Utility of native emission quenching of erythrosine B for the determination of diltiazem in different dosage forms.

This study introduces a practical and cost-effective method for tracking diltiazem (DLZ) analytically. It utilizes a fluorimetric approach that relies on the modulation of fluorescence intensity of a dye called erythrosine B. Through a one-pot experiment performed in an acidic environment, a complex is rapidly formed between DLZ and erythrosine B. By observing the decrease in erythrosine B emission, a linear calibration plot is established, enabling the detection and quantification of DLZ concentrations ranging from 40 to 850 ng/ml. The estimated limits of detection and quantitation were 10.5 and 32.1 ng/ml, respectively. The variables affecting the DLZ-dye complex system were carefully adjusted. The validity of the approach was confirmed through a thorough evaluation based on the criteria set by ICH guidelines. The accuracy and precision of the methodology were evaluated, and the standard deviation and relative standard deviation were below 2. The strategy was successfully employed to analyze DLZ in tablets and capsules, and no significant variation between the proposed and reported methods as the values of the estimated t-test and F-test at five determinations were below 2.306 and 6.338, respectively. Notably, the method adheres to the principle of green chemistry by utilizing distilled water as the dispersing medium.

Two green and sensitive spectrofluorimetric approaches for determination of Ambroxol and guaifenesin in their single and combined pharmaceutical formulations.

Ambroxol hydrochloride (AMX) and guaifenesin (GFN) are approved drugs utilized to treat coughs through their potent mucolytic and expectorant properties. Due to their massive, combined administration in many illnesses, there is a persistent need for their concurrent estimation in different pharmaceutical formulations. Two sensitive, environmentally friendly spectrofluorimetric methods were developed. AMX was determined using the first method (I) without interference from GFN. This method depends on the quenching of Erythrosine B (EB) native fluorescence at 552 nm after excitation at 527 nm due to the formation of a non-fluorescent AMX-EB ion-pair complex in Britton-Robinson buffer (BRB) solution pH (3.5). The concentration plot is linear over the 0.25-5.0 µg/mL range, with a mean percent found value of 99.74%. Method (II) depends on measuring the native fluorescence of aqueous GFN solution at two analytical wavelengths, either 300 or 600 nm, after excitation at 274 nm. Relative fluorescence intensity (RFI)-concentration plots are linear over the ranges of 0.02-0.5 and 0.1-2.0 µg/ml, with mean percent found at 99.96% and 99.91% at dual wavelengths, respectively. The proposed methods were successfully applied to assay both drugs in raw materials and different single and combined pharmaceutical formulations. These methods have been thoroughly validated following International Committee on Harmonisation (ICH) guidelines. National Environmental Methods Index, Analytical Eco-Scale, and Green Analytical Procedure Index were used to prove greenness, thereby enhancing their applicability. The proposed techniques provide straightforward, precise, and cost-effective solutions for routine formulation analysis in quality control laboratories.

Study on the interaction between erythrosine B and the cardiac drug amiodarone using fluorescence, scattering, and absorbance spectra and their analytical application.

In an acidic buffered solution, erythrosine B can react with amiodarone to form an association complex, which not only generates great enhancement in resonance Rayleigh scattering (RRS) spectrum of erythrosine B at 346.5 nm but also results in quenching of fluorescence spectra of erythrosine B at λemission = 550.4 nm/λexcitation = 528.5 nm. In addition, the formed erythrosine B-amiodarone complex produces a new absorbance peak at 555 nm. The spectral characteristics of the RRS, absorbance, and fluorescence spectra, as well as the optimum analytical conditions, were studied and investigated. As a result, new spectroscopic methods were developed to determine amiodarone by utilizing erythrosine B as a probe. Moreover, the ICH guidelines were used to validate the developed RRS, photometric, and fluorimetric methods. The enhancements in the absorbance and the RRS intensity and the decrease in the fluorescence intensity of the used probe were proportional to the concentration of amiodarone in ranges of 2.5-20.0, 0.2-2.5, and 0.25-1.75 µg/mL, respectively. Furthermore, limit of detection values were 0.52 ng/mL for the spectrophotometric method, 0.051 µg/mL for the RRS method, and 0.075 µg/mL for the fluorimetric method. Moreover, with good recoveries, the developed spectroscopic procedures were applied to analyze amiodarone in its commercial tablets.

Exploitation of erythrosine B as a fluorometric marker for lurasidone determination through electrostatic attraction; application to content uniformity test.

A recently developed antipsychotic drug, lurasidone, was determined using a simple, sensitive, and eco-friendly spectrofluorimetric approach. The suggested approach was based on the quantifiable quenching impact of lurasidone on the inherent fluorescence of erythrosine B in an acidic environment employing a Teorell-Stenhagen buffer (pH 4). Following excitation at 530 nm, the quenching of erythrosine B fluorescence was monitored at 552 nm. The system variables were systematically optimized to enhance the formation of the lurasidone-erythrosine B ion pair for analytical purposes. A linear calibration graph was built in the range of 20-600 ng mL-1 with 0.9998 as a coefficient of correlation. The quantitation and detection limits were 13.5 and 4.5 ng/mL, respectively. The analytical validity of the designed approach was assessed with respect to International Council on Harmonization (ICH) guiding principles. The proposed methodology was employed with high recoveries for assessing lurasidone in bulk powder and its therapeutic tablet dosage form. Additionally, the uniformity of tablet formulations was tested using the developed approach. Finally, the established approach was assessed for its greenness using various tools.

Efflux Pump Inhibitor Potentiates the Antimicrobial Photodynamic Inactivation of Multidrug-Resistant Acinetobacter baumannii.

