MERCOSUR stands for Mercado Común del Sur, or Southern Common Market, and is an economic and political agreement among Argentina, Brazil, Paraguay, (currently suspending for not having a democratically elected president) Uruguay, Venezuela and Bolivia. (in process of incorporation) Chile, Colombia, Ecuador, and Peru currently have associate member status.
The countries of MERCOSUR, through the coordinated effort of their regulatory agencies, has started the path to harmonization on some requirements for registration of pharmaceutical products. For example, the GMP standards are harmonized, (and up to international standards) to the point which when a member country exports a pharmaceutical product to another member country, the GMP certificate from the manufacturer member country can be adopted and published as own by the importing country. This is of especial relevance and application between Argentina and Brazil, and it goes both ways.
Regulatory Affairs in Latin America 