First derivative synchronous spectrofluorimetric method for the simultaneous determination of tramadol and celecoxib in their dosage forms and human plasma.

One of the most common features of many different clinical conditions is pain; hence, there is a crucial need for eliminating or reducing it to a tolerable level to retrieve physical, psychological and social functioning. A first derivative synchronous spectrofluorimetry technique is proposed for the simultaneous determination of celecoxib and tramadol HCl, a recent coformulation authorized for treating acute pain in adults. The method includes using synchronous spectrofluorimetry at ∆λ = 80 nm where tramadol HCl was determined using first derivative technique at λ = 230.2 nm, while celecoxib was determined at λ = 288.24 nm. The proposed method was successfully applied to their co-formulated dosage forms in addition to spiked human plasma and validated in agreement with the guidelines of the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH). The linear ranges were found to be 0.50-5.0 and 0.15-0.50, the limits of detection to be 0.088 and 0.011 and the limits of quantification to be 0.266 and 0.032 µg/ml for celecoxib and tramadol, respectively. Statistical analysis revealed no significant difference when compared with previously reported methods as evidenced by the values of the variance ratio F-test and Student t-test. The proposed method was successfully applied to commercial dosage forms and spiked human samples. Moreover, the greenness of the proposed method was investigated based on the analytical eco-scale approach, with the results showing an excellent green scale with a score of 95.

Study of the binding interaction of salmon sperm DNA with nintedanib, a tyrosine kinase inhibitor using multi-spectroscopic, thermodynamic, and in silico approaches.

The study of the intermolecular binding interaction of small molecules with DNA can guide the rational drug design with greater efficacy and improved or more selective activity. In the current study, nintedanib's binding interaction with salmon sperm DNA (ssDNA) was thoroughly investigated using UV-vis spectrophotometry, spectrofluorimetry, ionic strength measurements, viscosity measurements, thermodynamics, molecular docking, and molecular dynamic simulation techniques under physiologically simulated conditions (pH 7.4). The obtained experimental results showed that nintedanib and ssDNA had an apparent binding interaction. Nintedanib's binding constant (Kb) with ssDNA, as determined using the Benesi-Hildebrand plot, was 7.9 × 104 M-1 at 298 K, indicating a moderate binding affinity. The primary binding contact forces were hydrophobic and hydrogen bonding interactions, as verified by the enthalpy and entropy changes (ΔH0 and ΔS0), which were - 16.25 kJ.mol-1 and 39.30 J mol-1 K-1, respectively. According to the results of UV-vis spectrophotometry, viscosity assays, and competitive binding interactions with ethidium bromide or rhodamine B, the binding mode of nintedanib to ssDNA was minor groove. Molecular docking and molecular dynamic simulation studies showed that nintedanib fitted into the B-DNA minor groove's AT-rich region with high stability. This study can contribute to further understanding of nintedanib's molecular mechanisms and pharmacological effects.

Eco-friendly simultaneous multi-spectrophotometric estimation of the newly approved drug combination of celecoxib and tramadol hydrochloride tablets in its dosage form.

Food and Drug Administration (FDA) recently approved co-formulated celecoxib and tramadol for the treatment of acute pain in adults. Three spectrophotometric methods were efficiently applied to estimate the co-formulated Celecoxib and Tramadol in their tablets; second derivative 2D-spectrophotometry technique (method I), induced dual-wavelength technique (method II) and dual-wavelength resolution technique (method III). The proposed methods were successfully validated following the International Council for Harmonisation (ICH) guidelines and statistically assessed based on the correlation coefficients, relative standard deviations as well as detection and quantitation limits. The obtained results revealed non-significant differences compared to the reported results as revealed by the variance ratio F test and Student t test. Moreover, the applied techniques were further assessed concerning their greenness based on the analytical eco-scale method revealing an excellent green scale with a final score of 95. The proposed spectrophotometric techniques could be applied for the routine analysis and quality control of the studied drugs in their dosage form.

