カルボプラチン

外観

白色～灰色、結晶性粉末～粉末

溶解性

水にやや溶けにくく、アセトン及びエタノール(99.5)に極めて溶けにくい。

用途

DNA 鎖内及び鎖間の白金 -DNA 架橋を形成し、DNA の複製及び転写阻 害作用を示します。

効能

抗悪性腫瘍薬, 細胞増殖阻害薬

商品名

パラプラチン (ブリストル・マイヤーズスクイブ)

説明

Carboplatin is a second generation, platinum-containing antineoplastic agent with significantly reduced nephro-, neuro-, and ototoxicity in comparison to cisplatin. It is effective in the treatment of advanced ovarian carcinoma of epithelial origin and small cell carcinoma of the lung.

化学的特性

White Crystals

使用

Data on carboplatin production have not been found. Carboplatin is used in chemotherapy to treat cancer, and more particularly to treat cancer of ovary, embryonal carcinoma of the testis, microcellular carcinoma of the lung, neuroblastoma, and squamous cell carcinomas of the head and neck.

適応症

Carboplatin (Paraplatin) is an analogue of cisplatin. Its plasma half-life is 3 to 5 hours, and it has no significant protein binding. Renal excretion is the major route of drug elimination.
Despite its lower chemical reactivity, carboplatin has antitumor activity that is similar to that of cisplatin against ovarian carcinomas, small cell lung cancers, and germ cell cancers of the testis. Most tumors that are resistant to cisplatin are cross-resistant to carboplatin.
The major advantage of carboplatin over cisplatin is a markedly reduced risk of toxicity to the kidneys, peripheral nerves, and hearing; additionally, it produces less nausea and vomiting. It is, however, more myelosuppressive than cisplatin. Other adverse effects include anemia, abnormal liver function tests, and occasional allergic reactions.

一般的な説明

Carboplatin is available in 50-, 150-, and 450-mg vials for IVadministration in the treatment of ovarian cancer, bladdercancer, germ cell tumors, head and neck cancers, small celllung cancer, and NSCLC. Activation of the agent occurs byaquation in a manner similar to that seen for cisplatin. Thepresence of the chelating 1,1-cyclobutane-dicarboxylateslows this reaction 100-fold and reduces the toxicity of theagent. The sites of alkylation and mechanisms of resistanceare like those seen for cisplatin, and the two agents showcross-resistance. The agent is widely distributed upon IV administration but, because of its greater stability, it bindsslowly to plasma proteins, requiring 24 hours to reach 90%bound drug compared with 4 hours for cisplatin. The agent iseliminated in the urine with a terminal elimination half-lifeof 2 to 6 hours. Adverse effects include myelosuppression,which is dose limiting. Other adverse effects include renaltoxicity, nausea, vomiting, and peripheral neuropathy, butthese occur much less frequently than with cisplatin.

応用例（製薬）

Carboplatin, cis-diammine(1,1-cyclobutanedicarboxylato)platinum(II), is a second-generation platinum drug. Its structure is based on cisplatin with the difference that the chloride ligands are exchanged for a bidentate chelating ligand. A consequence is that carboplatin is less reactive than cisplatin and therefore is less nephrotoxic and orthotoxic than the parent compound. Unfortunately, it is more myelosuppressive than cisplatin, which reduces the patients’ white blood cell count and makes them susceptible to infections. Carboplatin was licensed by the FDA in 1989 under the brand name Paraplatin and has since then gained worldwide recognition. Carboplatin on its own or in combination with other anticancer agents is used in the treatment of a variety of cancer types including head and neck, ovarian, small-cell lung, testicular cancer and others.
Carboplatin is a pale-white solid showing good aqueous solubility. The synthesis starts with potassium tetrachloroplatinate, which is reacted to the orange [PtI₄]^2- anion.

生物活性

Antitumor agent that forms platinum-DNA adducts. Causes intra- and interstrand DNA crosslinks blocking DNA replication and transcription. Enhances radiation-induced single-strand DNA breakage and displays lower nephrotoxicity than analog cisplatin (cis-Diaminodichloroplatinum ).

作用機序

Carboplatin, another square planar Pt(II) complex, forms the same cytotoxic hydrated intermediate as cisplatin but does so at a slower rate, making it a less potent chemotherapeutic agent.

臨床応用

This drug induces fewer nonhematological toxicities (e.g., emesis, nephrotoxicity, and ototoxicity) compared to cisplatin, and it is approved for use only in the treatment of ovarian cancer. Unlabeled uses include combination therapy in lung, testicular, and head and neck cancers.

副作用

The ultimate damage done to cells as a result of carboplatin use, however, approaches that of cisplatin. The plasma half-life of carboplatin is 3 hours, and the drug is less extensively bound to serum proteins. Excretion is predominantly renal, and doses must be reduced in patients with kidney disease. Suppression of platelets and white blood cells is the most significant toxic reaction of carboplatin use.