DOTA-Tyr(3)-octreotate radiolabelled with 111-In: Stability and the effect of receptor-specific binding on distribution

Abstract

Radiolabeling, stability and pharmacokinetic analysis in rats of 111-In-DOTA-Tyr(3)-octreotate were studied. Radiolabeling of the peptide is simple and high radiolabeling yields were achieved.

The agent was stable in in vivo conditions; the radioactivity eliminated by urine was nearly completely in the parent form. The affinity of the agent to somatostatin receptor-rich organs was substantially higher than that of commercially available 111-In-DTPA-octreotide (OctreoScan).

The study confirmed high in vivo affinity of the peptide to somatostatin receptors and revealed that receptor binding alters both, distribution profile and elimination pathways of the agent in preclinical experiments.