Carbon quantum dots as a sensitive fluorescent probe for quantitation of pregabalin; application to real samples and content uniformity test

Recent Applications of Quantum Dots in Pharmaceutical Analysis

Nanotechnology has emerged as one of the most potential areas for pharmaceutical analysis. The need for nanomaterials in pharmaceutical analysis is comprehended in terms of economic challenges, health and safety concerns. Quantum dots (QDs)or colloidal semiconductor nanocrystals are new groups of fluorescent nanoparticles that bind nanotechnology to drug analysis. Because of their special physicochemical characteristics and small size, QDs are thought to be promising candidates for the electrical and luminescent probes development. They were originally developed as luminescent biological labels, but are now discovering new analytical chemistry applications, where their photo-luminescent properties are used in pharmaceutical, clinical analysis, food quality control and environmental monitoring. In this review, we discuss QDs regarding properties and advantages, advances in methods of synthesis and their recent applications in drug analysis in the recent last years.

A Design-assisted Spectrofluorometric Method Utilizing a One-pot Fluorescent Probe for the Quantitation of some Calcium Channel Blockers

Based on their reaction with highly fluorescent carbon quantum dots (CQDts), a precise and reliable spectrofluorometric approach was developed for the determination of three calcium channel blockers. The studied drugs are: lercanidipine, nimodipine and nifedipine. (CQDts) were produced using a one-step hydrothermal method with ascorbic acid as the carbon source. The produced CQDts were capped by alcohol to create yellow emitters displaying a high fluorescence emission at 524 nm when excited at 325 nm. The fluorescence intensity of CQDts was noticeably quenched by each of the three calcium channel blockers. The relation between their concentrations and fluorescence quenching is linear over the concentration range of 0.5-20 µg/mL for each of the three drugs. A full factorial design was used to optimize the effect of variable factors. Therefore, under optimum experimental design conditions, the detection limits for lercanidipine, nimodipine, and nifedipine were 0.11 ± 1.09, 0.10 ± 0.25 and 0.12 ± 0.71 µg/mL, respectively. The LOQ was 0.33, 0.30, and 0.37 µg/mL respectively. The quenching of fluorescent CQDts occurred through the inner filter effect (IFE) for nimodipine, while it was mixed with dynamic quenching for lercanidipine and nifedipine. The proposed method was effectively used to determine the cited drugs in their pharmaceutical products and had an acceptable level of precision. The selectivity of the CQDts system towards the studied drugs was examined indicating no interference from interfering species.

A Turn-On–Type Fluorescence Resonance Energy Transfer Eco-friendly Method for Nitazoxanide Quantification in Pharmaceutical Dosage Form and Spiked Plasma: Evaluation of Greenness Profile Using Different Assessment Tools

A brand-new class of anti-infective drugs that work against bacteria, viruses, and protozoan parasites is nitazoxanide and related thiazolides. Thiazolides have also been shown to cause cell cycle arrest and apoptotic cell death in cancer cells in recent years. In this study, an eco-friendly, spectrofluorimetric technique that is verified, easy, and sensitive has been proposed for quantifying nitazoxanide (NTZ), a broad-spectrum antiparasitic drug. When NTZ is reduced with zinc (Zn) powder in an acidic media, a highly fluorescent product is produced. To get the highest sensitivity, different experimental conditions impacting the response were examined and optimized. Following excitation at 299 nm, scanning of the fluorescent product was done at 440 nm. The intensity of the fluorescence was proportional to the drug concentration in the range of 0.1–0.6 μg/mL. The approach was validated according to International Conference on Harmonization (ICH) guidelines, and the outcome was satisfactory. The detection and quantitation limits were calculated to be 0.013 and 0.038 μg/mL, respectively. The suggested technique was successful in analyzing commercially available NTZ dosage forms. Furthermore, the proposed technique was used to assess NTZ levels in human plasma and it was bio-analytically validated according to European Medicines Agency (EMA) guidelines. The suggested method can be used in quality control laboratories as well as in pharmacokinetic studies. In order to picture the green profile of the developed method, four greenness assessment tools have been applied. National Environmental Methods Index (NEMI), analytical Eco-Scale Assessment (ESA), Green Analytical Procedure Index (GAPI) and Analytical Greenness metric (AGREE) are the relatively most widely used metrics. So, they were utilized to perform a detailed greenness comparison between the proposed method and some of the reported methods for the determination of NTZ. The developed method was found to be an excellent green method with the highest AGREE score.