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Dispersive liquid–liquid microextraction (DLLME) combined with ultra-high performance liquid chromatography-diode array detector (UHPLC-DAD) method has been developed and validated for the determination of parabens in personal care products.

The greening of pharmaceutical analysis is gaining interest. In this work, a natural deep eutectic solvent was synthesized and utilized as a green alternative in dispersive liquid–liquid microextraction for determination of chloramphenicol in honey.

Medicinal plants are widely used in the Kingdom of Saudi Arabia to treat various ailments in the form of folk medicine. Forty four such medicinal plant samples were collected from local markets and evaluated for the presence of 14 elements (Mn, Cr, Co, Ni, Cu, Mo, Al, Pb, Ba, Zn, Ag, Hg, Bi, Cd). Microwave-assisted digestion with inductively coupled plasma-mass spectrometry (ICP-MS) was applied to determine the elemental composition in these medicinal plants. Widespread occurrence of these elements was observed in all plant samples, except for Bi and Co where the lowest mean values of 0.03 ± 0.04 and 0.03 ± 0.15 were observed, respectively. The descending order for mean (μg/g) elemental occurrence observed was as follows: BaAlZnNiMnBaHgMoCuCrAgCdCoBi, whereas the range for these elements in the 44-medicinal plants was as follows: PbAlZnNiMnCuMoAgBaHgCoCdCrBi. Pb, Hg and Cd were found beyond the maximum limits in these medicinal plants, while the remaining elements were found well within the range of maximum limits. A number of medicinal plants showed high amounts of these elements. Some plants contained more than one element, such as

Rational and Objective Evaluate predictors of Emergency Department (ED) utilization by adult patients receiving hemodialysis (HD) and interventions to reduce ED utilization by HD patients. Study Design We searched Ovid MEDLINE, Ovid EMBASE, and The Cochrane Library for randomized controlled trials and observational studies up until April 2020. Selection Criteria for Studies We included studies that investigated predictors of ED utilization and/or interventions to reduce ED utilization in HD patients. Data Extraction We extracted data regarding study design, study population, and results regarding ED utilization from 38 studies using Excel software. Analytical Approach We performed narrative synthesis to group articles that investigated similar themes. Results 1060 titles and abstracts were screened, of which 98 were selected for full-text review. 38 studies met inclusion criteria and underwent data extraction. Quality was high according to the Downs and Black tool, with 11 rated as good, 22 as fair, and 5 as poor. 34 studies described predictors of ED utilization, while 4 studies investigated interventions where ED utilization was studied. Our narrative synthesis produced 8 concept subgroups in the core concepts of access to care, comorbidity burden, and new healthcare models. Poor access to care and high comorbidity burden are associated with increased ED use. No ED-based interventions designed to reduce ED utilization were identified, but recent changes in healthcare systems like the formation of ESRD Seamless Care Organizations (ESCOs) and greater involvement of palliative care services are associated with improved outcomes. Limitations Clinical heterogeneity and variability in the included studies precluded a meta-analysis. Conclusions HD patients' high ED use is multifactorial. Further research is required to understand and predict ED utilization in this vulnerable population, which will facilitate the development of interventions to reduce avoidable ED use.

Hydroxychloroquine is a drug that has been widely used during the early stages of COVID-19 pandemic. Different liquid chromatographic methods have been reported for the analysis of hydroxychloroquine in various biological matrices such as human plasma, serum, whole blood, oral fluid, rat plasma and tissues. In this comparative study, the most popular tools used for assessing the greenness profile: National Environmental Methods Index (NEMI), Eco-Scale Assessment (ESA), Green Analytical Procedure Index (GAPI) and Analytical Greenness metric (AGREE) were utilized to evaluate the ecological impact of eighteen liquid chromatographic methods developed for the bioanalysis of COVID-19 drug; hydroxychloroquine. NEMI is the simplest tool for evaluating the greenness profile of developed methods, but it is the least informative approach as all the reported methods had the same NEMI pictograms. On the other hand, GAPI is a dependable tool providing a complete picture about the method greenness starting from sampling until the final determination. ESA and AGREE tools are digitally presented and more easily applied. Therefore, their utilization for greenness assessment is highly recommended. Selection of the highest eco-friendly analytical procedure is of a paramount importance for protecting human health and the environment. Considering the greenness of the analytical procedures is highly recommended before proceeding to routine use in order to minimize the chemical hazards to the environment. The most eco-friendly analytical procedures for the analysis of hydroxychloroquine in biological samples according to ESA, GAPI and AGREE tools will be highlighted and discussed.

