Stability Study of Lorazepam Oral Solution Repackaged in Amber Colored ENFit Oral Syringes

Lorazepam is a benzodiazepine drug that hospital pharmacies commonly dispense to treat patients with severe anxiety and seizure disorders. Lorazepam oral concentrate, a marketed oral formulation of lorazepam, contains polyethylene glycol and propylene glycol in a solution (2 mg/mL). At Strong Memorial Hospital nurses draw patient-specific doses from a 30mL bulk bottle of lorazepam oral concentrate for administration. This study aims to investigate the stability of lorazepam when stored in repackaged amber-colored ENFit Oral syringes under typical hospital pharmacy conditions (stored at ambient temperature), to reduce waste.

Stability indicating HPLC assay was established to investigate the degradation profile of lorazepam treated at ambient temperature (∼25°C) and hot conditions (60°C) under acidic (1N HCL), basic (1N NaOH), and oxidative (H₂O₂) stress conditions. This HPLC assay established a robust calibration curve to check the stability of the repackaged lorazepam ENFit Oral Syringes. The repackaged syringes were stored at Strong Memorial Hospital's Inpatient Pharmacy at ambient temperature (72 ± 4°F) for 182 days and samples were taken to investigate the stability of the repackaged formulation.

After 182 days, both volumes (0.25 mL and 0.5 mL) of lorazepam repackaged formulation in the ENFit oral syringes, exhibited no visible changes and remained within the acceptable concentration range (100 ± 10%) when stored at ambient temperature (72 ± 4°F). The stability data demonstrated that lorazepam repackaged in amber-colored ENFit Oral Syringes remained stable at room temperature for up to 90 days.

This study represents a 30-day extension in the stability compared with the previously reported 60-day stability period for the repackaged lorazepam oral syringes.