An ultrasensitive green synchronous factorized spectrofluorimetric approach for the simultaneous determination of Favipiravir and Molnupiravir: Application to pharmaceutical, environmental, and biological matrices.

During the pandemic, Favipiravir (FVP) and Molnupiravir (MPV) have been widely used for COVID-19 treatment, leading to their presence in the environment. A green synchronous spectrofluorimetric method was developed to simultaneously detect them in environmental water, human plasma, and binary mixtures. Maximum fluorescence intensity was achieved at pH 8, with MPV exhibiting two peaks at 300 and 430 nm, and FVP showing one peak at 430 nm. A fluorescence subtraction method effectively removed interference, enabling direct determination of MPV at 300 nm and FVP at 430 nm. The method showed linearity within 2-13 ng/mL for FVP and 50-600 ng/mL for MPV, with recoveries of 100.35% and 100.12%, respectively. Limits of detection and quantification were 0.19 and 0.57 ng/mL for FVP and 10.52 and 31.88 ng/mL for MPV. Validation according to ICH and FDA guidelines yielded acceptable results. The method demonstrated good recoveries of FVP and MPV in pharmaceuticals, tap water and Nile water (99.62% ± 0.96% and 99.69% ± 0.64%) as per ICH guidelines and spiked human plasma (94.87% ± 2.111% and 94.79% ± 1.605%) following FDA guidelines, respectively. Its environmental friendliness was assessed using Green Analytical Procedure Index (GAPI) and the Analytical Greenness Metric (AGREE) tools.

Synchronous Spectrofluorimetry Coupled with Third-Order Derivative Signal Processing for the Simultaneous Quantitation of Telmisartan and Chlorthalidone Drug Combination in Human Plasma.

This study is the first to develop and optimize a method for the simultaneous determination of chlorthalidone (CLT) and telmisartan (TEL) in, human plasma samples as well as in their newly released pharmaceutical tablet form, (Telmikind-CT 40®). The method is based on measuring fluorescence intensity, employing synchronous fluorescence mode coupled to third-order derivative signal processing, 0.5% w/v cetyl trimethyl ammonium bromide was used as cationic surfactant to enhance the fluorescence signal intensity and improve method sensitivity. The third-order derivative synchronous spectra of CLT and TEL are well separated with two zero-crossing points which allowed for the determination of CLT and TEL at 362 nm and 351 nm, respectively. Different experimental parameters were carefully investigated and optimized, calibration curves were constructed over concentration ranges of 20-1200 ng.mL-1 and 5-800 ng.mL-1 for CLT and TEL respectively. The developed method is simple and rapid, analytical parameters were validated according to ICH guidelines and high sensitivity was achieved as represented by limits of detection (LOD) of 4.69 and 1.58 ng.mL-1 for CLT and TEL respectively.

Simultaneous determination of citalopram and tadalafil by the second derivative synchronous fluorescence method in biological fluids; application of Box-Behnken optimization design.

This is the first study focusing solely on that determination of tadalafil in the presence of citalopram as an antidepressant drug. The determination in biological fluids of a co-administered antidepressant drug and a sexual stimulation drug is a very critical and important step for psychotic and ischaemic heart disease patients, especially in cases of emergency and this requires therapeutic drug monitoring. A sensitive, efficient and rapid assay was selected satisfactorily and applied for simultaneous determination of citalopram and tadalafil either in their pure forms, in tablet dosage forms or in spiked human plasma. There was a large overlap for both drugs, forming the broad band found in conventional fluorescence spectra and their related synchronous fluorescence intensity. Therefore, the development of a highly sensitive second derivative synchronous fluorescence method was demonstrated that removed this overlap. The proposed method depended on measuring the amplitudes of the second derivative of synchronous fluorescence intensity at suitable wavelengths of 301 nm and 367 nm for citalopram and tadalafil at Δλ = 60 nm, respectively. Box-Behnken design as a response surface methodology was used to fit models and create an optimization process encompassing a set of factors and resulting in an optimum response value specifically designed for this method. Under optimum conditions, the linear dynamic ranges for citalopram and tadalafil estimation were 20-900 and 5-400 ng ml-1 with detection limits of 5.40 and 1.43 ng ml-1 , respectively.

