The Second International Standard for streptomycin.

A batch of highly purified streptomycin sulfate has been examined by nine laboratories in six different countries and has been assayed against the First International Standard for Streptomycin. The material examined has been established as the Second International Standard for Streptomycin, and the International Unit of Streptomycin is defined as the activity contained in 0.001282 mg of the International Standard.