anti cancer drugs

Molecule of the Day: Cisplatin

Cisplatin [Pt(NH3)2Cl2] is an metal complex that is used as an antineoplastic agent (anti-cancer drug). It is one of the archetypal transition metal complexes, being well-known and having a long history.

Cisplatin was first synthesised in 1845 by Michele Peyrone, and was known as Peyrone’s salt. Its medicinal effects, however, were not known until the late 20th century, until it was discovered by chance.

In 1961, a physics professor by the name of Barnett Rosenberg at Michigan State University embarked on a project to investigate the effect of electromagnetic radiation on cells during mitotic division. To his surprise, the setup caused the E. coli to elongate instead (below right), without undergoing cell division.

Eventually, the suspicion fell on the platinum electrodes. They were indeed the culprit; in the presence of oxygen, it had produced cisplatin. The researchers then decided to test its effects on mammalian cells by injecting it into mice with tumours; the results are remarkable, as can be seen from the images below. The tumour of the mouse that was injected with cisplatin (2nd row) had completely regressed by day 8, while the mouse that was not (1st row) eventually died on day 21.

Currently, cisplatin is used to treat various, but not all, forms of cancer, such as breast, lung, testicular, and ovarian cancer. When administered, the Cl atoms are displaced by water molecules, which themselves are displaced by guanine or adenine molecules in DNA. Since two ligands can be displaced, cross-linking of DNA occurs, interfering with cellular division.

Interestingly, its geometric isomer, transplatin, does not have any medicinal effect; it is believed to be due to its rapid hydrolysis when administered, causing it to be unable to react with the DNA to cross-link it. Additionally, the inter-strand cross-linking it causes could be more easily repaired by DNA repair mechanisms than the intra-strand cross-linking that cisplatin causes.

Cisplatin is synthesised from potassium tetrachloroplatinate via multiple ligand exchange reactions with potassium iodide, followed by ammonia, silver nitrate, and potassium chloride respectively.

I will be spending the next two days studying for my last pharmacology exam. We are covering vaccines, anti-cancer drugs, targeted therapies to treat cancer, biological response modifiers, vitamin and mineral replacement, fluid and electrolyte replacement, nutritional support, drugs for gastrointestinal tract disorders, and anti ulcer drugs.
Going to try to stay focused and take necessary breaks to prevent overload. Wish me luck.

Brazilian wasp has been found to have CANCER fighting venom.

The venom of the Brazilian wasp Polybia paulista contains a powerful “smart” drug that selectively targets and destroys tumour cells without harming normal cells, a study has shown.

In laboratory tests, the poison has been shown to suppress the growth of prostate and bladder cancer cells, as well as leukaemia cells resistant to a range of drugs.

New research has now revealed the secret of the venom toxin, known as MP1. Scientists found that it blows gaping holes in the protective membranes surrounding tumour cells by interacting with fatty molecules called lipids.

Dr Paul Beales, a researcher from Leeds University, said: “Cancer therapies that attack the lipid composition of the cell membrane would be an entirely new class of anti-cancer drugs.

“This could be useful in developing new combination therapies, where multiple drugs are used simultaneously to treat a cancer by attacking different parts of the cancer cells at the same time.”

Source

Potassium tetrachloroplatinate(II) is the chemical compound with the formula K2PtCl4. This reddish orange salt is an important reagent for the preparation of other coordination complexes of platinum. It consists of potassium cations and the square planar dianion PtCl42−


The chloride ligands on [PtCl4]2− are displaced by many other ligands to afford derivatives. The anti-cancer drug Cisplatin can similarly be prepared:[1]

PtCl42− + 2 NH3 → cis-PtCl2(NH3)2 + 2 Cl−

Historically, an important reaction involves ammonia and [PtCl4]2−. This reaction affords a deep green precipitate with the formula PtCl2(NH3)2. This material, known as Magnus’ green salt, is a semiconducting coordination polymer consisting of chains of alternating [PtCl4]2− and [Pt(NH3)4]2+ centres.

For more: https://en.wikipedia.org/wiki/Potassium_tetrachloroplatinate