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Background and Aim: Aberrant crypt foci (ACF) in the rectum have been reported to correlate with the risk of colorectal tumorigenesis and are useful biomarkers for predicting the risk of colorectal cancer because they are quantitative and can be evaluated in a short period of time. Leukotriene receptor antagonists (LTRAs) have been reported to have inhibitory effects on various carcinomas, but their effects on colorectal cancer are unknown. Based on the report that colorectal cancer overexpresses the cysteinyl leukotriene receptor, we investigated whether LTRA medication affects the number of ACF. Methods: The eligibility criteria were patients who were between 30 and 80 years old, had colorectal tumors that were suitable for endoscopic resection, and had at least five ACFs in the rectum. First, 30 patients were enrolled in the LTRA group, who were treated with montelukast sodium 10 mg for 8 weeks, and rectal ACFs were counted during treatment of colorectal tumors. 10 patients in the no medication follow-up group were enrolled as the control group. Results: One patient in the control group was not examined due to the COVID-19 pandemic, so we examined 30 patients in the LTRA group and 9 patients in the control group. The number of rectal ACFs decreased to -2.4 (SD 2.2) in the LTRA group compared to baseline, while there was no decrease to 0.4 (SD 2.3) in the control group, and there was a significant difference in ACF trends between the two groups (P = 0.002). The Ki67 labeling index, which is a cell proliferation activity, was -1.34 (SD 2.68) in the LTRA group compared to baseline, while it was 0.13 (SD 1.89) in the control group, but there was no significant difference between the two groups. Conclusion: The LTRA treatment decreased rectal ACF and may reduce the risk of colorectal cancer.

Sarıoğlu, Nurhan (Balikesir Author), In this study, we investigated the effects of certain respiratory drugs, which are mainly used on human serum paraoxonase-1 (hPON1; EC 3.1.8.1). hPON1 was purified from human serum, with 354.91 fold and 45% yield by using two simple step procedures including, first, ammonium sulfate precipitation, then, Sepharose-4B-l-tyrosine-1-naphthylamine hydrophobic interaction chromatography. SDS-polyacrylamide gel electrophoresis showed a single protein band belonging to hPON1 with 43 kDa. All the pharmaceutical compounds inhibited the PON1 enzyme highly at the micromolar level. The obtained IC50 values for nine different pharmaceutics ranged from 0.219 mu M (salbutamol sulfate) to 67.205 mu M (montelukast sodium). So, all drugs could be considered as potent hPON1 inhibitors. K-i values and inhibition types were determined by Lineweaver-Burk graphs. While varenicline tartrate and moxifloxacin hydrochloride inhibited the enzyme in a noncompetitive manner, others inhibited it in a mixed manner.

A rapid, simple, and sensitive second-derivative synchronous fluorimetric method has been developed and validated for the simultaneous analysis of a binary mixture of desloratadine (DSL) and montelukast sodium (MKT) in their co-formulated tablets. The method is based on measurement of the synchronous fluorescence intensities of the two drugs in McIlvaine's buffer, pH 2.3, in the presence of carboxy methyl cellulose sodium (CMC) as a fluorescence enhancer at a constant wavelength difference (Δλ) of 160 nm. The presence of CMC enhanced the synchronous fluorescence intensity of DSL by 216% and that of MKT by 28%. A linear dependence of the concentration on the amplitude of the second derivative synchronous fluorescence spectra was achieved over the ranges of 0.10–2.00 and 0.20–2.00 µg/mL with limits of detection of 0.02 and 0.03, and limits of quantification of 0.05 and 0.10 µg/mL for DSL and MKT, respectively. The proposed method was successfully applied for the determination of the studied compounds in laboratory-prepared mixtures and tablets. The results were in good agreement with those obtained with the comparison method. The high sensitivity attained by the proposed method allowed the determination of MKT in spiked human plasma with average % recovery of 100.11 ± 2.44 (n = 3). Copyright © 2014 John Wiley & Sons, Ltd.

