The proper dose of avertin (125-250 mg/kg) induces deep, rapid surgical anesthesia lasting at least 20 min. We have successfully used this drug preparation for implanting drug pumps intraperitoneally and subcutaneously.
The working solution is stable for a couple months when stored in the dark at 4 degrees. The decomposition products are irritants (dibromoacetic aldehye and hydrobromic acid) and may cause acute peritoneal inflammation, fibrinous serositis or postanesthetic mortality in mice. The pH should be < 5 (pH > 5 is considered toxic). Dosing should be tested empirically for each new batch and also when stored for over 2 months. Since 2,2,2-Tribromoethanol can be problematic, we use a fresh batch for each preparation (if it is dark in color, it should be recrystallized before use).
1.Prepare 100% stock solution by dissolving 5 grams of 2,2,2-Tribromoethanol in 5 ml of 2-Methyl-2-butanol. Use a glass vial with a small magnetic stirring bar to mix at room temp for 4 hrs or until fully dissolved (wrap all containers in aluminum foil). The 2,2,2-Triboromoethanol crystals should be peach colored and the solution should be light brown-yellow.
2.Prepare 2.5% working solution by adding 5 ml of the above solution dropwise to 195 mls of 0.15 M saline in a 200 ml screw cap bottle. Use a magnetic stir bar to mix vigorously at room temp for 4 hr or until fully dissolved. Any precipitates (white) should dissolve and the solution should be clear at this point.
3.Filter through a 0.2 micron Corning Sterile Syringe Filter (DO NOT use Nalgene) into a 50 ml conical tube covered with aluminum foil. Test pH and store at 4 degrees C. Although the Corning filters seem to be robust, we typically use a 30 ml syringe to pass ~30 ml through one filter and switch to a fresh filter because the solution is known to dissolve the Nalgene filters.
4.We typically inject 300 ul ip into a ~ 20 g mouse, but the dose should be determined empirically before use. Testing one mouse for each of the following doses is usually sufficient: 200, 250, 300, and 350 ul. Use the lowest dose that gives complete anesthesia.