This study was carried outto investigatethe ameliorative effect of both of Dandelion and Ginko.biloba extract on liver toxicities induced by thioacetamide (TAA) in male albino rats.Sixty male albino rats were divided into sixgroups (10 rats pereach).Group 1 (Negative control): which received 1 ml of saline orally and 1ml of saline intra-peritoneal (I/P),Group 2: received TAA for induction of hepatic injuryGroup 3:received TAA+ ginkgo biloba extract (50 mg/ b.wt.),Group 4: received TAA+ ginkgo biloba extract (100 mg/ kg b.wt.).Group 5: which received TAA + dandelion extract (250 mg/ kg b.wt).Group 6: which received TAA+ dandelion extract (500 mg/ kg b.wt.).TAA was administrated by I/P route at dose level of 250mg/kg b.wt , extracts were administrated orally, they were administrated 3 times/week for 4 weeks. The obtained results revealed that intoxication with TAAshowed a significant elevation in serum liver enzymes activity, total bilirubinplussignificant decrease in serum levels of total proteins andalbumin, significant increase in total cholesterol and triglycerides.At the same time ,intoxication with TAA exhibited severe oxidative damged stress ,represented by a significant increase in hepatic level of malondialdehyde (MDA)as well asa significant decrease in reduced glutathione (GSH).The characteristic pathological changes were represented by ,(TAA),severe degenerative andnecrotic alterationsin the hepatocytes. The treatment with G.biloba and D- in different treateddosesattenuatedTAA-induced,serum biochemical alterations, oxidative stressand histopathological changes in liver.

Background Obesity and diabetes are two chronic metabolic diseases whose prevalence is increasing at an alarming rate globally. A close association between obesity, diabetes, and insulin resistance has been identified, and many studies have pinpointed obesity as a causal risk factor for insulin resistance. However, the mechanism underlying this association is not entirely understood. In the past decade, ceramides have gained attention due to their accumulation in certain tissues and their suggested role in initiating insulin resistance. This study aims to determine the association of specific ceramides and their major metabolizing enzymes with obesity-associated insulin resistance. Methods The samples comprised subcutaneous adipose tissues collected from three cohorts: lean non-diabetic (controls; n = 20), obese-non-diabetic (n = 66), and obese-diabetic (n = 32). Ceramide levels were quantified using LC-MS/MS and mRNA expression level for different enzymes were estimated using real-time PCR-based RNA expression analysis. Results C16-ceramide (P = 0.023), C16-dihydro-ceramide (P P = 0.009) and C24-ceramide (P = 0.040) levels were significantly increased in the obese cohort compared to the control group. However, stratification of the obese group revealed a significant increase in the C16-ceramide levels (P = 0.027) and mRNA over expression of the serine palmitoyl transferases enzyme subunit SPT1 (P Conclusions The present study indicates that C16-ceramide plays a pivotal role in inducing insulin resistance. Overexpression of SPT1 in the obese-diabetic group and its positive correlation with C16-ceramide suggest that C16-ceramide was generated through the de novo pathway.

Summary We present a global atlas of 4,728 metagenomic samples from mass-transit systems in 60 cities over 3 years, representing the first systematic, worldwide catalog of the urban microbial ecosystem. This atlas provides an annotated, geospatial profile of microbial strains, functional characteristics, antimicrobial resistance (AMR) markers, and genetic elements, including 10,928 viruses, 1,302 bacteria, 2 archaea, and 838,532 CRISPR arrays not found in reference databases. We identified 4,246 known species of urban microorganisms and a consistent set of 31 species found in 97% of samples that were distinct from human commensal organisms. Profiles of AMR genes varied widely in type and density across cities. Cities showed distinct microbial taxonomic signatures that were driven by climate and geographic differences. These results constitute a high-resolution global metagenomic atlas that enables discovery of organisms and genes, highlights potential public health and forensic applications, and provides a culture-independent view of AMR burden in cities., Graphical abstract, Highlights • Cities possess a consistent “core” set of non-human microbes • Urban microbiomes echo important features of cities and city-life • Antimicrobial resistance genes are widespread in cities • Cities contain many novel bacterial and viral species, This systematic, worldwide catalog of urban microbiomes represents a metagenomic atlas important for understanding the ecology, virulence, and antibiotic resistance of city-specific microbial communities.