In order to define an enantioselective nuclear magnetic resonance (NMR) method for the antiasthmatic drug montelukast, a series of nine easily available products were evaluated as NMR chiral solvating agents (CSAs): D-dibenzoyltartaric acid, D-ditoluoyltartaric acid, (+)-camphorsulfonic acid, (S)-BINOL, (S)-3,3’-diphenyl-2,2’-binaphthyl-1,1’-diol, (R)-3,3'′-di-9-anthracenyl-1,1'′-bi-2-naphthol, (R)-3,3'′-di-9-phenanthrenyl-1,1'′-bi-2-naphthol, Pirkle's alcohol, and (−)-cinchonidine. It was proved that most of the studied agents constitute diastereomeric complexes with both drug enantiomers in CD2Cl2 or CDCl3 solutions, thus permitting the direct 1H NMR detection of the unwanted S-enantiomer, even at levels of 0.75%. (−)-Cinchonidine was found to be the more convenient CSA in terms of NMR enantiodiscrimination power and ease of experimental requirements. The final method was validated and applied to the fast monitoring of the optical purity of montelukast “in-process” samples, circumventing the need for tedious and slower analytical procedures like enantioselective chromatography or capillary electrophoresis. In addition, a method for the enantiopurity control of the commercial drug (montelukast sodium salt) was also established using (S)-BINOL as NMR CSA. Chirality 25: 780–786, 2013. © 2013 Wiley Periodicals, Inc.

Derivative and derivative ratio methods are presented for the determination of butamirate citrate, formoterol fumarate, montelukast sodium, and sodium cromoglycate. Using the second derivative ultraviolet (UV) spectrophotometry, butamirate citrate and formoterol fumarate were determined by measuring the peak amplitude at 260.4 and 261.8 nm, respectively, without any interference of their degradation products. Butamirate citrate degradation product, 2-phenyl butyric acid, was determined by the measurement of its second derivative amplitude at 246.7 nm where butamirate citrate displays zero crossing. Formoterol fumarate degradation product, desformyl derivative, could be evaluated through the use of the first derivative at peak amplitude of 264.8 nm where interference of formoterol fumarate is negligible. In the first mode, the zero-crossing technique was applied at 305 nm for the determination of montelukast sodium in the presence of its photodegradation product, cis-isomer. The derivative of ratio spectra of montelukast sodium and its cis- isomer were used to determine both isomers using the first derivative of the ratio spectra by measuring the amplitudes of the trough at 305 nm and the peak at 308 nm, respectively. The later technique was also used for the determination of a ternary mixture of sodium cromoglycate and its two degradation products using zero-crossing method. In the derivative ratio spectra of the ternary mixture, trough depths were measured at 271.6, 302.8 and 302.2 nm, using the second, the first, and the second mode to evaluate sodium cromoglycate, degradation product (1) and degradation product (2), respectively. All the methods were applied successfully to the pharmaceutical preparation and were validated according to ICH guidelines. Copyright © 2011 John Wiley & Sons, Ltd.

There is a lack of evidence for treatment of newly diagnosed asthma, and they are based mainly on expert opinion. This pilot study was aimed at evaluating the effects of inhaled corticosteroid (ICS) in two different doses and montelukast sodium on clinical symptoms and lung function in children with newly diagnosed asthma. This was a randomized, double-blind, parallel-group, 12-month pilot trial, studying the effects of budesonide 800 mcg/day and 400 mcg/day and montelukast 5 or 10 mg tablet according to age on clinical symptoms and lung function in 60 children with newly diagnosed asthma. After 6 months of treatment with different doses of inhaled budesonide and montelukast sodium, asthma control and lung function significantly improved in all three groups of treatment; there were no differences between groups. We found significant correlation between time of enrollment and individual answer to the treatment in montelukast group only; children enrolled later (at the end of heating season) responded better to treatment. The answer to both ICS doses was independent from time of enrollment. The results of the present pilot study suggest that natural exposure, even to perennial allergens, should be considered in choosing the initial asthma treatment. We showed that montelukast may be used as initial asthma therapy in children allergic to house-dust mites preferably at the end of the heating season. Therefore, ICS could be a better choice as initial asthma therapy during maximum allergen exposure.

