Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 52 7 2023 07 15 1495 1503 EN Saeideh Hashemi-Hafshejani Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Amir Amani 1. Department of Medical Nanotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran 2. Medical Biomaterials Research Center, Tehran University of Medical Sciences, Tehran, Iran 3. Natural Products and Medicinal Plants Research Center, North Khorasan University of Medical Science, Bojnurd, Iran Sanaz Jafarpour Azami Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Hossien Keshavarz Valian Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Mehdi Mohebali Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Mahboobeh Salimi Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Hossien Hassani Lafmejan Pour Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Saeedeh Shojaee Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran 2022 02 10 2022 06 29 Background: Toxoplasma infection is caused by Toxoplasma gondii, which is an intracellular protozoan parasite. This infection consequently lead various congenital disabilities during pregnancy in patients. Spiramycin (Spi), a macrolide antibiotic, is typically recommended for T. gondii infection in pregnant women. We aimed to prepare the nanoemulsion of spiramycin (NE-Spi) and to evaluate the activity of this formulation in tachyzoites of T. gondii, RH strain. Methods: This study was conducted in 2019-2021 at the School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. NE-Spi was prepared by spontaneous emulsification. The effects of this nanoemulsion on the viability of cultured cells were measured using MTT assay. To estimate the effects of NE-Spi on tachyzoites of T. gondii, RH strain, different concentrations of NE-Spi, S-Spi (suspension of spiramycin), and NE (nanoemulsion without any spiramycin) were added to tachyzoites and then stored for 30, 60, 90, 120 min and 24 h in 250 µg/ml concentration at room temperature. Finally, Tachyzoites mortality rates were evaluated by trypan blue staining. Of note, flow cytometry was conducted to confirm the obtained results. Results: The final particle size of NE-Spi was calculated to be 11.3 nm by DLS and TEM. Thereafter, using MTT assay, in 62.5 µg/ml concentration of NE-Spi, the Vero cells viability was obtained as 82%. The highest mortality rates of tachyzoites of T.gondii, RH strain were observed at 250 µg/ml concentration and after 120 min of exposure, but it was not significantly different from 24 h of exposure. Conclusion: NE-Spi has lethal efficacy on T. gondii RH strain in-vitro. https://ijph.tums.ac.ir/index.php/ijph/article/view/27820 https://ijph.tums.ac.ir/index.php/ijph/article/download/27820/7992