Eco-friendly simultaneous estimation of atenolol and losartan potassium in spiked human plasma via synchronous fluorescence with sustainability assessment.

A green, sensitive, and fast spectrofluorimetric technique for the simultaneous determination of atenolol (ATN) and losartan potassium (LSR) was developed. The proposed technique relied on the implementation of a first derivative synchronous fluorescence spectroscopy for the determination of the investigated drugs simultaneously without pretreatment procedures. The synchronous fluorescence of both drugs was measured in methanol at Δλ of 100 nm, and the first derivative peak amplitudes (1D) were measured at 321 nm for ATN and 348 nm for LSR, each at the zero-crossing point of the other. The method was rectilinear over the concentration ranges of 100-1000 ng/mL and 50-500 ng/mL for ATN and LSR, respectively. The proposed technique was successfully applied for the determination of the studied drugs in their laboratory-prepared mixture and pharmaceutical formulations, demonstrating high mean recoveries of 100.54% for ATN and 100.62% for LSR, without interference from common excipients. The results were in good agreement with those obtained by the comparison method. Three recent greenness assessment tools, the Eco-Scale tool, the Green Analytical Procedure Index (GAPI) metric, and the Analytical GREEnness metric approach, were employed to affirm the greenness of the proposed method. The developed method was proven to be eco-friendly.

Fast concurrent determination of guaifenesin and pholcodine in formulations and spiked plasma using first derivative synchronous spectrofluorimetric approach.

Guaifenesin and pholcodine are frequently co-formulated in certain dosage forms. A new fast first derivative synchronous spectrofluorometric method has been used for their simultaneous analysis in mixtures. Here, first derivative synchronous spectrofluorometry enabled the successful simultaneous estimation of guaifenesin at 283 nm and pholcodine at 275 nm using a wavelength difference (Δλ) of 40 nm. The method was fully validated following International Council of Harmonization guidelines. For guaifenesin and pholcodine, linearity was determined within the corresponding ranges of 0.05-0.30 and 0.10-6.0 µg/ml. The two drugs were effectively analyzed using the developed approach in their respective formulations, and the results showed good agreement with those attained using reference methods. The method demonstrated excellent sensitivity, with detection limits down to 0.007 and 0.030 µg/ml and quantitation limits of 0.020 and 0.010 µg/ml for guaifenesin and pholcodine, respectively. Therefore, the procedure was successful in determining these drugs simultaneously in vitro in spiked plasma samples and syrup dosage form. The developed methodology also offered an environmentally friendly advantage by utilizing water as the optimal diluting solvent throughout the whole work. Different greenness approaches were investigated to ensure the method's ecofriendly properties.

A novel derivative synchronous fluorescence method for the rapid, non-destructive and intuitive differentiation of denitrifying bacteria.

It is challenging to differentiate bacteria residing in the same habitat by direct observation. This difficulty impedes the harvest, application and manipulation of functional bacteria in environmental engineering. In this study, we developed a novel method for rapid differentiation of living denitrifying bacteria based on derivative synchronous fluorescence spectroscopy, as exemplified by three heterotrophic nitrification-aerobic denitrification bacteria having the maximum nitrogen removal efficiencies greater than 90%. The intact bacteria and their living surroundings can be analyzed as an integrated target, which eliminates the need for the complex pre-processing of samples. Under the optimal synchronous scanning parameter (Δλ = 40 nm), each bacterium possesses a unique fluorescence spectral structure and the derivative synchronous fluorescence technique can significantly improve the spectral resolution compared to other conventional fluorescence methods, which enables the rapid differentiation of different bacteria through derivative synchronous fluorescence spectra as fast as 2 min per spectrum. Additionally, the derivative synchronous fluorescence technique can extract the spectral signals contributed by bacterial extracellular substances produced in the biological nitrogen removal process. Moreover, the results obtained from our method can reflect the real-time denitrification properties of bacteria in the biological nitrogen removal process of wastewater. All these merits highlight derivative synchronous fluorescence spectroscopy as a promising analytic method in the environmental field.