Inflammatory mediators and drugs which affect inflammation can influence the healing of injured tissues. Leukotrienes are potent inflammatory mediators, and similar to prostaglandins, are metabolites of arachidonic acid which can have positive or negative effects on bone and cartilage tissues. Here we tested the hypothesis that blocking the negative regulation of leukotrienes, would lead to enhanced endochondral bone formation during fracture repair. A closed femoral fracture was created in mice. Animals were divided into three groups for treatment with either montelukast sodium, a cysteinyl leukotriene type 1 receptor antagonist (trade name Singulair), zileuton, a 5-lipoxygenase enzyme inhibitor (trade name Zyflo), or carrier alone. The fractures were analyzed using radiographs, quantitative gene expression, histology and histomorphometry, and immunohistochemistry. Both the montelukast sodium group and the zileuton group exhibited enhanced fracture repair when compared with controls. Both treatment groups exhibited increased callous size and earlier bone formation when compared to controls as early as day 7. Gene expression analysis of treatment groups showed increased markers of chondrocyte proliferation and differentiation, and increased early bone formation markers when compared with controls. Treatment with montelukast sodium directly targeted the cysteinyl leukotriene type 1 receptor, leading to increased chondrocyte proliferation at early time points. These novel findings suggests a potential mechanism by which the cysteinyl leukotriene type 1 receptor acts as a negative regulator of chondrocyte proliferation, with important and previously unrecognized implications for both fracture repair, and in a broader context, systemic chondrocyte growth and differentiation.

This work verifies the potential of CE in the analysis of significant impurities of montelukast sodium - an active ingredient for the treatment of bronchial asthma. Using 20 mM borate buffer pH 9.2 with 10 mM SDS and 10 mM (2-hydroxypropyl)-gamma-CD (2HP-gamma-CD) it was possible to separate montelukast and several impurities, including its cis-isomer, after exposure to light and oxygen. The obtained method surpasses a chromatographic method for montelukast sodium in terms of time of analysis (9 min of CE analysis vs. 35 min HPLC) and efficiency (CE offered over 900 000 theoretical plates for montelukast). Good repeatability of the method was supported by the low % RSD for the migration time of montelukast (0.53%). For the first time, the capillary electrophoretic method was employed for temporal study of the degradation of montelukast. The results showed that degradation of montelukast and the formation of the cis-isomer mainly occurred during the first 2 days of exposure, and occurred to a higher degree when there was no contact with the air (oxygen) in the exposed sample.

BACKGROUND Asthma is a chronic inflammatory airway disease. Exhaled nitric oxide (eNO) is a marker reflecting airway inflammation. This study was conducted to investigate whether montelukast, a leukotriene receptor antagonist, could be used for the management of asthma and how fast the montelukast sodium decreased airway inflammation as demonstrated by eNO levels. METHODS Twenty children aged 6-14 years (mean age: 9.2 +/- 2.4 years; mean weight 30 +/- 4.6 kg) with mild to moderate asthma were recruited for the study. They received montelukast plus an inhaled short-acting beta2 agonist as open and uncontrolled therapy. Asthma score (AS) and peak expiratory flow rate (PEFR) and eNO concentrations were measured at pretreatment (0 week) and post-treatment (1 and 2 weeks) as well as 2 weeks after withdrawal of therapy. RESULTS In one week, the eNO levels (33.3 +/- 15.5 p.p.b. vs 14.8 +/- 8.6 p.p.b.; P < 0.05), and AS (4.2 +/- 1.3 vs 1.8 +/- 1.3; P < 0.05) decreased rapidly, and PEFR (206.9 +/- 69.7 L/min vs 236.2 +/- 69.8 L/min; P < 0.05) increased. Concurrent beta2 agonist use decreased from a mean +/- SD of 2.2 +/- 0.4-1.3 +/- 0.3 puffs per weeks (P < 0.05). After the withdrawal of treatment for 2 weeks, the eNO levels (29.2 +/- 16.1 p.p.b) rebounded again, although the improvements in AS (1.1 +/- 1.3) and PEFR (245.0 +/- 91.3 L/min) persisted. CONCLUSION Oral montelukast sodium treatment of these children with mild to moderate asthma effectively improved asthmatic symptoms and suppressed airway inflammation in 1 week, suggesting that this leukotriene antagonist combined with short-acting beta2 agonists may provide effective treatment option in mild to moderate childhood asthma. Larger, controlled, and double-blinded studies are needed to confirm these preliminary open uncontrolled observations.

