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Recently, the aim of analytical community is to reduce the usage of hazardous chemicals; so eco-friendly, rapid, selective and cost-effective methods were developed for simultaneous determination of montelukast sodium (MKT) and loratadine (LRT). The first method was based on chromatographic separation performed on precoated silica gel 60 GF254 plates with ethyl acetate-ethanol 9: 1 (v/v) as the mobile phase. The developed plates were scanned and quantified at 260 nm. The method gives linear correlation over concentration ranges of 0.3-3.6 μg/spot and 0.2-4.0 μg/spot for MKT and LRT, respectively. It was also successfully applied to analysis of both drugs in their pharmaceutical preparation and human plasma. The other methods are UV-spectrophotometric methods based on smart spectra manipulating to zero order spectrum of each drug. These methods are named response correlation (RC), a-centering and ratio derivative methods. RC and a-centering methods were dependent on the presence of an isosbestic point between the overlapped spectra of both drugs. While ratio derivative method based on manipulation of the ratio spectra of both drugs. The two drugs obey Beer-Lambert law over the concentration ranges of 3.0-30.0 μg/mL in the three spectrophotometric methods. Moreover, the greenness of the developed methods is assessed using suitable analytical Eco-Scale and Green Analytical Procedure Index., (Published by Oxford University Press 2023.)

Meat and meat products are indispensable part of our diet. Heat processing of these tasty foods such as fried fish causes to form heterocyclic aromatic amines (HAAs). The sources of heating have directly affected on the level and type of HAAs. In this research, 2-amino-1-methyl-6-phenylimidazo [4'5-b] pyridine (PhIP), 2-amino-3-methylimidazo [4,5-f]quinolone (IQ), 2-amino-3,4-dimethylimidazo [4,5-f] quinoline (MeIQ) and 2-amino-3,4-dimethylimidazo [4,5-f] quinoxaline (MeIQx) were determined using an efficient analytical methodology coupled with high-performance liquid chromatography. The effective parameters were optimized by central composite design. The results of this survey demonstrated that rang of relative standard deviation were between 4.5 and 8.2, extraction recoveries were obtained 86-97% and limits of detection were between 0.40 and 0.63 for 4 HAAs. The amounts of HAAs found in 20 different fried fish samples were between 0 and 4.8 ng g-1. PhIP with 1.57 ng g-1 and MeIQ with 2.08 ng g-1 have the lowest and highest average level of HAAs, respectively., (© The Author(s) 2021. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Two selective and sensitive chromatographic methods were developed for simultaneous determination of new combination of quinfamide and mebendazole in bulk powder and in pharmaceutical formulation. The first method is HPTLC by which separation was obtained using silica gel HPTLC F254 plates and a simple mobile phase consisting of methanol:toluene (2:6, v/v) and the separated bands were scanned at 254 nm. The second method RP-HPLC that comprised isocratic separation of both drugs on a Phenomenex C18 column using a green mobile phase consisting of double distilled water:methanol (30:70, v/v) at a flow rate of 0.8 mL/min and UV detection at 254 nm. The developed methods were validated and proved to meet ICH guidelines. Successful application of the developed methods was carried out for determination of quinfamide and mebendazole in Vermox Plus® tablets. Statistical comparison between the developed chromatographic methods and the reported simultaneous equation spectrophotometric method showed that there was no significant difference between them, proving the ability of applying the proposed methods in quality control testing of the studied drugs. The developed methods are considered the first chromatographic methods for simultaneous determination of quinfamide and mebendazole; moreover, they offered sensitive and selective eco-friendly methods for analysis of the studied drugs., (© The Author(s) 2019. