Serum antibacterial activity after oral suspensions and capsules of triacetyloleandomycin and erythromycin estolate.

Comparison of serum antibacterial activity against a beta-hemolytic streptococcus and a penicillin-resistant staphylococcus was made in a cross-over study in volunteers after ingestion of oral suspensions and capsules of triacetyloleandomycin and erythromycin estolate. Oral suspensions yielded earlier peak titers, but ultimate peak titers and duration of activity were similar to those observed after ingestion of capsules. Antibacterial activity of serum against both organisms was consistently greater with both erythromycin estolate preparations than with the triacetyloleandomycin preparations. These in vitro data were comparable to observations made previously in monkeys infected with the same organisms, although comparative clinical efficacy in monkeys did not reflect these implied therapeutic differences.