Pentobarb Anesthesia

Lance Corey lance at
Mon Sep 25 10:55:16 EST 1995

f628 at (Larry P. Gonzalez) wrote:

>I need some info about the free-acid form of pentobarbital.

>We have  been using sodium pentobarbital for anesthesia in rats, but
>recently ran out.  Since we had some of the free-acid form in the lab,
>I tried substituting that for the salt, adjusting for differences in
>molecular weight.  The acid is not soluble in water, but will readily
>dissolve in 95-100% ethanol.   Therefore,  I administered about
>38mg/kg of the free-acid dissolved in ethanol to 300g rats.  This
>produced a solid level of anesthesia and animals recovered nicely, and
>they appeared healthy initially.  However, all of the animals
>receiving this preparation have died within 2 to 4 days of

>Can anyone shed some light on what is going on?


I can't tell you why the rats died, but you should be able to dissolve
the free acid in an equal molar amount of sodium hydroxide in water.
You'll end up with water and sodium pentabarbital.

	Lance Corey
	Dept. Pharmacology & Therapeutics
	University of British Columbia

More information about the Neur-sci mailing list