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background: Synthetic colorants are largely used in the pharmaceutical products to increase the attractiveness of products and to help patients distinguish between pharmaceuticals. Despite their commercial advantages, synthetic colorants may, in some cases, have a negative impact on the human body. It is therefore imperative to measure the quantities in food products and pharmaceuticals with a fast, reliable, and sensitive method. Objective: The analyzed synthetic colorants in this study are Erythrosine [(E) E127], Quinoline Yellow [(QY) E104], and Indigo Carmine [(IC) E132]. The aim of this study was to develop and validate a new method for the preconcentration and simultaneous determination of these colorants in pharmaceutical preparations. Method: The developed method has many advantages such as novelty, sensitivity, cost effectiveness, speed, and environmental friendliness. This method is based on the cloud-point extraction (CPE) method coupled with first-derivative spectrophotometry (FDS). In the proposed method, QY, E, and IC were extracted from an aqueous solution by using mixed micelles of TritonX-100 and cetyltrimethylammonium bromide. The effect of the main parameters such as solution pH, surfactant and salt concentration, incubation time, and temperature on the CPE of colorants were investigated and optimized. Under the optimal conditions, the extracted surfactant-rich phase was diluted with acetone, and the first-derivative absorbance values were measured at wavelengths 408, 497, and 637 nm for QY, E, and IC, respectively. The CPE-FDS method was applied in the range of 1.0-6.0 μg/mL for E and QY, and 0.3-1.8 μg/mL for IC. Results: The results showed higher correlation coefficients of 0.9990-0.9993 for each colorant. Furthermore, the method was validated for precision and accuracy and assessed the colorants' contents in the synthetic mixtures that contained different ratios of colorants and pharmaceutical samples. The LOD and LOQ values were 31.0 and 103.0 ng/mL for E, 57.0 and 190.0 ng/mL for QY, and 48.0 and 160.0 ng/mL for IC, respectively. The RSDs at the intermediate concentration level (1.2 μg/mL for IC and 3 μg/mL for QY and for E) were <5%. The recovery values in different ratios of colorants were in the ranges of 90.42-101.14, 92.40-105.54, and 96.15-101.25% for E, IC, and QY, respectively. CPE-FDS was also successfully applied to the simultaneous analysis of the QY, IC, and E contents in the various pharmaceutical samples. The obtained results were statistically compared with those obtained by the green HPLC method that was previously reported by Yoshioka et al. and modified by us in this study. Conclusions: The data observed indicated that the CPE-FDS method does not require use of great samples for determination of trace amounts of E, IC, and QY and allows for the determination of analytes in high matrix effect samples such as suspension and syrup. The study concludes that the proposed CPE-FDS method could be considered an alternative to the existing chromatographical methods for the simultaneous determination of trace amounts of E, IC, and QY in pharmaceutical dosage forms for routine analysis. Highlights: A new and effective procedure, simultaneous determination, trace amounts of E, QY, and IC was developed. This is the first report that uses CPE coupled with FDS for the analysis of E, QY, and IC. CPE avoids the use of costly, hazardous, and flammable solvents in large quantities. FDS resolves two or three overlapping spectra and eliminates matrix interferences. CPE-FDS did not require use of large samples for determination of trace colorants.

