guido g.jacobs at iph.fgov.be
Fri Nov 21 14:42:36 EST 1997

Francisco Rojas wrote:
> Can anybody tell me how could I obtain the LD50 of a drug in rats?
> I know something about that, but I´d like a little help.
> The LD50 could be between 5-10 mg/kg w.
> How many animals per group?, Which should be the initial dose?, And the
> last one?
> Yours sincerely:
> Dr. Francisco Rojas ( fcorojas at arrakis.es).
> Thank you.How to do an LD50 test and calculating is described into the OECD 
guideline for testing of chemicals, n° 401. 
This is a guideline accepted by the 26 memberstates of the OECD (Europe, 
USA, Canada, Australie etc.) 
It is also published in the European O.J. Nr L248, 30.9.1996
Traditional methods use 20 to 30 animals per test and death of a 
proportion of the animals is the endpoint. Dose levels should be 
sufficient in number, at least three, and spaced appropriate to produce 
tests group with a range of toxic effects and mortality rates. The data 
should be sufficient to produce a dose response curve

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