Established in 1999, Guangzhou Tosun Pharmaceutical Limited is a Pharmaceutical company based in Guangzhou, China, and specialized in providing Pharmaceutical Reference Standards, API Impurities, Reference Listed Drugs (RLDs), Intermediates, Excipients etc. We supply products to pharmaceutical, and biotech companies as well as R&D labs at various research institutes and organizations. ? We respond to our client’s inquiries within 24 hrs. ? We ship In-stock products in 24 hrs. ? Tosun offers custom synthesis of the products which are new or not in our stock.