Single-fraction irradiation has no effect on uptake of radiolabeled pegylated liposomes in a tumor xenograft model.
OBJECTIVE
These studies were performed with the intention of examining the effect of single-fraction doses of radiotherapy (RT) on the tumor deposition of radiolabeled pegylated liposomes in an animal xenograft tumor model.


METHODS
Human KB head-and-neck xenograft tumors were established in female nude mice. The effect of single fraction tumor RT doses (5, 10, 15, and 20 Gy) on the tumor uptake of intravenously administered (111)In-DTPA-labeled pegylated liposomes (IDLPL) was examined using two protocols: (1) to test the effect of RT delivered 30 min before liposome injection on the time course of tumor uptake over a 96-h period; (2) to test the effect of RT at times ranging from 72-h to 1-h before liposome injection on the levels of liposome uptake at 24 h. Tumor and normal tissue/organ (blood, liver, spleen, lung, and kidney) liposome uptake was determined by dissection and quantitation in a gamma counter.


RESULTS
There was no demonstrable effect of RT on tumor uptake of IDLPL (p > 0.1 for all comparisons). Reassuringly, neither was there an effect of RT on the pharmacokinetics and biodistribution of radiolabeled liposomes to normal tissues.


CONCLUSIONS
Single fraction doses of RT appear to have no effect on tumor or normal tissue biodistribution and pharmacokinetics of radiolabeled pegylated liposomes in this animal model.
ICRF Oncology Unit, Imperial College of Science, Technology and Medicine, Hammersmith Hospital, London, United Kingdom. Harrington.Kevin@mayo.edu
K J
KJ
Harrington
G
G
Rowlinson-Busza
P S
PS
Uster
R G
RG
Vile
A M
AM
Peters
J S
JS
Stewart
D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000097:blood / Q000378:metabolism* / Q000532:radiotherapy*; D005079:Excipients / Q000493:pharmacokinetics / Q000528:radiation effects*; D005260:Female; D006801:Humans; D007205:Indium Radioisotopes / Q000097:blood / Q000493:pharmacokinetics; D008081:Liposomes / Q000737:chemistry / Q000493:pharmacokinetics / Q000528:radiation effects*; D051379:Mice; D008819:Mice, Nude; D004369:Pentetic Acid / Q000097:blood / Q000493:pharmacokinetics; D011092:Polyethylene Glycols / Q000493:pharmacokinetics / Q000528:radiation effects*; D011853:Radiobiology; D011879:Radiotherapy Dosage; D014018:Tissue Distribution; D014183:Transplantation, Heterologous
D005079:Excipients; D007205:Indium Radioisotopes; D008081:Liposomes; D011092:Polyethylene Glycols; D004369:Pentetic Acid