Stability of levetiracetam oral solution repackaged in oral plastic syringes

Objectives: With the increased use of levetiracetam oral solution in hospitals, there is a need to re-package this solution product in plastic oral syringes to facilitate dispensing and dosing. Without any stability data, these re-packaged syringes can only be assigned a maximum beyond-use date of 14 days when stored at controlled cold temperature based on USP. This study was designed to evaluate the long-term stability of levetiracetam solution in oral syringes for up to 6 months. Method: Commercially available levetiracetam oral solution (100 mg/mL) was drawn into 1-mL and 10-mL amber polypropylene oral syringes. The samples were stored at refrigeration (2-8°C) or room temperature (21-25°C), and they were pulled for evaluation at monthly intervals for up to six months. At each time point, the samples were evaluated by visual inspection, pH measurement, and high performance liquid chromatography (HPLC). A separate forced stability study was conducted to confirm that the HPLC method was stability indicating. Results: Over the period of 6 months storage, there was no significant change in visual appearance or pH for any of the levetiracetam stability samples. The HPLC results indicated that levetiracetam retained 97-108% of the initial concentration in 1-mL and 10-mL oral syringes at both refrigeration and room temperature. Implications: Commercial levetiracetam 100 mg/mL oral solution was stable for up to 6 months in amber polypropylene oral syringes stored at both refrigeration and room temperature conditions