The lipophilicity of a series of anticancer propargylquinoline derivatives is investigated using both chromatographic and computational methods. The parameters of the tested compounds' relative lipophilicity (logkw) are determined experimentally by the high-performance liquid chromatographic method (RP-HPLC, Accucore C18 column), using mixtures of acetonitrile and water as mobile phases. Mobile phase acetonitrile concentrations range between 50 and 80%. The logk values of the investigated compounds are linearly dependent upon the acetonitrile concentration. The analysis led to the calculation of the logkw parameter values for each of the tested compounds. The parameter logkw is discussed in terms of the relationship between structure and lipophilicity and consequently, transformed into the parameter logPHPLC using the calibration curve. The partition coefficients of the tested compounds (logPcalc) are also calculated by selected computer programs. A regression analysis and the sum of ranking differences are used to compare the lipophilic parameters of 15 acetylenequinoline derivatives, which were experimentally obtained (logPHPLC) and calculated using different mathematical methods (logPcalc). The 13C NMR spectra are used to examine the electronic relationships between properties and lipophilicity for the studied compounds. A regression study conducted on 15 compounds exhibits a linear correlation between lipophilicity and electronic properties, expressed as the 13C NMR chemical shift (R2 = 0.98)., (© The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

In this study, development and validation of a HPLC method was described for simultaneous determination of potassium sorbate, sodium benzoate, quinoline yellow and sunset yellow. A Box-Behnken design using three variables at three levels was employed to determine the optimum conditions of chromatographic separation: pH of mobile phase, 6.0-7.0; flow rate, 0.8-1.2 mL min(-1) and the ratio of mobile phase composed of a 0.025 M sodium acetate/acetic acid buffer, 80-90%. Resolution was chosen as a response. The optimized method was validated for linearity, the limits of detection and quantification, accuracy, precision and stability. All the validation parameters were within the acceptance range. The applicability of the developed method to the determination of these food additives in commercial lemonade and lemon sauce samples was successfully demonstrated., (© The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Qualitative and quantitative approaches are important issues in field of carcinogenic risk assessment of the genotoxic carcinogens. Herein, we provide quantitative data on low-dose hepatocarcinogenicity studies for three genotoxic hepatocarcinogens: 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and N-nitrosodiethylamine (DEN). Hepatocarcinogenicity was examined by quantitative analysis of glutathione S-transferase placental form (GST-P) positive foci, which are the preneoplastic lesions in rat hepatocarcinogenesis and the endpoint carcinogenic marker in the rat liver medium-term carcinogenicity bioassay. We also examined DNA damage and gene mutations which occurred through the initiation stage of carcinogenesis. For the establishment of points of departure (PoD) from which the cancer-related risk can be estimated, we analyzed the above events by quantitative no-observed-effect level and benchmark dose approaches. MeIQx at low doses induced formation of DNA-MeIQx adducts; somewhat higher doses caused elevation of 8-hydroxy-2'-deoxyquanosine levels; at still higher doses gene mutations occurred; and the highest dose induced formation of GST-P positive foci. These data indicate that early genotoxic events in the pathway to carcinogenesis showed the expected trend of lower PoDs for earlier events in the carcinogenic process. Similarly, only the highest dose of IQ caused an increase in the number of GST-P positive foci in the liver, while IQ-DNA adduct formation was observed with low doses. Moreover, treatment with DEN at low doses had no effect on development of GST-P positive foci in the liver. These data on PoDs for the markers contribute to understand whether genotoxic carcinogens have a threshold for their carcinogenicity. The most appropriate approach to use in low dose-response assessment must be approved on the basis of scientific judgment., (© The Author 2015. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

A simple, sensitive, and reproducible ultra-performance LC method for the determination of moxifloxacin (MOXI) oxidation stability under permanganate treatment in acidic conditions (pH 3.0-6.0) was developed. Besides the MOXI peak [retention time (RT) = 2.58], four additional products (RT = 0.86, 0.91, 1.42, and 1.89) were observed in all conditions tested. The oxidation process followed second-order reaction kinetics and depended upon solution acidity. The highest reaction rate constant was observed at pH 3.0, and this value decreased as the pH was increased to 6.0. The oxidation products were characterized, and their fragmentation pathways, derived from MS/MS data, were proposed. Two of these products were identified as hydroxyl derivatives of MOXI and two others as their oxidation product analogs with molecular ions of 418.4 and 416.4 m/z, respectively.

Two simple and accurate methods for the determination of pitavastatin calcium (PIT) in tablet dosage forms were developed and validated using column liquid chromatography (LC) and UV spectrophotometry. The LC separation was achieved on a Phenomenex Luna C18 column (250 mm, 4.6 mm id, 5 microm) in the isocratic mode using acetonitrile-water-triethylamine (80 + 19.8 + 0.2, v/v/v), adjusted to pH 3.5 +/- 0.05 with orthophosphoric acid, as the mobile phase at a flow rate of 1.5 mL/min. The retention time was 5.70 min. Both the methods were performed at 238 nm, the wavelength of maximum absorbance of PIT in methanol. In the LC method, quantification was achieved with a photodiode array detector over the concentration range of 0.1-2.5 microg/mL with a mean recovery of 100.26 +/- 0.75%. In the UV method, quantification was achieved over the concentration range of 2-20 microg/mL with mean recovery of 99.65 +/- 1.24%. Both methods were validated, and the results were compared statistically. They were found to be simple, specific, accurate, and precise. The methods were successfully applied for the determination of PIT in tablet dosage form without any interference from common excipients.

