ACIDIC AND NEUTRALIZED METOCLOPRAMIDE FORMULATIONS SENSITIZE IONIZING-RADIATION INDUCED CYTOTOXICITY IN A HUMAN LUNG ADENOCARCINOMA XENOGRAFTED TO SCID MICE

A neutralized formulation (Neu-Sensamide) of metoclopramide (MCA) has been shown to possess reduced sedative side effects compared with the conventional acidic formulations (Primperan). The acidic formulation o f MCA has also been shown to sensitize the effect of ionizing radiatio n (6-8 Gy) using human squamous cell carinomas from the head and neck xenografted to nude mice, In the present study, 2 mg MCA/kg body weigh t 1-3 h before treatment with 1 Gy radiation (single dose) was evaluat ed in scid mice xenografted with a human lung adenocarcinoma. MCA give n alone in acidic or neutralized formulations did not show any effect on tumor growth retardation. However, when combined with radiation, bo th acidic and neutralized formulations of MCA sensitized the cytotoxic effect of radiation directed against the tumors by increasing tumor d oubting time, tumor quadrupling time and specific growth delay, and by decreasing area under growth curve measurements, In addition, there w as no statistically significant difference between the two formulation s of MCA in the efficacy of sensitizing the cytotoxicity of a single l ow dose (1 Gy) of radiation.