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Bevacizumab (BVC) is commonly co-administered with 5-fluorouracil (FLO) as a highly successful treatment for colon cancer. In this study, two spectrofluorimetric techniques were combined to provide an approach for concurrent quantification of BVC and FLO that is very sensitive, quick, easy and accurate. The inclusion of Tween-80 micellar system increased the native fluorescence intensity values of BVC and FLO, while the second derivative of the synchronous fluorescence intensity of the cited drugs at Δλ=100 nm allowed the concurrent estimation of cited drugs. The effect of various experimental conditions on the synchronous fluorescence of cited drugs were extensively examined to optimize them. The second derivative synchronous fluorimetry peak amplitudes for BVC and FLO were recorded at 450 nm and 440 nm, respectively. At a range of 100–1100 and 100–600 ng mL−1, the fluorescence-concentration graphs were built, with smaller quantification limits of 60.0 and 70.0 ng mL−1 and detection limits of 20.0 and 23.0 ng mL−1 for BVC and FLO, respectively. Without any major interference, the technique was effectively used to determine the cited drugs in raw material along with pharmaceutical formulations. The proposed technique was shown to be extremely precise and accurate when related to the reported techniques statistically. [ABSTRACT FROM AUTHOR]

Two simple, rapid and novel sensitive fluorimetric and spectrophotometric methods were investigated for the assay of sildenafil citrate (SIL), dapoxetine (DAP), vardenafil (VAD) and tadalafil (TAD) using gold nanoparticles (Au NPs). On the spectrofluorimetric method, gold nanoparticles were used as a fluorescence probe. The addition of drugs to Au-NPs solution caused considerable quenching of the emission band of Au-NPs, which was likely due to the complexation of the drug to gold NPs. Under the optimum conditions, the quenched fluorescence (FL) intensity was linear with the studied concentrations. The quenching mechanism of the studied drugs on the emission band of Au-NPs was explained by Stern-Volmer law. The second spectrophotometric method was based on aggregation of synthesized gold nanoparticles. Gold nanoparticles showed absorption at 522 nm. Upon interaction with the cited drugs, the band at 522 nm disappeared with the formation of a new red-shifted band at 673, 660, 665, and 663 nm for SIL, TAD, VAD, and DAP, respectively. Different experimental factors were optimized for higher sensitivity. The calibration curves were linear with a concentration range of 0.1-12 μg/mL for the studied drugs. The methods were applied successfully to determine the studied drugs in minor concentrations in pure form, pharmaceutical dosage forms, and biological fluids (human serum and urine). [ABSTRACT FROM AUTHOR]

[Display omitted] • Simultaneous quantitative study of FIN and TAD this work, introduce a sensitive, optimized first derivative synchronized spectrofluorometric approach. • The proposed approach made it possible to successfully analyze quantitatively both cited drugs in the raw materials and dosage form. • Furthermore, the approach's increased sensitivity allowed for a quantitative estimation of FIN and TAD in spiked human plasma. • The analytical eco-scale, the national environmental method index, the AGREE evaluation approach and the green analytical procedure index were all used to evaluate the given technique's greenness. Finasteride and tadalafil are combined in a pharmaceutical capsules called Entadfi™, that has received FAD approval. It was indicated for the management of male benign prostatic hyperplasia-related urinary tract issues. In the current study, finasteride and tadalafil concentrations in raw form, laboratory prepared mixtures, pharmaceutical preparation and spiked human plasma were all quantitatively estimated using a sensitive synchronized fluorescence spectroscopic approach united with first derivative. When excited at 260 nm, finasteride display its emission at 320 nm. Yet, when excited at 280 nm, tadalafil displayed its emission at 340 nm. The application of micellar surfactant as sodium dodecyl sulphate (SDS) significantly increased the fluorescence intensity.The overlapping of the fluorescence spectra was entirely eliminated by derivatizing the synchronous spectra to the first derivative, which also made it possible to simultaneously quantify the cited drugs. Without interfering with one another, the first-order synchronous spectra of tadalafil and finasteride at 320 and 330 nm, respectively. The approach revealed linearity alongside an acceptable correlation coefficient for finasteride and tadalafil concentrations over the range of 10 –50 ng/mL. That approach was utilized to estimation of the cited drugs in dosage forms, simultaneously with %recoveries for tadalafil and finasteride of 99.62 ± 0.78 and 100.19 ± 0.60, respectively. Also, four various tools, the national environmental method index, the AGREE evaluation method, the green analytical procedure index and the analytical eco-scale were used to evaluate how environmentally friendly the given approach was. With regard to the metrics of the greenness aspects, the proposed approach appeared to be better than the previously published spectrophotometric methods and HPLC. [ABSTRACT FROM AUTHOR]

[Display omitted] • Charge transfer reaction used for colorimetric determination of two beta 2 agonists. • DDQ and chloranilic acid reagents were used in this study. • Proposed methods used for determination of selected drugs in dosage forms. • Proposed methods used for determination of selected drugs in spiked plasma. Beta 2 agonists are well known for their use in the treatment of asthma and COPD however in the last few years new indications of beta 2 agonist appeared like reduction of local fats and treatment of preterm labour which required the formulation of new dosage forms and administration strategies. The new developments require accurate, economic and feasible methods the determination of these drugs to facilitate testing the newly introduced dosage forms and to study the pharmacokinetics and pharmacodynamics regarding the modern uses. In this study two rapid, sensitive and economic colorimetric methods for the determination of salmeterol xinafoate and salbutamol in pharmaceutical dosage forms and spiked plasma were developed and validated. The developed methods depends on the optimized reaction of the studied drugs with two charge transfer reagents, 2,3-dochloro-5,6-dicyano-1,4-benzoquonone (DDQ) and chloranilic acid (CA) to produce coloured complexes measured at 460 and 529 nm for DDQ and CA respectively. The developed methods showed high accuracy of 99.52 ± 1.108, 101.03 ± 0.389, 100.04 ± 1.520 and 100.3 ± 0.951 for salmetrol xinafoate and salbutamol with DDQ and CA respectively. The proposed methods were successfully used for the determination of the studied drugs in their dosage forms and spiked plasma with high accuracy and precision and the results were compared to reported methods. [ABSTRACT FROM AUTHOR]

