The International Unit (IU) of Streptomycin is defined as the activity present in 0.001282 mg or 1.282 µg of the International Standard, as referenced in the literature article below.
According to the reported value from the article above, which is not verified in-house, the following formula is applicable:
Potency (IU/mg dry basis) × 1.282 µg/1 IU = Potency (µg/mg)