Eco-friendly-assessed micellar-fluorimetric platform for concurrent analysis of empagliflozin and prucalopride succinate in biological fluids: Docking simulation.

Fluorescence spectroscopy has an important role in the determination of very small quantities of substances, especially in biological fluids. For this reason, most analysts have adopted the use of this technique in their biological studies and research, which helps them in the determination of any substance found in trace amounts. In addition to the high sensitivity of the fluorimetric technique, it has the advantages of simplicity and being green for the environment. All these reasons encourage the use of fluorimetric spectroscopy for quantifying co-administered therapy in biological fluids, which is considered a crucial step for patients, particularly in emergent cases requiring monitoring of administered therapeutic drugs. In this work, a sensitive, simple, economic, and environmentally friendly fluorimetric analytical technique was developed for the simultaneous determination of prucalopride succinate (a novel anti-constipation agent) and empagliflozin (an anti-diabetic agent) in pharmaceutical forms and spiked plasma depending on third-derivative signal processing at 333 and 314 nm, respectively. Conventional fluorescence spectra of both drugs showed a large overlap that hindered their simultaneous determination. So, third-order derivative fluorescence was adopted to overcome this overlap. The third-derivative corresponding to each spectrum was recorded using data points = 17 and a scaling factor of 10. The greenness of the proposed method was evaluated using an eco-scale scoring system, revealing excellent greenness. Analytical method parameters were validated following ICH guidelines. The method showed high sensitivity, covering a concentration range of 50-1100 ng/mL and 4-500 ng/mL for empagliflozin and prucalopride, respectively, allowing the pharmacokinetic study of both drugs in biological fluids. The LOD values were 14.09 and 0.91 ng/mL, while the LOQ values were 42.72 and 2.77 ng/mL for empagliflozin and prucalopride, respectively.

Earth-friendly-assessed silver-nanoparticles spectrophotometric method for rapid and sensitive analysis of Molnupiravir, an FDA-approved candidate for COVID-19: application on pharmaceutical formulation and dissolution test.

Molnupiravir is the first oral direct-acting antiviral prodrug recently approved for the COVID-19 pandemic. Here and for the first time, we present a novel, sensitive, robust, and simple silver-nanoparticles spectrophotometric technique for molnupiravir analysis in its capsules and dissolution media. This spectrophotometric technique involved silver-nanoparticles synthesis through a redox reaction between the reducing agent (molnupiravir) and the oxidizing agent (silver nitrate) in presence of polyvinylpyrrolidone as a stabilizing agent. The produced silver-nanoparticles have an intense surface plasmon resonance peak at 416 nm where the measured absorbance values were utilized for the quantitative analysis of molnupiravir. The produced silver-nanoparticles were recognized by using the transmission electron microscope. Under optimal conditions, a good linear rapport was accomplished between molnupiravir concentrations and the corresponding absorbance values in a range of (100-2000) ng/mL with a detection limit of 30 ng/mL. Greenness assessment was implemented using eco-scale scoring and GAPI disclosing the excellent greenness of the suggested technique. The suggested silver-nanoparticles technique was authenticated according to recommendations of the ICH and statistically assessed with the reported liquid chromatographic method without significant differences regarding accuracy or precision. Accordingly, the suggested technique is deemed a green and cheap alternative for assaying molnupiravir due to its reliance primarily on water. Furthermore, the suggested technique's high sensitivity can be employed for investigating molnupiravir bioequivalence in future studies.

Application of green first derivative synchronous spectrofluorometric method for quantitative analysis of fexofenadine hydrochloride and pseudoephedrine hydrochloride in pharmaceutical preparation and spiked human plasma.

