DrugLib.com — Drug Information Portal

Rx drug information, pharmaceutical research, clinical trials, news, and more

Mitosol (Mitomycin) - Description and Clinical Pharmacology

 
 



DESCRIPTION

Mitomycin is an antibiotic isolated from the broth of Streptomyces verticillus Yingtanensis which has been shown to have antimetabolic activity.

Mitomycin is a blue-violet crystalline powder with the molecular formula of C15H18N405 and a molecular weight of 334.33. Its chemical name is 7-amino-9α-methoxymitosane and it has the following structural formula:

Mitosol® is a sterile lyophiliized mixture of mitomycin and mannitol, which, when reconstituted with Sterile Water for Injection, provides a solution for application in glaucoma filtration surgery. Mitosol® is supplied in vials containing 0.2 mg of mitomycin. Each vial also contains mannitol 0.4 mg, at a 1:2 ratio of mitomycin to mannitol. Each mL of reconstituted solution contains 0.2 mg mitomycin and has a pH between 5.0 and 8.0.

CLINICAL PHARMACOLOGY

Mechanism of Action

Mitosol® inhibits the synthesis of deoxyribonucleic acid (DNA). The guanine and cytosine content correlates with the degree of mitomycin-induced cross-linking. Cellular RNA and protein synthesis may also be suppressed.

Pharmacokinetics

Absorption

The systemic exposure of mitomycin following ocular administration of Mitosol® in humans is unknown. Based on a comparison of the proposed dose of up to 0.2 mg to intravenous (IV) doses of mitomycin used clinically for treatment of oncologic indications (up to 20 mg/m2), systemic concentrations in humans upon ocular administration are expected to be multiple orders of magnitude lower than those achieved by IV administration.

Metabolism

In humans, mitomycin is cleared from ophthalmic tissue after intraoperative topical application and irrigation, as metabolism occurs in other affected tissues. Systemic clearance is affected primarily by metabolism in the liver. The rate of clearance is inversely proportional to the maximal serum concentration because of saturation of the degradative pathways.

Excretion

Approximately 10% of an injectable dose of mitomycin is excreted unchanged in the urine. Since metabolic pathways are saturated at relatively low doses, the percent of a dose excreted in urine increases.

NONCLINICAL TOXICOLOGY

Carcinogenesis, Mutagenesis, Impairment of Fertility

Adequate long-term studies in animals to evaluate carcinogenic potential have not been conducted with Mitosol®. Intravenous administration of mitomycin has been found to be carcinogenic in rats and mice. At doses approximating the recommended clinical injectable dose in humans, mitomycin produces a greater than 100 percent increase in tumor incidence in male Sprague-Dawley rats, and a greater than 50 percent increase in tumor incidence in female Swiss mice. The effect of Mitosol® on fertility is unknown.

CLINICAL STUDIES

In placebo-controlled studies reported in the medical literature, mitomycin reduced intraocular pressure (IOP) by 3 mmHg in patients with open-angle glaucoma when used as an adjunct to ab externo glaucoma surgery by Month 12. In studies with a historical control reported in the medical literature, mitomycin reduced intraocular pressure (IOP) by 5 mmHg in patients with open-angle glaucoma when used as an adjunct to ab externo glaucoma surgery by Month 12.

-- advertisement -- The American Red Cross
 
Home | About Us | Contact Us | Site usage policy | Privacy policy

All Rights reserved - Copyright DrugLib.com, 2006-2017