Although studies have shown that urban environments and mass-transit systems have distinct genetic profiles, there are no systematic worldwide studies of these dense, human microbial ecosystems. To address this gap in knowledge, we created a global metagenomic and antimicrobial resistance (AMR) atlas of urban mass transit systems from 60 cities, spanning 4,728 samples and 4,424 taxonomically-defined microorganisms collected for three years. This atlas provides an annotated, geospatial profile of microbial strains, functional characteristics, antimicrobial resistance markers, and novel genetic elements, including 10,928 novel predicted viral species, 1302 novel bacteria, and 2 novel archaea. Urban microbiomes often resemble human commensal microbiomes from the skin and airways, but also contain a consistent “core” of 31 species which are predominantly not human commensal species. Samples show distinct microbial signatures which may be used to accurately predict properties of their city of origin including population, proximity to the coast, and taxonomic profile. These data also show that AMR density across cities varies by several orders of magnitude, including many AMRs present on plasmids with cosmopolitan distributions. Together, these results constitute a high-resolution, global metagenomic atlas, which enables the discovery of new genetic components of the built human environment, highlights potential forensic applications, and provides an essential first draft of the global AMR burden of the world’s cities.

A synthesis of phenotypic and quantitative genomic traits is provided for bacteria and archaea, in the form of a scripted, reproducible workflow that standardizes and merges 26 sources. The resulting unified dataset covers 14 phenotypic traits, 5 quantitative genomic traits, and 4 environmental characteristics for approximately 170,000 strain-level and 15,000 species-aggregated records. It spans all habitats including soils, marine and fresh waters and sediments, host-associated and thermal. Trait data can find use in clarifying major dimensions of ecological strategy variation across species. They can also be used in conjunction with species and abundance sampling to characterize trait mixtures in communities and responses of traits along environmental gradients., Measurement(s)Trait • phenotypic trait • quantitative genomic traitTechnology Type(s)digital curationFactor Type(s)habitat • speciesSample Characteristic - OrganismArchaea • BacteriaSample Characteristic - Locationglobal Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.12221732

Green analytical chemistry (GAC) aims at eliminating the harmful impacts of hazardous chemicals on human health and the environment. Replacing the polluting analytical methodologies with cl...

In this work, a fast analytical method based on hydrophilic interaction liquid chromatographic-Ultraviolet detection (HILIC-UV) using a short narrow bore cyano-bonded silica column packed with full...

The Microbe Directory (TMD) is a comprehensive database of annotations for microbial species collating features such as gram-stain, capsid-symmetry, resistance to antibiotics and more. This work presents a significant improvement to the original Microbe Directory (2018). This update adds 68,852 taxa, many new annotation features, an interface for the statistical analysis of microbiomes based on TMD features, and presents a portal for the broad community to add or correct entries. This update also adds curated lists of gene annotations which are useful for characterizing microbial genomes. Much of the new data in TMD is sourced from a set of databases and independent studies collating these data into a single quality controlled and curated source. This will allow researchers and clinicians to have easier access to microbial data and provide for the possibility of serendipitous discovery of otherwise unexpected trends.

Greening the analytical methods used for analysis of pharmaceuticals has been receiving great interest aimed at eliminating or minimizing the amount of organic solvents consumed daily worldwide without loss in chromatographic performance. Traditional analytical LC techniques employed in pharmaceutical analysis consume tremendous amounts of hazardous solvents and consequently generate large amounts of waste. The monetary and ecological impact of using large amounts of solvents and waste disposal motivated the analytical community to search for alternatives to replace polluting analytical methodologies with clean ones. In this context, implementing the principles of green analytical chemistry (GAC) in analytical laboratories is highly desired. This review gives a comprehensive overview on different green LC pathways for implementing GAC principles in analytical laboratories and focuses on evaluating the greenness of LC analytical procedures. This review presents green LC approaches for eco-friendly analysis of pharmaceuticals in industrial, biological, and environmental matrices. Graphical Abstract Green pathways of liquid chromatography for more eco-friendly analysis of pharmaceuticals.

