A novel ultrafast synthesis of N, S-doped carbon quantum dots as a fluorescent nanoprobe for entacapone and clonazepam estimation in tablets and human plasma: Compliance with greenness metrics and content uniformity testing

• Published in: Sustainable chemistry and pharmacy 2024-04, Vol.38, p.101488, Article 101488
• Main Authors: Magdy, Galal, Aboelkassim, Eman, El-Domany, Ramadan A., Belal, Fathalla
• Format: Article
• Language: English
• Subjects: Clonazepam; Entacapone; Greenness; N,S-CDs
• ISSN: 2352-5541; 2352-5541
• DOI: 10.1016/j.scp.2024.101488

An ultrafast and green method was proposed for the microwave-assisted synthesis of N, S-doped carbon quantum dots (N,S-CDs) in only 90 s. The proposed method used thiourea as a source of sulfur and nitrogen and Dill (Anethum vulgaris) as a green carbon source. Characterization of the produced N,S-CDs was performed using several microscopic and spectroscopic methods. They were utilized as a fluorescent nanoprobe for the entacapone (ENT) and clonazepam (CLZ) estimation. After excitation at 310 nm, the developed N,S-CDs revealed an emission band at 380 nm. HR-TEM showed spherical N,S-CDs with a size range of 1–5 nm. The proposed method is the first report on the estimation of each of ENT and CLZ using N,S-CDs and the first one to use Dill as a carbon source for the preparation of N,S-CDs. The prepared N,S-CDs exhibited native fluorescence that was quantitatively quenched by each of ENT and CLZ over the ranges of 1.0-15.0 and 2.0 – 25.0 μM, respectively. The mechanism of N,S-CDs fluorescence quenching was carefully studied. The suggested approach was employed for the determination of ENT and CLZ in their pharmaceutical formulations and human plasma samples with acceptable % RSD and % recoveries (98.50-101.31%). Moreover, the content uniformity testing of the CLZ tablets was efficiently carried out according to the United States Pharmacopoeia recommendations. The excellent greenness and eco-friendliness of the proposed approach were demonstrated using the complementary Green Analytical Procedure Index (ComplexGAPI) and the Analytical GREEnness (AGREE). Validation of the proposed method was performed using ICHQ2 (R1) guidelines. [Display omitted] •The current study introduces the first report on the use of N,S-CDs as nanosensors for the determination of entacapone and clonazepam.•Determination of the studied drugs is based on the quantitative and selective quenching of N,S-CDs' native fluorescence.•A rapid and green microwave-assisted approach was adopted for synthesis of N,S-CDs using thiourea and Dill for the first time in only 90 s.•The adopted method was successfully applied for the determination of the studied drugs in their pharmaceutical formulations and human plasma samples.•The excellent greenness and eco-friendliness of the designed approach were demonstrated using ComplexGAPI and AGREE tools.