Stability of extemporaneously compounded cobimetinib oral suspensions

IntroductionThe stability of cobimetinib prepared in a simple aqueous suspension was evaluated. This evaluation aimed to determine how well the compound maintains its integrity over time in a non-complex vehicle for pediatric applications. By monitoring concentration and purity over a defined period, the study provides insight into optimal storage conditions and potential limitations of the preparation.MethodsCobimetinib tablets were dispersed in purified water to prepare oral suspensions with final concentrations of 1 mg/mL and 12 mg/mL. Each suspension was equally aliquoted and stored under two conditions: room temperature (20 ± 2 °C) and refrigerated conditions (4 °C) (n = 3 per condition). Samples were prepared and analyzed at predefined time points (days 0, 1, 2, 3, 7, 9, and 14) to evaluate stability over time. Physical stability was assessed by pH measurement, as well as visual inspection. Cobimetinib concentrations were quantified using ultra-performance liquid chromatography coupled with ultraviolet detection and mass spectrometry (UPLC-UV-MS).ResultsNo changes in pH were observed throughout the study. Visual inspections revealed no color change. The cobimetinib oral suspensions at concentrations of 1 mg/mL and 12 mg/mL retained 90 to 110% of their initial concentrations over 14 days when stored at both room temperature and 4 °C.ConclusionThe extemporaneously compounded cobimetinib oral suspensions, at concentrations of 1 mg/mL and 12 mg/mL, demonstrated acceptable stability for up to 14 days under both room temperature and 4 °C. These findings support its potential as a viable alternative dosage form for short-term use in clinical settings.