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Rifaximin (RFX) is a non-absorbable antibiotic with broad-spectrum efficacy. It treats travelers’ diarrhea, irritable bowel syndrome, non-systematic bacterial diarrhea, bowel infections, overgrowth syndrome, and enteric infections. In this work, carbon dots prepared from Ziziphus spina-christi leaves’ powders are utilized as a green fluorometric biosensor for the assessment of RFX. The morphological lineaments of the prepared carbon dots were recognized by using TEM and SEM techniques. The prepared carbon dots manifest a fluorescence emission peak at 432 nm after an excitation fluorescence peak at 366 nm. The absorbance band of RFX (absorbance peaks at 370 nm and 443 nm) could be thoroughly overlapped with fluorescence excitation/emission bands of the produced carbon dots. A fluorometric tool has been designed and validated for the evaluation of RFX reliant on the inner filter effect methodology, in which the produced carbon dots act as an inner filter effect fluorophore and RFX as an inner filter effect absorber. The quenching degree in the fluorescence activity of the prepared carbon dots depended on the concentration of RFX. The analytical parameters were checked and directed for successfully applied assessment of RFX concentration in different pharmaceutical formulations. The proposed tool’s greenness and eco-friendliness profile was evaluated using the most recent greenness assessment tool, which is the complementary green analytical procedure index (Complex-GAPI) and the Analytical GREEnness metric (AGREE). Additionally, using the recently released White Analytical Chemistry (WAC) tool, the whiteness characteristic—which indicated the method’s sustainability—was investigated.

Gabapentin (GAB) is a cyclohexane acetic acid, structurally related to the neurotransmitter gamma-aminobutyric acid (GABA), and considered the principal inhibitory neurotransmitter in the central nervous system (CNS) of mammals. An ultra-performance liquid chromatography–tandem mass spectrophotometry (UPLC-MS/MS) method for assessing pregabalin (PRE) in human plasma, was developed and validated, via PRE usage as an internal standard. The plasma underwent protein precipitation using methanol, prior to analysis. Chromatographic separation was completed using a mobile phase of methanol: 0.1% formic acid solution, (65:35, v/v), at a flow rate of 0.2 mL/min, with an isocratic approach, on an Agilent Eclipse plus column (50 × 2.1 mm and 1.8 μm), in 1.6 min of running time. An Agilent triple quadrupole was used for mass analysis, to detect the ion transitions for GAB and PER, respectively, at m/z of 172.1 → 154.1 and 160.10 → 142.10. The calibration curve, over the linear range of 0.050–10.0 μg/mL, showed a high correlation coefficient, r = 0.9993. The limits of detection and quantitation were 13.37 ng/mL and 40.52 ng/mL, respectively, based on the standard deviation and slope equation. The results for intra- and inter-day measurement accuracy and precision were in acceptable ranges. The method was extended into the assessment of oral administrations of GAB at different doses, of one 600 mg/tablet and two capsules (each one of them has 300 mg of GAB), to volunteers who were used in pharmacokinetics and bioequivalent studies. The AGREE assessment tool was used to visualize the proposed method’s greenness degree, which revealed a high AGREE rating score, supporting the accepted method’s greenness profile.

Anabolic-androgenic steroids (AASs), a class of compounds frequently misused by competitors and unfortunately by the general population, have lately attracted international attention. Thus, extraordinary demands for developing low cost, precise, rapid, and facile protocols for detection and/or determination of AAS have arisen. Hence, the current strategy explores for the first time the redox features of 21-hydroxypregn-4-ene-3, 20-dione, namely, 11-desoxycorticosterone (DCS) AA drug steroid at a glassy-carbon electrode (GCE) in a wide pH range (pH 2.0–10.0) by adsorptive differential pulse-anodic stripping voltammetry (DP- ASV) and cyclic voltammetry (CV). At pH 2, DP-ASV and CV at the optimized pH 2–3 displayed an irreversible anodic peak at 0.4 V versus Ag/AgCl electrode. The dependency of the anodic peak current of the CV at 0.4 V at various concentrations and scan rate of the DCS drug was characteristic of an electrode-coupled electron transfer of EE type mechanism. At the optimized parameters, the proposed strategy allowed quantification of DCS in the concentration range 2.5 -13.19 nM (0.83-4.36 ng mL−1) with satisfactory limits of detection (LOD) and quantization (LOQ) of 9.3 × 10−1 nM (3.1 × 10−1 ng mL−1) and 3.1 nM (1.02 ng mL−1), respectively. A relative standard deviation (RSD) of ±3.93% (n = 5) at 4.0 ng mL−1 DCS was achieved. The established probe was fruitfully employed and validated for trace determination of DCS residues in environmental water. The interference of several common diverse species on DCS sensing was insignificant revealing good selectivity. The established probe exhibited good sensitivity, selectivity, precision, and accuracy, short analytical time, and low cost compared with the reported methods, for DCS determination.