# Structural Biochemistry/Osteoporosis (Zanamivir & Oseltamivir)
## History of Osteoporosis

Osteoporosis is a bone disease that can lead to fractures and deteriorating bone strength. Bisphosphonate, also known as Diphosphonate are drugs known for treating the reducing the risk of contracting the illness. It is one of the key elements used by chemist as a pathway to finding the drugs for Osteoporosis. BIsphosphonate, which have cellular selectivity due to structural alignment, has an impressive ability to bind with a naturally occurring mineral called Hydroxylapatite, that can make up 70% of bone. They inhibit the function of osteoclasts, which break down the bones to compensate for the lack of calcium in blood. Alendronate (Fosamax), ibandronate (Boniva), risedronate (Actonel), and zoledronic acid (Reclast) are three examples of drugs used to treat osteoperosis.

## History of Influenza Viruses

Influenza viruses, also referred to as the flu is a disease that is more severe that a normal cold and is highly contagious. The virus can be transferred through air, cough, sneeze, as well as direct contact. It affects all age group, but young children have a tendency to catch the disease more than adults. It is a seasonal disease that spread around the world and kill thousands and thousands of people each year.

## Zanamivir (Relenza)

Osteoporosis: The company Biota discovered Zanamivir, a drug made help bone conditions such as Osteoporosis and similar diseases. Of its kind, it was the first commercial drug on the market to serve as patients with bone diseases, but unfortunately, it was proven to have low effectivity due to its poor bioavailability of 2%. The human body was unable to fully absorb the dosage because of Zanamivir's zwitterionic character.
Influenza: In an experiment on animals and man, inhaling doses of Zanamivir is an effective treatment for influenza. Although Zanamivir is and ester prodrug, if taken orally, the medicine will not successfully distribute through out the body and therefore, will not fight against the infectious disease. Due to this matter, many attempts have been made to better the pharmacological properties of Zanamivir by changing the structure of the compound.

## Oseltamivir (Tamiflu)

Osteoporosis: Following the discovery of Zanamivir, to improve bone diseases, Gilead group generated a drug called Oseltamivir. This new medicine serves the same purpose as Zanamivir but it was highly effective and it outsold Zanamivir by 3 to 1. This drug was more successful than Zanamivir because its carboxylate is an ethyl ester prodrug, in which enhancing the molecule to be cationic, and therefore, an increase in oral absorption (75%).
Influenza: By looking to improve the oral intake of Zanamivir, researchers redesigned the structural compound of pyran by removing carboxylic acid, and changing it into a carbocyclic scaffold, in which discovered an active antiviral product (Oseltamivir) that targets influenza viruses and can be taken orally. Overall, Statistics shows that in Japan, Oseltamivir was more commonly used, roughly 90 times more than Zanamivir.

## References

Kozarich, John W. "The Biochemistry of Diseases: Desperately Seeking Syzygy." Annu. Rev. Biochem. (2009): 55-63. Web.
Colman, Peter M. "New Drug Antiviral and Resistance." Annu. Rev. Biochem. (2009): 95-118. Web.
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