The quality of over-the-counter (OTC) pain relievers is important to ensure the safety of the marketed products in order to maintain the overall health care of patients. In this study, the multivariate curve resolution-alternating least squares (MCR-ALS) chemometric method was developed and validated for the resolution and quantification of the most commonly consumed OTC pain relievers (acetaminophen, acetylsalicylic acid, ibuprofen, naproxen, and caffeine) in commercial drug formulations. The analytical performance of the developed chemometric methods such as root mean square error of prediction, bias, standard error of prediction, relative error of prediction, and coefficients of determination was calculated for the developed model. The obtained results are linear with concentration in the range of 0.5–7 μg/mL for acetaminophen and 0.5–3.5 and 0.5–3 μg/mL for naproxen and caffeine, respectively, while the linearity ranges for acetyl salicylic acid and ibuprofen were 1–15 μg/mL. High values of coefficients of determination ≥0.9995 reflected high predictive ability of the developed model. Good recoveries ranging from 98.0% to 99.7% were obtained for all analytes with relative standard deviations (RSDs) not higher than 1.62%. The optimized method was successfully applied for the analysis of the studied drugs either in their single or coformulated pharmaceutical products without any separation step. The optimized method was also compared with a reported HPLC method using paired t-test and F-ratio at 95% confidence level, and the results showed no significant difference regarding accuracy and precision. The developed method is eco-friendly, simple, fast, and amenable for routine analysis. It could be used as a cost-effective alternative to chromatographic techniques for the analysis of the studied drugs in commercial formulations.

The study presents the application of multivariate curve resolution alternating least squares (MCR-ALS) with a correlation constraint for simultaneous resolution and quantification of ketoprofen, naproxen, paracetamol and caffeine as target analytes and triclosan as an interfering component in different water samples using UV-Vis spectrophotometric data. A multivariate regression model using the partial least squares regression (PLSR) algorithm was developed and calculated. The MCR-ALS results were compared with the PLSR obtained results. Both models were validated on external sample sets and were applied to the analysis of real water samples. Both models showed comparable and satisfactory results with the relative error of prediction of real water samples in the range of 1.70–9.75 % and 1.64–9.43 % for MCR-ALS and PLSR, resp. The obtained results show the potential of MCR-ALS with correlation constraint to be applied for the determination of different pharmaceuticals in complex environmental matrices.

Background: Considering the environmental impact of analytical procedures necessitates replacing the polluting analytical methods with green alternatives. Objective: This study aims to develop and validate a multivariate curve resolution–alternating least-squares (MCR-ALS) method with correlation constraint for the simultaneous determination of theophylline, ambroxol, and guaifenesin as target analytes in the presence of methylparaben and propylparaben as interfering components. In addition, a partial least-squares regression (PLSR) method was also developed andoptimized. Method: The developed methods were validated according to International Conference on Harmonization guidelines and successfully applied for the quantification of the target analytes in different pharmaceutical dosage forms. Results: Figures of merit such as root mean square error of prediction, bias, standard error of prediction, and relative error of prediction for both models were calculated, and they showedsimilar and satisfactory results. Correlation coefficients ranged between 0.9988 and 0.9992, reflectinghigh predictive ability. The optimized methods werecompared with a reported HPLC method using one-wayanalysis of variance and showed no significant difference regarding accuracy and precision. Conclusions: The proposed chemometrics methods can be used as an eco-friendly alternative for chromatographic techniques for the quality control analysis of the studied mixture in different pharmaceutical dosage forms. Highlights: An MCR-ALS model was developed. The developed model was compared with a PLSR model. Both models were validated and successfully used for the determinationof a multicomponent pharmaceutical mixture. The developed method is eco-friendly, fast, reliable, and cost-effective.

Background: Green analytical chemistry (GAC) aims to eliminate or minimize the amount of hazardous solvents consumed and generated daily worldwide. Considering the environmental impact of all analytical procedures and replacing the polluting methodologies with clean ones is of a paramount interest. Objective: This work aims to develop and validate a sustainable, fast, and economic ultrahigh-performance liquid chromatography method for simultaneous determination of methylxanthines in commercial tea samples as well as to evaluate the greenness profile of the proposed method using two greenness assessment tools: National Environmental Methods Index (NEMI) and analytical Eco-scale. Methods: The method was designed based on applying GAC principles in method development. The green chromatography approach was applied by using benign mobile phases. The chromatographic separation was optimized to minimize sample preparation, achieve short analysis time with low solvent consumption, and minimize waste generation. Results: All the studied analytes were separated in only 1.7 min. The detection limits of the studied analytes ranged from 0.015 to 0.03 mg/L, while LOQs were in the range of 0.05 to 0.1 μg/L with UV detection. The proposed method neither uses nor generates harmful chemicals, it passes the four quadrants of the NEMI greenness profile, and it has a high Eco-scale score. Conclusions: Compared with the reported methods, the proposed method is greener, more economical, and faster; therefore, it can be used as a green alternative to the existing conventional methods for routine analysis of the studied analytes without harming the environment.

