sofosbuvir
Sofosbuvir is an antiviral used to treat hepatitis C, an infection which is caused by the hepatitis C virus.
Antivirals are used to treat viral infections.
Viruses
Viruses are microorganism that can only replicate if they are inside a host cell. They consist of genetic material (DNA or RNA) wrapped in a protein capsule.
Viruses can't reproduce (replicate itself) without a host. When viruses find a host, we say that the host is infected with the virus. Once it has a host it uses the host's cells to replicate its genetic material and replicate itself.
If you've ever had the flu or chicken pox, then you've been a host for a virus!
Viruses are spread by a carrier that can infect other organisms. The carrier can be water, air or even other animals.
How does it work?
Antiviral medications generally focus on interrupting the process of replicating genetic material.
Genetic material in humans is DNA (deoxyribonucleic acid). It is converted by the cell into RNA (ribonucleic acid) inside the nucleus, and the RNA is transported into the cell membrane. Inside the cell membrane, the ribosome is involved in translating the information from the RNA molecule into proteins and other cell products.
DNA and RNA are made up of nucleotides that contain bases cytosine, thymine, adenine, guanine and uracil in long chains.
If the chain is incomplete, the instructions don't work properly. The anti-viral medication sofosburvir works by interrupting the formation of RNA strands.
Sofosburvir is a pretty new medicine. It was only discovered in 2007 and approved for use by the TGA in 2014.
Sofosbuvir interacts with the hepatitis C protein NS5B. This protein plays a key role in the viruses processes for replicating genetic material. Sofosbuvir inhibits its ability to do this.
But, sofosbuvir isn't actually the drug that inhibits the hepatitis C viruses ability to do this. In fact it is metabolised in the body by enzymes into a new drug with a different chemical structure!
This new 'active' drug is the one which inhibits the viruses replication of its genetic material. When a medicine is metabolised, like sofosbuvir, into an 'active' drug it is called a pro-drug.
Can you identify the similarities and differences between the chemical structures sofosbuvir and it metabolite show above? Which part of the molecule has changed?