Feasibility of rapidly assessing reactive impurities mediated excipient incompatibility using a new method: A case study of famotidine-PEG system

The present work demonstrates the utility of temperature controlled set up with pressurized headspace oxygen as an approach to effectively reduce the time required for solid-state drug-excipient compatibility study. To illustrate the utility, the incompatibility of polyethylene glycol (PEG) and polyethylene oxide (PEO) with Famotidine (Fam) was shown. Owing to thermal and oxidative stress, polyethylene ether moieties of PEG generated reactive impurities, resulting in the degradation of Fam. The chemical degradation was evaluated via liquid chromatography. Around 20% of degradation was observed in the pressurized oxygen set up, whereas, no degradation was found in the absence of oxidative stress. On increasing the excipient fraction, the Fam degradation increased proportionally. Formation of aldehydes and free radicals from excipients were proposed as the precursors for Fam degradation. The generation of aldehydes and free radicals was confirmed by infrared and Electron Spin Resonance (ESR) spectroscopic analysis, respectively. Overall, the present study demonstrated the utility of pressurized oxygen set up as a rapid and routine tool for studying drug-excipient incompatibility at temperatures relevant drug-product manufacture.