Although to present such variation, they possess, in common, insaturados rings that allow to the incorporation of electron excess and the consequent production of reactive free radicals. They can present another functional group that adds them new mechanisms of action, as alquilao (mitomicina C), enzymatic inhibition (actinomicina-D and mitramicina), or inhibition of the function of the DNA for intercalation (bleomicina, daunorrubicina and adriamicina and its analogous mitroxantona). As all the quimioterpicos, the antibiotics act in such a way on the malignant cells as on the normal ones. Therefore, also they present the calls collateral effect undesirable (Control of the cancer, 2006). The mitticos inhibitors can paralyze mitose in metfase, due to its action on the tubulina, formadora protein of microtbulos that constitute the spindle to espiralar, for which the chromosomes migram. In this way, the chromosomes, during metfase, are hindered of migrar, occurring the interruption of the cellular division (Control of the cancer, 2006).
This function has been useful in ‘ ‘ sincronizao’ ‘ of the cells when the mitticos inhibitors are combined with specific agents of phase S of the cycle. Had to its way of specific action, the mitticos inhibitors must be associates to other agents for bigger effectiveness of the chemotherapy In this group of drugs are enclosed the alkalis of wrinkle rsea (vincristina, vimblastina and vindesina) and the derivatives of the podofilotoxina (OV-16, etoposdeo; the VM-26, teniposdeo) (Control of the cancer, 2006) .2.3. The development of FrmacosDo clinical point of view, is important the development of frmacos with action on the intermediate metabolism of the cells in proliferation, therefore these agents are very studied and clinically used.