Feasible spectrofluorimetric approach for the ultrasensitive determination of lomefloxacin based on synergistic effects of micellization and metal complexation.

The purpose of the present work was to establish a fast and convenient strategy for lomefloxacin analysis using a fluorimetric approach. The methodology was based on the complex formation of the drug with aluminum ion to give a product having high fluorescence. Adding sodium dodecyl sulfate led to further boosting the intensity of fluorescence which was recorded at 429 nm after excitation at 332 nm. The relationship of emission intensity with lomefloxacin concentration was linear at 10-130 ng mL-1 with a correlation coefficient of 0.9996. The quantitation limit was 11.4 ng mL-1 and detection limit was 3.8 ng mL-1. The reaction conditions were carefully studied which included the pH, buffer type, its concentration, the type and concentration of surfactant and the diluting solvent. The method was utilized to quantify the aforementioned drug in tablet formulations and in real human plasma with high accuracy and reliability.

Green sensitive spectrofluorimetric determination of pemetrexed as antineoplastic drug: Application in pharmaceutical dosage forms and spiked human plasma.

A recent antineoplastic medication is pemetrexed, this medicine is now being developed and produced on a large scale, thus approaches for quality control are urgently needed. Spectrofluorimetric guidelines for the simple estimation of pemetrexed were validated. Pemetrexed's assay depends on observations of its native fluorescence at wavelengths 275/450 nm and pH 4. The proposed approach was also used to identify the examined drug in both its formulation and in human plasma that had been spiked.

Green innovative fluorescence approach for the feasible and reliable assay of thiol-containing drugs; captopril as a model.

In the present study, a novel spectrofluorimetric approach was designed for the analysis of captopril as a thiol-containing compound. The approach is based on the formation of a ternary fluorescent compound between the target thiol compound, ortho-phthaldehyde, and a suitable primary amine-containing compound. The produced 1-thio-alkyl-isoindole derivative exhibited very high emission activity in a faintly alkaline aqueous solution that could be monitored at 448 nm (excitation at 334 nm). 2-Amino-6-methyl-6-hydroxy-heptane was selected as the primary amine candidate that gave the high fluorescence intensity with the stability of the formed product. At the optimal experimental condition, the intensity of fluorescence of the formed product was linearly related to the concentration of captopril in 20-450 ng mL-1 range. Commercial pharmaceutical tablets were analyzed, and the obtained results agreed with those of the published method regarding precision and accuracy. The mechanism of the reaction was discussed. In addition, the greenness of the approach was rated following eco-scale criteria.

Spectrofluorimetric first derivative synchronous approach for determination of olanzapine and samidorphan used for treatment of schizophrenia in pharmaceutical formulations and human plasma.

The combination of olanzapine and samidorphan has just been authorised for the treatment of schizophrenia. The current study created a very accurate, sensitive and selective spectroscopic technique based on the first derivative of synchronous fluorescence for determining olanzapine and samidorphan in their pharmaceutical prescriptions without prior separation. For the quantitative analysis of samidorphan and olanzapine, the adopted approach is focused on measuring the synchronised fluorescence intensity of the examined medicines at fixed wavelength range (Δλ) = 50 nm and the first derivative's peak magnitudes were observed at 300 and 350 nm, respectively. The effects of various factors on the synchronised fluorescence intensity of the referenced medications were researched and adjusted. Both medications' calibrating charts were shown to be linear throughout a range of concentrations of 0.1-1.1 µg mL-1. LOD for SAM and OLA were 0.02 and 0.01, respectively. In addition, LOQ was determined for SAM and OLA as follow, 0.07 and 0.06, respectively. The devised approach was effectively used to the quantitative measurement of the two medicines in Lybalvi® tablets with various samidorphan and olanzapine ratios, in addition to spiked human plasma. A variance ratio F-test and student t-test were needed to be able to compare the results to another published analytical technique and found no significant differences.

A feasible fluorimetric approach anchored in diaryl pyrrolone derivative for the facile analysis of milnacipran in tablets; evaluation of the method greenness.