Background: Acinetobacter baumannii, a nosocomial pathogen, poses a major public health problem due to generating resistance to several antimicrobial agents. Antimicrobial photodynamic inactivation (APDI) employs a nontoxic dye as a photosensitizer (PS) and light to produce reactive oxygen species that destroy bacterial cells. The intracellular concentration of PS could be affected by factors such as the function of efflux pumps to emit PS from the cytosol. Objective: To evaluate the augmentation effect of an efflux pump inhibitor, verapamil, three multidrug-resistant A. baumannii were subjected to APDI by erythrosine B (EB). Methods and results: The combination of EB and verapamil along with irradiation at 530 nm induced a lethal effect and more than 3 log colony-forming unit reduction to all A. baumannii strains in planktonic state. In contrast, EB and irradiation alone could produce only a sublethal effect on two of the strains. Conclusions: These data suggest that verapamil increases the intracellular concentration of EB, which potentiates the lethal efficacy of APDI. Verapamil could be applied with EB and green light to improve their antimicrobial efficacy against A. baumannii-localized infections.

Evaluation of the on-off fluorescence method for facile measurement of vilazodone in pharmaceutical dosage form; Application to content uniformity testing and greenness evaluation.

Vilazodone is a recently approved antidepressant medicine used for treating major depressive disorder. A simple, extremely sensitive, accurate and green spectrofluorimetric method was constructed for its determination through formation of ion-pair complex with erythrosine B. The formation of ion-pair complex lowers the dye's native fluorescence emission measured at 552 nm (λ ex = 530 nm). In terms of analysis, the system's parameters for producing the vilazodone-erythrosine B complex have been optimized. The reaction was carried out in Teorell-Stenhagen buffering solution (pH 4.6). The fluorescence emission intensity of the dye decreased linearly in the range of 20 - 600 ng mL-1 and the correlation coefficient was 0.9999. The quantitation and detection limit values were 18.5 and 6.1 ng mL-1, respectively. The proposed strategy has been validated according to the ICH criteria. The proposed technique was thoroughly employed for evaluating vilazodone in raw material and pharmaceutical tablet dosage form. Furthermore, it was also successfully used for content uniformity testing. Lastly, using four advanced tools namely the Eco-Scale, the National Environmental Method Index (NEMI), the Green Analytical Procedure Index (GAPI), and the Analytical Greenness metric approach (AGREE), the greenness of the established technique was evaluated.

Integrated spectroscopic approaches for the facile one pot quantification of olanzapine in pharmaceutical formulation and spiked human plasma.

In this work, the xanthene dye, erythrosine B, was employed as a probe for the determination of olanzapine using two fast and highly simple analytical approaches. The assay was based on the formation of a binary complex between the drug and erythrosine B in a slightly acidic aqueous buffered solution. In the first method, the absorbance of the formed product was monitored at 558 nm. The reaction stoichiometry was investigated, and the stability constant of the formed complex was estimated. The linear range of the method that obeyed Beer's law was in the concentration range of 0.6-8.0 µg/ml. The calculated detection and quantitation limits were 0.2 and 0.6 µg/mL. Upon adding the drug solution to erythrosine B, the native fluorescence of the dye was quenched and monitored at 550 nm after excitation at 528 nm. Thus, the fluorescence quenching was utilized as the quantitative signal in the spectrofluorimetric approach. The extent of quenching in the fluorescence intensity was rectilinear with the drug concentration in a range of 0.1-2.5 µg/ml with a detection limit of 0.032 µg/ml. Both approaches were analytically validated based on the guiding rules of the ICH with acceptable results, and were utilized efficiently in the analysis of olanzapine in commercial tablets containing the cited drug. In addition, owing to its high sensitivity and selectivity, the spectrofluorimetric method was applied for drug analysis in spiked human plasma with satisfactory % recoveries. Finally, the greenness of the methods was confirmed using eco-score scale and Analytical Green Evaluation metrics.

Integration of a facile sustainable resonance Rayleigh scattering switchable-based system for feasible determination of centrophenoxine, a nootropic and antioxidant agent; application to crude materials and dosage forms.

The proposed research adheres to a certain methodology to ensure that the technique used for analyzing the centrophenoxine drug is sustainable and green. It is important to highlight that several tools that have been recently developed were utilized as potential indicators of environmental sustainability and applicability. The present research presents a novel and entirely innovative method utilizing ultrasensitive spectrofluorimetry for the detection of centrophenoxine (CPX) drug. The employed methodology in this study involved the utilization of one-step, one-pot, and direct spectrofluorimetric technique, which was found to be both efficient and environmentally sustainable in the validation and assessment of the drug. Simply, when CPX and erythrosine B reagent were combined in an acidic environment, the highly resonance Rayleigh scattering product was immediately produced. The sensitivity limits were observed to be within the range of 15-47 ng mL-1, whereas the linearity was assessed to be in the range of 50-2000 ng mL-1. The optimal settings for all modifiable parameters of the system were ascertained through an analysis of centrophenoxine-erythrosine B complexes. Moreover, the system demonstrated compliance with International Council for Harmonization (ICH) specifications without encountering any issues. The suggested process was then rated on different recent environmental safety measuring metrics to see how good it was for the environment. Fortunately, the WAC standards that combine ecological and functional elements utilizing the Green/Red/Blue (RGB 12) design also acclaimed the current analytical technique as a white one. Additionally, a new applicability evaluation tool (BAGI) was employed to estimate the practicability of the planned method in the analytical chemistry field.