[en] [¹¹¹In]-DTPA-D-Phe¹-octreotide (OctreoScan^R, Mallinkrodt) is widely used for detection of neuroendocrine tumors and has lately been proposed for radionuclide therapy. We found, using HPLC and a GF-250 column (Zorbax^R, Hewlett Packard), that OctreoScan^R can be separated in two radiolabeled components of about equal amount. The analytical conditions for a quantitative isolation indicate that the two-peptide components of OctreoScan^R have different lipophilicity. The isolated components are stable and do not transform into each other at room temperature during 6 hours (shelf-life of OctreoScan^R). (author)