General properties of Macrolides 4. ADME 2)Distribution: does not cross BBB. 3 Elimination: it is concentrated in the liver, where some is unactive while some is excreted in active form in the bile4. ADME 2) Distribution: does not cross BBB. 3) Elimination: it is concentrated in the liver, where some is unactived, while some is excreted in active form in the bile. General properties of Macrolides