4.11. Biodistribution Study

Ehrlich ascites carcinoma (EAC) was used in this study. The parent line was supplied from the ascitic fluid of Swiss Albino mice purchased from the Egyptian National Cancer Institute, Cairo University. Adult male Swiss albino mice weighing 22–25 g purchased from the breeding unit of the Egyptian Organization for Biological Products and Vaccines, Cairo, Egypt, were used in this study. Animals were on pellet diet and tap water. Animal treatment was in accordance with the National Institute of Health Guide for Animal, as approved by the Institutional Animal Care and Use Committee. The EAC was withdrawn from the ascitic fluid of a mice bearing EAC (10 days old) under aseptic conditions and diluted using physiological sterile saline solution. The diluted cell line was mixed for 5 min by vortex shaker. To generate Ehrlich solid tumor, 200 μL of the diluted ascitic fluid was injected intramuscularly in the right lower limb of male mice (22–25 g). Palpable solid mass was observed 10 days after inoculation.

For commencing the biodistribution study the animals were divided into two groups the first included normal mice (no tumor inoculation) and the second group included tumor inoculated mice. Five individuals were used for each time point. Exactly 100 μL (23.25 MBq) of purified ¹³¹I-2b was injected in the tail vein of each mice. Mice were anesthetized with a mixture of xylazine (10 mg/kg) and ketamine (80 mg/kg) then weighed and dissected. Blood was collected via cardiac puncture, and all organs were separated and washed with physiological saline. For the tumor muscle, sample of the tumor was isolated completely from the leg and washed with normal saline then weighed. Another sample of the contralateral normal muscle was used as control to measure the tumor uptake of compound 2. All the collected biological samples were placed in previously weighed plastic containers, and the activity was counted in automatic scintillation gamma counter. A standard dose containing the same injected amount was counted simultaneously and accounted as 100% activity [66] The uptake was expressed as percentage injected dose/gram tissue (%ID/g). Blood, bone, and muscles were assumed to be 7%, 10%, and 40% of the total body weight, respectively [67]. Data are reported as the mean ± SE. Data were analyzed using compare means function in SPSS software (Version 20.0).