Erythromycin drug disposition

Disposition in the Body. Erythromycin base is destroyed by gastric acid erythromycin stearate is hydrolysed in the intestine and absorbed as free erythromycin the estolate is absorbed as the ester and then hydrolysed. About 5 to 10% of a dose is excreted in the urine unchanged and large amounts of unchanged drug are excreted in the bile. 

Kobayashi, Y., Sakai, R., Ohshiro, N., Ohbayashi, M., Kohyama, N. and Yamamoto, T. (2005) Possible involvement of organic anion transporter 2 on the interaction of theophylline with erythromycin in die human liver. Drug Metabolism and Disposition The Biological Fate of Chemicals, 33, 619-622. 

Lown, K.S.. Kolars, f.C., Thummel, K.E., Barnett. (.L.. Kunze, K.L., Wrighton, S.A., Merion. R.M., and Watkin, P.B. (1994) Interpatient heterogeneitiy in expression of CYP3A4 and CYP3A5 in small bowel. Lack of prediction by the erythromycin breast test. Drug Metabolism and Disposition. H, 947-955. 

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