A simple, rapid, sensitive and eco-friendly method has been developed for the simultaneous determination, preconcentration and extraction of phthalate esters (dimethyl phthalate, diethyl phthalate, dibutyl phthalate, benzyl butyl phthalate and bis(2-ethylhexyl) phthalate) in perfumes using dispersive liquid–liquid microextraction (DLLME) coupled to gas chromatography-mass spectrometry (GC-MS). Various factors affecting the DLLME efficiency, including the type and volume of the extracting and dispersing solvents, salt addition and vortex extraction time were optimized. Under optimum conditions, the proposed method provided low detection limits (0.003–0.070 ng mL−1), high extraction recovery (85.6–95.8%), wide linearity range (1.0–1000 ng mL−1) with good regression coefficients (>0.9984) and good precision (RSD% < 4.2%). The optimized method was successfully utilized for the analysis of different branded perfume samples and satisfactory results were obtained.

Electromagnetic radiation is the fastest growing environmental factor due to the vast development in technology in the last decades. Awareness about radiation has received more attention worldwide due to its health hazards. Adolescents are exposed to radiation from various sources on a daily basis. The number of studies conducted to assess the knowledge and perception of adolescents and young adults regarding radiation and its risks is limited, especially in the Middle East. The aim of this study was to assess the knowledge and perception about radiation and its associated hazards among adolescents and young adults. Additionally, our aim was to identify the best methods of education regarding radiation and its protective measures. A cross-sectional study was conducted among 506 participants in Saudi Arabia. It was found that the overall knowledge and awareness on radiation sources and its hazards among adolescents and young adults is inadequate. The majority of participants had misconceptions regarding radiation sources and its detriments to health. Socio-demographic variables were associated with the participants’ perception. Educating adolescents on radiation and its safety measures is much needed. It was found that the most preferred methods of education are social media and health care providers. The findings of this study will provide insight when designing future interventions to promote specific messages to enhance knowledge and improve awareness regarding radiation.

Analytical chromatographic methods are widely used for the analysis of organic compounds in different matrices. Traditional gas and liquid chromatographic methods are characterized by large consumption of resources and waste generation leading to harmful impacts on operators’ safety and on the environment. With the scientific and public awareness about the environment and human health, analytical community members have been motivated to use green alternatives and replace polluting analytical methodologies with clean ones. In this context, implementing the principles of green analytical chemistry in analytical laboratories is highly desired. Liquid chromatography could be greener by using more eco-friendly solvents, reducing the solvent volume needed by using shorter and/or smaller diameter columns packed with fully porous sub-2-μm particles or superficially porous particles, and high temperature mobile phases. Gas chromatography (GC) could also be greener by appropriate selection of carrier gas, speeding up GC analysis time, and using low thermal mass technology in order to reduce energy consumption. Also, new green approaches such as automation, miniaturization of analytical devices, direct analysis, and the possibility of locating the chromatograph online or at-line are considered a step forward in reducing the environmental impact of chromatographic analyses.

Fast separations are very desirable in laboratories that analyze large numbers of samples per day or those needing short turn-around times. Traditional HPLC methods using conventional stationary phases and standard column dimensions require significant amounts of organic solvents and generate large volumes of waste. With growing awareness about the environment, the development of green technologies has been receiving increasing attention. In this work, a very fast green analytical method based on LC-UV using a short narrow bore column packed with fully porous sub-2 μm particles has been developed for simultaneous determination of nine pharmaceuticals in wastewater and surface water. The chromatographic separation was optimized in order to achieve short analysis time and good resolution for all analytes in a single run. All analytes could be separated in 1 min with good resolution. Sample preparation was executed by solid phase extraction using Oasis HLB cartridges. The method developed was validated based on parameters such as linearity, precision, accuracy, detection, and quantification limits. The recovery ranged from 70.9 to 92.5% with SDs not higher than 5.4%, except for acetaminophen and sulphanilamide. LODs ranged from 0.6-2.5 μg/L, while the LOQs were in the range 2-8 μg/L.