Characterizing dissolved organic matter and bacterial community interactions in a river network under anthropogenic landcover.

Anthropogenic landcover could rise nutrient concentrations and impact the characteristics and bioavailability of dissolved organic matter (DOM) in a river network. Exploring the interactions between DOM and microbials might be conducive to revealing biogeochemistry behaviors of organic matter. In this study, synchronous fluorescence spectra (SFS) with Gaussian band fitting and two-dimensional correlation spectroscopy (2D-COS) were employed to identify DOM fractions and reveal their interactions with bacterial communities. DOM was extracted from a river network under eco-agricultural rural (RUR), eco-residential urban (URB), eco-economical town (TOW), and eco-industrial park (IND) regions in Jiashan Plain of eastern China. The overlapping peaks observed in the SFS were successfully separated into four fractions using Gaussian band fitting, i.e., tyrosine-like fluorescence (TYLF), tryptophan-like fluorescence (TRLF), microbial humic-like fluorescence (MHLF), and fulvic-like fluorescence (FLF) materials. Across all four regions, TRLF (44.79% ± 7.74%) and TYLF (48.09% ± 8.85%) were the dominant components. Based on 2D-COS, variations of TYLF and TRLF were extremely larger than those of FLF in RUR-TOW. However, in URB-IND, the former exhibited lower variations compared to the latter. These suggested that FLF be likely derived continuously from lignin and other residue of terrestrial plant origin along the river network, and TYLF and TRLF be originated discontinuously from domestic wastewater in RUR-TOW. By high-throughput sequenced OTUs, the number of organisms in RUR-TOW could be higher than those in URB-IND, while genes associated with carbohydrate metabolism were lower in former than those in the latter. According to co-occurrence networks, microbes could promote the production of TYLF and TRLF in RUR-TOW. In contrast, microbial communities in URB-IND might contribute to decompose FLF. The obtained results could not only reveal interactions between DOM fractions and bacterial communities in the river network, but this methodology may be applied to other water bodies from different landscapes.

Eco-friendly synchronous fluorescence spectrofluorimetric method for simultaneous determination of montelukast sodium and fexofenadine hydrochloride in their antiallergic rhinitis fixed-dose combination tablets.

An innovative, simple, accurate, sensitive, and eco-friendly synchronous fluorescence spectrofluorimetric method has been developed for the simultaneous analysis of montelukast sodium (MON) and fexofenadine hydrochloride (FEX). The method relies on measuring the relative synchronous fluorescence intensity of both drugs using Δλ of 60 nm in methanol at 405 nm for MON and 288 nm for FEX. The experimental parameters influencing the developed method were investigated and optimized. The method was linear over the ranges 0.1-2.0 and 2.0-20.0 µg/ml for MON and FEX, respectively. The limits of detection were 0.018 and 0.441 µg/ml, and the limits of quantitation were 0.055 and 1.336 µg/ml for MON and FEX, respectively. The developed method was applied successfully for the determination of the two drugs in their newly released fixed-dose combination prescribed for the treatment of allergic rhinitis. The mean per cent recoveries were found to be 100.680 ± 0.890 and 100.110 ± 0.940 for MON and FEX, respectively. Furthermore, the method was found to be eco-friendly green as was evaluated according to the Green Analytical Procedure Index tool guidelines and analytical eco-scale.

Novel spectrofluorimetric technique for determination of amoxicillin and ethopabate in chicken tissues, liver, kidney, eggs, and feed premix.

A new smart spectrofluorometric method was developed for the quantitation of amoxicillin and ethopabate simultaneously for the first time. The method is based on measuring their first derivative synchronous amplitudes in water at Δλ = 80 nm. The peak amplitudes were recorded at their crossing points; 240 nm for amoxicillin and 280 nm for ethopabate. The method is linear over the concentration ranges of 100.0-1,000.0 ng/ml for amoxicillin and 2.0-20.0 ng/ml for ethopabate. The limits of detection were 20.0 ng/ml and 0.58 ng/ml and limits of quantitation were 60.0 ng/ml and 1.92 ng/ml for amoxicillin and ethopabate, respectively. The method sensitivity permitted the determination of the two drugs below their maximum residue limit stated by the federal regulations. The developed method was applicable to the analysis of both drugs in the veterinary powders, feed premix, chicken tissues, liver, kidney, and eggs samples with percentage recoveries ranging 93.72-104.71%.