Exhaled nitric oxide (ENO) is a surrogate marker of airway inflammation in asthma. In 12 children aged 6–11 years with mild to moderate persistent asthma, ENO concentrations were measured before and after 4 weeks of treatment with montelukast sodium, a leukotriene receptor antagonist, and 2 weeks after withdrawal of therapy. Baseline ENO levels (mean and 95% confidence interval) were significantly elevated in patients with asthma compared to age-matched nonasthmatic control subjects, with levels of 83 (42–123) vs. 13 (11–15) ppb (P < 0.001). After treatment with montelukast sodium, there was a significant (P < 0.01) reduction in ENO to 58 (27–89) ppb which again rose to 69 (38–99) ppb 2 weeks after treatment was withdrawn. During treatment, the fall in ENO was accompanied by nonsignificant improvements in prebronchodilator forced expiratory volume in 1 s (FEV1) from 81–85% predicted or reductions in use of albuterol from a mean of 2.5 to 1.6 puffs/day. Individual ENO measurements and change in ENO concentrations with treatment did not correlate with either pulmonary function changes or use of bronchodilator. These data show that ENO is elevated in children with relatively mild asthma treated with bronchodilator alone, and that treatment with montelukast sodium for 4 weeks results in a significant reduction in ENO concentrations, even in the absence of significant changes in pulmonary function. These findings suggest an anti-inflammatory role for leukotriene D4 receptor antagonism in the treatment of children with mild to moderate asthma. Pediatr Pulmonol. 1999; 28:402–407. © 1999 Wiley-Liss, Inc.

A study was conducted to (i) characterize the multiple-dose pharmacokinetics of oral montelukast sodium (MK-0476), 10 mg d-1 in healthy young subjects (N = 12), (ii) evaluate the pharmacokinetics of montelukast in healthy elderly subjects (N = 12), and (iii) compare the pharmacokinetics and oral bioavailability of montelukast between elderly and young subjects. Following oral administration of montelukast sodium, 10 mg d-1 (the therapeutic regimen for montelukast sodium) for 7 d, there was little difference in the plasma concentration-time profiles of montelukast in young subjects between day 1 and day 7 dosing. On average, trough plasma concentrations of montelukast were nearly constant, ranging from 18 to 24 ng mL-1 on days 3-7, indicating that the steady state of montelukast was attained on day 2. The mean accumulation ratio was 1.14, indicating that this dose regimen results in a 14% accumulation of montelukast. In elderly subjects, mean values of plasma clearance (Cl), steady-state volume of distribution (Vss), plasma terminal half-life (t1/2), and mean residence time in the body (MRTIV) following a 7 mg intravenous (5 min infusion) administration of montelukast sodium in the elderly were 30.8 mL min-1, 9.7 L, 6.7 h, and 5.4 h, respectively. Following a 10 mg oral dose, the bioavailability of montelukast in healthy elderly averaged 61%, very close to that (62%) determined previously in healthy young subjects. Also following the 10 mg oral administration, the mean values of AUC0-->infinity, Cmax, tmax, and t1/2, and the mean plasma concentration-time profile of montelukast in the elderly, were generally similar to those in young subjects, indicating that age has little or no effect on the pharmacokinetics of montelukast. There is no need to modify dosage as a function of age.