High temperature in HPLC is considered a valuable tool helping to overcome the increase in the column backpressure when using small packing particles such as sub-2 μm, as it allows reduction in the mobile-phase viscosity. In this study, a fast analytical method based on HPLC-UV was developed using a sub-2 μm column at elevated temperature for the simultaneous determination of nine sulphonamides. Owing to the lower viscosity of the mobile phase, the separation could be achieved in 3 min at 60°C for all analytes. The effect of temperature, the organic modifier percentage and the flow rate on the retention time was studied. The method developed was used for the determination of selected sulphonamides in surface and wastewater samples. Sample preparation was carried out by solid-phase extraction on Oasis HLB cartridges. The method developed was validated based on the linearity, precision, accuracy, detection and quantification limits. The recovery ranged from 70.6 to 96 % with standard deviations not higher than 4.7%, except for sulphanilamide. Limits of detection ranged from 1 to 10 μg/L after optimization of all analytical steps. This method has the highest performance in terms of analytical speed compared with other published HPLC-UV methods for the determination of sulphonamides in water.

A high efficiency HPLC method was developed by coupling three sub-2 μm columns in series and operating them at high temperature for the separation of selected non-steroidal anti-inflammatory drugs and veterinary antibiotics in environmental samples. The separation was performed at 80 °C to reduce the solvent viscosity, thus reducing the column backpressure. The chromatographic performance of high temperature-extended column length HPLC method was used to determine the most widely used non-steroidal anti-inflammatory drugs and veterinary antibiotics such as sulphonamides in wastewater samples. The method could simultaneously determine 24 pharmaceuticals in short analysis time with high efficiency. The method involved pre-concentration and clean-up by solid phase extraction (SPE) using Oasis HLB extraction cartridges. It was validated based on linearity, precision, detection and quantification limits, selectivity and accuracy. Good recoveries were obtained for all analytes ranging from 72.7% to 98.2% with standard deviations not higher than 6%, except for acetaminophen and acetyl salicylic acid, for which low recovery was obtained. The detection limits of the studied pharmaceuticals ranged from 2 to 16 μg L−1, while limits of quantification were in the range from 7 to 54 μg L−1 with UV detection.

Efficiency in HPLC can be enhanced by increasing the column length and/or decreasing the particle size. The use of high temperature in HPLC has emerged as a valuable tool to overcome the increase in column backpressure when using small packing particles, as it allows for reduction in mobile phase viscosity. In this study, high plate count was obtained by coupling sub-2 μm columns at elevated temperature to reduce the viscosity of the mobile phase, thus reducing the column backpressure. At 80 °C, up to three columns of 15 cm × 4.6 mm I.D. packed with 1.8 μm particles could be coupled generating ~84,000 theoretical plates for the last eluting compound. The number of theoretical plates was increased on average by a factor of ~3.6 when three columns were coupled at 80 °C compared with one column at 30 °C. The relationships between separation efficiency and column length were examined using Van Deemter plots constructed at 30 °C and 80 °C for different column lengths. The advantages of using coupled columns in combination with elevated temperature for the environmental analysis were illustrated using test mixtures comprised of eight sulfonamides separated on one column at 30 °C and three coupled columns at 80 °C by isocratic elution. Sample clean up was carried out by employing solid-phase extraction (SPE) using Oasis HLB cartridges. The method developed was validated based on parameters such as linearity, precision, accuracy, detection and quantification limits. Recoveries generally ranged from 71.7 to 99% (with the exception of sulfanilamide), with standard deviations not higher than 4.7%. The detection limits of the method ranged from 0.6–2 μg L−1, while limits of quantification were in the range 2–6.7 μg L−1 with UV detection.

