CISPLATIN

• structure of cisplatin

  • platin is a platinum complex that forms cis-trans stereoisomers
  • the cis isomer, cisplatin, is used as an anti-cancer drug
  • the trans isomer, transplatin, doesn't have the same effect and is not used in chemotherapy

  
• cisplatin prevents DNA replication
• cisplatin is administered intravenously -> very useful in treating solid tumours
• for a cell to replicate, the double helix DNA molecule must unwind
• cisplatin prevents it from unwinding by forming dative bonds with the nitrogen in the DNA base guanine
• nitrogen atoms in the bases displace the chlorine ligands in the cisplatin complexes
• the nitrogen atoms in guanine form dative bonds with platinum
• • cis-platin forms cross links within the same strand of DNA - not easily repaired
  • trans-platin forms cross links between strands of DNA - more easily repaired which means it isn't used

  
• use of cis-platin 


  important drug used to prolong life of cancer patients - some risks with its usage
• risks of using cis-platin

  1. prevents normal cells in the body from replicating (especially cells that replicate frequently e.g. hair and blood)
  2. causes hair loss and suppresses the immune system which is controlled by white blood cells
  3. patients may experience side-effects e.g. nausea, vomiting and serious complications (kidney damage)
  4. patients can become resistant to cisplatin
• why is cisplatin used when the side effects are dangerous?

  1. long-term benefits outweigh the short-term side effects
  2. doctors use it in small amounts to reduce the side effects
  3. target the tumour directly using methods that deliver the drug directly to the tumour and prevent damage to healthy cells