Application of Fluorescence Spectroscopy in Wheat Crop: Early Disease Detection and Associated Molecular Changes.

The application of fluorescence spectroscopy combined with chemometrics was explored in the current study for the detection of stripe rust in wheat. The healthy and stripe rust leaves were collected from the disease screening nursery. The variations in the blue-green region and chlorophyll fluorescence intensity in leaves provides the basis for the detection of stripe rust infection. With the progress of disease, the variations in the synchronous fluorescence spectroscopy (SFS) spectrum was witnessed. SFS is an excellent tool for the simultaneous measurement of multiple compound samples, in case of plants it generates evidence regarding the occurrence of leaf fluorophore bands thus revealing the biochemical variations going on at different infection stages. Based on the results of the current study, it is inferred that p-coumaric acid has the highest intensity in healthy samples followed by the asymptomatic leaf samples, whereas the band intensity of α-tocopherol, sinapic acid, chlorogenic acid, ferulic acid, tannins, flavonoid, carotenoids and anthocyanins increases in the diseased and the asymptomatic samples accordingly to the rust infection. Principal component analysis (PCA) beautifully differentiated the healthy and the infected leaf samples. It is evident that the asymptomatic samples are grouped with the diseased samples or independently; indicating the start of disease infection, the decision that is hard to make with the visual assessments. The results of the current study suggest that the fluorescence emission and the SFS spectral signatures acquired for stripe rust could be utilized as fingerprints for early disease detection.

Analysis of Carcinogenic Polycyclic Aromatic Hydrocarbons in the Complex Background of the Petroleum Fluorescence Using Multivariate Curve Resolution Alternating Least Square and Total Synchronous Fluorescence Spectroscopic Technique.

Multivariate curve resolution alternating least square (MCR-ALS) analysis allows the simultaneous retrieval of pure concentration and spectral profiles for each of the analysed chemical components from the composite spectrum even in the presence of unknown interferences. Total synchronous fluorescence spectroscopy (TSFS), a multidimensional fluorescence technique that describes the variation of synchronous fluorescence profile acquired as a function of increasing offset, has become a useful analytical technique. Suitably arranged TSFS data set can be easily processed using MCR-ALS and thereby a simple and sensitive analytical tool could be developed. The present work successfully used the combination of the MCR-ALS and TSFS to analyse the three carcinogenic and mutagenic polycyclic aromatic hydrocarbons (PAHs) namely Benzo[a]Pyrene, Chrysene and Pyrene in the presence of complex fluorescence background originated from petroleum product. MCR-ALS assisted TSFS can be used for the routine analyses of these carcinogenic PAHs to ensure the quality of water and other samples belonging to different part of the ecosystem.

First-derivative synchronous spectrofluorimetric method for estimation of losartan potassium and atorvastatin in their pure forms and in tablets.

Losartan potassium (LOS) and atorvastatin (ATR) are used in combination for long-term treatment of stroke and for treatment of hypertension with high-level cholesterol. Both drugs were simultaneously determined and validated using a novel, easy, fast, and economical first-derivative synchronous fluorescence spectroscopic method. Methanol was used as the solvent for both drugs at a Δλ 80 nm and with a scanning rate of 600 nm/min. Peaks were determined as at 288.1 nm and 263.6 nm for LOS and ATR, respectively. The proposed method was validated according to International Conference on Harmonization guidelines and, subsequently, the developed method was applicable to the analysis of the two compounds in their different formulations without interference from each other. Amplitude-concentration plots were rectilinear over the concentration ranges 1.0-10.0 µg/ml and 0.5-5.0 µg/ml for LOS and ATR, respectively. Detection limits were found to be 0.096 µg/ml and 0.030 µg/ml and quantitation limits were 0.291 µg/ml and 0.093 µg/ml for LOS and ATR, respectively. The proposed method was successfully applied to the analysis of both compounds in synthetic mixtures and in laboratory-prepared tablets. These results were in accordance with the results acquired using the comparison method, high-performance liquid chromatography.