Fexofenadine hydrochloride and pseudoephedrine hydrochloride are prescribed in a combined dosage form for the treatment of allergic rhinitis. In the present work, a sensitive synchronous fluorescence spectroscopic method was applied in conjunction with first derivative for quantitative estimation of fexofenadine hydrochloride and pseudoephedrine hydrochloride in pure form, pharmaceutical tablets and spiked human plasma. Fexofenadine hydrochloride showed its conventional emission spectrum at 294 nm when excited at 267 nm. On the other hand, pseudoephedrine hydrochloride showed its conventional emission spectra at 286 nm when excited at 261 nm. The fluorescence intensities were greatly enhanced by the use of sodium dodecyl sulphate as a micellar surfactant. Application of the synchronous mode to measure the fluorescence spectra of the above drugs provided sharp narrowing bands, but the overlap was not completely resolved. Derivatization of the synchronous spectra to the first order completely resolved the overlap of the fluorescence spectra and allowed simultaneous quantitative determination of the drugs under study. Fexofenadine hydrochloride and pseudoephedrine hydrochloride could be determined from their first-order synchronous spectra at 286 and 294 nm, respectively, without interfering with each other. The method showed linearity with an excellent correlation coefficient in the concentration range of 100-1500 ng/mL for Fexofenadine hydrochloride and 50-1000 ng/mL for pseudoephedrine hydrochloride. The method was successfully applied for the simultaneous determination of the studied drugs in pharmaceutical formulation, with mean percent recoveries for Fexofenadine hydrochloride and pseudoephedrine hydrochloride of 99.49 ± 0.931 and 98.67 ± 0.634, respectively, and in spiked human plasma, with mean percent recoveries for Fexofenadine hydrochloride and pseudoephedrine hydrochloride of 95.21 ± 1.938 and 94.89 ± 1.763, respectively. Furthermore, the greenness of the described method was assessed using four different tools namely, the national environmental method index, the analytical eco-scale, the green analytical procedure index and the AGREE evaluation method. The proposed method seemed to be superior to the reported HPLC method with respect to the metrics of the greenness characters.

Spectrofluorimetric quantitative analysis of favipiravir, remdesivir and hydroxychloroquine in spiked human plasma.

Favipiravir, remdesivir and hydroxychloroquine have been suggested in COVID-19 Treatment Guidelines Panel of many countries. Synchronous spectrofluorometric measurement provides sensitive tool for resolving the overlapped spectra of multicomponent drugs through converting the wider spectra to narrower sharp spectra. This work introduces the first fluorescence spectroscopic method for quantitative analysis of favipiravir, remdesivir and hydroxychloroquine in spiked human plasma. Testing the fluorescence spectra of favipiravir, remdesivir and hydroxychloroquine shows severe overlap, which hinders the direct quantification of the cited drugs. To overcome the overlapping issue, the drugs under the study have been measured in the synchronous mode at Δλ = 60 nm. Favipiravir could be measured directly at 423 nm without interference of remdesivir or hydroxychloroquine. Synchronous measuring the cited drugs at Δλ = 130 nm with mathematical transforming to the first order derivative spectra allowing remdesivir and hydroxychloroquine at 384 nm and 394 nm, respectively without interference from favipiravir. Different factors affecting the spectrofluorometric measurement process have been verified. The drugs under the study have been successfully quantitatively analyzed in the spiked plasma using the proposed method.

Analysis of the ternary antiretroviral therapy dolutegravir, lamivudine and abacavir using UV spectrophotometry and chemometric tools.