A method has been developed for the quantitation of imazaquin residues in soil. The herbicide was extracted from soil with methanol-water (2 + 1, v/v) and cleaned up by strong anion-exchange solid-phase extraction cartridges. Analysis was performed by using high-performance liquid chromatography with ultraviolet detection. Average recoveries through the method ranged from 90.7 to 100.6%, with relative standard deviation equal to or lower than 6.6%. The limit of detection was estimated to be 0.0015 mg/kg, and the minimum quantitation concentration of imazaquin in soil was 0.005 mg/kg. This method was successfully applied to evaluate imazaquin residue levels in soil and its dissipation rates in a soybean field in the Xisanqi District of Beijing, People's Republic of China. The dissipation study showed that the half life of imazaquin in soil was 10.37 +/- 0.0135 days at 3 different application rates.

Background: Cigarette smoke from 2R1 research brand cigarettes and specific toxicants in smoke inhibit oviductal functioning. Our purpose was to test the hypothesis that smoke from commercial cigarettes, including harm reduction cigarettes, inhibits oviductal functioning and to measure the concentration of previously identified toxicants in smoke from research and commercial cigarettes., Methods: Mainstream (MS) and sidestream (SS) smoke solutions from two research, six traditional commercial and three harm reduction brands were tested in vitro using an oviductal assay that measures ciliary beat frequency, oocyte retrieval rate and smooth muscle contraction., Results: Generally, smoke from each brand of cigarette was inhibitory in the three oviductal bioassays. SS, the major component of environmental tobacco smoke, was usually more inhibitory than MS, the smoke inhaled by active smokers. Nine cigarette toxicants, previously shown to be highly inhibitory in the oviductal bioassays, were quantified in MS and SS. 4-Methylpyridine, which was inhibitory by itself in picomolar doses, was present in the highest concentration in MS and SS solutions from all brands tested. In general, toxicant concentrations were higher in SS than in MS solutions., Conclusions: These data show that commercial brands of cigarettes, including harm reduction cigarettes, contain toxicants that inhibit biological processes in the oviduct and could affect reproductive outcomes.

Objectives: The antibacterial spectrum of moxifloxacin includes all the major respiratory pathogens, and its pharmacokinetics demonstrate high peak concentrations in plasma as well as at respiratory sites. Nevertheless, tonsillar tissue concentrations have never been investigated. In this study we determined the moxifloxacin concentrations in plasma and tonsillar tissue after the administration of three doses of moxifloxacin 400 mg to adult patients with chronic or recurrent tonsillitis undergoing tonsillectomy., Methods: This was an uncontrolled, open-label, randomized, parallel group study including 35 patients assigned randomly to five groups of 7 patients each, depending on the time between the last dose of moxifloxacin and plasma and tissue sampling. Moxifloxacin was given orally once daily for 3 days; its concentrations were measured using a validated HPLC assay and fluorescence detection. Each sample was analysed twice and the mean value obtained used for the statistical analysis. Pharmacokinetic data were analysed by presenting descriptive statistics of moxifloxacin concentrations in plasma and tonsillar tissue., Results: C(max) occurred at 3 h in tonsillar tissue (mean 8.96 mg/L) and in plasma (mean 3.20 mg/L), the tissue/plasma concentration ratios (mean values) being constantly >2, ranging between 2.37 (after 2 h) and 2.93 (after 24 h), which indicates a prolonged maintenance of moxifloxacin concentration in tonsillar tissue compared with plasma. Variability among patients was present at 6 h, with the tonsillar tissue/plasma concentration ratio ranging between 0.8 and 3.4., Conclusions: Moxifloxacin achieves a good penetration in tonsillar tissue, which compares favourably with that reported for other fluoroquinolones. The moxifloxacin concentrations we observed exceed the MICs for the usual respiratory tract pathogens.