Synchronous fluorescence spectroscopy combined with chemometrics for determination of total phenolic content and antioxidant activity in different tea types.

BACKGROUND: The aim of this study is to monitor the antioxidant activity (AA) and total phenolic content (TPC) variations of different kinds of teas depending on the infusion temperature and time by using synchronous fluorescence spectroscopy (SFS) combined chemometrics as a rapid method. In this study, black tea, oolong tea, green tea, and green tea powder (matcha) samples were brewed at 80 °C and 96 °C for 2.5 to 30 min. Synchronous fluorescence spectra were recorded at different wavelength interval (Δλ) values for optimal models. AA and TPC of tea samples were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and Folin-Ciocalteu methods as reference methods, respectively. Partial least square (PLS) method was used for correlation between reference methods and SFS method. RESULTS: Results showed that SFS combined with chemometrics could be an alternative rapid way to monitor TPC and AA of teas with 0.932 and 0.918 of validation R2 values in fermented teas (black tea-oolong) while with 0.961 and 0.860 of validation R2 values in non-fermented teas (green tea and green tea powder), respectively. Limit of detection (LOD) and root mean square error of prediction (RMSEP) values were ≤ 6.61 µg mL-1 and ≤ 17.42, respectively. CONCLUSION: Based on the lowest R2 value (0.860) on TPC analysis, the proposed method is more appropriate for AA analysis of green tea and green tea powder. Furthermore, infusion time was more effective for obtaining different amounts of TPC and AA in fermented tea types while only infusion temperature was effective on green tea and green tea powder samples. Therefore, obtained calibration-validation models gave better results for fermented tea types.

Indirect synchronous fluorescence spectroscopy and direct high-performance thin-layer chromatographic methods for enantioseperation of zopiclone and determination of chiral-switching eszopiclone: Evaluation of thermodynamic quantities of chromatographic separation.

Economic and enantioselective synchronous fluorescence spectroscopy and high-performance thin-layer chromatography methods have been developed and validated as per ICH guidelines for the separation of zopiclone enantiomers using L-(+)-tartaric acid as a chiral selector, followed by determination of the chiral-switching eszopiclone. Synchronous fluorescence spectroscopy was successfully applied for chiral recognition of R & S enantiomers of zopiclone at ∆λ = 110 nm based on creating of diastereomeric complexes with 0.06M tartaric acid in an aqueous medium containing 0.2M disodium hydrogen orthophosphate. Synchronous fluorescence intensities of eszopiclone were recorded at 296 nm in concentration range 0.2- to 4-µg/mL eszopiclone. High-performance thin-layer chromatography method depends on resolution of zopiclone enantiomers on achiral HPTLC silica-gel plates using acetonitrile:methanol:water (8:2:0.25, v/v/v) containing L-(+)-tartaric acid as a chiral mobile-phase additive followed by densitometric measurements at 304 nm in concentration range of 1 to 10 µg/band of eszopiclone. The effect of chiral-selector concentration, pH, and temperature on the resolution have been studied and optimized for the proposed methods. The cited procedures were successfully applied to determine eszopiclone in commercial tablets of pure and racemic forms. Enantiomeric excess was evaluated using optical purity test and integrated peak area to describe the enantiomeric ratio. Thermodynamics of chromatographic separation, enthalpy, and entropy were evaluated using the Van't Hoff equation. The proposed methods were found to be selective for identification and determination of the eutomer in drug substances and products.

Enantiomeric assay of escitalopram S(+)-enantiomer and its "in-process impurities" using two different techniques.

