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Oseltamivir, sold under the brand name Tamiflu among others, is an antiviral medication used to treat and prevent influenza A and influenza B, viruses that cause the flu. [5] Many medical organizations recommend it in people who have complications or are at high risk of complications within 48 hours of first symptoms of infection. [ 6 ]
The current production method is based on the first scalable synthesis developed by Gilead Sciences [4] starting from naturally occurring quinic acid or shikimic acid.Due to lower yields and the extra steps required (because of the additional dehydration), the quinic acid route was dropped in favour of the one based on shikimic acid, which received further improvements by Hoffmann-La Roche.
Shikimic acid can also be extracted from the seeds of the sweetgum (Liquidambar styraciflua) fruit, [2] which is abundant in North America, in yields of around 1.5%. For example, 4 kg (8.8 lb) of sweetgum seeds is needed for fourteen packages of Tamiflu. By comparison, star anise has been reported to yield 3% to 7% shikimic acid.
An equianalgesic chart is a conversion chart that lists equivalent doses of analgesics (drugs used to relieve pain). Equianalgesic charts are used for calculation of an equivalent dose (a dose which would offer an equal amount of analgesia) between different analgesics. [1]
Oseltamivir (also Tamiflu) is an oral antiviral drug against influenza (flu). It was the second inhibitor of the viral neuraminidase to be developed, after zanamivir, and the first to be taken as an oral tablet. It was originally synthesised from shikimic acid extracted from the star anise plant.
[10] [11] [12] An industrial method for the production of shikimic acid using fermentation of E. coli bacteria was discovered in 2005, [13] [14] and applied in the 2009 swine flu pandemic to address Tamiflu shortages, eventually reversing price increases for star anise as a raw material of shikimic acid. [15]
The drug is used to treat patients that have contracted influenza. However, the Vietnamese girl who had received a prophylactic dose (75 mg once a day) was found to be non-responsive to the medication. In growing fears of a global avian flu pandemic, scientists began to look for a cause of resistance to the Tamiflu medication.
Aminoshikimic acid is an intriguing alternative to shikimic acid as a starting material for the synthesis of neuraminidase inhibitors such as the antiinfluenza agent oseltamivir. [3] Aminoshikimic acid is also a versatile chiral starting material for the synthesis of new pharmaceuticals.