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Oseltamivir Uses and its Impurities

Oseltamivir was invented and patented by Californian company Gilead Sciences in 1996.1 Swiss pharmaceutical company Hoffmann-La Roche (Roche) then purchased the rights to develop and market the drug worldwide under the trade name Tamiflu. Oseltamivir is an antiviral neuraminidase inhibitor used for the treatment and prophylaxis of infection with influenza viruses A (including pandemic H1N1) and B. Oseltamivir exerts its antiviral activity by inhibiting the activity of the viral neuraminidase enzyme found on the surface of the virus, which prevents budding from the host cell, viral replication, and infectivity.


Oseltamivir is an important antiviral drug, which possess three chirality centers in its structure. From eight possible stereoisomers, only two have been synthesized and evaluated so far.These isomers are synthesized using stereo selective organocatalytic Michael addition, cyclization and reduction Process.2


 What is Influenza?

Influenza is a generally a benign disease, It is a contagious viral infection that can cause mild to severe symptoms and life-threatening complications, including death, even in healthy children and adults. Influenza is an infection affecting populations worldwide caused by highly contagious, epidemically aggressive and mutagenic viruses. More than 2,00,000 hospitalizations and an average of 25,470 deaths occur in the USA each year due to seasonal influenza. Resistance of influenza A viruses to adamantanes increased globally in 2003 and has since become universal for circulating influenza A (H1N1) and A (H3N2) subtypes3.


Oseltamivir phosphate is an ethyl ester prodrug widely used in the treatment and prevention of both Influenza virus A and B infections. The conversion of oseltamivir to its active metabolite oseltamivir carboxylate is dependent on ester hydrolysis mediated by carboxylesterase 1 (CES1).


Oseltamivir is also used to treat and prevent infections from avian (bird) influenza (a virus that usually infects birds but can also cause serious illness in humans).


Simson Pharma Pvt. Ltd is a supplier, manufacturer and exporter of Oseltamivir Impurity. These impurities are provided with a certificate of analysis along with the characterization data like NMR MASS, IR and HPLC Purity.

Simson Phrama Pvt ltd is the supplier of all Oseltamivir  USP, EP, BP, JP pharmacopeia impurities, unknown impurity, APIs, stable isotopes and intermediates with structure elucidation by 13C NMR, 1H NMR, MASS, CHNS, HPLC data.


1. The evolution of Tamiflu synthesis

2. Stereoisomers of oseltamivir – synthesis

3. Oseltamivir for the treatment of influenza in children and adolescents

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