Abstract
Dantrolene is known to have a low solubility in water. Studies have demonstrated that it dissolves more rapidly in warm water. However, the overall benefit of warming has not been measured. This study evaluated the overall time benefit of warming.
The first step was to measure how long it took to warm the 10 ml plastic ampoules of sterile water from ambient temperature (20°C) to 45°C. We found that when immersed in a water bath held at 45°C, this required a minimum of seven minutes. Therefore the ampoules used for the study were kept immersed in a water bath held at 45°C for at least 10 minutes.
It took an average of 82.6 seconds to draw 60 ml (six ampoules) of water into a 60 ml syringe. Squirting the water into the dantrolene vial and mixing until dissolved took 102.8 seconds (SD 8.3) for the warmed water and 129.0 seconds (SD 14.6) for the ambient temperature water (P=0.009). Redrawing the dantrolene solution into the syringe took an average of 32 seconds for the warmed water and 35.2 seconds for the ambient temperature water. After the redrawing phase the average temperature of the warmed solution was 32.2°C. The average total preparation time for the warmed solution was 217.4 seconds (SD 20.0) and for the ambient temperature preparation was 243.0 seconds (SD 11.7) (P=0.038).
Thus the time difference in preparation was about 256 seconds, which is the time that could be saved in preparing the standard dose of 10 vials of dantrolene using water at 45°C. However, as it required about seven minutes to initially warm the sterile ampoules, there would be a net increase, not decrease in the time required. These findings indicate that warming is of no benefit in speeding dantrolene preparation.