Folate receptor-targeted liposomes as possible delivery vehicles for boron neutron capture therapy.
BACKGROUND
The folate receptor is amplified in a variety of human tumors including over 90% of ovarian carcinoma. FR-targeted liposomes have previously been used by us to selectively deliver entrapped boron-containing compounds to tumor cells for neutron capture therapy (NCT). In the present study we have evaluated the delivery of Na3(B20H17NH3), which has been loaded into FR-targeted liposomes, in mice bearing xenograft implants of FR (+) KB subcutaneous tumor.


METHODS
Na3(B20H17NH3) was passively entrapped into FR-targeted liposomes, which were administered intravenously into nude mice bearing s.c. implants of the FR(+) human oral carcinoma KB cell line. Normal and tumor boron content was measured by direct current plasma-atomic emission spectroscopy.


RESULTS
Mice that received FR-targeted liposomes containing boron showed the highest tumor boron levels at 24 hours (6.1 micrograms/g) and tumor/blood boron ratios continued to rise for up to 120 hours.


CONCLUSIONS
Boron delivery via FR-targeted liposomes is feasible and potentially can improve tumor uptake compared to non-targeted liposomes, and may improve cellular and subcellular localization.
Stephenson
Stacy M
SM
Division of Pharmaceutics, Ohio State University, Columbus, OH 43210, USA.
Yang
Weilian
W
Stevens
Phillip J
PJ
Tjarks
Werner
W
Barth
Rolf F
RF
Lee
Robert J
RJ
D000818:Animals; D001896:Boron Compounds / Q000008:administration & dosage* / Q000493:pharmacokinetics; D016754:Boron Neutron Capture Therapy / Q000379:methods*; D002352:Carrier Proteins / Q000378:metabolism*; D004337:Drug Carriers; D005260:Female; D058973:Folate Receptors, GPI-Anchored; D006801:Humans; D007624:KB Cells; D008081:Liposomes / Q000008:administration & dosage / Q000378:metabolism* / Q000493:pharmacokinetics; D051379:Mice; D008819:Mice, Nude; D011956:Receptors, Cell Surface; D014018:Tissue Distribution; D023041:Xenograft Model Antitumor Assays
D001896:Boron Compounds; D002352:Carrier Proteins; D004337:Drug Carriers; D058973:Folate Receptors, GPI-Anchored; D008081:Liposomes; D011956:Receptors, Cell Surface