A green, fluorescent probe employing erythrosine-B for tracing the accidental administration of levamisole in milk and plasma samples.

A simple and sensitive fluorescent probe has been developed and optimized to detect the non-intentional administration of levamisole (LVM). LVM is used as an anthelmintic therapy in cows, and hence, its residues appear in the drained milk until 60 hours after administering the drug. Meanwhile, levamisole is known to be an adulterant to cocaine and could be detected in addicts' plasma samples. Owing to its severe side effects, including agranulocytosis, which is lethal in many cases, detection and quantification of LVM in milk and plasma samples are of utmost importance. Therefore, a sensitive and selective analytical method is required for this purpose. This work develops a highly fluorescent probe obtained through the reaction between LVM and erythrosine-B in an acidic medium, where the produced ion pair complex has been measured at 553 nm after excitation at 528 nm. The proposed method provides linearity over the concentration range of 0.5-2.0 µg mL-1 for LVM, with a corresponding detection and quantitation limit of 0.5 and 0.3 µg mL-1. Full validation was performed, permitting the application of the suggested method to perform simple extraction steps. All the applied procedures followed the guidelines offered by green analytical chemistry, where the Green Analytical Procedure Index (GAPI) assessed the greenness of the proposed tool, and the yielded pictograms proved the eco-friendliness of the offered tool.

Quality-by-design ecofriendly potentiometric sensor for rapid monitoring of hydroxychloroquine purity in the presence of toxic impurities.

Hydroxychloroquine (HCQ) is prescribed to treat malaria and certain autoimmune diseases. Recent studies questioned its efficiency in relieving COVID-19 symptoms and improving clinical outcomes. This work presents a quality-by-design approach to develop, optimize, and validate a potentiometric sensor for the selective analysis of HCQ in the presence of its toxic impurities (key starting materials), namely 4,7-Dichloroquinoline (DCQ) and hydroxynovaldiamine (HND). The study employed a custom experimental design of 16 sensors with different ion exchangers, plasticizers, and ionophores. We observed the Nernstian slopes, correlation coefficients, quantification limit, response time, and selectivity coefficient for DCQ and HND. The computer software constructed a prediction model for each response. The predicted responses strongly correlate to the experimental ones, indicating model fitness. The optimized sensor achieved 93.8% desirability. It proved a slope of 30.57 mV/decade, a correlation coefficient of 0.9931, a quantification limit of 1.07 × 10-6 M, a detection limit of 2.18 × 10-7 M, and a fast response of 6.5 s within the pH range of 2.5-8.5. The sensor was successfully used to determine HCQ purity in its raw material. The sensor represents a potential tool for rapid, sensitive, and selective monitoring of HCQ purity during industrial production from its starting materials.

Comparative Study of Augmented Classical Least Squares Models for UV Assay of Co-Formulated Antiemetics Together with Related Impurities.

The classical least squares (CLS) model and three augmented CLS models are adopted and validated for the analysis of pyridoxine HCl (PYR), cyclizine HCl (CYC), and meclizine HCl (MEC) in a quinary mixture with two related impurities: the CYC main impurity, Benzhydrol (BEH), which has carcinogenic and hepatotoxic effects, and the MEC official impurity, 4-Chlorobenzophenone (BEP). The proposed augmented CLS models are orthogonal signal correction CLS (OSC-CLS), direct orthogonal signal correction CLS (DOSC-CLS), and net analyte processing CLS (NAP-CLS). These models were applied to quantify the three active constituents in their raw materials and their corresponding dosage forms using their UV spectra. To evaluate the CLS-based models sensibly, we design a comparative study involving two sets: the training set to construct models and the validation set to assess the prediction abilities of these models. A five-level, five-factor calibration design was established to produce 25 mixtures for the calibration set. In addition, 16 experiments were performed for a test set distributed equally between the in-space and out-space samples. The primary criterion for comparing the models' performance was the validation set's root mean square error of prediction (RMSEP) value. Finally, augmented CLS models showed acceptable results for assaying the three analytes. The results were compared statistically with the reported HPLC methods; however, the DOSC-CLS model proved the best for assaying the dosage forms.