The enantiomeric purity of escitalopram oxalate ESC and its "in-process impurities," namely, ESC-N-oxide, ESC-citadiol, and R(-)-enantiomer were studied in drug substance and products using high-performance liquid chromatography (HPLC)-UV (Method I), synchronous fluorescence spectroscopy (SFS) (Method IIA), and first derivative SFS (Method IIB). Method I describes as an isocratic HPLC-UV for the direct resolution and determination of enantiomeric purity of ESC and its "in-process impurities." The proposed method involved the use of αl -acid glycoprotein (AGP) chiral stationary phase. The regression plots revealed good linear relationships of concentration range of 0.25 to 100 and 0.25 to 10 µg mL-1 for ESC and its impurities. The limits of detection and quantifications for ESC were 0.075 and 0.235 µg mL-1 , respectively. Method II involves the significant enhancement of the fluorescence intensities of ESC and its impurities through inclusion complexes formation with hydroxyl propyl-ß-cyclodextrin as a chiral selector in Micliavain buffer. Method IIA describes SFS technique for assay of ESC at 225 nm in presence of its impurities: R(-)-enantiomer, citadiol, and N-oxide at ∆λ of 100 nm. This method was extended to (Method IIB) to apply first derivative SFS for the simultaneous determination of ESC at 236 nm and its impurities: the R(-)-enantiomer, citadiol, and N-oxide at 308, 275, and 280 nm, respectively. Linearity ranges were found to be 0.01 to 1.0 µg mL-1 for ESC and its impurities with lower detection and quantification limits of 0.033/0.011 and 0.038/0.013 µg mL-1 for SFS and first derivative synchronous fluorescence spectra (FDSFS), respectively. The methods were used to investigate the enantiomeric purity of escitalopram.

Interaction studies of lead(II) ion with cyclic ß-(1→3),(1→6) glucans extracted from Bradyrhizobium japonicum based on 'chelation enhanced fluorescence' (CHEF) effect.

Cyclic ß-(1→3),(1→6) glucans (CBGs) isolated from Bradyrhizobium japonicum bacteria are the periplasmic oligosaccharides having cyclic structures. This paper presents the isolation of CBGs from the bacteria cultured using optimized medium that improved yields to 350-450 mg per gram of cellular dry weight along with analytical interaction with lead(II) ions in the range 33.0-2.0 ppm with CBG as a binding ligand, using constant wavelength synchronous fluorescence spectroscopy. The binding ability of CBGs towards lead(II) is clearly evident from the scanning electron microscopy (SEM) images. The theoretical calculations using HEX 8.0 gave an insight about the interaction between CBG and lead(II) to be in the ratio of 3:1. The method displayed the sensitivity and selectivity towards lead(II) ions up to 2.0 ppm. This observed property of CBGs can potentially hold an application in bioremediation of the soil contaminated with lead.

Rapid discrimination between buffalo and cow milk and detection of adulteration of buffalo milk with cow milk using synchronous fluorescence spectroscopy in combination with multivariate methods.

This research paper describes the potential of synchronous fluorescence (SF) spectroscopy for authentication of buffalo milk, a favourable raw material in the production of some premium dairy products. Buffalo milk is subjected to fraudulent activities like many other high priced foodstuffs. The current methods widely used for the detection of adulteration of buffalo milk have various disadvantages making them unattractive for routine analysis. Thus, the aim of the present study was to assess the potential of SF spectroscopy in combination with multivariate methods for rapid discrimination between buffalo and cow milk and detection of the adulteration of buffalo milk with cow milk. SF spectra of cow and buffalo milk samples were recorded between 400-550 nm excitation range with Δλ of 10-100 nm, in steps of 10 nm. The data obtained for ∆λ = 10 nm were utilised to classify the samples using principal component analysis (PCA), and detect the adulteration level of buffalo milk with cow milk using partial least square (PLS) methods. Successful discrimination of samples and detection of adulteration of buffalo milk with limit of detection value (LOD) of 6% are achieved with the models having root mean square error of calibration (RMSEC) and the root mean square error of cross-validation (RMSECV) and root mean square error of prediction (RMSEP) values of 2, 7, and 4%, respectively. The results reveal the potential of SF spectroscopy for rapid authentication of buffalo milk.

