Antimony preparations are the drugs of choice for the treatment of leishmaniasis over 90 years, a disease that currently affects 12 million people worldwide. Its introduction was based on 19th century concepts of therapeutic effects of metal salts as arsenicals and other metals, most of them abandoned due to toxic effects or better drugs. In the last three decades, there was a great improvement in the knowledge of cell biology and immunology of those infections, but chemotherapy has not been improved in the same strength. The structure and mechanism of action of the two pentavalent antimonial drugs of choice, meglumine antimoniate and sodium stibogluconate, are not well known and the contamination of those pharmaceutical by toxic contaminants have been verified.

N-nitrosamines are carcinogenic compounds that have been found during the last three decades in a variety of consumer products, including cosmetic and personal care products, and their raw materials. These compounds are formed from amine precursors and nitrosating agents present in the formulations. This paper reviews the formation and occurrence of N-nitrosamines in cosmetic products, as well as presents considerations about analytical, toxicological and regulatory aspects.

Agradecimentos: The authors are grateful for the financial support provided by the Brazilian agencies Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, grant #2018/03571-2), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, grants #301737/2017-7, 406855/2016-1, and 310844/2020-7), and Instituto Nacional de Ciências e Tecnologias Analíticas Avançadas (INCTAA: FAPESP, grant #2014/50951-4; CNPq, grant #465768/2014-8). Scholarships were awarded to V.D. (CNPq, grant #131091/2018-2) and L.S.A (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior). The authors also thank CAQI/IQSC/USP for the use of the SEM facilities

Agradecimentos: The authors are grateful for the financial support provided by the Brazilian public agencies Sao Paulo State Research Foundation (FAPESP, 2018/03571-2 and 2014/50951-4) and CNPq (465768/2014-8 and 301737/2017-7). Scholarships were awarded to P.C.C.A (CAPES), C. R.-S. (CNPq, 154061/2018-2), and A.R.R. (FAPESP, 2018/09697-8). The authors also thank SANASA (Sociedade de Abastecimento de Agua e Saneamento, Campinas, Sao ˜ Paulo, Brazil) for collaboration in this study

Agradecimentos: The authors are grateful for the financial support provided by the Brazilian public agencies São Paulo State Research Foundation (FAPESP, 2018/03571-2 and 2014/50951-4) and CNPq (465768/2014-8 and 301737/2017-7)