A sustainable approach for the degradation kinetics study and stability assay of the SARS-CoV-2 oral antiviral drug Molnupiravir.

Molnupiravir (MPV) is the first direct-acting oral antiviral drug that effectively decreases nasopharyngeal infections with SARS-CoV-2 virus. The stability of MPV was tested by subjecting the drug to various stress conditions. The drug is liable to oxidative, acidic, and alkaline degradation and showed significant stability against thermal degradation. Mass spectrometry identified the degradation products and guided suggestion of the degradation patterns. Interestingly, while inspecting the UV-absorption spectra, we observed no absorbance at 270 nm for the products of the three degradation pathways (c.f. intact MPV). Direct spectrophotometry seemed a solution that perfectly fit the purpose of the stability assay method in our case. It avoids sophisticated instrumentation and complex mathematical data manipulation. The method determined MPV accurately (100.32% ± 1.62) and selectively (99.49% ± 1.63) within the linear range of 1.50 × 10-5-4.0 × 10-4 M and down to a detection limit of 0.48 × 10-5 M. The proposed method is simple and does not require any preliminary separation or derivatization steps. The procedure proved its validity as per the ICH recommendations. The specificity was assessed in the presence of up to 90% degradation products. The study evaluated the greenness profile of the proposed analytical procedure using the National Environmental Methods Index (NEMI), the Analytical Eco-Scale, and the Green Analytical Procedure Index (GAPI). The three metrics unanimously agreed that the developed procedure results in a greener profile than the reported method. The method investigated the degradation reactions' kinetics and evaluated the reaction order, rate constant, and half-life time for each degradation process.

Assessment of binding interaction to salmon sperm DNA of two antiviral agents and ecofriendly nanoparticles: comprehensive spectroscopic study.

The direct binding of antiviral agents; Daclatasvir and valacyclovir and green synthesized nanoparticles to salmon sperm DNA have been assessed in a comparative study. The nanoparticles were synthesized by the hydrothermal autoclave method and have been fully characterized. The interactive behavior and competitive binding of the analytes to DNA in addition to the thermodynamic properties were deeply investigated by the UV-visible spectroscopy. The binding constants were monitored in the physiological pH conditions to be 1.65 × 106, 4.92 × 105 and 3.12 × 105 for daclatasvir,valacyclovir and quantum dots, respectively. The significant changes in the spectral features of all analytes have proven intercalative binding. The competitive study has confirmed that, daclatasvir, valacyclovir, and the quantum dots have exhibited groove binding. All analytes have shown good entropy and enthalpy values indicating stable interactions. The electrostatic and non-electrostatic kinetic parameters have been determined through studying the binding interactions at different concentrations of KCl solutions. A molecular modelling study has been applied to demonstrate the binding interactions and their mechanisms. The obtained results were complementary and afforded new eras for the therapeutic applications.

Green approach for tracking the photofate of ciprofloxacin and levofloxacin in different matrices adopting synchronous fluorescence spectroscopy: a kinetic study.

First derivative synchronous fluorescence spectroscopy (FDSFS) was applied to detect and quantify either ciprofloxacin (CIP) or levofloxacin (LEV) simultaneously with their photodegradation products, where the photolytic pathway for each analyte was found to be pH dependent. Under the guidance of early published articles, the structure of the produced photolytic products could be concluded, and further related to their resultant fluorescence spectra. The proposed method was subjected to full validation procedure which enables its application in investigating the photodegradation kinetics for both drugs. The obtained kinetic parameters were in accordance with previous reports and could be linked to predict the antibacterial activity of the resultant photodegradation products. These facts prove the suitability of the suggested FDSFS to serve as a stability-indicating assay method and to trace the photofate of CIP and LEV in the ecosystem as potential contaminants. Furthermore, the greenness of the suggested analytical methodology was evaluated via 'Green Analytical Procedure Index' (GAPI), which classifies it as an eco-friendly assay. Eventually, no extraction, treatment or preparation steps were needed during all analysis steps, which renders the proposed assay an appealing tool in environmental analysis.

