title: Evaluation of the intestinal absorption of erythromycin in man: absolute bioavailability and comparison with enteric coated erythromycin.
abstract: To determine the role of acid hydrolysis on the gastrointestinal absorption of erythromycin, six healthy subjects received erythromycin as a 240 mg intravenous dose, a 250 mg oral solution administered via endoscope directly into the duodenum and bypassing the stomach, and an enteric-coated 250 mg capsule. Blood samples were collected for 6 hours and serum erythromycin quantified by a microbiological method. The time to achieve maximum serum concentrations for the solution was 0.25 +/- 0.08 (mean +/- SD) hours and for the capsule was 2.92 +/- 0.55 hours. The absolute bioavailability of erythromycin from the capsule was 32 +/- 7% and for the duodenal solution 43 +/- 14%. The ratio of the areas under the serum erythromycin concentration-time curve of capsule to solution was 80 +/- 28% (range 38 to 110%). There is substantial loss of erythromycin apart from gastric acid hydrolysis, which cannot be accounted for by hepatic first-pass metabolism. Attempts to further improve the oral bioavailability of erythromycin beyond 50% by manipulation of formulation are likely to be futile.
authors.affiliation: Department of Clinical and Experimental Pharmacology, University of Adelaide, Australia.
authors.forename: A A
authors.initials: AA
authors.lastname: Somogyi
authors.forename: F
authors.initials: F
authors.lastname: Bochner
authors.forename: D
authors.initials: D
authors.lastname: Hetzel
authors.forename: D B
authors.initials: DB
authors.lastname: Williams
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001682:Biological Availability; D002214:Capsules; D002626:Chemistry, Pharmaceutical; D004333:Drug Administration Routes; D004386:Duodenum; D004917:Erythromycin / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000097:blood / Q000493:pharmacokinetics*; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D007408:Intestinal Absorption; D008297:Male; D012996:Solutions
chemical_list: D002214:Capsules; D012996:Solutions; C010948:erythromycin lactobionate; D004917:Erythromycin