The second international reference preparation of lymecycline

The second International Reference Preparation of Lymecycline was established. Nine laboratories in 8 countries collaborated in assaying its potency in terms of the first International Reference Preparation, of which stocks had become exhausted. The best estimate of potency was taken to be 948 IU/mg, which was the unweighted geometric mean of a total of 124 assays. On this basis, the International Unit of lymecycline was defined as the activity contained in 0.0010548 mg of the second International Reference Preparation.