Pharmaceutical Testing

Alqahtani, Ali, et al. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy (2025): 125820.

The accurate determination of pharmaceutical compounds is essential for ensuring drug quality and safety. In this study, a highly sensitive and environmentally friendly fluorescent sensor based on sulfur and nitrogen co-doped graphene quantum dots (S,N-GQDs) was developed to determine glimepiride in pharmaceutical formulations and spiked human plasma. The sensor exhibited a blue fluorescence emission at 431 nm when excited at 362 nm, with the fluorescence quenching mechanism following a static quenching process, supported by thermodynamic studies.

A Box-Behnken experimental design was utilized to optimize parameters, including pH, buffer volume, S,N-GQDs concentration, and incubation time, resulting in a quadratic model for optimal conditions. The sensor showed a linear response to glimepiride in the concentration range of 0.5–4.0 μg/mL, with a low limit of detection (LOD) of 0.078 μg/mL. Validation according to ICH guidelines confirmed the method's reliability and accuracy.

In addition to its high analytical performance, the method was evaluated for its environmental friendliness using AGREE and BAGI metrics, revealing it to be a sustainable and practical analytical tool. This fluorescent sensor offers a promising alternative for routine quality control in pharmaceutical industries, ensuring the safe and accurate determination of glimepiride in various sample matrices.

da Silva, Rafael, Rafael Turra Alarcon, and Éder Tadeu Gomes Cavalheiro. Journal of Electroanalytical Chemistry (2025): 118938.

The development of alternative electrode materials is crucial in electroanalytical chemistry to reduce dependence on mercury and noble metals. This study presents an innovative voltammetric sensor for the determination of sildenafil, a widely used vasodilator drug for erectile dysfunction, in pharmaceutical formulations and synthetic urine. The sensor utilizes an acetylene black (AB)-based composite electrode, enhanced with silver nanoparticles and vegetable oil polyurethane.

Silver nanoparticles were deposited on the AB surface using thermal reduction in the presence of ethylene glycol, resulting in a high yield as confirmed by thermogravimetric analysis and energy-dispersive X-ray spectroscopy. The modified AB particles served as the conducting phase in composite electrodes, optimized for experimental and instrumental conditions.

The sensor demonstrated high sensitivity for sildenafil detection in 0.10 mol/L phosphate buffer at pH 3.0, with a limit of detection of 0.89 µmol/L. When applied to pharmaceutical formulations and spiked synthetic urine, the results were consistent with both label values and chromatographic determinations. Statistical analysis using the Student's t-test confirmed the accuracy of the method, showing no significant difference within a 95% confidence level.

This innovative voltammetric sensor provides a reliable, cost-effective, and environmentally friendly approach for routine quality control of sildenafil in pharmaceutical formulations, ensuring safe and accurate drug delivery.

Mostafa, N. S., Nada S. Ayish, and Mona A. Abdel Rahman. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 326 (2025): 125168.

A new spectrofluorimetric method has been developed and validated for the simultaneous, sensitive determination of Naproxen (NAP) and Domperidone (DOM) in pharmaceutical formulations and human plasma. This innovative approach provides an eco-friendly, cost-effective alternative to conventional methods, offering simplicity and high sensitivity without the need for prior separation.

The method is based on measuring the second derivative fluorescence intensity of NAP at 345 nm and DOM at 292 nm after excitation at 235 nm, with no interference between the two drugs. Extensive optimization of experimental variables was conducted to ensure maximum sensitivity, with the limit of detection (LOD) determined to be 12.286 ng/mL for NAP and 3.240 ng/mL for DOM.

The method complies with ICH guidelines for validation and demonstrated excellent performance in pharmaceutical formulations and human plasma samples. The successful application of this method highlights its potential for routine quality control testing in pharmaceutical laboratories, offering a rapid, reliable, and environmentally friendly solution.

Additionally, the green chemistry profile of the method was assessed, confirming its minimal environmental impact compared to traditional techniques. This research presents a significant advancement in pharmaceutical analysis, ensuring the efficient monitoring of drug quality in both commercial and clinical settings.