Simple and affordable synchronous spectrofluorimetric determination of the natural anticancer polyphenols; resveratrol and curcumin in human plasma.

In this work, resveratrol and curcumin, two natural polyphenols, were simultaneously determined in human plasma samples using a rapid, sensitive, green, and affordable synchronous fluorescence spectroscopic approach. Several factors affecting the performance of the procedure, including Δλ, pH, diluting solvent, and organized medium, were optimized. Based on the findings, the fluorescence of resveratrol and curcumin was measured at 304 and 443 nm, respectively, with Δλ of 80.0 nm and ethanol as the diluting solvent. Excellent linearity was demonstrated by the approach (r = 0.9999) over the concentration range of 5.00-1000.00 and 2.00-400.00 ng/mL for resveratrol and curcumin, respectively. The obtained detection limits for resveratrol and curcumin were 0.027 and 0.042 ng/mL, respectively, indicating the high sensitivity of the proposed method. Moreover, the method exhibited excellent precision (both inter and intra-day), with %RSD < 1 %. The "green analytical process index" and "Analytical GREEnness" metric tools were used to compare the green profiles of the proposed method to those of the published methods. These two greenness evaluation tools verified that the suggested methodology satisfied the greatest number of green criteria, proposing its usage as a green alternative for the routine analysis of the investigated natural anticancer polyphenols in human plasma.

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.

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.