ブレオマイシン 化学特性,用途語,生産方法
効能
抗生物質, 抗悪性腫瘍薬
説明
Bleomycin is a complex of no less than 16 glycopeptide antibiotics made from the family Streptomyces verticilus, which have different R groups. Bleomycines exhibit
antitumor, antiviral, and antibacterial activity. When bound to DNA, they disturb the spiraling of both single and double strands of DNA. To a lesser degree, they inhibit RNA and
protein synthesis. It is administered both intravenously and intramuscularly.
使用
Bleomycin sulfate USP (Blenoxane)is used to traet squamous cell carcinoma of head, neck, esophagus, skin, GU tract; testicular tumor; Hodgkin’s lymphomas.
適応症
The bleomycins are a group of glycopeptides that are
isolated from Streptomyces verticillus. The clinical
preparation, bleomycin sulfate (Blenoxane), is a mixture
of several components. Bleomycin binds to DNA,
in part through an intercalation mechanism, without
markedly altering the secondary structure of the nucleic
acid. The drug produces both single- and double-strand
scission and fragmentation of DNA. It is thought that
the bleomycins, which are avid metal-chelating agents,
form a bleomycin–Fe ++ complex that can donate electrons
to molecular oxygen, thus forming the superoxide
and hydroxyl free radicals. It is these highly reactive intermediates
that attack DNA and produce DNA strand
breakage and maximum cytotoxicity in the late G2 and
early M-phases of the cell cycle.
定義
A species of
bleomycin noted for its adverse pulmonary effects
in humans. It is a complex of related glycopeptide
antibiotics from Streptomyces verticillus consisting
of bleomycin A2 and B2.
一般的な説明
Bleomycin is a glycopeptide antibiotic complex isolatedfrom Streptomyces verticillus initially by Umezawa.Atleast 13 different fractions of bleomycin have been isolatedwith the clinically used product (Blenoxane) being a mixtureof predominantly A2
2 (55%–70%) and B
2 (25%–32%)fractions.Of these fractions, A
2 appears to possessthe greatest antineoplastic activity. Copper is found inthe naturally occurring material, and its removal is importantfor the material used clinically because it significantlyreduces activity.
Bleomycin is notable for its lack of myelotoxicity, andthis allows it to be combined with other myelosuppressantswithout a resulting additive effect. The acute toxicities seenwith bleomycin are erythema (reddening of the skin), hyperpigmentation(skin darkening) found predominately on theextremities, and pulmonary toxicity. The pulmonary toxicitymay first occur as pneumonitis (inflammation of lung tissue),which normally responds to glucocorticosteroid therapy.Chronic pulmonary toxicity is expressed as pulmonaryfibrosis, which is irreversible and limits utility of the agent.
空気と水の反応
Water soluble
危険性
Possible carcinogen.
火災危険
Flash point data for Bleomycin are not available. Bleomycin is probably nonflammable.
作用機序
Bleomycin is poorly absorbed orally, but it can be
given by various parenteral routes. Its plasma half-life is
not affected by renal dysfunction as long as creatinine
clearance is greater than 35 mL/minute.
Bleomycin hydrolase, which inactivates bleomycin,
is an enzyme that is abundant in liver and kidney but
virtually absent in lungs and skin; the latter two organs
are the major targets of bleomycin toxicity. It is thought
that bleomycin-induced dermal and pulmonary toxicities
are related to the persistence of relatively high local
concentrations of active drug.
臨床応用
Bleomycin, in combination with cisplatin or etoposide,
is important as part of the potentially curative
combination chemotherapy of advanced testicular carcinomas.
Bleomycin is used in some standard regimens
for the treatment of Hodgkin’s and non-Hodgkin’s lymphomas,
and it is useful against squamous cell carcinomas
of the head and neck, cervix, and skin.
副作用
A potentially fatal lung toxicity occurs in 10 to 20%
of patients receiving bleomycin. Patients particularly at
risk are those who are over 70 years of age and have
had radiation therapy to the chest. Rarely, bleomycin
also may cause allergic pneumonitis. Bleomycin skin
toxicity is manifested by hyperpigmentation, erythematosus
rashes, and thickening of the skin over the
dorsum of the hands and at dermal pressure points,
such as the elbows. Many patients develop a low-grade
transient fever within 24 hours of receiving bleomycin.
Less common adverse effects include mucositis, alopecia,
headache, nausea, and arteritis of the distal extremities.
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