Highly sensitive high-performance thin-layer chromatographic method for the simultaneous determination of Remdesivir, Nirmatrelvir and Ritonavir in their pure forms and pharmaceutical formulations

In the wake of the COVID-19 pandemic, variations of SARS-CoV-2 have emerged as a significant public health issue due to heightened transmissibility and evasion of natural immunity, vaccine efficacy, and monoclonal antibody treatments. Objectives: Remdesivir, Nirmatrelvir, and Ritonavir are presented as promising recently developed antiviral medicines for COVID-19, supported by clinical evidence. Therefore, optimizing an analytical method for their simultaneous determination is of significant value in quality control laboratories and subsequent confirmatory studies. A straightforward, sensitive, and selective HPTLC approach has been described and confirmed for the simultaneous quantification of these medicines in bulk and pharmaceutical formulations. Methods: The HPTLC method was conducted with a silica gel aluminum plate 60F254 (10*10) as the stationary phase and a mobile phase composed of dichloromethane, methanol, and triethylamine in a volume ratio of (90:10:0.1 by volume). The fabricated plates were scanned densitometrically utilizing a UV detector. Detection occurred at 254 nm across a concentration range of 10-80 µg/spot. The Rf values for Nirmatrelvir, Remdesivir, and Ritonavir were determined to be 0.13, 0.38, and 0.53, respectively. Results: The method has been validated for many parameters, including linearity, accuracy, precision, limit of detection (LOD), limit of quantification (LOQ), and robustness. The results fall within the acceptance criteria established by the International Conference on Harmonisation (ICH). Conclusion: The proposed method has been successfully applied for simultaneous determination of the studied drugs in both bulk and commercial dosage form.