Green fluorometric strategy for simultaneous determination of the antihypertensive drug telmisartan (A tentative therapeutic for COVID-19) with Nebivolol in human plasma.

Telmisartan (TEL) and Nebivolol (NEB) are frequently co-formulated in a single dosage form that is frequently prescribed for the treatment of hypertension, moreover, telmisartan is currently proposed to be used to treat COVID19-induced lung inflammation. Green rapid, simple, and sensitive synchronous spectrofluorimetric techniques for simultaneous estimation of TEL and NEB in their co-formulated pharmaceutical preparations and human plasma were developed and validated. Synchronous fluorescence intensity at 335 nm was used for TEL determination (Method I). For the mixture, the first derivative synchronous peak amplitudes (D1) at 296.3 and 320.5 nm were used for simultaneous estimation of NEB and TEL, respectively (Method II). The calibration plots were rectilinear over the concentration ranges of 30-550 ng/mL, and 50-800 ng/mL for NEB and TEL, respectively. The high sensitivity of the developed methods allowed for their analysis in human plasma samples. NEB`s Quantum yield was estimated by applying the single-point method. The greenness of the proposed approaches was evaluated using the Eco-scale, National Environmental Method Index (NEMI), and Green Analytical Procedure Index (GAPI) methods.

Deduction of the operable design space of RP-HPLC technique for the simultaneous estimation of metformin, pioglitazone, and glimepiride.

A reversed-phase RP-HPLC method was developed for the simultaneous determination of metformin hydrochloride (MET), pioglitazone (PIO), and glimepiride (GLM) in their combined dosage forms and spiked human plasma. Quality risk management principles for determining the critical method parameters (CMPs) and fractional factorial design were made to screen CMPs and subsequently, the Box-Behnken design was employed. The analytical Quality by Design (AQbD) paradigm was used to establish the method operable design region (MODR) for the developed method depended on understanding the quality target product profile (QTPP), analytical target profile (ATP), and risk assessment for different factors that affect the method performance to develop an accurate, precise, cost-effective, and environmentally benign method. The separation was carried out using a mobile phase composed of methanol: 0.05 M potassium dihydrogen phosphate buffer pH 3.7 with 0.05% TEA (78:22, v/v). The flow rate was 1.2 mL/min. DAD detector was set at 227 nm. Linagliptin (LIN) was used as an internal standard. The proposed method was validated according to The International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH). The assay results obtained by using the developed method were statistically compared to those obtained by the reported HPLC method, and a satisfying agreement was observed.

Using of eosin Y as a facile fluorescence probe in alogliptin estimation: Application to tablet dosage forms and content uniformity testing.

New simple sensitive and reliable spectrofluorimetric approach was established for the determination of the antidiabetic drug; Alogliptin (ALG) in its pure and tablet forms. The developed approach is depended on the suppressive action of ALG on the eosin Y native fluorescence. The quenching action of ALG on the eosin Y native fluorescence was measured at acidic medium pH: 3.5, emission wavelength 541 nm (λex. 260 nm). The relative fluorescence intensity (RFI) was measured, and it was directly proportional to ALG concentration in the concentration range of (15-110) µg/mL. The developed and optimized approach was entirely validated regarding to ICH guidelines. The developed method application was successfully extended for ALG content uniformity test (CU). The distribution fraction (DF), rate constants (K), and free energy changes (ΔG°) were calculated. The results obtained were compared to that of the published spectrophotometric one.

Voltammetric estimation of residual nitroxynil in food products using carbon paste electrode.

