Radioprotection in mice following oral delivery of amifostine nanoparticles.

PURPOSE: Amifostine (Ethyol) is an approved cytoprotective agent prescribed to reduce certain side-effects in the chemotherapy of ovarian or non-small cell lung cancer, or in radiation treatment of head-and-neck cancer. The usefulness of this drug is further hampered, because it is not effective when given orally. The objective of this part of the project was to evaluate the radioprotective efficacy of orally active amifostine nanoparticles.

MATERIALS AND

METHODS

Radioprotective efficacy was evaluated by measuring the ability of the amifostine nanoparticles (equivalent to 500 mg/Kg) to inhibit whole-body gamma irradiation -induced injury in mice. All mice received acute whole-body gamma irradiation from a Cesium-137 source and the radioprotective efficacy of the formulation was determined by measuring 30-day survival at 9 Gy, bone marrow hemopoeitic progenitor cell survival at 9 Gy and 8 Gy, and intestinal crypt cell survival at 11 Gy.

RESULTS

Thirty-day survival, hemopoietic progenitor cell survival, as well as the jejunal crypt cell survival were all significantly enhanced when the mice were treated orally with the amifostine nanoparticles 1 h prior to irradiation.

CONCLUSIONS

These results clearly and unequivocally demonstrate that the amifostine nanoparticles developed in our laboratory provides significant protection from acute whole-body gamma irradiation injury in mice.