Experimentally designed sensor for the real-time detection of Molnupiravir degradation: Optimization, Characterization, and Application"

Isobutyric acid is short-chain fatty acid. In pharmaceutical analysis, quantifying isobutyric acid is essential for ensuring the purity and stability of pharmaceutical products. Molnupiravir, for instance, is an antiviral drug approved by the FDA to treat COVID-19. Isobutyric acid is a known impurity that may be present in Molnupiravir formulations due to the synthesis process or degradation over time. Isobutyric acid can irritate the lungs. Repeated exposure may cause bronchitis to develop with cough, phlegm, and/or shortness of breath. The current study is the first study for isobutyric acid determination used carbon paste electrodes. Tetradodecyl ammonium chloride surfactant (TDAC) used as ionophore in a quality-by-design approach to develop and optimize a carbon-paste sensor for isobutyric acid . Twenty-one sensors with different compositions were tested, and the results were computationally analyzed to generate prediction models. Using the prediction models, the function predicted with 96.7% desirability that a sensor containing 16.85% ion-exchanger, 0% graphene, and o -NPOE as a plasticizer would achieve a Nernstian slope of 57.035 mV/decade, an R-squared approaching unity, and a response time of 6.2 seconds. The sensor accurately measured isobutyric acid concentrations within a wide linear range (9.0×10 ^-8 –1.0×10 ^-2 mol L ^-1 ) with high sensitivity and selectivity. The sensor’s morphologya and compostion were examined using the scanning electron microscope and energy-dispersive X-ray analysis. Isobutyric acid was determined in different smamples like waste water, urine and plasma and spiked Molnupiravir standard samples. Molnupiravir thermal stability also was examined using proposed electrode. The results obtained from electrochemical method was compared with data obtained from HPLC method.