Piperaquine is an antimalarial drug, a bisquinoline first synthesised in the 1960s, and used extensively in China and Indochina as prophylaxis and treatment during the next 20 years. Usage declined in the 1980s as piperaquine-resistant strains of P. falciparum arose and artemisinin-based antimalarials became available. However, Chinese scientists have been studying whether piperaquine can still be used therapeutically in combination with artemisinin. Piperaquine is characterized by slow absorption and a long biological half-life, making it a good partner drug with artemisinin derivatives which are fast acting but have a short biological half-life. The fixed-dose combination dihydroartemisinin-piperaquine (Eurartesim) was submitted for approval to the European Medicines Agency in 2009.