In the present work a new, feasible, and green approach was employed for the analysis of milnacipran. A drug is used in the management of depression in addition to fibromyalgia. It inhibits of the reuptake of two essential neurotransmitters serotonin and nor-adrenaline. In slightly alkaline buffer (pH 8.5) the primary amino group of milnacipran reacted with fluorescamine to give a substituted pyrrolone derivative which exhibited high fluorescence activity. The fluorescence of produced derivative was measured at (λex 385 nm, λem 477 nm), and the experimental factors were cautiously optimized. The measured intensity of fluorescence was plotted versus the respective concentration of milnacipran to setup the calibration plot which has a linear concentration range of 50-300 ng/mL. The ICH guidelines were utilized to totally validate the presented approach. In addition the method could be efficiently incorporated in the analysis of commercial milnacipram tablets with no considerable effect on the results of the assay for milnacipran. The developed approach is characterized by its high simplicity and greenness of the procedure which make it suitable for routine analysis.

Combining subsidiary and synchronous approaches for concurrent spectrofluorimetric assurance of lopinavir and ritonavir in tablets utilized in convention for treatment of coronavirus infection (COVID-19) and biological fluids.

In this think about, assurance of lopinavir and ritonavir down to organic concentration level has been carried out. The assurance is based on expanding the selectivity of the spectrofluorimetric procedure by combining both subordinate and synchronous spectrofluorimetric approaches, which allow effective estimation of lopinavir at 248.8 nm and ritonavir at 300.1 nm within the nearness of each other at Δλ of 60 nm. Worldwide Conference on Harmonization approval rules were taken after to completely approve the strategy, and linearity was gotten for the two drugs over the extend of 0.4-2.4 µg mL-1 for Lopinavir and 0.1-0.6 µg mL-1 for ritonavir. Application of of the strategy was successfully carried out within the commercial tablets with great understanding with the comparison strategies. As the detection limits were down to 0.133 and 0.022 µg mL-1 and quantitation limits were 0.395 and 0.068 µg mL-1 for lopinavir and ritonavir, individually; the in vivo assurance of lopinavir and ritonavir in spiked plasma tests was pertinent. The rate recuperations in natural tests were 99.10 ± 0.77 and 99.54 ± 0.60 for lopinavir and ritonavir, individually. Water was utilized as the ideal weakening dissolvable within the proposed strategy which includes an eco-friendly justify.

Resonance Rayleigh scattering and spectrofluorimetric approaches for the selective determination of rupatadine using erythrosin B as a probe: application to content uniformity test.

In this study, spectrofluorimetric and resonance Rayleigh scattering techniques were applied for the first time for determination of rupatadine through two validated methods. The proposed methods were based on a facile association complex formation between rupatadine and erythrosin B reagent in acidic medium. Spectrofluorimetric determination relied on the quenching effect of rupatadine on the fluorescence intensity of erythrosin B at 556 nm (excitation = 530 nm). Conversely, the resonance Rayleigh scattering (RRS) method relied on enhancement in the resonance Rayleigh scattering spectrum of erythrosin B at 344 nm after the addition of rupatadine. The developed methods produced linear results over ranges 0.15-2.0 µg/ml and 0.1-1.5 µg/ml, with detection limits of 0.030 µg/ml and 0.018 µg/ml for the spectrofluorimetric method and the RRS method, respectively. All reaction conditions for rupatadine-erythrosin B formation were optimized experimentally and both methods were validated according to International Council for Harmonisation guidelines. The developed methods were applied to estimate rupatadine content in its pharmaceutical tablet dosage form with acceptable recoveries. Furthermore, a content uniformity test for the commercial rupatadine tablets was successfully applied by the suggested spectroscopic methods according to United States Pharmacopeia guidelines.

In Vitro Antimycobacterial Activity and Physicochemical Characterization of Diaryl Ether Triclosan Analogues as Potential InhA Reductase Inhibitors.

