Carboplatin in the body

Carboplatin binds to DNA damages the DNA in a cell. The DNA damage caused by carboplatin results in cell death. It is an "alkylating agent". The platinum agents form strong chemical bonds with thiol sulfurs and amino nitrogens in proteins and nucleic acids. Platinum and platinum complexes and compounds find use in industry in alkylation reactions too.

The development of carboplatin followed a familiar pattern. Cisplatin was introduced in the 1960s and found success in the 70s and 80s. When drugs are successful, researchers frequently attempt to improve on them by producing related compounds. These analogs, if they prove effective, are developed as drugs in themselves and are called second-generation drugs.

Analogs often improve on the original drugs, whether by being more effective, having fewer or milder side effects, and by being effective against strains of the disease that have become resistant to the original drug (this often happens when the pathogen is a fast changing bacteria or virus.) Sometimes analogs can be taken more easily, too, such as orally rather and intravenously.

Analogs of cisplatin include carboplatin, spiroplatin, and iproplatin, Carboplatin has been the most successful of these second-generation drugs.

Carboplatin and cisplatin work in similar ways, forming an identical type of adduct with DNA. They attack tumors similarly but carboplatin is less toxic to the nervous system and the kidneys. Carboplatin also stays in the body longer. It has a half-life of 30 hours versus cisplatin’s 3 hours. Lower doses can be given to get the same effect on the tumor, and this reduces the challenge to the rest of the body.

Inside the body carboplatin undergoes a chemical reaction with water intracellularly resulting in the generation of a positively charged aquated species that attacks nucleophilic sites on DNA. This is the "alkylation" action of carboplatin, that hinders the growth of the tumor by stoping division of cancer cells. Chemotherapy with cytotoxic anticancer agents is a mainstay of cancer treatment.

More on treatment with carboplatin.