A simple and sensitive voltammetric method was developed and validated for the recognition of the veterinary drug nitroxynil (NTX). The method is based on studying its voltammetric behavior at a carbon paste electrode. Square wave voltammetry (SWV) was successfully applied in this study. The anodic peak current obtained was a linear function of NTX concentration in Britton Robinson buffer of pH 3 over the range of 3.9 × 10-6-1.0 × 10-4 M with lower detection and quantitation limits of 3.1 × 10-7 and 9.4 × 10-7 M, respectively. The proposed method was first applied to the assessment of the drug in commercial vials. The method was further used to monitor the residual amounts of the drug in bovine meat, kidney, fat, and milk samples. The results obtained were favourably compared with those given by reference method. The interference likely to be introduced by co-administered drugs was evaluated. The electrode reaction was elucidated, and electron transfer kinetics were studied.

Analytical quality by design based on design space in reversed-phase-high performance liquid chromatography analysis for simultaneous estimation of metformin, linagliptin and empagliflozin.

Employing the Quality by Design paradigm through this work helped conclude the method operable design region for optimizing the high performance liquid chromatography (HPLC) assay using Design of Experiments and response surface methodology to obtain a good resolution and determination of all analysed compounds and to achieve a suitable analysis time. A deep understanding of the quality target product profile, analytical target profile and risk assessment for parameters that affect the method performance led to developing an accurate, precise and cost-effective method. Quality risk management principles were applied for determining the critical method parameters affecting the simultaneous determination of metformin hydrochloride (MET), linagliptin (LIN) and empagliflozin (EMP) by reversed-phase HPLC . The ternary mixture was successfully resolved in 5 min with a linearity range of (0.1-600) µg ml-1 for MET and (0.05-50) µg ml-1 for LIN and EMP. The newly developed method was validated according to the International Council for Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use guidelines. Good agreement was observed with the assay results of the reported UPLC one. To evaluate the greenness of the proposed method, an analytical Eco-Scale method was used.

A highly sensitive spectrofluorimetric method for the determination of bilastine in its pharmaceutical preparations and biological fluids.

Allergic rhinitis and urticaria are extremely prevalent among all age groups. From the clinical experience, usually, an essential second-generation non-sedating H1-antihistaminic drug, such as bilastine is given to relieve allergic symptoms. Bilastine is preferred to be used instead of oral corticosteroids and first -generation sedating H1-antihistaminics to avoid their side effects. A highly sensitive and simple spectrofluorometric method was developed and validated for the determination of bilastine in its dosage forms and biological fluids. The quantum yield was calculated and was found to be as high as 0.48. Aqueous water solution of bilastine gives high native fluorescence emission at 298 nm after excitation at 272 nm. A rectilinear calibration plot was obtained over the concentration range of 1.0-50.0 ng mL-1. The limits of quantitation and detection were 1.0 and 0.33 ng mL-1, respectively. The parameters influencing its spectrofluorimetric behavior, viz, type of solvent, pH and organized media were studied. The proposed method was successfully applied for the determination of the drug in pharmaceutical dosage form and the results obtained were in good agreement with those of given by reported method. The high sensitivity of the proposed method enabled the estimation of the drug in biological matrices, including human plasma and urine samples after simple protein precipitation, and the results obtained were satisfactory.

Simultaneous estimation of recently FDA approved co-formulated ophthalmic solution benoxinate and fluorescein: Application to aqueous humor.

Nine simple, cost-effective, and sensitive spectrophotometric methods were developed to simultaneously assay benoxinate HCl and fluorescein sodium in their co-formulated eye drops without barring common excipients. A direct UV spectrophotometric method (method I) was developed for their FLU assay at 481 nm over the concentration range of 0.6-10.0 µg mL-1. Meanwhile, BEN was assayed over the concentration range of 1.0-25.0 µg mL-1 by different UV based methods, namely, conventional dual-wavelength method (DW) (method II), first derivative1D spectrophotometry (method III), second derivative2D spectrophotometry (method IV), ratio spectra difference spectrophotometry (method V), the first derivative of ratio spectra (method VI), ratio subtraction method (method VII), isosbestic point method (ISP) (method VIII) and absorption factor method (method IX). The performance of the proposed methods was assessed relying on the correlation coefficients, relative standard deviations, and limits of detection and quantitation. The variance ratio F-test and Student t-test showed no significant differences between the obtained results of the developed methods and those of reference methods. The proposed methods were also applied to determine studied drugs in commercial eye drops and aqueous humor.

