API of the month: Granisetron
Granisetron hydrochloride (Kytril, Kevatril, Ribosetron) is an antiemetic drug used to treat nausea induced by chemotherapy and radiotherapy. This side effect can be not only deeply unpleasant but, with increasing severity and accompanying medical complications such as dehydration, malnutrition, metabolic disorders and aspiration pneumonia, can even become life-threatening.
A highly selective antagonist of 5-hydroxytryptamine (5-HT3) receptors, granisetron competitively blocks the action of the serotonin that is released from mucosal enterochromaffin cells in the small intestine following exposure to radiation or cytotoxic substances. This obstruction of 5-HT3 binding prevents serotonin stimulating the vagal neurons and activating the emesis trigger zones in the medulla oblongata, resulting in the suppression of nausea and vomiting1.
Granisetron hydrochloride is metabolised by the liver, with a single dose usually lasting four to 12 hours, depending upon the individual metabolism2. It is generally well tolerated, with fewer significant side effects or drug interactions than other 5-HT3 receptor antagonists, thanks to its high selectivity. In rare cases it can impact on heart rhythm, causing QT prolongation, and may also cause serotonin syndrome, particularly when taken in combination with other serotonergic drugs3.
Developed by Beecham in 1988 and approved in the UK in 1991 and the US in 19944, granisetron hydrochloride can be obtained in a three-step synthesis by methylation, reaction with acid chloride and amide formation, during which a number of process-related by-products may form. As well as process impurities, degradation impurities can also form in the final granisetron hydrochloride, which is prone to oxidation due to its electron-rich tertiary amine group.
For a full accounting of granisetron process and degradation impurities and their formation, download our scientists’ overview here.
We offer a high quality range of impurity and API reference standards for the granisetron family, in order to best support your quality control and assurance programmes and safeguard your analytical accuracy. Discover the range here and order quickly and easily through our web shop, or get in touch with your local sales office for further information and advice.