Experimentally designed potentiometric sensor for green real-time and direct assay of hazardous bromate in bakery products.

Bakeries add extra potassium bromate to the dough to make homogeneous, elastic, fluffy bread. Bromate causes renal damage and cancer. FAO/WHO stated that bromate residues shouldn't be in baked products. A potentiometric sensor's membrane recipe was optimized for sensitive and selective bromate assay. We planned a custom experimental design of 21 sensors that included numerical and categorical factors (NPPE: PVC, matrix%, membrane thickness, and ionophore type). We defined sensor performance outcomes (Nernstian slope, quantification limit, correlation coefficient, response time and selectivity), and each sensor's outcome was determined. The computer software developed a predictive model for each outcome and the desirability function suggested the optimum sensor recipe. The sensor achieved a slope of -63.54 mV/decade and detection limit of 2 × 10-6 mol/L. The greenness profile was evaluated by the National Environmental Approach Index protocol. The developed sensor represents a reliable, fast, in-site tool for the assay of bromate in bakery products.

Facile fabrication of a portable PANI-NFs/c-MWCNT nano-composite electrochemical sensor for gefitinib: application to human plasma.

A novel potentiometric solid contact (SC) sensor was developed to determine the anticancer drug gefitinib by employing a polyaniline nanofibers/carboxylated multi-walled carbon nanotube (PANI-NFs/c-MWCNT) nano-composite as an ion to electron transducer. The FDA approved gefitinib as the first line treatment of non-small cell lung cancer (NSCLC) that represents 90% of lung carcinomas. The PANI-NFs/C-MWCNT nano-composite was synthesized and characterized using Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). Twenty-three polyvinyl chloride (PVC) based sensors were fabricated through a systematic approach using different plasticizers and cationic exchangers to investigate their effects on the performance of the developed sensors. The incorporation of calix[8]arene (CX-8) notably enhanced the sensitivity of the developed sensor, confirmed by the docking study. The optimized sensor attained a fast and stable Nernstian slope of 29.14 mV per decade over the concentration range from 1.0 × 10-2 to 1.5 × 10-6 M with a LOD of 1.0 × 10-6 M. The proposed method represents the first potentiometric sensor for GEF assay according to the authors' knowledge. It was validated as per the IUPAC guidelines and efficiently applied to determine GEF in its tablets and human plasma. This encourages quality control, bioavailability, and clinical centers to utilize the portable GEF sensor in its routine analysis.

Tracing the influence of caffeine on the pharmacokinetic parameters of three headache relieving pharmaceuticals applying synchronous fluorescence spectroscopy.

A simple, sensitive, and selective first derivative synchronous fluorimetric method was developed and optimized to track the influence of caffeine content in beverages on the pharmacokinetic parameters of three pharmaceuticals used in relieving headache namely, aspirin (ASP), ibuprofen (IBU), and ergotamine tartrate (ERG). A full validation procedure was carried out to impart validity to the proposed method to apply it to biological fluids. The unique dissolving power of micellar solutions was utilized to avoid multiple extraction steps for both thein vitroandin vivoexperiments, aiming to obtain acceptable recoveries and to accomplish sustainability, where 0.1 M sodium dodecyl sulphate (SDS) was used for this purpose. Moreover, the developed bioanalytical method was subjected to full validation to avoid interferences emerging from biological matrices. The greenness of the proposed method was assessed according to the Analytical Eco-Scale and proved to be excellent green carrying a score of 98%.