Gastroenterology manifestations and COVID-19 outcomes: A meta-analysis of 25,252 cohorts among the first and second waves.

A meta-analysis was performed to identify patients with coronavirus disease 2019 (COVID-19) presenting with gastrointestinal (GI) symptoms during the first and second pandemic waves and investigate their association with the disease outcomes. A systematic search in PubMed, Scopus, Web of Science, ScienceDirect, and EMBASE was performed up to July 25, 2020. The pooled prevalence of the GI presentations was estimated using the random-effects model. Pairwise comparison for the outcomes was performed according to the GI manifestations' presentation and the pandemic wave of infection. Data were reported as relative risk (RR), or odds ratio and 95% confidence interval. Of 125 articles with 25,252 patients, 20.3% presented with GI manifestations. Anorexia (19.9%), dysgeusia/ageusia (15.4%), diarrhea (13.2%), nausea (10.3%), and hematemesis (9.1%) were the most common. About 26.7% had confirmed positive fecal RNA, with persistent viral shedding for an average time of 19.2 days before being negative. Patients presenting with GI symptoms on admission showed a higher risk of complications, including acute respiratory distress syndrome (RR = 8.16), acute cardiac injury (RR = 5.36), and acute kidney injury (RR = 5.52), intensive care unit (ICU) admission (RR = 2.56), and mortality (RR = 2.01). Although not reach significant levels, subgroup-analysis revealed that affected cohorts in the first wave had a higher risk of being hospitalized, ventilated, ICU admitted, and expired. This meta-analysis suggests an association between GI symptoms in COVID-19 patients and unfavorable outcomes. The analysis also showed improved overall outcomes for COVID-19 patients during the second wave compared to the first wave of the outbreak.

Synchronous spectrofluorometric methods for simultaneous determination of diphenhydramine and ibuprofen or phenylephrine in combined pharmaceutical preparations.

Simple and rapid synchronous fluorometric methods were adopted and validated for the simultaneous analysis of a binary mixture of diphenhydramine (DIP) and ibuprofen (IBU) (Mix I) or DIP and phenylephrine (PHE) (Mix II) in their co-formulated pharmaceuticals without prior separation. Analysis of Mix I is based on the measurement of the peak amplitudes (D1 ) of synchronous fluorescence intensities at 265.1 nm for DIP and 260 nm for IBU. The relationship between the concentration and the amplitude of the first-derivative synchronous fluorescence spectra showed good linearity over the concentration ranges 0.50-10.00 µg ml-1 and 0.50-7.90 µg ml-1 for DIP and IBU, respectively. Analysis of Mix II was based on measurement of the peak amplitude (D1 ) synchronous fluorescence intensities at 230 nm for DIP and at 253.9 nm for PHE. Moreover, for Mix II, the peak amplitude (D2 ) synchronous fluorescence intensities were measured at 227.9 nm for DIP and at 264.9 nm for PHE. Calibration plots were rectilinear over the concentration range 0.30-3.50 µg ml-1 and 0.03-0.75 µg ml-1 for DIP and PHE, respectively. The proposed methods were successfully applied to determine the studied compounds in pure form and in pharmaceutical preparations.

Derivative Quotient Spectrophotometry and an Eco-Friendly Micellar Chromatographic Approach with Time-Programmed UV-Detection for the Separation of Two Fluoroquinolones and Phenazopyridine.