Three methods were developed for the determination of two ternary mixtures containing drotaverine hydrochloride (DR) with caffeine and paracetamol (mixture 1) and DR with metronidazole and diloxanide furoate (mixture 2). The first method depends on HPLC separation on an RP C18 column at ambient temperature with the mobile phase methanolwater, pH 3.1 (50 + 50, v/v) and UV detection at 213 nm for mixture 1, and the mobile phase acetonitrile25 mM potassium dihydrogen phosphate, pH 4.6 (55 + 45, v/v) with UV detection at 235 nm for mixture 2. The other two chemometric methods applied were partial least squares (PLS-1) and principal component regression (PCR). These approaches were successfully applied to quantify the five drugs in two ternary mixtures using information included in the UV absorption spectra of appropriate solutions in the wavelength range of 210300 nm with 1 nm intervals. Calibration of PCR and PLS-1 models was evaluated by internal validation (prediction of compounds in its own designed training set of calibration), by cross-validation (obtaining statistical parameters that show the efficiency for a calibration fit model), and by external validation (using laboratory-prepared mixtures and pharmaceutical preparations). The proposed methods were successfully applied for the determination of the two ternary combinations in laboratory-prepared mixtures and commercial tablets; the results of PLS-1 and PCR methods were compared with the HPLC method, and a good agreement was found.

A high-performance liquid chromatographic (HPLC) method was developed for determination of oxyphenonium bromide (OX) and its degradation product. The method was based on the HPLC separation of OX from its degradation product, using a cyanopropyl column at ambient temperature with mobile phase of acetonitrile25 mM potassium dihydrogen phosphate, pH 3.4 (50 + 50, v/v). UV detection at 222 nm was used for quantitation based on peak area. The method was applied to the determination of OX and its degradation product in tablets. The proposed method was also used to investigate the kinetics of the acidic and alkaline degradation of OX at different temperatures, and the apparent pseudo first-order rate constant, half-life, and activation energy were calculated. The pH-rate profile of the degradation of OX in Britton-Robinson buffer solutions within the pH range 212 was studied.

Three methods are developed for the determination of two multicomponent mixtures containing guaiphenesine (GU) with salbutamol sulfate (SL), methylparaben (MP) and propylparaben (PP) [mixture 1]; and acephylline piperazine (AC) with bromhexine hydrochloride (BX), methylparaben (MP) and propylparaben (PP) [mixture 2]. The resolution of the two multicomponent mixtures has been accomplished by using numerical spectrophotometric methods such as partial least squares (PLS-1) and principal component regression (PCR) applied to UV absorption spectra of the two mixtures. In addition HPLC method was developed using a RP 18 column at ambient temperature with mobile phase consisting of acetonitrile-0.05 M potassium dihydrogen phosphate, pH 4.3 (60:40, v/v), with UV detection at 243 nm for mixture 1, and mobile phase consisting of acetonitrile-0.05 M potassium dihydrogen phosphate, pH 3 (50:50, v/v), with UV detection at 245 nm for mixture 2. The methods were validated in terms of accuracy, specificity, precision and linearity in the range of 20-60 microg ml(-1) for GU, 1-3 microg ml(-1) for SL, 20-80 microg ml(-1) for AC, 0.2-1.8 microgml(-1) for PP and 1-5 microg ml(-1) for BX and MP. The proposed methods were successfully applied for the determination of the two multicomponent combinations in laboratory prepared mixtures and commercial syrups.

Green analytical chemistry is an aspect of green chemistry which introduced in the late nineties. The main objectives of green analytical chemistry are to obtain new analytical technologies or to modify an old method to incorporate procedures that use less hazardous chemicals. There are several approaches to achieve this goal such as using environmentally benign solvents and reagents, reducing the chromatographic separation times and miniaturization of analytical devices. Traditional methods used for the analysis of pharmaceutically active compounds require large volumes of organic solvents and generate large amounts of waste. Most of them are volatile and harmful to the environment. With the awareness about the environment, the development of green technologies has been receiving increasing attention aiming at eliminating or reducing the amount of organic solvents consumed everyday worldwide without loss in chromatographic performance. This review provides the state of the art of green analytical methodologies for environmental analysis of pharmaceutically active compounds in the aquatic environment with special emphasis on strategies for greening liquid chromatography (LC). The current trends of fast LC applied to environmental analysis, including elevated mobile phase temperature, as well as different column technologies such as monolithic columns, fully porous sub-2 μm and superficially porous particles are presented. In addition, green aspects of gas chromatography (GC) and supercritical fluid chromatography (SFC) will be discussed. We pay special attention to new green approaches such as automation, miniaturization, direct analysis and the possibility of locating the chromatograph on-line or at-line as a step forward in reducing the environmental impact of chromatographic analyses.