Herein, a simple spectrophotometric method coupled with chemometric techniques i.e. partial least square (PLS) and genetic algorithm (GA) were utilized for the simultaneous determination of the vital ternary antiretroviral therapy dolutegravir (DTG), lamivudine (LMV), and abacavir (ACV) in their combined dosage form. Calibration (25 samples) and validation (13 samples) sets were prepared for these drugs at different concentrations via implementing partial factorial experimental designs. The zero order UV spectra of calibration and validation sets were measured and then subjected for further chemometric analysis. Partial least squares with/without variable selection procedures i.e. genetic algorithm (GA) were utilized to untangle the UV spectral overlapping of these mixtures. Cross-validation and external validation methods were applied to compare the performance of these chemometric techniques in terms of accuracy and predictive abilities. It was found that six latent variables were optimum for modelling DTG, four latent variables for modelling LMV and three latent variables for modelling ACV. Although, good recoveries with prompt predictive ability were attained by these PLS, GA-PLS showed better analytical performance owing to its capability to remove redundant variables i.e. the number of absorbance variables have been reduced to about 21-29%. The proposed chemometric methods can be reliably applied for simultaneous determination of DTG, LMV, and ACV in their laboratory prepared mixtures and pharmaceutical preparation posing these chemometric methods as worthy and substantial analytical tools in in-process testing and quality control analysis of many antiretroviral pharmaceutical preparations.

Flourimetric study on antidiabetic combined drugs; empagliflozin and linagliptin in their pharmaceutical formulation and human plasma.

Empagliflozin and linagliptin are newly approved FDA combination that used for the treatment of type 2 diabetes mellitus (T2DM) under trade name Glxambi. Two spectroflourimetric methods were developed for simple quantitative determination of empagliflozin and linagliptin in their pharmaceutical formulation and human plasma without need any tedious processing operations. Empagliflozin has a native fluorescence nature, therefore can be directly determined by measuring emission peak at 305 nm after excitation at 234 nm. There is no any interference from linagliptin at this emission wavelength. On the other hand, linagliptin is a very weak florescent compound that needs to react with fluorogenic reagent to be quantitatively determined without any reaction of empagliflozin. So, quantitative analysis of linagliptin was achieved by coupling with NBD-Cl which is an electro active halide reagent (targeting only Linagliptin with no effect on empagliflozin). Dark yellow fluorophore with high fluorescence is a result of this reaction and can be measured at emission wavelength 538 nm after excition at wavelength 469 nm. Experimental conditions of the suggested methods were well checked and optimized. The regression plots were found to be linear over the range of 40-1200 ng/mL and 3-700 ng/mL for empagliflozin and linagliptin, respectively. The obtained results by the suggested methods were statistically compared with those obtained by the reported methods, showing no significant difference with respect to accuracy and precision at p = 0.05.

Application of different spectrofluorimetric methods for determination of lesinurad and allopurinol in pharmaceutical preparation and human plasma.

Lesinurad and allopurinol combination is newly FDA approved for treatment of patients suffering from hyperuricemia associated with uncontrolled gout. In the present work, two different highly sensitive, selective and accurate fluorescence spectroscopic methods were developed for quantitative analysis of lesinurad and allopurinol in their pharmaceutical dosage form without any tedious operation procedure. Lesinurad was quantitatively analyzed based on its unique native fluorescence nature. Lesinurad fluorescence emission was quantitatively determined at 343 nm after excitation at 288 nm without any interference from allopurinol. Allopurinol, has free terminal secondary amino group, reacted with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBDCl) through nucleophilic substitution mechanism forming highly fluorescent dark yellow fluorophore. Allopurinol was quantitavely analyzed based on measurement the emission fluorescence intensity of the fluorescent dark yellow fluorophore at 535 nm after excitation at 465 nm. Different parameters which affect the described methods of the studied drugs were carefully checked and optimized. Calibration graphs were found to be linear over the concentration range of 0.25-4.0 µg/mL for lesinurad and 0.2-20 µg/mL for allopurinol. The proposed methods were successfully applied for the quantitative analysis of the two drugs in Duzallo® pharmaceutical dosage form and spiked human plasma.

Simultaneous determination of elbasvir and grazoprevir in their pharmaceutical formulation by synchronous fluorescence spectroscopy coupled to dual wavelength method.