In this study, two analytical approaches were exploited for the resolution of binary mixtures of ciprofloxacin HCl (CIP) or norfloxacin (NOR) and phenazopyridine HCl (PHZ). In the first approach, the amplitudes of the first derivative of the ratio spectra were measured at 267 or 287 nm for CIP and at 268 or 291 nm for NOR. PHZ could be directly determined in the presence of CIP or NOR at 405 nm. The calibration graphs were rectilinear over the ranges of 1.0-16.0 µg/mL for CIP or NOR and 1.0-10.0 µg/mL for PHZ. In the second approach, an accurate, reliable and environmentally nontoxic micellar liquid chromatographic (MLC) method was developed. A good chromatographic separation was achieved using a 150 mm × 4.6 mm i.d., 5 µm particle size Spherisorb ODS-2 column. Eco-friendly mobile phase containing 0.12 M sodium dodecyl sulphate, 0.3% triethylamine and 6%n-butanol in 0.02 M orthophosphoric acid of pH 3.0 was pumped at a flow rate of 1 mL/min. Time programmed UV-detection was applied to allow sensitive determination of the studied drugs. The analytes were eluted without interferences in <10 min. Methocarbamol was used as an internal standard. The MLC method was found to be rectilinear over the concentration range of 0.5-20.0 µg/mL for CIP, NOR or PHZ. These optimized and validated methods were successfully applied for the simultaneous analysis of the studied drugs in their synthetic mixtures and co-formulated tablets. Moreover, the second method was further extended to the determination of these drugs in human urine with direct injection and without any pretreatment.

Hydroxylated near-infrared BODIPY fluorophores as intracellular pH sensors.

In this study, a series of new, highly sensitive BF2-chelated tetraarylazadipyrromethane dyes are synthesized and analyzed to be suitable as on/off photo-induced electron transfer modulated fluorescent sensors for determination of intracellular pH. The ethanolic solutions of the new indicators feature absorption maxima in the range of 696-700 nm and a fluorescence emission maximum at 720 nm. Molar absorptivity and fluorescence quantum yield data were determined for the studied set of aza-BODIPY indicators. These indicators have high molar absorption coefficients of ∼80,000 M(-1) cm(-1) and quantum yields (up to 18%). Corresponding pKa values of indicators are determined from absorbance and fluorescence measurements and range from 9.1 to 10.8, depending on the selective positioning of electron-donating functionalities. The excellent photostability of the aza-BODIPY indicators makes them particularly suitable for long duration measurements. The in vitro cellular staining of living tissues in PC3 cells based on the isosbestic point at pH 7.8 and pH 9.3 has been employed which shows an increase in fluorescence intensity at 800 nm with increase in pH for certain compounds and fluorescence intensity decreases at 700 nm. Therefore, the new indicators are suitable for exploitation and adaptation in a diverse range of analytical applications.

Simultaneous determination of aliskiren hemifumarate, amlodipine besylate, and hydrochlorothiazide in their triple mixture dosage form by capillary zone electrophoresis.

A novel, specific, reliable, and accurate capillary zone electrophoretic method was developed and validated for the simultaneous determination of aliskiren hemifumarate, amlodipine besylate, and hydrochlorothiazide in their triple mixture dosage form. Separation was carried out in a fused-silica capillary (57.0 cm total length and 50.0 cm effective length, 75.6 µm internal diameter) by applying a potential of 17 kV and a running buffer consisting of 40 mM phosphate buffer at pH 6.0 with UV detection at 245 nm. The method was suitably validated with respect to specificity, linearity, LOD, and LOQ, accuracy, precision, and robustness. The method showed good linearity in the ranges 1-10, 2.5-25, and 30-300 µg/mL with LODs of 0.11, 0.33, and 5.83 µg/mL for amlodipine besylate, hydrochlorothiazide, and aliskiren hemifumarate, respectively. The proposed method was successfully applied for the analysis of the studied drugs in their coformulated tablets. The results of the proposed method were statistically compared with those obtained by the RP-HPLC reference method revealing no significant differences in the performance of the methods regarding accuracy and precision.