Separation and identification of snuff constituents by using GC-MS and ICP-OES as well as health risk assessment of some existing heavy metals.

The identification of volatile organic components in snuff was accomplished using GC-MS analysis in this study. The findings of the GC-MS analysis revealed the presence of nicotine, its derivatives, and several other toxic chemicals that are hazardous to human health. Furthermore, the content of 34 elements in four brands of snuff consumed in Neyshabur City was determined by ICP-OES analysis (with five repetitions). The health hazards of measured heavy elements were examined from two perspectives: carcinogenic (7 heavy elements were checked) and non-carcinogenic (4 heavy elements were checked). The investigation of non-carcinogenic hazards from inhalation was based on the computation of the hazard quotient (HQ) factor, and the results indicated that inhaling five heavy metals, Cu, Pb, Ni, Zn, and Cd, does not represent a substantial health risk ((HQ < 1). In contrast, the computed HQ factors for Cr and As were relatively high (1 < HQ < 10), indicating a substantial health risk from breathing these two elements. The carcinogenic factor (CR value) results revealed that the degree of carcinogenic risk for Cd was very low (CR value less than 1 × 10-6) and did not pose a concern to the consumer population. However, the risk of As, Cr, and Ni exposure is considerable in the carcinogenic risk range (CR values between 1 × 10-6 and 1 × 10-4).

Is a spot urine sample a good substitution to estimate 24-h urinary sodium excretion in a population ≥ 50 years old? A validation study.

PURPOSE: A variety of prediction equations have been able to estimate 24-h urinary sodium excretion from spot urine samples; however, Iranians over the age of 50 have not been compared and verified. Using spot urine samples as a substitute for 24-h urine samples to estimate 24-h urine sodium excretion among the population age 50 and older are the purpose of this study. METHODS: A 24-h urinary sodium excretion was studied by well-known Kawasaki, INTERSALT, Tanaka, and World Health Organization/Pan American Health Organization (WHO/PAHO) formulas. On 360 individuals, the mean bias, agreements between estimated and measured values, correlation, absolute and relative differences, and misclassification rates were evaluated for four equations. RESULTS: As a result, the mean urinary sodium excretion for a 24-h period was 136.3 ± 52.21 mmol/24-h, which corresponds to a calculated intake of 9.1 ± 3.8 g of salt per day. According to the WHO/PAHO formula, the mean bias between measured values and estimated 24-h urinary sodium excretion is - 21.6 mg/day (95% confidence interval (CI) - 144.8, 101.6 mg/day), which is the smallest difference compared with the other three formulas. The lowest rate of individual misclassification of salt intake was 40% for WHO/PAHO, especially for those who consumed less than 9 g/day, while Kawasaki had the lowest misclassification rate at higher levels of salt intake. CONCLUSION: As a result of our research, the WHO/PAHO equations accurately predict 24-h urinary sodium excretion among Iranians aged ≥ 50 more than other equations, both at the population level and at the individual level. However, further study is needed in regard to different ages in Iran.

Study of Mesalazine Solubility in Ternary Mixtures of Ethanol, Propylene Glycol, and Water at Various Temperatures.

Mesalazine is a low-permeable and low-soluble drug, which makes it a class IV drug in the Biopharmaceutics Classification System. Hence, its solubilization can be helpful for various stages of formulation development. The purpose of this study was to investigate the solubilization manner and thermodynamics of mesalazine in ternary solvent combinations of {ethanol (1) + propylene glycol (2) + water (3)} using the shake-flask technique at (298.2-313.2) K. In the following, the mathematical representation of the acquired solubility data using some popular models was evaluated. The accuracies of the applied models were described by percentages of mean relative deviation (MRD%). Based on obtained results (MRD% < 10.0), it can be concluded that the trained models can adequately predict the solubility of mesalazine in the investigated ternary solvent combinations. The findings also revealed that the solution composition and temperatures greatly influence the solubility of mesalazine. In addition, the thermodynamic characteristics of the mesalazine dissolution process indicate that the mesalazine dissolution process is endothermic and entropy-driven. The generating data in the current work also expands the available solubility database for mesalazine in the solvent mixtures.

Introducing hierarchical hollow MnO2 microspheres as nanozymes for colorimetric determination of captopril.

A simple sensor was developed for the colorimetric determination of captopril (CPT). Herein, hierarchical hollow MnO2 microspheres (HH-MnO2) were applied as nanozymes with peroxidase-mimetic activity. Free cation radicals with a strong absorption signal (λmax at 653 nm) were generated via a redox reaction between 3, 3', 5, 5'-tetramethylbenzidine (TMB) and HH-MnO2. Captopril could successfully prevent the generation of blue-colored free cation radicals. The influence of CPT concentration on the absorption of the generated radicals was monitored by UV-Vis spectroscopy. The corresponding linear concentration range was from 1.0 to 30.0 µg mL-1 (4.6-138.1 µmol L-1), and the detection limit was found to be 0.26 µg mL-1 (1.2 µmol L-1). As a practical usage, the developed sensor was effectively utilized to measure the content of CPT in pharmaceutical formulations.

