtained from the livers of rats that had been orally administered with 12 known cholestatic compounds repeatedly for 28 days at three dose levels. Qualitative analyses were performed using two statistical approaches (hierarchical clustering and principle component analysis), in addition to pathway analysis. The transcriptional benchmark dose (tBMD) and tBMD 95% lower limit (tBMDL) were used for quantitative analyses, which revealed three compound sub-groups that produced different types of differential gene expression; these groups of genes were mainly involved in inflammation, cholesterol biosynthesis, and oxidative stress. Furthermore, the tBMDL values for each test compound were in good agreement with the relevant no observed adverse effect level. These results indicate that our novel strategy for drug safety evaluation using mechanism-based classification and tBMDL would facilitate the application of toxicogenomics for risk assessment of cholestatic DILI.

Effect of Sulindac Binary System on In Vitro and In Vivo Release Profiles: An Assessment of Polymer Type and Its Ratio.

The bioavailability of sulindac (SDC), a nonsteroidal anti-inflammatory drug, is low due to poor aqueous solubility and poor dissolution rate. For this reason it is necessary to enhance the solubility and enhance dissolution of the drug by dispersing SDC in polyethylene glycols 6000 (PEG 6000) and polyvinyl pyrrolidone 40000 (PVP 40000) matrices using the coevaporation technique. Studying the influence of SDC to polymer ratio on drug content, percent yield, particle size, and in vitro release was performed. Differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy were used to characterize any change in crystal habit of SDC in the prepared formulae. The anti-inflammatory effect of SDC was studied using the hind paw edema model. It was found that incorporation of SDC in PEG 6000 and PVP 40000 matrices resulted in improving the dissolution rate, which was found to depend on the polymer and its weight ratio of the drug. It is clearly obvious that the dissolution rate was remarkably improved in drug PVP 40000 molecular dispersions when compared to drug PEG 6000 systems. Solid dispersion of SDC in PEG and PVP improved the anti-inflammatory effect of SDC and it was found that formula SDV5 exhibited a more pronounced inhibition of swelling than other formulae.

Assessment of the involvement of oxidative stress and Mitogen-Activated Protein Kinase signaling pathways in the cytotoxic effects of arsenic trioxide and its combination with sulindac or its metabolites: sulindac sulfide and sulindac sulfone on human leukemic cell lines.

The purpose of the study was to characterize the involvement of reactive oxygen species (ROS) in mediating the cytotoxic effects of arsenic trioxide (ATO) in combination with sulindac or its metabolites: sulfide (SS) and sulfone (SF) on human leukemic cell lines. Jurkat, HL-60, K562, and HPB-ALL cells were exposed to the drugs alone or in combinations. Cell viability was measured using WST-1 or XTT reduction tests and ROS production by dichlorodihydrofluorescein diacetate staining (flow cytometry). Modulation of (a) intracellular glutathione (GSH) level was done by using L: -buthionine sulfoximine (BSO) or diethylmaleate (DEM), (b) NADPH oxidase by using diphenyleneiodonium (DPI), and (c) MAP kinases by using SB202190 (p38), SP600125 (JNK), and U0126 (ERK) inhibitors. ATO cytotoxicity (0.5 or 1 µM) was enhanced by sulindacs, with higher activity showed by the metabolites. Strong cytotoxic effects appeared at SS and SF concentrations starting from 50 µM. The induction of ROS production seemed not to be the major mechanism responsible for the cytotoxicity of the combinations. A strong potentiating effect of BSO on ATO cytotoxicity was demonstrated; DEM (10-300 µM) and DPI (0.0025-0.1 µM; 72 h) did not influence the effects of ATO. Some significant decreases in the viability of the cells exposed to ATO in the presence of MAPK inhibitors comparing with the cells exposed to ATO alone were observed; however, the effects likely resulted from a simple additive cytotoxicity of the drugs. The combinations of ATO with sulindacs offer potential therapeutic usefulness.

Oral colon targeted delivery systems for treatment of inflammatory bowel diseases: synthesis, in vitro and in vivo assessment.

The aim of this study was to investigate the potential of prodrugs of some non-steroidal anti-inflammatory drugs (NSAIDs) as colon targeted delivery systems for treatment of inflammatory bowel diseases. Naproxen, sulindac and flurbiprofen (Fbp) were used. The carboxylic group of those drugs was conjugated onto the amino group of l-aspartic acid or the hydroxyl group of alpha- or beta-cyclodextrin (CyD). Prodrugs hydrolysis in buffers of pH range 1.2-7.2 and in rat gastrointestinal tract homogenates and the effect of oral pretreatment of rats with clindamycin on the hydrolysis of the prodrugs was examined. Additionally, the effect of oral administration of Fbp-beta-CyD prodrug on the experimentally induced colitis in rats was evaluated. The in vivo inflammatory response was assessed macroscopically, histologically and by measurement of reduced glutathione (GSH) levels in colon tissues. No significant hydrolysis of the proposed seven prodrugs in buffers having pH range of 1.2-7.2 was observed over 72h. Negligible % of drug released from Fbp-alpha-CyD or Fbp-beta-CyD prodrugs was detected in rat stomach contents, intestinal tissues and intestinal contents homogenates. On the other hand, Fbp-alpha-CyD and Fbp-beta-CyD prodrugs released about 60% Fbp within 4h in rat colon homogenate. Oral pretreatment of rats with clindamycin significantly reduced % Fbp released from Fbp-alpha-CyD or Fbp-beta-CyD prodrugs. Oral administration of Fbp-beta-CyD to rats after induction of colitis significantly attenuated the severity of the colonic injury and reduced the score of the macroscopic and microscopic damage. Additionally, there was a significant increase in the level of GSH. The present study provided an evidence that Fbp-beta-CyD prodrug may be beneficial in treatment of inflammatory bowel disease.

