Preparation of a carbon-11 labelled antibiotic, erythromycin A lactobionate

Erythromycin A is labelled with the positron-emitting radionuclide, carbon-11(t½= 20.4 min), by the fast reductive methylation of N-demethylerythromycin A with [11C]formaldehyde to provide an agent that permits the non-invasive study of the antibiotic in vivo.