Deep eutectic solvent dependent carbon dioxide switching as a homogeneous extracting solvent in liquid-liquid microextraction.

A miscible-immiscible deep eutectic solvent (DES) containing monoethanolamine/4-methoxyphenol was used as an extraction solvent in a homogeneous liquid-liquid microextraction (HLLME). The method was used to preconcentrate chlorobenzenes in water samples followed by separating and analyzing them by gas chromatography-mass spectroscopy (GC-MS). A special feature of the new extraction method is that a green miscible solvent was used as an extractant in the HLLME method. The developed extraction technique provided enrichment factors in the range of 13.1-42.1 for extraction from only 1.0 mL of the aqueous sample solution. The effects of various experimental parameters were investigated and optimized. The optimal conditions were as follows: vortex time: 30.0 s, bubbling CO2 gas: 1.0 min, salt concentration: 5.0% w/v, rate and time of centrifuge: 4000.0 rpm and 3.0 min, respectively, and DES volume: 30.0 µL. The limit of detections and the limit of quantifications for the four targeted analytes varied from 0.01-0.15 and 0.025-0.5 µg L-1, respectively. The precision and long-term precision tests for the developed method were found to be less than 11.0%. Two real samples, including toilet air freshener and car perfume, were analyzed. The applied DES in the HLLME method provides a fast means of sample preparation for environmental aqueous sample solutions.

Electrodeposition of poly-ethylenedioxythiophene-graphene oxide nanocomposite in a stainless steel tube for solid-phase microextraction of letrozole in plasma samples.

Coated stainless steel was used as an in-tube solid-phase microextraction for the extraction of letrozole from plasma samples. The coating process on the inner surface of the stainless steel was conducted by a simple electrodeposition process. The coated composite was prepared from 3,4-ethylenedioxythiophene and graphene oxide. In this composite, graphene oxide acts as an anion dopant and sorbent. The coated nanostructured polymer was characterized using different techniques. The operational factors affecting the extraction process, including pH, adsorption, and desorption time, the recycling flow rate of the sample solution, sample volume, desorption solvent type and its volume, and ionic strength were optimized to achieve the best extraction efficiency of the analyte. The total extraction time including adsorption and desorption steps was about 15.0 min. The developed method demonstrated a linear range of 5.0-1500.0 µg/L with a limit of detection of 1.0 µg/L. The repeatability of the developed extraction approach in terms of intraday, interday, and fiber to fiber was attained in the range of 4.9-8.3%. After finding the optimal conditions, the potential of the described approach for letrozole quantitation was investigated in plasma samples, and satisfactory results were obtained.

Employment of a natural deep eutectic solvent as a sustainable mobile phase additive for improving the isolation of four crucial cardiovascular drugs by micellar liquid chromatography.

Modification of micellar liquid chromatography (MLC) with a natural deep eutectic solvent (NADES) and butanol was effectively performed for analysis of four crucial cardiovascular drugs namely aspirin, atorvastatin, metformin, and metoprolol. The multivariate software tools were employed for screening and optimizing the primary experimental parameters including sodium dodecyl sulphate concentration ([SDS]) as well as the volume percentages of NADES, butanol, and glacial acetic acid (GAC). By using the desirability function, the optimal framework of the mobile phase was obtained at volume ratio of 83:10:3.5:3.5, respectively, for SDS (0.09 mol L-1), butanol, NADES, and GAC. Moreover, the curvature and effect plots were applied for evaluating the robustness of the procedure. At the optimal conditions, the drugs were excellently separated within a total analysis time of 12 min when the flow rate of the mobile phase was 1 mL min-1. To certify the performance of the developed procedure, the Food and Drug Administration guidelines for bioanalytical analysis have been implemented. The designed MLC system was successfully utilized for the quantification of the drugs in urine and plasma samples.

Designing a sustainable mobile phase composition for melamine monitoring in milk samples based on micellar liquid chromatography and natural deep eutectic solvent.

