Evaluation of the effect of anti-toxoplasmic drugs on the biodistribution of the radiopharmaceutical sodium pertechnetate


Ranny Beatriz de Carvalho Holanda Leite, João Cláudio da Costa Urbano, Renan Leopoldo Pereira Castro, Clarice Maux Vianna da Silva, Aldo da Cunha Medeiros, Ítalo Medeiros de Azevêdo, Vanessa Santos de Arruda Barbosa, Cecília Maria de Carvalho Xavier Holanda

The human toxoplasmosis is a disease caused by the parasite Toxoplasma gondii that can affect the growing baby in pregnancy and it is the most common Central Nervous System infection in patients with AIDS. Its treatment is made by the synergistic association of the drugs pyrimethamine (PM) and sulfadiazine (SDZ). Objective: The aim of this study was to evaluate whether the combined use of PM and SDZ changes the sodium pertechnetate (Na99mTcO4 − ) biodistribution in non-infected animals by the T. gondii. It was used on 24 male Swiss mice equally divided into four groups: one control group and three treated groups. Methods: The control group received 0.5 ml of distilled water; the treated group 1 received 0.5 ml of a PM solution; the treated group 2 received 0.5 ml of a SDZ solution and the treated group 3 received 0.5 ml of the PM + SDZ, all by the gavage method for 10 days. On the 10th day and 1 hour after the last dose, all groups received 0.1 ml of Na99mTcO4 − (0.66 MBq) via the femoral vein. After 40 minutes, the animals were euthanized, and blood and brain samples were isolated. The percentage of total activity injected per gram of organ (%ATI/g) was calculated on the gamma counter. Statistical analysis was performed using the T-test, considering a level of significance of p < 0.05. Results: There was a statistically significant increase in %ATI/g in the blood, from the control group to the treated group with PM + SDZ (from 2.53 ± 0.17 to 4.53 ± 0.31) and also in the brain (from 0.09 ± 0.01 to 0.19 ± 0.04). There was no statistically significant difference between the control group and those treated alone with PM and SDZ. Conclusions: It can be concluded that both the drugs used alone and in combination do not interfere in the biodistribution of the radiopharmaceutical in nuclear medicine exams.