Impurity-profiling UPLC methods for quantitative analysis of some antiemetics formulated with pyridoxine.

Cyclizine hydrochloride (CYC) and meclozine hydrochloride (MEC) are antihistaminic drugs generally co-formulated with pyridoxine hydrochloride (PYR) to treat nausea and vomiting in pregnancy. Several analytical techniques have been applied for the determination of CYC or MEC with PYR, but determination of CYC impurity; benzhydrol (BEH) or MEC impurity; or 4-chlorobenzophenone (BEP) has not been paid attention to. Therefore, micellar UPLC method is introduced for analysis of ternary mixtures containing PYR together with both CYC and BEH (mixture I) or MEC and BEP (mixture II). Chromatographic separation was achieved using a Hypersil gold C8 column (50 × 2.1 mm, 1.9 µm) using 0.01 M sodium dodecyl sulfate modified to pH 3.5 using phosphoric acid:acetonitrile (45:55 by volume) for mixture I and 0.1% sodium dodecyl sulfate, 0.1% sodium bicarbonate adjusted to pH 2.6 by phosphoric acid:acetonitrile (47:53 by volume) for mixture II as mobile phases. The separated peaks were detected at 230 and 245 nm for mixtures I and II, respectively. The adopted methods were validated in conformance with the International Conference on Harmonization (ICH) recommendations and were properly applied in commercial pharmaceutical formulation analysis. Comprehensive ecological comparison was achieved, confirming a higher ecological value of the presented methods compared to the earlier reported methods.

Adoption of Advanced Chemometric Methods for Determination of Pyridoxine HCl, Cyclizine HCl, and Meclizine HCl in the Presence of Related Impurities: A Comparative Study.

BACKGROUND: Noising is an undesirable phenomenon accompanying the development of widely used chemometric models such as partial least square regression (PLSR) and support vector regression (SVR). OBJECTIVE: Optimizations of these chemometric models by applying orthogonal projection to latent structures (OPLS) as a preprocessing step which is characterized by canceling noise is the purpose of this research study. Additionally, a comprehensive comparative study between the developed methods was undertaken highlighting pros and cons. METHODS: OPLS was conducted with PLSR and SVR for quantitative determination of pyridoxine HCl, cyclizine HCl, and meclizine HCl in the presence of their related impurities. The training set was formed from 25 mixtures as there were five mixtures for each compound at each concentration level. Additionally, to check the validity and predictive ability of the developed chemometric models, independent test set mixtures were prepared by repeating the preparation of four mixtures of the training set plus preparation of another four independent mixtures. RESULTS: Upon application of the OPLS processing method, an upswing of the predictive abilities of PLSR and SVR was found. The root-mean-square error of prediction of the test set was the basic benchmark for comparison. CONCLUSION: The major finding from the conducted research is that processing with OPLS reinforces the ability of models to anticipate the future samples. HIGHLIGHTS: Novel optimizations of the widely used chemometric models; application of a comparative study between the suggested methods; application of OPLS preprocessing methods; quantitative determination of pyridoxine HCl, cyclizine HCl and meclizine HCl; checking the predictive power of developed chemometric models; analysis of active ingredients in their pharmaceutical dosage forms.

Solid-state potentiometric sensor for the rapid assay of the biologically active biogenic amine (tyramine) as a marker of food spoilage.

Tyramine (TYR) is a vasoactive biogenic amine found in food products due to improper storage and poor hygiene. High TYR intake results in a wide range of life-threatening physiological reactions. The work optimizes a solid-state potentiometric sensor in the absence of a reported potentiometric method for rapid and direct TYR assay. The optimization study included thirteen membrane cocktails of different compositions. The optimized sensor proved a near-Nernstian slope of 57.30 mV/decade, a quantification limit of 10.6 ppm, and a detection limit of 7.9 ppm. Validation results confirmed the sensor ability for the direct assay of TYR in blue cheese, aged cheese, Egyptian pickled cottage cheese, and pickled herring. A comparison with the reported chromatographic method expresses the merits and potentials of the developed sensor for the rapid testing of food edibility, quality, and safety based on its TYR content. Chemical compounds studied in this article: Tyramine (PubChem CID: 5610); Tyramine hydrochloride (PubChem CID: 66449); Poly(vinyl chloride) (PubChem SID: 24864273); Tricresyl phosphate (PubChem CID: 6529); sodium phosphotungstate tribasic hydrate (PubChem SID: 329753864).

