RESUMEN
For a number of cytotoxics, a relationship between efficacy and plasma concentrations has recently been demonstrated. Lean body mass has been demonstrated to be a useful parameter for predicting drug clearance for a number of non-cytotoxic drugs. However, the role of lean body mass in predicting drug clearance for any cytotoxic drug has not been previously reported. Our purpose was to investigate lean body mass as a predictor of epirubicin clearance. Pharmacokinetic studies were performed in 10 patients receiving single agent epirubicin. Although preliminary, this study suggests that lean body should be further evaluated and tested in dose optimization studies.
Asunto(s)
Superficie Corporal , Peso Corporal/fisiología , Epirrubicina/farmacocinética , Índice de Masa Corporal , Epirrubicina/sangre , Epirrubicina/toxicidad , Humanos , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismo , Espectrofotometría AtómicaRESUMEN
Blood-brain barrier disruption with a hyperosmolar agent, mannitol, has previously been demonstrated to increase intracerebral methotrexate levels in rats. To determine the optimum conditions for blood-brain barrier disruption without producing neurological sequelae, adult Sprague-Dawley rats were infused with mannitol via the internal carotid artery at rates varying from 0.25 to 0.5 ml.s-1.kg-1. Methotrexate and Evans blue were used as markers of blood-brain barrier disruption. The optimum rate of mannitol that produced blood-brain barrier disruption without neurological sequelae was 0.25 ml.s-1.kg-1 for 20 s. The duration of blood-brain barrier opening was maximal for approximately 5 min and then rapidly reversed. Methotrexate levels on the mannitol-infused side were four to five times that of the noninfused hemisphere. Light microscopy and electron microscopy did not demonstrate any consistent changes that could be attributed to blood-brain barrier disruption nor did it elucidate the mechanism. This model should prove useful in the investigation of the treatment of intracerebral tumors with blood-brain barrier disruption. This study shows that maximal intracerebral methotrexate levels were obtained when methotrexate was infused before or within 5 min of the mannitol infusion.