Carbon dots (CDs) have recently attracted attention as a new class of photoluminescent materials with promising optical, chemical, and electrical properties. They have been proposed for various applications, such as pharmaceutical sensing, biomarker detection, and cellular bioimaging, by virtue of their economical synthesis, cheap starting materials, water-solubility, excellent chemical stability, good biocompatibility, and low toxicity. Hetero-atom doping is a reliable and adaptable strategy for enhancing the photoluminescence, electrical, and structural characteristics of CDs. Herein, we present an update on heteroatom-doped CDs. Various modern synthetic routes are highlighted, ranging from synthetic processes to doping components. In addition, the optical and biological properties and the possible applications of heteroatom-doped CDs are discussed. This review (with 227 references) will provide an overview of recent advances in doped CDs and their expected future perspectives.

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A novel sustainable, simple, sensitive, and green spectrofluorimetric method was developed for the concurrent estimation of venlafaxine and agomelatine in pharmaceuticals and biological fluids. The method relies on synchronous fluorescence spectroscopy, where venlafaxine and agomelatine were measured at 276 and 328 nm, respectively, using Δλ of 20 nm. The potential factors affecting the fluorescence intensity were optimized by the one-factor-at-a-time (OFAT) strategy, where synchronous fluorescence intensity was significantly enhanced using a 1% w/v sodium dodecyl sulfate micellar system. The method was fully validated and exhibited excellent linearity (r2 > 0.999 for both drugs) with very low limits of detection (LODs) in the range of 0.14–0.84 ng/mL. Consequently, the proposed approach was efficiently adopted to analyze the co-administered drugs in their pharmaceuticals and in spiked human plasma with excellent % recovery between 97.4 and 102.2%. Finally, the method's greenness was evaluated using different metric tools, including Green Analytical Procedure Index (GAPI) and Analytical GREEnness (AGREE), which proved its excellent greenness.

A new green micellar liquid chromatographic method was developed and validated for the quantitative estimation of nicotinamide (NICO) and clindamycin phosphate (CLD) in bulk and pharmaceutical gel formulation. The analytes are well resolved in less than 6.0 minutes using micellar mobile phase consisting of 0.10M sodium dodecyl sulfate (SDS), 0.3% triethylamine, and 10% 2-propanol in 0.02M orthophosphoric acid at pH 3.0, running through an Eclipse XDB-C column (150 mm×4.6 mm, 5 μm particle size) with flow rate 1.0 mL/min. The effluent was monitored with diode array detection at 210 nm. The retention times of NICO and CLD were 3.8 minutes and 5.6 minutes, respectively. The method was validated according to the International Conference on Harmonisation (ICH) guidelines in terms of linearity, limit of detection, limit of quantification, accuracy, precision, robustness, and specificity to prove its reliability. Linear correlation was achieved by plotting the peak area of each drug against its concentration. It was found to be rectilinear in the ranges of 1.0-40.0 μg/mL and 0.5-15.0 μg/mL with limits of detection of 0.06 μg/mL and 0.03 μg/mL and limits of quantification of 0.19 μg/mL and 0.09 μg/mL for NICO and CLD, respectively. The method was successfully implemented for the simultaneous determination of the analytes in their bulk powder and combined gel formulation with high % recoveries. The ease of sample treatment facilitates and greatly expedites the treatment with reduced cost and improved accuracy of the procedure.

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A new, simple isocratic HPLC method was developed and validated for the simultaneous estimation of four vasoactive phytochemicals: ascorbic acid (ASC), rutin (RUT), hesperidin (HSP), and diosmin (DSM) in different pharmaceutical preparations.