[Display omitted] • When determining POL and CIN in their raw material states and dosage forms, the established spectrofluorimetric method was simple, specific, precise and accurate. • The method was successfully validated in terms of precision, accuracy, LOD and LOQ, selectivity, and linearity. • Compared to HPTLC, the proposed approach is less complex, involving many changes and no need for many steps. • The application of the existing technique for the quality control of both compounds in pharmaceutical dosage forms could be recommended for these benefits. For the treatment of internal and external hemorrhoids, policresulen (POL) and cinchocaine hydrochloride (CIN) are used in combination. Using a new, simple, fast, and economical first-derivative synchronous fluorescence spectroscopic process, both drugs were simultaneously determined and validated. At Δλ 60 nm and with a scanning rate of 600 nm/min, methanol was used as the solvent for both products. In the concentration ranges of 5.0–21.0 μg mL−1 and 0.5–6.0 μg mL−1 for POL and CIN, the amplitude-concentration plots were rectilinear. The detection limits were found to be 0.770 μg mL−1 and 0.118 μg mL−1 and the quantitation limits for POL and CIN were 2.541 μg mL−1 and 0.391 μg mL−1. To evaluate all compounds in synthetic mixtures and medicinal dosage types, the proposed method has been successfully applied. These findings were in line with the results obtained using high-performance thin layer chromatography, the comparison process. [ABSTRACT FROM AUTHOR]

Abstract Simple, sensitive and reliable spectro-chemometric and high performance liquid chromatography (HPLC) methods were developed for simultaneous determination of binary mixture of etilefrine hydrochloride and chlorpheniramine maleate without prior separation in their bulk drugs and dosage forms. The spectro-chemometric methods used are, derivative spectrophotometry, derivative ratio, and isosbestic point methods. The HPLC method involves the use of reversed-phase separation mode using eluant of pH 3.5, consisted of phosphate buffer/acetonitrile (30:70 v/v) and Zorbax ODS column. All variables influencing the spectrophotometric and HPLC methods were carefully investigated and optimized. The developed methods were evaluated according to United State Pharmacopeia (USP) and International Conference of Harmonization (ICH) rules. The current methods were successfully implemented for direct the determination of these drugs in their trade pharmaceutical formulations. The obtained results were contrasted with those calculated after application of reference method. The data obtained from both methods were statistically analyzed by F- and t-tests. The results of such study showed excellent agreement in respect to the accuracy and precision of the suggested and reference methods. Graphical abstract First derivative spectra of etilefrine hydrochloride (30 μg mL−1) and chlorpheniramine maleate (30 μg mL−1). Image 1 Highlights • Novel Spectro-chemometric and HPLC methods for simultaneous determination of binary mixture of etilefrine hydrochloride and chlorpheniramine were developed. • The current methods were successfully implemented for direct the determination of these drugs in their trade pharmaceutical formulations. • The spectro-chemometric methods used are, derivative spectrophotometry, derivative ratio, and isosbestic point methods. • The developed methods were validated according to USP and ICH guidelines. [ABSTRACT FROM AUTHOR]

A simple, selective and sensitive kinetic spectrophotometric method was described for estimation of four phenolic sympathomimetic drugs namely; terbutaline sulfate, fenoterol hydrobromide, isoxsuprine hydrochloride and etilefrine hydrochloride. This method is depended on the oxidation of the phenolic drugs with Folin-Ciocalteu reagent in presence of sodium carbonate. The rate of color development at 747–760 nm was measured spectrophotometrically. The experimental parameters controlling the color development were fully studied and optimized. The reaction mechanism for color development was proposed. The calibration graphs for both the initial rate and fixed time methods were constructed, where linear correlations were found in the general concentration ranges of 3.65 × 10 − 6 –2.19 × 10 − 5 mol L − 1 and 2–24.0 μg mL − 1 with correlation coefficients in the following range 0.9992–0.9999, 0.9991–0.9998 respectively. The limits of detection and quantitation for the initial rate and fixed time methods were found to be in general concentration range 0.109–0.273, 0.363–0.910 and 0.210–0.483, 0.700–1.611 μg mL − 1 respectively. The developed method was validated according to ICH and USP 30 –NF 25 guidelines. The suggested method was successfully implemented to the estimation of these drugs in their commercial pharmaceutical formulations and the recovery percentages obtained were ranged from 97.63% ± 1.37 to 100.17% ± 0.95 and 97.29% ± 0.74 to 100.14 ± 0.81 for initial rate and fixed time methods respectively. The data obtained from the analysis of dosage forms were compared with those obtained by reported methods. Statistical analysis of these results indicated no significant variation in the accuracy and precision of both the proposed and reported methods. [ABSTRACT FROM AUTHOR]

Highlights: [•] Simultaneous determination of beclomethasone dipropionate (BEC) and salbutamol (SAL). [•] Spectrophotometric methods include dual wavelength, ratio difference, and mean centering. [•] Constant center method coupled with a novel method namely, spectrum subtraction. [•] TLC-spectrodensitometric method was applied for separation and determination. [•] Validated according to the ICH guidelines & compared to the official methods. [Copyright &y& Elsevier]