Effect of Extreme Temperature on Naloxone Nasal Spray Dispensing Device Performance

The opioid epidemic has led to the wide-spread distribution of naloxone to emergency personnel and to the general public. Recommended storage conditions based on prescribing information are between 15°C and 25°C (59°F and 77°F), with excursions permitted between 4°C and 40°C (39°F and 104°F). Actual storage likely varies widely with potential exposures to extreme temperatures outside of these ranges. These potentially prolonged extreme temperatures may alter the volume of naloxone dispensed from the nasal spray device, which could result in suboptimal efficacy.

The aim of this study was to assess the naloxone volume deployed following nasal spray device storage at extreme temperatures over an extended period of time.

Naloxone nasal spray devices were exposed to storage temperatures of -29°C (-20°F), 20°C (68°F), and 71°C (160°F) to simulate extreme temperatures and a control for 10 hours. First, the density was measured under each temperature condition. Following the density calculation part of the experiment, the mass of naloxone dispensed from each nasal spray device at each temperature was captured and used to calculate volume: calculated volume (microliter, µl) = spray mass (mg converted to g)/mean density (g/mL). Measurements and calculations are reported as means with standard deviation and standard error, and a one-way ANOVA was used to evaluate mean dispensed volume differences at different temperatures.

There was no difference in the mean volume deployed at -29°C (-20°F), 20°C (68°F), and 71°C (160°F), and measurements were 101.44µl (SD = 9.56; SE = 5.52), 99.01µl (SD = 6.31; SE = 3.64), and 108.28µl (SD = 2.04; SE = 1.18), respectively; P value = .289, F-statistic value = 1.535.

The results of this study suggest that naloxone nasal spray devices will dispense the appropriate volume, even when stored at extreme temperatures outside of the manufacturer's recommended range.