A microbiological assay and a liquid chromatographic method were validated for quantitation of moxifloxacin in tablets. The microbiological method consisted of a cylinder-plate agar diffusion assay using Micrococcus luteus ATCC 9341 as the test microorganism and phosphate buffer (0.1M, pH 8.0) as the diluent solution. The response graphs for standard and sample solutions were linear (r = 0.9479), and no parallelism deviations were detected in the tested levels of concentration (4.0, 8.0, and 16.0 microg/mL). The interday precision was 2.73%. Recovery values were between 96.25 and 100.5%. The chromatographic analyses were performed using a Shim-pack CLC-ODS column (250 x 4.6 mm, 5 microm) with a mobile phase consisting of (A) a mixture of phosphoric acid (0.17%, v/v) with tetramethylammonium hydroxide (0.05M) and acetonitrile (95 + 5, v/v) and (B) methanol (55 + 45, v/v) adjusted to pH 3.0. The flow rate was 1.0 mL/min, and detection was made at 294 nm. The method was linear in a range from 12.0 to 42 microg/mL (r = 0.9999), and the interday precision was 1.39%. Recovery ranged between 101.9 and 103.81%. Both validated methods were used to quantify the moxifloxacin content in tablets exposed to ultraviolet radiation, and similar results were obtained.

The effects of the flavonoids quercetin, apigenin and chrysin (10 microM) on the genetic toxicity of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and benzo[a]pyrene (BaP) was investigated at sub-cytotoxic concentrations in Chinese hamster V79 cells expressing human or rat cytochromes P450. In V79 r1A2-NH and V79 h1A1-MZ cells, none of the flavonoids increased DNA strand breaks (SB) (measured by the Comet assay) or produced detectable DNA adducts (measured by 32P-post-labelling). Neither IQ nor BaP produced DNA damage in the absence of expressed CYP1A2 or CYP1A1, respectively. DNA damage measured as SB and DNA adducts was detectable in V79 r1A2-NH cells expressing rat CYP1A2 when treated with IQ (2.5-50 microM) and this was inhibited by quercetin. Likewise, DNA damage (SB and DNA adducts) was elevated in V79 h1A1-MZ cells expressing human CYP1A1 when treated with BaP (0.1-0.5 microM) and this was inhibited by chrysin and apigenin, but not by quercetin. The specificity of CYP1A1 inhibition by chrysin and apigenin and CYP1A2 inhibition by quercetin was confirmed by ethylresorufin O-deethylase assay.

To obtain accurate estimates of DNA adduct levels yielded by genotoxic compounds, it is essential to completely digest adducted nucleotides to mononucleotides. We previously developed a suitable method, called modified method I, to obtain DNA adducts of heterocyclic amines as 32P-labeled-mononucleoside adduct 5'-phosphate forms, by use of nuclease P1 (NP1) and phosphodiesterase I (PDEI) to digest adducted oligonucleotides. In this study, we applied method I to 2-amino-3-methylimidazo[4,5-f]quinoline (IQ)-DNA adduct analysis and found that one of the IQ-DNA adducts, 5-(deoxyguanosin-N2-yI)-2-amino-3-methylimidazo[4,5-f]quinoline 3',5'-diphosphate (pdGp-N2-IQ), was resistant to the 3'-phosphatase activity of NP1, but sensitive to that of T4 polynucleotide kinase (PNK). DNA obtained from the liver of rats fed IQ was 32P-labeled by the standard method and the 32P-labeled nucleotides obtained were incubated with PNK and NP1 to remove 3'-phosphate groups and then digested with PDEI. Three spots were obtained. One major spot was identified as N-(deoxyguanosin-8-yl)-2-amino-3-methylimidazo[4,5-f]quinoline 5'-phosphate (pdG-C8-IQ) and a second abundant adduct as pdG-N2-IQ. The third spot, of which the structure is unknown, was minor. The new method is called modified method II. Modified method II could be applicable to a wide variety of chemicals.