Calixarene based portable sensor for the direct assay of indiscriminate ephedrine content of weight loss herbal preparations.

A novel potentiometric sensor was developed and optimized for the quantitative analysis of ephedrine in non-prescribed herbal supplements used as adjunctive therapy for weight loss. An initial optimization study aimed to reach the optimum membrane composition, sensor assembly, and experimental conditions. The study evaluated the effect of several factors on the sensor performance including different ion-exchangers, plasticizers, ionophores, membrane thicknesses, soaking solution concentrations, soaking time intervals, and pH. The optimized polyvinyl chloride membrane included tungstophosphoric acid hydrate as a cation exchanger, tricresyl phosphate as a plasticizer, and calix[8]arene as an ionophore to enhance the sensitivity and selectivity of the developed sensor. The polyvinyl chloride membrane was drop-casted over a polyaniline modified glassy carbon electrode surface to form a solid-state sensor. The proposed membrane succeeded to quantify ephedrine over a linear range of 6 × 10-6 to 1 × 10-2 M with a LOD of 3.60 × 10-6 M, acceptable selectivity, and fast response time. The IUPAC characterization of sensor response and International Conference on Harmonization validation parameters were calculated. The method successfully determined ephedrine concentration in spiked herbal mixtures and determined labeled and undeclared ephedrine content of weight loss herbal preparations.

Impurity profiling high-performance-thin-layer chromatography method involving the assay of essential human micronutrient niacin with eco-scale assessment.

Currently, analytical scientists are paying special attention to reducing reliance on hazardous chemicals in various analytical methods. By embracing this concept, we developed an eco-friendly high-performancethin-layer chromatography (HPTLC) method as an alternative for the conventional HPLC method for the determination of an essential human micronutrient, niacin (NIA), which is used improve the lipid profile of patients. Furthermore, the proposed HPTLC method is capable of determining the structurally related impurities of NIA such as pyridine-2,5-dicarboxylic acid, isonicotinic acid, pyridine, and 5-ethyl-2-methylpyridine, which exhibit nephrotoxic and hepatotoxic effects. The separation of this challenging mixture was achieved on HPTLC sheets using a mixture of ethyl acetate/ethanol/ammonia solution (6:4:0.05, v/v/v), and then the dried plates were scanned at 254 nm. The analytical eco-scale assessment protocol was used to assess the greenness profile of the presented method and compare it with the reported HPLC method. The suggested method was found to be greener with regard to the consumption of solvents and the yielding of waste. The results suggest that the described method can be safely implemented for the routine analysis of NIA pharmaceutical dosage without the interference of potential impurities in quality control laboratories.

Validated Analytical Methods for the Determination of Drugs Used in the Treatment of Hyperemesis Gravidarum in Multiple Formulations.

