Studies on Absorption of a Newly Developed Enteric‐Coated Erythromycin Base

RYTHROMYCIN is widely used in the E treatment of less serious infections, particularly in community practice. Laboratory studies indicate that common respiratory pathogens (beta-haemolytic streptococci, pneumococci) , many strains of Haemophilus influenzae, many staphylococci, and Mycoplasma pneunzoniae are inhibited by erythromycin. Erythromycin is used clinically as an alternative to penicillin for the treatment of common infections and is preferred by many practitioners because of its “wide spectrum of antimicrobial activity.” I n Australia, oral erythromycin accounts for 13.4 per cent of all prescriptions for solid doseform antimicrobials.’ Despite widespread use, controversy continues to exist over the optimal dosage form of oral erythromycin. The antimicrobially active form of “erythromycin” ir erythromycin base. The preparation which on bioassay appears to give highest concentrations in the blood is propionyl erythromycin laurylsulfate (erythromycin estolate) .2 However, erythromycin estolate is occasionally associated with cholestatic ja~ndice.~ I n addition, the high blood levels shown on bioassay may be spurious because of deesterifi~ation.~ Bioassay measures only free base, and the time re-