Investigation on the interaction of cefpirome sulfate with lysozyme by fluorescence quenching spectroscopy and synchronous fluorescence spectroscopy.

The reaction mechanism of cefpirome sulfate with lysozyme at different temperatures (298, 310 and 318 K) was investigated using fluorescence quenching and synchronous fluorescence spectroscopy under simulated physiological conditions. The results clearly demonstrated that cefpirome sulfate caused strong quenching of the fluorescence of lysozyme by a static quenching mechanism. The binding constants obtained using the above methods were of the same order of magnitude and very similar. Static electric forces played a key role in the interaction between cefpirome sulfate and lysozyme, and the number of binding sites in the interaction was close to 1. The values of Hill's coefficients were > 1, indicating that drugs or proteins showed a very weakly positive cooperativity in the system. In addition, the conclusions obtained from the two methods using the same equation were consistent. The results indicated that synchronous fluorescence spectrometry could be used to study the binding mechanism between drug and protein, and was a useful supplement to the fluorescence quenching method. In addition, the effect of cefpirome sulfate on the secondary structure of lysozyme was analyzed using circular dichroism spectroscopy.

Investigation on the effect of fluorescence quenching of bovine serum albumin by cefoxitin sodium using fluorescence spectroscopy and synchronous fluorescence spectroscopy.

The reaction mechanism of cefoxitin sodium with bovine serum albumin was investigated using fluorescence spectroscopy and synchronous fluorescence spectroscopy at different temperatures. The results showed that the change of binding constant of the synchronous fluorescence method with increasing temperature could be used to estimate the types of quenching mechanisms of drugs with protein and was consistent with one of fluorescence quenching method. In addition, the number of binding sites, type of interaction force, cooperativity between drug and protein and energy-transfer parameters of cefoxitin sodium and bovine serum albumin obtained from two methods using the same equation were consistent. Electrostatic force played a major role in the conjugation reaction between bovine serum albumin and cefoxitin sodium, and the type of quenching was static quenching. The primary binding site for cefoxitin sodium was sub-hydrophobic domain IIA, and the number of binding sites was 1. The value of Hill's coefficients (nH ) was approximately equal to 1, which suggested no cooperativity in the bovine serum albumin-cefoxitin sodium system. The donor-to-acceptor distance r < 7 nm indicated that static fluorescence quenching of bovine serum albumin by cefoxitin sodium was also a non-radiation energy-transfer process. The results indicated that synchronous fluorescence spectrometry could be used to study the reaction mechanism between drug and protein, and was a useful supplement to the conventional method. Copyright © 2015 John Wiley & Sons, Ltd.

Products of biotransformation of polycyclic aromatic hydrocarbons in fishes of the Athabasca/Slave river system, Canada.

Concentrations of products of biotransformation of polycyclic aromatic hydrocarbons (PBPAH) were measured in bile of five fishes of nutritional, cultural and ecological relevance from the Athabasca/Slave river system. Samples were collected in Alberta and the Northwest Territories, Canada, during three seasons. As a measure of concentrations of PBPAHs to which fishes are exposed and to gain information on the nature and extent of potential exposures of people or piscivorous wildlife, concentrations of biotransformation products of two- and three-ringed, four-ringed and five-ringed PAHs were measured using synchronous fluorescence spectroscopy. Spatial and seasonal differences were observed with greater concentrations of PBPAHs in samples of bile of fish collected from Fort McKay as well as greater concentrations of PBPAHs in bile of fish collected during summer compared to those collected in other seasons. Overall, PBPAHs were greater in fishes of lower trophic levels and fishes more closely associated with sediments. In particular, goldeye (Hiodon alosoides), consistently contained greater concentrations of all the PBPAHs studied.

An eco-friendly first and second derivative synchronous spectrofluorimetry for quantification of florfenicol in presence of its different degradation products. Application to kinetic stability study.