Modified micellar liquid chromatography (MLC) with a natural deep eutectic solvent (NADES), produced from choline chloride (ChCl) and ethylene glycol (EG), was employed for melamine (MEL) monitoring in milk matrix. This sustainable mobile phase was attained through chemometrical optimization of crucial variables including concentration of sodium dodecyl sulphate ([SDS]) along with volume percentages of both NADES and glacial acetic acid (GAC). The desirability function and central composite design were utilized as chemometrical tools. Retention time (tR-MEL), and chromatographic peak width of MEL at 50% of its height (W50%-MEL) were considered for finding the best possible arrangement of the influential factors in the configuration of the mobile phase. Under the optimal experimental conditions of 0.10 mol L-1 SDS, 4% (v/v) NADES, and 4% (v/v) GAC, the results showed that both tR-MEL and W50%-MEL drastically decreased when NADES was a part of the mobile phase composition. This indicated that ChCl-EG-based NADES had a significant impact on improving the chromatographic behaviour of an ionizable polar compound, MEL. At the optimal point, MEL was eluted in approximately 10 min without being interfered by coexisting proteins and endogenous species in milk. The practical performance of the mobile phase was established through direct injection of milk samples into the MLC system. The eligibility criteria of the United State-Food and Drug Administration (US-FDA) were considered for validation of the introduced methodology.

Quantitative structure-retention relationship for chromatographic behaviour of anthraquinone derivatives through considering organic modifier features in micellar liquid chromatography.

A simple and informative quantitative structure-retention relationship (QSRR) model has been introduced for prediction of retention times in some anthraquinone derivatives using reversed-phase micellar liquid chromatography (MLC) technique. In the developed multiple linear regression model, the structural descriptors of analytes as well as the empirical parameters of organic modifiers in the applied MLC systems have been considered. Retention times of 77 chromatographic samples (16 anthraquinones were evaluated by using 6 different organic modifiers) were experimentally determined and utilized as the independent variables of the QSRR model. Five small-chain alcohols (methanol, ethanol, propanol, butanol, and pentanol) as well as acetonitrile were used as the eluent modifiers. A five-parametric model was attained for the logarithm of the retention time values which covered about 96 and 95% variance of the chromatographic data in training and cross-validation, respectively. The presence of an excellent correlation coefficient for external validation test (= 0.94) and a well-applicable domain proved the prediction ability of the constructed model. Both validity and reliability of the formulated model were examined through its application on diverse random-selected training and test sets. Moreover, quantum chemical calculations were performed in the framework of density functional theory to simulate the interactions between AQs and modifiers and gain mechanistic details about the retention behavior in the MLC system.

Analysis of malondialdehyde in human plasma samples through derivatization with 2,4-dinitrophenylhydrazine by ultrasound-assisted dispersive liquid-liquid microextraction-GC-FID approach.

A sensitive and reliable ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) procedure was developed and validated for extraction and analysis of malondialdehyde (MDA) as an important lipids-peroxidation biomarker in human plasma. In this methodology, to achieve an applicable extraction procedure, the whole optimization processes were performed in human plasma. To convert MDA into readily extractable species, it was derivatized to hydrazone structure-base by 2,4-dinitrophenylhydrazine (DNPH) at 40 °C within 60 min. Influences of experimental variables on the extraction process including type and volume of extraction and disperser solvents, amount of derivatization agent, temperature, pH, ionic strength, sonication and centrifugation times were evaluated. Under the optimal experimental conditions, the enhancement factor and extraction recovery were 79.8 and 95.8%, respectively. The analytical signal linearly (R2 = 0.9988) responded over a concentration range of 5.00-4000 ng mL-1 with a limit of detection of 0.75 ng mL-1 (S/N = 3) in the plasma sample. To validate the developed procedure, the recommend guidelines of Food and Drug Administration for bioanalytical analysis have been employed.

Simultaneous determination of captopril and hydrochlorothiazide by using a carbon ionic liquid electrode modified with copper hydroxide nanoparticles.

A carbon electrode modified with the ionic liquid octylpyridinium hexafluorophosphate and copper hydroxide nanoparticles was employed in an electrochemical assay for simultaneous determination of captopril (CPT) and hydrochlorothiazide (HCT). The electrode showed two well-defined oxidation peaks for CPT (at 0.22 V) and HCT (at 0.73 V, both vs. Ag/AgCl) at pH 8.0 using square wave voltammetry. Calibration plots are linear in the concentration ranges of 0.7-70 µM (CPT) and 3-600 µM (HCT), with detection limits of 12 and 60 nM, respectively. The electrode was repeatedly applied to simultaneous determination of CPT and HCT in pharmaceutical formulation without showing any fouling. Graphical abstract Application of carbon ionic liquid electrode (CILE) modified with Cu(OH)2 nanoparticles (Cu(OH)2NP/CILE) for the simultaneous determination of captopril (CPT) and hydrochlorothiazide (HCT) in pharmaceutical formulation is presented.

Green-modified micellar liquid chromatography for isocratic isolation of some cardiovascular drugs with different polarities through experimental design approach.