Longitudinal assessment of air conduction audiograms in a phase III clinical trial of difluoromethylornithine and sulindac for prevention of sporadic colorectal adenomas.

A phase III clinical trial assessed the recurrence of adenomatous polyps after treatment for 36 months with difluoromethylornithine (DFMO) plus sulindac or matched placebos. Temporary hearing loss is a known toxicity of treatment with DFMO, thus a comprehensive approach was developed to analyze serial air conduction audiograms. The generalized estimating equation method estimated the mean difference between treatment arms with regard to change in air conduction pure tone thresholds while accounting for within-subject correlation due to repeated measurements at frequencies. Based on 290 subjects, there was an average difference of 0.50 dB between subjects treated with DFMO plus sulindac compared with those treated with placebo (95% confidence interval, -0.64 to 1.63 dB; P = 0.39), adjusted for baseline values, age, and frequencies. In the normal speech range of 500 to 3,000 Hz, an estimated difference of 0.99 dB (-0.17 to 2.14 dB; P = 0.09) was detected. Dose intensity did not add information to models. There were 14 of 151 (9.3%) in the DFMO plus sulindac group and 4 of 139 (2.9%) in the placebo group who experienced at least 15 dB hearing reduction from baseline in 2 or more consecutive frequencies across the entire range tested (P = 0.02). Follow-up air conduction done at least 6 months after end of treatment showed an adjusted mean difference in hearing thresholds of 1.08 dB (-0.81 to 2.96 dB; P = 0.26) between treatment arms. There was no significant difference in the proportion of subjects in the DFMO plus sulindac group who experienced clinically significant hearing loss compared with the placebo group. The estimated attributable risk of ototoxicity from exposure to the drug is 8.4% (95% confidence interval, -2.0% to 18.8%; P = 0.12). There is a <2 dB difference in mean threshold for patients treated with DFMO plus sulindac compared with those treated with placebo.

Determinaçäo dos efeitos das drogas antiinflamatórias näo esteróides (indometacina, butazona, clinoril, naprosin, benflogin e inflaril) nos leucogramas de ratos portadores de processo inflamatório crônico / Assessment of the effects of non-steroidal anti-inflammatory drugs (indomethacin, phenylbutazone, sulindac, naproxen, benzydamine and neflumic acid) on rat leucograms with chronic inflammatory process

Neste trabalho procurou-se avaliar os efeitos dos antiinflamatórios näo esteróides: Indometacina (indocid), Butazona (Fenilbutazona), Clinoril (Sulindac), Naprosin (Naproxen), Benflogin (Cloridrato de Benzidamina) e Inflaril (Acido neflúmico) nos leucogramas de ratos portadores de um processo inflamatório crônico provocado pela introduçäo intradérmica de lamínulas de vidro nos períodos de 3, 12 e 18 dias. O sangue para a contagem total dos leucócitos, eletrônica e diferencial, esfregaço, foi obtido por punçäo intracardíaca (Burhoe). A Indometacina, o Clinoril e a Butazona indicaram diminuiçäo de linfócitos e eosinófilos e aumento de monócitos e neutrófilos em todos os períodos e observaçäo em todos os períodos; o Inflaril reduziu o número de linfócitos, neutrofilia e eosinopenia em todos os períodos; o Inflaril reduziu o número de linfócitos e eosinófilos de aumentou os monócitos, com exceçäo de 3§ período, e os neutrófilos nos três períodos; e o Benflogin elevou os linfócitos na 1ª e 3ª fases, e os monócitos nos três períodos, e reduziu os neutrófilos nos dois primeiros, e os eosinfófilos nos dois últimos períodos. Todas as drogas usadas provocaram reduçäo de leucócitos em todos os períodos de tratamento, exceçäo feita ao Naprosin no 3§, ao Benflogin no 2§ e ao Inflaril no 1§ e 2§ períodos

Valoración del efecto sintomático de carprofeno en osteartrosis / Evaluation of the symptomatic effect of carprofen in osteoarthrtis

Mediante estudio doble ciego, se comparó el efecto sintomático de carprofeno y sulindac en pacientes con osteoartrosis de cadera, rodilla o ambas. Se analizan los resultados obtenidos para todos los síntomas relacionados con el proceso articular degenerativo: dolor en todas sus formas de manifestación y rigidez articular subjetiva; se hizo el registro con escalas de intensidad y escala visual analógica. Se consideraron también las opiniones globales del investigador y los pacientes así como la aparición de efectos indeseables. Se concluye que el efecto sintomático de carprofeno y sulindac es semejante aun cuando la analgesia total fue un suceso más común con el primero. La tolerancia fue muy superior en el grupo tratado con carprofeno registrándose efectos indeseables con una frecuencia tres veces mayor con sulindac que con carprofeno