Two rapid, simple, sensitive and selective derivative spectrofluorimetric methods (first and second derivative synchronous spectrofluorimetric (FDSFS and SDSFS) procedures) have been developed for the analysis of florfenicol in the presence of its various degradation products. FDSFS was applied to assay the drug in the presence of its alkaline, oxidative and photolytic degradation products while SDSFS was used to quantify it in the presence of its acidic degradation product. These methods permitted quantification of florfenicol at corresponding λ Em of 288, 287, 279 and 284 nm without interferences from any of its degradation products. Full validation procedures were applied to the suggested method according to International Conference of Harmonization guidelines. Moreover, different degradation kinetic parameters were calculated such as half-life (t 1/2), degradation rate constant (K) and activation energy (E a). Using the analytical eco-scale, green analytical procedure index and analytical greenness metric approach AGREE as greenness assessment tools, the proposed method was found to be environmentally friendly.

Development of a highly sensitive and green first-derivative synchronous fluorescence spectroscopic method for the simultaneous quantification of telmisartan and rosuvastatin: Greenness metric assessment and application to a pharmacokinetic study in rats.

Hypertension and hyperlipidemia frequently coexist and are correlated with elevated cardiovascular adverse outcomes. Fixed dose combination tablets containing antihypertensive and antihyperlipidemic drugs have the potential to improve patient compliance. Telmisartan and rosuvastatin fixed dose combination tablet has been recently formulated. This study provided the first fluorescence spectroscopic method for simultaneously quantifying telmisartan and rosuvastatin in tablet dosage form and plasma. The native fluorescence spectra of telmisartan and rosuvastatin completely overlapped, making direct measurement unachievable. However, through the implementation of synchronous fluorescence measurements of telmisartan and rosuvastatin at a Δλ = 60, distinct narrow bands were observed at 358 nm and 375 nm, respectively. Regrettably, the challenge of overlapping remained unresolved. Nevertheless, by converting these synchronous spectra into first-order spectra, the problem of overlapping was completely resolved. This conversion also allowed for the selective quantification of telmisartan and rosuvastatin at 374 nm and 358 nm, respectively. The validity of this method was confirmed in accordance with ICH guidelines, yielding satisfactory results in terms of the validation characteristics. The method demonstrated linear relationships between the response and the studied drugs concentrations in working range of 50-1000 ng/mL for telmisartan and 100-2000 ng/mL for rosuvastatin. The described methodology was applied for the pharmacokinetic study of telmisartan and rosuvastatin in rat plasma after a single oral dose of 4 mg/kg telmisartan and 50 mg/kg rosuvastatin. Pharmacokinetic analyses revealed a moderate drug-drug interaction between the two drugs, which was not considered to be clinically significant. Moreover, the described method was assessed in terms of sensitivity and environmental sustainability against three previously documented methods. The comparison effectively underscores the supremacy of the proposed technique over the documented techniques.

Rapid detection of bactericidal efficacy of nanoparticles coated polyurethane foam by synchronous fluorescence spectroscopy.

The ability of right-angled synchronous fluorescence spectroscopy (SFS) was explored to analyse the bacterial load in water treated with green synthesized silver nanoparticles (AgNPs) coated polyurethane foam (PUF). Gram negative (Escherichia coli, Pseudomonas aeruginosa) and Gram positive (Staphylococcus aureus) bacteria cultured in nutrient broth were diluted in autoclaved water containing NPs-coated PUF. The survival rate of S. aureus and E. coli lowered after ten minutes as compared to P. aeruginosa; however, after thirty minutes, the percentage viability dropped and recorded as 3.4%, 0.9%, and 0.1% for E. coli, P. aeruginosa and S. aureus respectively in the treated suspensions. No spectral change was observed in the fluorescence emission from the positive control and treated bacterial suspension owing to the masking effect of the emission from nutrient broth. In parallel, SF spectra recorded for directly picked bacterial colony dissolved in water showed remarkable drop in tryptophan emission after treatment with NPs-coated PUF. The SF data changes were assisted by hierarchical cluster analysis, which also made it possible to distinguish between positive control and treated bacterial suspensions. SFS has shown to be a reliable substitute for the culture plate approach for the quick identification of bacterial contamination in water.