Two sets of diphenyl ether derivatives incorporating five-membered 1,3,4-oxadiazoles, and their open-chain aryl hydrazone analogs were synthesized in good yields. Most of the synthesized compounds showed promising in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv. Three diphenyl ether derivatives, namely hydrazide 3, oxadiazole 4 and naphthylarylidene 8g exhibited pronounced activity with minimum inhibitory concentrations (MICs) of 0.61, 0.86 and 0.99 µg/mL, respectively compared to triclosan (10 µg/mL) and isoniazid (INH) (0.2 µg/mL). Compounds 3, 4, and 8g showed the InhA reductase enzyme inhibition with higher IC50 values (3.28-4.23 µM) in comparison to triclosan (1.10 µM). Correlation between calculated physicochemical parameters and biological activity has been discussed which justifies a strong correlation with respect to the inhibition of InhA reductase enzyme. Molecular modeling and drug-likeness studies showed good agreement with the obtained biological evaluation. The structural and experimental information concerning these three InhA inhibitors will likely contribute to the lead optimization of new antibiotics for M. tuberculosis.

Potential repurposed SARS-CoV-2 (COVID-19) infection drugs.

The global outbreak of COVID-19 viral infection is associated with the absence of specific drug(s) for fighting this viral infection. About 10 million people are already infected, about 500 000 deaths all over the world to date. Great efforts have been made to find solutions for this viral infection, either vaccines, monoclonal antibodies, or small molecule drugs; this can stop the spread of infection to avoid the expected human, economic and social catastrophe associated with this infection. In the literature and during clinical trials in hospitals, several FDA approved drugs for different diseases have the potential to treat or reduce the severity of COVID-19. Repurposing of these drugs as potential agents to treat COVID-19 reduces the time and cost to find effective COVID-19 agents. This review article summarizes the present situation of transmission, pathogenesis and statistics of COVID-19 in the world. Moreover, it includes chemistry, mechanism of action at the molecular level of the possible drug molecules which are liable for redirection as potential COVID-19 therapeutic agents. This includes polymerase inhibitors, protease inhibitors, malaria drugs, lipid lowering statins, rheumatoid arthritis drugs and some miscellaneous agents. We offer research data and knowledge about the chemistry and biology of potential COVID-19 drugs for the research community in this field.

Microenvironment improvement protocol for the sensitive spectrofluorimetric determination of an hepatitis C virus antiviral (Simeprevir): application to human plasma.

Simeprevir (SPV) is a powerful antihepatitis C virus agent that was newly introduced into the pharmaceutical market. We here established and validated an easy, simple, and sensitive spectrofluorimetric method for its estimation at λem 427 nm (λex 337 nm). The suggested procedure was based on two times enhancement in the original emission of SPV through modifying its microenvironment in buffered aqueous solution by adding Triton X-100. The relationship between the concentration of SPV and the observed fluorescence intensity was linear in the range 0.06-1.0 µg ml-1 with a correlation coefficient of 0.9997. The limits of detection and quantitation were 21 and 64 ng ml-1 , respectively. The present method was effectively applied to quantify SPV content in pharmaceutical tablets and human plasma spiked with the drug with no interference from tablet excipients or plasma components.

Determination of cefotaxime, cefoperazone, ceftazidime and cefadroxil using surface plasmon resonance band of silver nanoparticles

The aim of this work is to evaluate simple, sensitive, effective and validated procedures for the determination of cefotaxime, cefoperazone, ceftazidime and cefadroxil. In this study, the methods based on the ability of the cited drugs to reduce Ag+ ions to silver nanoparticles (Ag-NPs) in the presence of Polyvinyl Pyrrolidone (PVP) as a stabilizing agent producing very intense surface plasmon resonance peak of Ag-NPs (λmax. = 410-430 nm). The plasmon absorbance of the Ag-NPs allows the quantitative spectrophotometric determination of the cited drugs. The calibration curves are linear with concentration ranges of 0.4-3.2, 1-8, 0.5-4.0 and 1.5-9.0 µg/mL for cefotaxime, cefoperazone, ceftazidime and cefadroxil, respectively. Apparent molar absorptivity, detection and quantitative limits are calculated. Applications of the proposed methods to representative pharmaceutical formulations are successfully presented. The extracellular synthesis of nanoparticles is fast, and the method doesn't require various elaborate treatments and tedious extraction procedures.