Experimental study evaluates radioprotective drugs administered before exposure either orally or intravenously. Specifically studied are the sources of radiation, choice of radiation dose, choice of animals, administration of drugs, the toxicity of protective agents and types of protective drug

Smith, D. E.

Thomson, J. F.

English

NASA Technical Reports Server

August 1968	 Brif 68-10320 
.. 
AEC-NASA TECH BRIEF 
-IV 
AEC-NASA Tech Briefs describe innovations resulting from the research and development program 
of the U.S. AEC or from AEC-NASA interagency efforts. They are issued to encourage commercial 
application. Tech Briefs are published by NASA and may be purchased, at 15 cents each, from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Experimental Study and Evaluation of Radioprotective Drugs 
A two-part study has been conducted to survey 
the general aspects of the testing and evaluation of 
radioprotective drugs and to use these testing and 
evaluation methods to ascertain the radioprotective 
effects of certain compounds administered orally and 
by I.V. 
Interest in drugs which protect against the damag-
ingor lethal effects of radiation is of moment because 
of the hazards of radiation therapy, the nuclear 
industry, nuclear war, and space travel. This study was 
concerned solely with compounds that are adminis-
tered before exposure. The effectiveness of the com-
pounds were evaluated for protection against lethal 
effects which occur within 30 days after irradiation. 
The evaluation techniques to determine an agent's 
capacity to decrease an organism's sensitivity to 
ionizing radiation are essentially the same as those 
used in the evaluation of other types of drugs. Such 
factors as drug dosage, administration route, detoxifi-
cation rate, tissue distribution, therapeutic index, time 
after administration, and species, strain, sex, nutrition, 
and environmental status of the experimental animal 
are common to almost all testing techniques. 
Mostof the techniques that are unique to the evalu-
ation of radioprotective drugs are referable to the 
damaging agent, the ionizing radiation. Radiation 
may be of different qualities, of electromagnetic or of 
particle nature, in a wide variety of energies, of vari-
able dose rates, etc. The response of the organism will, 
in most cases, be markedly affected by these factors of 
quality, energy and dose rate, and the efficacy of a 
protective compound will thus depend to a large 
extent on the nature of the radiation. Specifically 
studied are the sources of radiation, choice of radia-
tion dose, choice of animals, administration of drugs, 
the toxicity of protective agents, and the types of pro-
tective drugs.
The remainder of the study concerned the descrip-
tion of experiments designed to study the effective-
ness of orally administered aminothiols in lethally 
irradiated mice. It has been known for a long time 
that these drugs were radioprotective when injected 
intravenously, but their effectiveness after oral ad-
ministration was generally reported as poor. The mice 
were subjected to single, total-body exposures of 775 
rads of X-rays. This dose produced 100 mortality in 
control mice, the deaths occurring between the tenth 
and eighteenth day after exposure. When mice 
received solutions of cysteine or 2-mercaptoethyla-
mine (MEA) in 20 gum arabic 1 hour prior to 
exposure, survival increased in proportion to the dose. 
With MEA, 100% survival occurred after 750 mg/kg; 
90 survival was observed in mice pretreated with 
2700 mg/kg of cysteine. These doses are 3 to 5 times 
as much as is required to produce the same degree of 
protection after intravenous injection. 
Notes: 
I. This study has been reported in Methods of 
Evaluating Radioprotective Drugs, by D. E. 
Smith and J. F. Thomson in Methods of Drug 
Evaluation, North-Holland Publishing Company 
(1966). 
2. Inquiries concerning this innovation may be di-
rected to:
Office of Industrial Cooperation 
Argonne National Laboratory 
9700 South Cass Avenue 
Argonne, Illinois 60439 
Reference: B68-10320 
Source: D. E. Smith and J. F. Thomson,

Biological and Medical Research Division

(ARG- 10196) 
(continued overleaf) 
This document was prepared under the sponsorship of the Atomic 
Energy Commission and/or the National Aeronautics and Space 
Administration. Neither the United States Government nor any per-
son acting on behalf of the United States Government assumes any
liability resulting from the use of the information contained in this 
document, or warrants that the use of any information, apparatus, 
method, or process disclosed in this document may not infringe pri-
vately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19680000320 2020-03-12T06:13:22+00:00Z
Patent status: 
Inquiries about obtaining rights for commercial 
use of this innovation may be made to: 
Mr. George H. Lee, Chief 
Chicago Patent Group 
U.S. Atomic Energy Commission 
Chicago Operations Office 
9800 South Cass Avenue• 
Argonne, Illinois 60439 
Brief 68-10320	 Category 04


Experimental study and evaluation of radioprotective drugs

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