Quantitative multicomponent analysis is considered an analytical goal to save time and cost in analysis. Hence, this work aimed to provide sensitive and selective UV-spectrophotometric, chemometric manipulation, and ultra-performance LC (UPLC) methods for the determination of well-known coformulated antiemetics used in pregnancy, namely pyridoxine HCl (PYR), meclozine HCl, and cyclizine. The developed UV-spectrophotometric methods are dual wavelength in ratio spectra and first derivative of the ratio spectra with which PYR was determined selectively at 290.8 nm, whereas the other drugs in a ternary mixture were determined from their ratio spectra using a spectrum of PYR as a divisor in 0.1 M HCl. An ecofriendly partial least-squares regression chemometric method was applied to raw UV absorbance data for the determination of the ternary mixture in a 218-355 nm range using a three-factor, three-level design with water as the green solvent. A gradient UPLC method was developed and successfully resolved the ternary mixture within 5 min. Different ratios of water (adjusted to pH 3 with phosphoric acid) and methanol were delivered at 0.5 mL/min as the mobile phase into a Hypersil Gold C18 column (50 × 2.1 mm, 1.9 µm). The developed methods were successfully applied to different pharmaceutical formulations containing the aforementioned drugs and validated according to the International Conference on Harmonization guidelines. The results obtained were reproducible and reliable and can be applied for routine analysis and QC in laboratories.

Simultaneous determination of hydrochlorothiazide and benazepril hydrochloride or amiloride hydrochloride in presence of hydrochlorothiazide impurities: chlorothiazide and salamide by HPTLC method.

Simple, selective and sensitive high-performance thin layer chromatographic (HPTLC) method has been developed and validated for the simultaneous determination of hydrochlorothiazide (HCZ) in the presence of its impurities (chlorothiazide (CT) and salamide (DSA)), in two quaternary mixtures with benazepril hydrochloride (BZ) or amiloride hydrochloride (AM). The separation was carried out on HPTLC silica gel 60 F254 using ethyl acetate-methanol-glacial acetic acid (85:2:0.3 v/v/v) followed by densitometric measurement of bands at 240 nm for the first mixture containing HCZ, CT, DSA, BZ and by using ethyl acetate-methanol-water-ammonia (90:10:5:3 v/v/v) followed by densitometric measurement at 278 nm for the second mixture containing HCZ, CT, DSA, AM. Calibration curves were constructed in the range of (0.2-1.8 µg/band) and (0.4-2.2 µg/band) with good accuracy for HCZ and BZ, respectively, for the first mixture and in the range of (0.6-1.8 µg/band) and (0.4-2.4 µg/band) with good accuracy for HCZ and AM, respectively, for the second mixture. The developed method was validated according to ICH guidelines and demonstrated good accuracy and precision. Moreover, the methods were successfully applied for the determination of HCZ and BZ and AM in pure form and pharmaceutical dosage forms. The results were statically compared with the reported methods with no significant difference, indicating the ability of the proposed method to be used for routine analysis of drug product.

Linear support vector regression and partial least squares chemometric models for determination of Hydrochlorothiazide and Benazepril hydrochloride in presence of related impurities: a comparative study.

Partial least squares regression (PLSR) and support vector regression (SVR) are two popular chemometric models that are being subjected to a comparative study in the presented work. The comparison shows their characteristics via applying them to analyze Hydrochlorothiazide (HCZ) and Benazepril hydrochloride (BZ) in presence of HCZ impurities; Chlorothiazide (CT) and Salamide (DSA) as a case study. The analysis results prove to be valid for analysis of the two active ingredients in raw materials and pharmaceutical dosage form through handling UV spectral data in range (220-350 nm). For proper analysis a 4 factor 4 level experimental design was established resulting in a training set consisting of 16 mixtures containing different ratios of interfering species. An independent test set consisting of 8 mixtures was used to validate the prediction ability of the suggested models. The results presented indicate the ability of mentioned multivariate calibration models to analyze HCZ and BZ in presence of HCZ impurities CT and DSA with high selectivity and accuracy of mean percentage recoveries of (101.01±0.80) and (100.01±0.87) for HCZ and BZ respectively using PLSR model and of (99.78±0.80) and (99.85±1.08) for HCZ and BZ respectively using SVR model. The analysis results of the dosage form were statistically compared to the reference HPLC method with no significant differences regarding accuracy and precision. SVR model gives more accurate results compared to PLSR model and show high generalization ability, however, PLSR still keeps the advantage of being fast to optimize and implement.