2008 Volume 34 Issue 6 Pages 601-605
Enbrel Injection is dissolved before use.We investigated the influence of the temperature of the vial containing Enbrel Injection and the water for injection on the reconstitution time of this drug.The procedures for the dissolution of Enbrel were conducted in the order given in the instructions under“Preparation of injection” in the guidebook for self-injection of Enbrel.Completion of reconstitution was designated as the time when no grains or lumps could be observed in a visual inspection.When the temperature of the vial and water for injection were both 5°C,the mean time for reconstitution was 314.8 seconds but when the temperature of the vial was 5°C and that of the water for injection was 25°C,dissolution time was 170.6 seconds.The heat of dissolution of Enbrel in water for injection at 25°C was determined to be 14.2±8.8 J and dissolution occurred by an endothermic reaction.
These results indicate that water for injection at higher temperatures increases the speed of dissolution showing the validity of determining the time for dissolution.They also confirm that there is no problem with the existing instructions for the dissolution of the drug,which state that the water for injection should be kept at room temperature and the injection vial kept in a refrigerator.