In the present study, a sensitive, selective and accurate synchronous fluorescence spectroscopic method was utilized for simultaneous estimation of elbasvir and grazoprevir in their pharmaceutical formulation. The developed method based on measurement of the synchronous fluorescence intensity of the studied drugs at constant wavelength difference (Δλ) = 50 nm. Elbasvir can be determined directly at 312 nm without interference from grazoprevir. Grazoprevir can be determined by application of dual wavelength method by taking the difference in synchronous fluorescence intensity at 390 & 372 nm to remove interference from elbasvir. Calibration graphs were found to be linear over the concentration range of 50-700 ng/mL for elbasvir and 100-900 ng/mL for grazoprevir. The developed method was successfully applied to the quantitative analysis of the two drugs in Zepatier® tablets.

Application of different spectrofluorimetric approaches for quantitative determination of acetylsalicylic acid and omeprazole in recently approved pharmaceutical preparation and human plasma.

Acetylsalicylic acid and omeprazole were recently formulated by the new FDA-approved drug Yosprala ® Tablets. This novel combination was prescribed to reduce the risk of myocardial infarction in patients who were at risk for developing peptic ulcer while taking acetylsalicylic acid. In the current work, two different high precision sensitive fluorescence spectroscopic methods were developed for quantitative analysis of the above drugs in pharmaceutical dosage form and spiked human plasma. Acetylsalicylic acid was quantitatively analyzed due to its unique native fluorescence nature. The fluorescence emission of acetylsalicylic acid was quantitatively determined at 404 nm after excitation at 296 nm without any interference from omeprazole. Omeprazole, which has a free terminal secondary amino group, reacted with 4-chloro-7-nitrobenzo-2-oxa-1, 3-diazole (NBD-Cl) by a nucleophilic substitution mechanism to form a highly fluorescent dark yellow fluorophore. Omeprazole was quantitatively analyzed by measuring the emission fluorescence intensity of the dark yellow fluorophore at 535 nm after excitation at 465 nm. Various parameters affecting the described methods were carefully checked and optimized. The calibration curves were found to be linear over the concentration range of 50-1600 ng/ml for acetylsalicylic and 30-2000 ng/ml for omeprazole. The proposed methods were successfully applied to the quantitative analysis of the two drugs in the pharmaceutical dosage form Yosprala ® and in spiked human plasma.

Second derivative synchronous fluorescence determination of avanafil in the presence of its acid-induced degradation product aided by powerful Lean Six Sigma tools augmented with D-optimal design.

In this work, the quantitative determination of an erectile dysfunctional drug avanafil in the presence of its acid-induced degradation product was achieved via the application of a pre-optimized novel spectrofluorimetric method. The fluorescence emission wavelength was recorded at 370 and 407 nm, after being excited at 268 and 271 nm for avanafil and its acid-induced degradation product, respectively. Direct determination of avanafil based on its native fluorescence is restricted because the emission spectra of both components are heavily overlapped. Therefore, to overcome this constraint, a novel second derivative synchronous fluorescence method was evolved to eliminate this overlapping. The ideal determination wavelength was found to be 377 nm. Augmentation of lean six sigma (LSS) with response surface methodology (RSM) play a significant role in the development of robust specifications to ensure quality at the six sigma level with a high level of statistical confidence and targeted performance. All of the experimental conditions were optimized using D-optimal design as a RSM to select the optimal parameters. In addition, this work includes a graphical representation of the relationships between various variables that can greatly affect the results and the intensity of the synchronous fluorescence.

An enhanced first derivative synchronous spectrofluorimetric method for determination of the newly co-formulated drugs, amlodipine and celecoxib in pharmaceutical preparation and human plasma.

