Chemo Drugs supplies Semi-Synthetic Macrolide Antibiotic Tablets. Chemo Drugs is an ISO 9001:2000 accredited company. The Semi-Synthetic Macrolide Antibiotic Tablets of model name Roxithromycin is used to treat respiratory tract, urinary and soft tissue infections. Semi-Synthetic Macrolide Antibiotic Tablets is derived from erythromycin, containing the same 14-membered lactone ring. Roxithromycin prevents bacteria from growing, by interfering with their protein synthesis. Roxithromycin binds to the subunit 50S of the bacterial ribosome, and thus inhibits the translocation of peptides. Semi-Synthetic Macrolide Antibiotic Tablets or Roxithromycin has similar antimicrobial spectrum as erythromycin, but is more effective against certain gram-negative bacteria, particularly Legionella pneumophila.