The three IQ (2-amino-3-methylimidazo[4,5-f]quinoline) compounds IQ, MeIQx (2-amino-3,4-dimethyl[4,5-f]quinoxaline) and MeIQ (2-amino-3,4-dimethylimidazo[4,5-f]quinoline) have been found in boiled pork juice. To determine which Maillard reaction products are important in the formation of IQ-type mutagens in boiled pork juice, six Maillard reaction products were separately added to the pork juice before reflux boiling and then the mutagenicity of each sample was examined with Salmonella typhimurium TA98 in the presence of S9 mix. The addition of four Maillard reaction products enhanced the mutagenicity of pork juice 1.2-2.9-fold after reflux boiling. The highest level of enhancement was observed with tetrahydrothiophene, followed by 2,3-dimethylpyrazine, 3-methylpyridine and 2-methylpyridine. However, the addition of 2-acetylpyrrole and imidazole greatly inhibited the mutagenicity of pork juice. To confirm which IQ-type mutagens were changed, four major mutagenic fractions were monitored after HPLC separation by their mutagenicity with Salmonella typhimurium TA98. By comparing the retention time of authentic IQ compounds from boiled pork juice with added tetrahydrothiophene or 2,3-dimethylpyrazine, we show that four major HPLC fractions have significantly increased mutagenicity compared with the same fractions in boiled pork juice alone. In contrast, the mutagenicity of these fractions was considerably reduced with the addition of imidazole or 2-acetylpyrrole to the pork juice before refluxing. The residual amounts of tetrahydrothiophene and 2,3-dimethylpyrazine added to the boiled pork juice after heating were measured by gas chromatography and found to be inversely correlated with the mutagenicity of the pork juice.(ABSTRACT TRUNCATED AT 250 WORDS)

Fast, efficient liquid chromatographic separations of aza-arenes were obtained using both, reversed-phase, and adsorbent packings. Aza-arenes with 2-5 rings are separated within 20 minutes. Sample recovery is quantitative and permits subsequent uv and fluorescence spectrophotometric identifications. The detection limit for most aza-arenes was 1 ng with a 254-nm uv detector. An application to an air pollution problem demonstrates the usefulness of this approach.

A rapid and sensitive method for the measurement of nicotine in plasma, urine, saliva and breast milk is described. An internal standard (quinoline) is added to the samples and these are made alkaline and extracted with diethyl ether. The solvent is evaporated to small bulk and extracted with dilute acid which is then made alkaline. The nicotine is finally extracted into butyl acetate and an aliquot of this extract is injected onto a gas-chromatograph fitted with a nitrogen detector. Quantitation relies on comparison of peak areas and the calibration curve is linear over the concentration range 0.5 to 100 ng ml-1. Nicotine concentrations as low as 0.1 ng ml-1 can be measured. In addition, a micro-method is described which requires only 100 microliter of sample and yields an accurate result in 5 min.

Ciprofloxacin, a new carboxyquinoline antimicrobial agent, was compared with tobramycin in the treatment of chronic osteomyelitis due to Pseudomonas aeruginosa in rabbits. Treatment with tobramycin for four weeks was ineffective (94% had positive bone cultures). In contrast, ciprofloxacin administered for four weeks sterilized the bones of all but one (94%) of 18 treated rabbits. Treatment with ciprofloxacin for two weeks was less effective than treatment for four weeks but was more effective than either treatment with tobramycin or no therapy. Two of 10 isolates from rabbits treated with ciprofloxacin for two weeks were susceptible to MICs of ciprofloxacin that were 16- and fourfold greater than the MIC for the parent strain; the other eight isolates remained sensitive to ciprofloxacin with MICs equivalent to that of the parent strain.

A method has been developed to determine quantitatively quinoline, isoquinoline, and each of the methylquinoline isomers in cigarette smoke. This method was applied to the smoke of several different commercial cigarettes with and without filter tips. Quantitative analyses were accomplished by capillary gas chromatography, using a 50-m OV-101 fused silica capillary column and a 50-m Dexsil 300 fused silica column. Quinoline, isoquinoline and all seven of the methylquinolines were found in cigarette smoke. When cigarettes were analyzed with and without filter tips, these compounds were reduced by filtration, but not as much as tar was reduced. The significance of these data is discussed in view of the biological activity of specific isomers of these environmental pollutants.