BACKGROUND: A new combination of amlodipine and celecoxib has been recently introduced in order to relieve the symptoms of osteoarthritis and help treat hypertension that commonly associated with osteoarthritis. OBJECTIVE: The current study is the first to develop and optimize a sensitive, simple and accurate first derivative synchronous spectrofluorimetric method for the simultaneous determination of amlodipine and celecoxib in bulk powder, pharmaceutical preparation and spiked human plasma. METHOD: The method implies the use of synchronous methodology using Δλ = 100 nm and measuring the fluorescence amplitudes of the first derivative each at the zero-crossing point of the other. For amlodipine and celecoxib, the emission wavelengths were at 455 nm and 368 nm, after excitation at 367 nm and 264 nm, respectively. RESULTS: The method was found to be linear over a wide concentration ranges of (5-600 ng/ml), (100-2000 ng/ml) with lower limits of detection of (1.16 ng/ml) and (17.16 ng/ml) for amlodipine and celecoxib, respectively. Enhancement of the fluorescence intensity was achieved by complex formation between the studied drugs and the surfactant sodium dodecyl sulfate and optimizing other experimental conditions. The method was further extended for application for determination of the studied drugs in spiked human plasma with excellent % recoveries of (95.20 ± 6.095) and (98.67 ± 6.394) for amlodipine and celecoxib, respectively. Validation of the method was successfully implemented according to recommendations delivered by guidelines of the International Conference on Harmonization.

Validated Liquid Chromatography-Tandem Mass Spectroscopic Method for Simultaneous Determination of Certain Drugs Used in Cataract Surgery in Rabbit Aqueous Humor.

A sensitive, selective, accurate and precise ultra-high performance liquid chromatography-Tandem mass spectrometry (MS/MS) method was developed and validated for the simultaneous determination of drugs used as eye drops in cataract surgery in aqueous humor. Cataract surgery requires a powerful mydriatic eye drops combination such as cyclopentolate hydrochloride and phenylephrine hydrochloride to dilate the pupil and facilitate eye lens replacement and also requires strong fluoroquinolone antibiotic such as lomefloxacin hydrochloride. The method was performed with positive ion electrospray ionization and the analytes were quantified and monitored on a triple quadrupole mass spectrometer using multiple reaction monitoring scanning mode. Liquid-liquid extraction was used for the purification and preconcentration of analytes from rabbit aqueous humor matrix. Chromatographic elution was performed using an Phenomenex Luna® C18 (150 mm × 2.1 mm, 1.6 µm) column and moxifloxacin hydrochloride as internal standard with a mobile phase consisting of methanol:water:formic acid (70:29:1, by volume) at flow rate of 0.2 mL/min. Satisfactory results regarding linearity, recovery, stability, accuracy and precision of the analytes were obtained. Full validation of the procedure was performed according to the US Food and Drug Administration guidance for industry: bioanalytical method validation and European Medicines Agency (EMA) guideline on bioanalytical method validation.

D-optimal design as a useful tool response surface methodology for the optimization of signals from synchronous fluorescence prior to simultaneous determination of avanafil and tadalafil.

A rapid, smart and sensitive first derivative spectrofluorimetric method has been carried out for the simultaneous estimation of avanafil and tadalafil either in their pure form, tablet dosage form or spiked human plasma. The measurements of normal emission spectra or synchronous fluorescence intensity of both drugs show severe overlap which hindered their determination using normal fluorescence or synchronous intensity. Therefore, a highly sensitive first derivative synchronous fluorescence procedure was used to resolve this overlap. The method is based upon measurement of the amplitude of the first derivative of synchronous fluorescence intensity of both drugs at Δλ = 70 nm and at suitable wavelength of 396 nm and 364 nm for avanafil and tadalafil, respectively. Under the optimum conditions, the linear determination ranges are 50-1800 and 5-400 ng mL-1 with a detection limit of 12.93 and 1.46 ng mL-1 for avanafil and tadalafil, respectively. A response surface methodology was used for optimization using D-optimal design which can be used for determination of the exact optimum parameters specifically designed for this method. In addition; it is a good way to graphically clarify the relationship between various experimental variables and the synchronous fluorescence intensity.