the antimicrobial activity of a new semi-synthetic oral erythromycin derivative , er 42859 , was evaluated in vitro and in vivo in comparison with erythromycin , spiramycin , josamycin , oleandomycin and the newer semi-synthetic derivatives flurithromycin , roxithromycin and a-56268 .
C0014806
erythromycin
C0035891
roxithromycin