Abstract

The first KRAS inhibitor to receive Food and Drug Administration approval is sotorasib, which binds to the cysteine residue on KRAS^G12C to lock the protein inactive, preventing cell growth and encouraging apoptosis. To estimate sotorasib levels in pre-clinical or clinical studies, it is necessary to establish a reliable, sensitive, and precise bioanalytical technique. Recently, some studies demonstrated sotorasib by validated liquid chromatography-mass spectrometric methods. However, these methods can predominantly estimate plasma samples by using electrospray ionization in negative or positive mode, and the application of these methods has been complex. This study evaluated the critical quality parameters in method validation under the International Council for Harmonization and United States Food and Drug Administration guidelines, along with the stability-indicating studies using umbralisib as an internal standard, intending to develop a validated liquid chromatography-mass spectrometry method for measuring sotorasib. The analyte was extracted from the appropriate matrix using a simple protein precipitation method. Sotorasib levels were determined by  utilizing positive and negative multiple reaction monitoring mode using an electrospray ionization source and mass spectrometry. An isocratic mobile phase consisting of methanol and ammonium acetate buffer pH 4.0 (50:50 v/v) was used in the chromatographic detection on a Waters symmetry C18 column (150×4.6 mm, 3.5 µm), with a flow rate of 1.0 ml/min. In a total run duration of 5.0 mins, sotorasib and umbralisib eluted at 2.969 and 2.043 mins, respectively. The correlation coefficient value of 0.999 indicates that the technique was linear for the 2.50-50.00 ng/ml concentration ranges. The accuracy, intraday precision and interday precision were measured at the lower limit of quantification, low-quality control, middle-quality control, and high-quality control levels. The percentage coefficient of variation values were 3.13, 0.46, 0.39, and 0.24 %, respectively. A stability-indicating, simple, economical, fast, rapid, and robust liquid chromatography-mass spectrometric method was developed to measure sotorasib, and validation studies were performed in human plasma.