Stability of diazepam rectal gel in ambulance-like environments

The objective of the present study was to evaluate the stability of diazepam rectal gel (Diastat) in various conditions of temperature and light exposure as might be found in ambulances. Three lots of Diastat (Xcel Pharmaceuticals, San Diego, CA) in various fill/syringe configurations were evaluated in controlled conditions of a freeze-thaw cycle, hard freeze (-30 degrees C for 72 hours), extreme light exposure (1,000 ft candles for 1 month), and long-term evaluation at either 30 degrees C or 40 degrees C. In the various configurations and tests, diazepam concentration always exceeded 95% of label, with no changes of note in excipients or physicochemical properties. The estimated shelf-life at 30 degrees C exceeds 48 months. Based on the results of the present study, the restocking frequency of Diastat in ambient storage conditions (eg, ambulances), could be up to 48 months in nonfreezing environments, as long as this does not exceed the labeled expiration date on the product.