6-меркаптопурин моногидра

Описание

6-Mercaptopurine (6-MP) is an inhibitor of purine synthesis and interconversion. It is rapidly converted to 6-mercaptopurine ribonucleoside-5''-monophosphate, which inhibits phosphoribosyl pyrophosphate (PRPP) amidotransferase, the rate-limiting enzyme in purine synthesis. It also inhibits the conversion of IMP to adenylosuccinic acid and xanthylic acid and blocks AMP formation in vitro. 6-MP (30 mg/kg) inhibits growth of sarcoma 180, adenocarcinoma E 0771, and adenocarcinoma 755 tumors and reduces the size of leukemia L1210 subcutaneous growths in mice. It also decreases delayed-type hypersensitivity and thyroid inflammation in a guinea pig model of thyroiditis when administered pre- or post-disease onset. Formulations containing mercaptopurine have been used for maintenance therapy in patients with acute lymphoblastic leukemia.

Химические свойства

white to light yellow crystal powder

Использование

An immunosuppressive drug used to treat leukemia. It is also used for pediatric non-Hodgkin lymphoma, polycythemia vera, and psoriatic arthritis

Показания

Mercaptopurine (Purinethol) is an analogue of hypoxanthine and was one of the first agents shown to be active against acute leukemias. It is now used as part of maintenance therapy in acute lymphoblastic leukemia. Mercaptopurine must be activated to a nucleotide by the enzyme HGPRTase. This metabolite is capable of inhibiting the synthesis of the normal purines adenine and guanine at the initial aminotransferase step and inhibiting the conversion of inosinic acid to the nucleotides adenylate and guanylate at several steps. Some mercaptopurine is also incorporated into DNA in the form of thioguanine. The relative significance of these mechanisms to the antitumor action of mercaptopurine is not clear.
Resistance to mercaptopurine may be a result of decreased drug activation by HGPRTase or increased inactivation by alkaline phosphatase.
The plasma half-life of an intravenous bolus injection of mercaptopurine is 21 minutes in children and 47 minutes in adults. After oral administration, peak plasma levels are attained within 2 hours. The drug is 20% bound to plasma proteins and does not enter the CSF. Xanthine oxidase is the primary enzyme involved in the metabolic inactivation of mercaptopurine.
Mercaptopurine is used in the maintenance therapy of acute lymphoblastic leukemia. It also displays activity against acute and chronic myelogenous leukemias.
The major toxicities of mercaptopurine are myelosuppression, nausea, vomiting, and hepatic toxicity.

Общее описание

Odorless light yellow to yellow crystalline powder. Becomes anhydrous at 284°F.

Реакции воздуха и воды

6-Mercaptopurine monohydrate is sensitive to light and oxidation. Insoluble in water.

Профиль реактивности

6-Mercaptopurine monohydrate reacts with strong oxidizing agents, strong bases and strong acids.

Пожароопасность

Flash point data for 6-Mercaptopurine monohydrate are not available. 6-Mercaptopurine monohydrate is probably combustible.

Механизм действия

Because the major mechanism of action of mercaptopurine is inhibition of de novo purine nucleotide biosynthesis rather than apoptosis secondary to the incorporation of false nucleotides into DNA, there is a lower risk for mutagenesis and secondary malignancy compared to thioguanine.

Клиническое использование

Mercaptopurine is used in the treatment of acute lymphatic and myelogenous leukemias.

Побочные эффекты

Bone marrow suppression is the major use-limiting toxicity, although the drug can be hepatotoxic in high doses. Dosage adjustments should be considered in the face of renal or hepatic impairment.

Метаболизм

It is available in an oral dosage form, but absorption can be erratic and is reduced by the presence of food. The drug is extensively metabolized on first pass and excreted by the kidneys.

Методы очистки

Crystallise 6-mercaptopurine from pyridine (30mL/g), wash it with pyridine, then triturate with water (25mL/g) and adjust to pH 5 by adding M HCl. Recrystallise it by heating, then cooling, the solution. Filter off the solid, wash it with water and dry it at 110o. It has also been crystallised from water (charcoal) as yellow crystals of the monohydrate which become anhydrous on drying at 140o. It has UV: at 230 and 312nm ( 14,000 and 19,600) in 0.1N NaOH; 222 and 327nm ( 9,2400 max and 21,300), and 216 and 329nm ( 8,740 and 19,300) in MeOH. It forms a 1:1 complex with Zn2+ , Pb2+ , Co2+, and Ni2+ in aqueous dioxan. It is an antineoplastic. [Albert & Brown J Chem Soc 2060 1954, IR: Brown & Mason J Chem Soc 682 1957, UV: Fox et al. J Am Chem Soc 80 1669 1958, UV: Mason J Chem Soc 2071 1954, Beilstein 26 III/IV 2097.]