Manufacturing Process

The alkaloid mixture from the extraction of Vinca rosea plants (as in vinblastine extraction) was chromatographed to give vincristine which was then converted to the sulfate, according to US Patent 3,205,220. Vincristine may also be prepared in a semisynthetic process starting from vinblastine. Vinblastine or a salt thereof, preferably the sulfate, is oxidized with chromic acid or with one of its salts at a low temperature, the reaction mixture is neutralized or rendered alkaline and the product is separated therefrom by extraction, the extract is evaporated to dryness, the dry residue is optionally formylated, vincristine, and optionally N-demethylvinblastine also, are isolated from the product, and the product(s) are optionally converted into their salts; preferably into the sulfates, according to US Patent 3,899,493.

Therapeutic Function

Cancer chemotherapy

Air & Water Reactions

Very hygroscopic. Water soluble.

Reactivity Profile

Sensitive to hydrolysis, oxidation and heat. Incompatible with strong oxidizing agents. .

Fire Hazard

Flash point data for Vincristine sulfate are not available; however, Vincristine sulfate is probably combustible.

Biological Activity

Anticancer agent; microtubule disrupter. Induces apoptosis in human lymphoma cells.

Veterinary Drugs and Treatments

Vincristine is used as an antineoplastic primarily in combination drug protocols in dogs and cats in the treatment of lymphoid and hematopoietic neoplasms. In dogs, it may be used alone in the therapy of transmissible venereal neoplasms. Because vincristine can induce thrombocytosis (at low doses) and has some immunosuppressant activity, it may also be employed in the treatment of immune-mediated thrombocytopenia.

Drug interactions

Potentially hazardous interactions with other drugs Antibacterials: possible increased risk of ventricular arrhythmias with delamanid. Antiepileptics: phenytoin levels may be reduced. Antifungals: metabolism possibly inhibited by itraconazole and posaconazole (increased risk of neurotoxicity). Antimalarials: avoid with piperaquine with artenimol. Antipsychotics: avoid concomitant use with clozapine (increased risk of agranulocytosis). Cytotoxics: toxicity possibly increased by asparaginase, crisantaspase and pegasparagase - give at least 3-24 hours before asparaginase, crisantaspase and pegasparagase; increased risk of hepatotoxicity with dactinomycin.

Metabolism

Vincristine is metabolised in the liver by the cytochrome P450 isoenzymes CYP3A4 and CYP3A5 and excreted mainly in the bile; about 70-80% of a dose is found in faeces, as unchanged drug and metabolites (40-50%), while 10-20% appears in the urine.

Purification Methods

The salt is recrystallised from MeOH. It has UV max at 220, 255 and 296nm (log  4.65, 4.21 and 4.18). It is a monoamine oxidase inhibitor and is used in cancer research [Son et al. J Med Chem 33 1845 1990, Horio et al. Proc Natl Acad Sci USA 85 3580 1988].

Brand name

Oncovin (Lilly); Vincasar (Sicor).

General Description

Vincristine sulfate is available as a 1-mg/mL solution in 1-,2-, and 5-mL vials for IV administration in acute leukemiaand as part of a multidrug regime for Hodgkin’s and neuroblastoma, Ewing sarcoma, Wilms tumor, soft tissuesarcoma, testicular cancer, liver cancer, and head and neckcancers. It has also been utilized in treating pediatric cancer.Vincristine is highly protein bound (75%) and may also bindto platelets that contain large amounts of tubulin. Numerousmetabolites have been detected and several have been identified,one of which is the 4-O-desacetyl derivative. The metabolismthat does occur is believed to largely be mediatedby CYP3A. Elimination occurs primarily in the bile with aterminal elimination half-life of 23 to 85 hours. The mostcommonly seen toxicity for vincristine is a dose-limitingneurotoxicity caused by effects on axonal microtubules.Symptoms are variable and include peripheral neuropathy,ataxia, seizure, bone pain, and coma. Constipation is also acommonly seen toxicity, and laxatives may be used prophylactically.Other toxicities include alopecia, skin rash, mildmyelosuppression, secretion of antidiuretic hormone,azospermia, and amenorrhea.