Oral versus intraperitoneal administration of irinotecan in the treatment of human neuroblastoma in nude mice

The present study evaluated the plasma pharmacokinetics of irinotecan (CPT-11) and its effects against a human neuroblastoma in xenograft, given by different administration routes. One-third of the LD50 was administered either intraperitoneally (59 mg/kg mouse weight (MW)) or orally (404 mg/kg MW) to nude mice. The plasma levels of CPT-11 and its active metabolite SN-38 decreased rapidly when CPT-11 was administered intraperitoneally, but remained relatively high for 4–8 h after oral administration. Then, a human neuroblastoma xenograft was inoculated in another set of 21 nude mice. When the estimated tumor weight reached 150–200 mg, CPT-11 was administered in the total LD50 either intraperitoneally or orally in three doses at 4-day intervals (q4d ×3) to the mice in each experimental group. Oral administration was found to be superior to intraperitoneal injection in terms of tumor inhibition and to be an effective route for CPT-11 administration in the treatment of human neuroblastoma in nude mice.