Drugs Exp Clin Res. 1998;24(5-6):331-3.Related Articles, Links A comparative evaluation of the influence of the complex drug Ukrain and its components on the effects of radiation. Boyko VN, Zholus RB. Research Institute of Military Medicine, St. Petersburg, Russian Federation. The development of cancer therapy is associated with an increased application of therapeutic schedules that combine radiation and different drugs. Ukrain is a promising drug proved to be efficient in the treatment of different tumors when used either before, during or after radiation therapy. Therefore, the issue of the influence of this drug on the effects of radiation is of interest. In previous studies, the ability of Ukrain to ameliorate the harmful consequences of irradiation was demonstrated. Ukrain is a semi-synthetic thiophosphoric derivative of Chelidonium majus L. alkaloids, i.e., it is a complex preparation. Therefore, it is necessary to elucidate which of its components are the active agents that mediate its antiradiation effects. The aim of this study was to compare the radioprotective effects of Ukrain and its components in experiments with animals irradiated by doses within a broad range (from LD50/30 to LD100/30). A total of 1,240 outbred male white mice were gamma-irradiated with an IGUR apparatus using 137Cs as the radiation source. Doses applied ranged from 5.25-7.5 Gy with a 0.75 increment between dosages. Dose rate was 1.41 Gy/min. The experiments have shown that the radioprotective effects of Ukrain are far superior to all its components taken separately, both measured by survival of mice irradiated by different doses, and by the protection coefficient a. These observations suggest that the influence of Ukrain on radiation effects does not result from the antiradiation properties of its components but rather from the concerted action of the specific combination found in Ukrain.