Bilayer pseudo-stationary phase micellar liquid chromatography (MLC) was developed for simultaneous isocratic isolation of hydrochlorothiazide, as a basic-polar (hydrophilic) cardiovascular drug, as well as triamterene and losartan potassium, as acidic-nonpolar (hydrophobic) cardiovascular drugs. Utilizing a deep eutectic solvent (DES), as a novel green mobile phase additive in combination with acetonitrile (ACN) and acetic acid (ACA), drastically improved the chromatographic behavior of the drugs. Concentration of sodium dodecyl sulphate (SDS), as well as volume percentages of ACN, DES, and ACA were optimized by using a central composite design. The optimal composition of the mobile phase (0.12 mol L-1 SDS, 5% ACN, 4% DES, and 2% ACA) was chosen through the desirability function. The chromatographic peaks of both hydrophilic and hydrophobic drugs, respectively, emerged at high and low retention time values in the shortest total analysis time of 20 min (at a flow rate of 2 mL min-1). Analytical characterization of the developed approach was investigated through Food and Drug Administration (FDA) guidelines. Applicability of the method was evaluated by analysing of human plasma samples which were directly injected into the system.

Gas-assisted dispersive liquid-phase microextraction using ionic liquid as extracting solvent for spectrophotometric speciation of copper.

Gas-assisted dispersive liquid-phase microextraction (GA-DLPME) has been developed for preconcentration and spectrophotometric determination of copper ion in different water samples. The ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate and argon gas, respectively, were used as the extracting solvent and disperser. The procedure was based on direct reduction of Cu(II) to Cu(I) by hydroxylamine hydrochloride, followed by extracting Cu(I) into ionic liquid phase by using neocuproine as the chelating agent. Several experimental variables that affected the GA-DLPME efficiency were investigated and optimized. Under the optimum experimental conditions (IL volume, 50µL; pH, 6.0; acetate buffer, 1.5molL(-1); reducing agent concentration, 0.2molL(-1); NC concentration, 120µgmL(-1); Ar gas bubbling time, 6min; argon flow rate, 1Lmin(-1); NaCl concentration, 6% w/w; and centrifugation time, 3min), the calibration graph was linear over the concentration range of 0.30-2.00µgmL(-1) copper ion with a limit of detection of 0.07µgmL(-1). Relative standard deviation for five replicate determinations of 1.0µgmL(-1) copper ion was found to be 3.9%. The developed method was successfully applied to determination of both Cu(I) and Cu(II) species in water samples.

Analysis of losartan and carvedilol in urine and plasma samples using a dispersive liquid-liquid microextraction isocratic HPLC-UV method.

BACKGROUND: A simple, precise and sensitive HPLC method has been developed for simultaneous determination of carvedilol and losartan in human plasma and urine samples. The analytes were extracted by a dispersive liquid-liquid microextraction method. A mobile phase of 15 mM sodium dihydrogen phosphate buffer (pH 4.0)/acetonitrile/2-propanol (70/27.5/2.5, v/v/v) was used to separate the drugs using a Waters® ODS column (250 × 4.6 mm) and detected by a UV detector at 222 nm. RESULTS: The developed method is selective for studied drugs possessing a linearity range of 0.1-1.0 and 0.05-0.75 µg/ml, respectively, for losartan and carvedilol with precision <15%. The accuracy is better than 15% and the mean recovery of carvedilol and losartan was 98.9 and 100.2% for plasma and 100.7 and 100.5% for urine samples, respectively. CONCLUSION: The developed method is applicable for therapeutic drug monitoring and PK analyses.

Spectrofluorimetric determination of human serum albumin using terbium-danofloxacin probe.

A spectrofluorimetric method is proposed for the determination of human serum albumin (HSA) and bovine serum albumin (BSA) using terbium-danofloxacin (Tb(3+)-Dano) as a fluorescent probe. These proteins remarkably enhance the fluorescence intensity of the Tb(3+)-Dano complex at 545 nm, and the enhanced fluorescence intensity of Tb(3+)-Dano is proportional to the concentration of proteins (HSA and BSA). Optimum conditions for the determination of HSA were investigated and found that the maximum response was observed at: pH = 7.8, [Tb(3+)] = 8.5 × 10(-5) mol L(-1), [Dano] = 1.5 × 10(-4) mol L(-1). The calibration graphs for standard solutions of BSA, HSA, and plasma samples of HSA were linear in the range of 0.2 × 10(-6) - 1.3 × 10(-6) mol L(-1), 0.2 × 10(-6) - 1.4 × 10(-6) mol L(-1), and 0.2 × 10(-6) - 1 × 10(-6) mol L(-1), respectively. The detection limits (S/N = 3) for BSA, HSA, and plasma sample of HSA were 8.7 × 10(-8) mol L(-1), 6.2 × 10(-8) mol L(-1), and 8.1 × 10(-8) mol L(-1), respectively. The applicability of the method was checked using a number of real biological plasma samples and was compared with the UV spectrometric reference method. The results was showed that the method could be regarded as a simple, practical, and sensitive alternative method for determination of albumin in biological samples.