|Letrozole Chemical Properties|
|Letrozole Usage And Synthesis|
|Pharmacological Function||Letrozole is a new generation of selective aromatase inhibitors. It is a synthetic benzyl triazole derivative, can inhibit aromatase and decrease estrogen levels, further eliminates the stimulation of estrogen on tumor growth. The activity of letrozole in the body is 150-250 times more than that of the first generation of aromatase inhibitors - aminoglutethimide. Due to its high selectivity, and shall not affect the sugar cortical hormone, mineralocorticoid and thyroid functions, large dosage is of no inhibition for adrenal corticosteroid secretions, therefore, it has a higher therapeutic index. Preclinical studies have shown that Letrozole is of no potential toxicity to each system and target organ in the body, no mutagenic and carcinogenic effect, little side reaction, well tolerated, and compared with other aromatase inhibitors and anti-estrogen drugs, it has a stronger antitumor effect. Applicable to the treatment of advanced breast cancer in postmenopausal patients who anti-estrogen ineffective, and early breast cancer.|
In December 2005, the British drug and health care products regulatory approved letrozole (furlong) produced by Swiss Novartis used to treat breast cancer patients, and allowed it to treat early invasive breast cancer patients after the surgery caused by positive postmenopausal hormone. This is the second aromatase inhibitors approved by UK after Astrazeneca's Arimidex June in 2005. Two drugs in clinical trials have shown that compared with the current standard Tamoxifen treatment, it can better prevent the risk of breast cancer recurrence.
|Distinctions Between Letrozole and Anastrozole||Letrozole tablets: suitable for advanced breast cancer after menopause, most used in the treatment of anti-estrogen treatment failure after second-line therapy.|
Anastrozole: an effective selective inhibitor for three azole aromatase, it inhibits the aromatase relied by cytochrome P-450, further blocks estrogen biosynthesis, which is the main factor to stimulate breast cancer cell growth. The 50% inhibitory concentration (IC50) value of human placenta aromatase is 15 nmol/L.
|Adverse Reactions and Side Effects||Randomized trials show that orally take 2.5 mg of letrozole every day, adverse reactions incidence may be related to the drug is 33%, and is significantly less than that of the AG group which is 46%. Most adverse reactions of letrozole are mild or moderate, mainly include nausea (2% ~ 9%), headache (0% ~ 7%), bone pain (4% ~ 10%), hot flashes (0% ~ 9%) and weight gain (2% ~ 8%), and other rare reactions like constipation, diarrhea, itching, rash, joint pain, chest pain, abdominal pain, fatigue, insomnia, dizziness, edema, hypertension, arrhythmia, thrombosis, difficulty breathing, vaginal bleeding, etc.|
|Chemical Properties||Melting point is 181～183 oC.|
|Usage||Pyrrole type aromatization enzyme inhibitors. Used in the treatment of breast cancer.|
This information is edited by ChemicalBook Xiao Nan.
|Production Method||4-bromine methyl phenyl nitrile (I) and triazole react in chloroform, products (Ⅱ) and 4-fluorine benzene nitriles react in dimethyl formamide, generate to letrozole in the presence of potassium tert-butyl alcohol.|
|Chemical Properties||white to light yellow crystal|
|Usage||A nonsteroidal aromatase inhibitor structurally related to Fadrozole. Antineoplastic|
|Letrozole Preparation Products And Raw materials|