Kinetics of cisplatin in an anuric patient undergoing hemofiltration dialysis

After in vitro tests, a tracer dose of cisplatin was administered to an anuric cancer patient. Plasma total platinum levels were monitored as a function of time, as was filterable platinum elimination by hemofiltration dialysis. Based on the derived pharmacokinetic parameters, the patient was later given 50-mg doses of cisplatin, once as a single agent, then four times in combination with doxorubicin, VM-26, and cyclophosphamide. Plasma levels could be fitted by a sum of three exponentials after the infusion was stopped. The mean corresponding half-lives are 30 minutes, 6 hours, and 5 days. Depending on the rate of infusion, plasma peaks ranged between 1.1 micrograms/ml (5.7 X 10(-6) M) and 2.27 micrograms/ml (1.16 X 10(-5) M). During the hemofiltration process immediately following the infusion, the elimination rate was first-order, with a mean half-life of 60 minutes. The mean amount eliminated during the first hemofiltration session was 8% of the dose, decreasing to about 3% on Days 2 and 3. A partial tumor response was observed after two treatment courses, evidenced by the relief of abdominal pain and bowel obstruction episodes and a 50% decrease in peritoneal metastases.

Metabolism and disposition studies of 9-hydroxyellipticine and 2-methyl-9-hydroxyellipticinium acetate in animals

Radiolabeled 9-hydroxyellipticine (iv and ip routes) and the corresponding radioactive quaternary salt, 2-methyl-9-hydroxyellipticinium acetate (iv route), were administered to mice. Tissue distribution was then followed up to 64 hours by means of autoradiography. Both drugs accumulated in the kidneys, lungs, and liver; 9-hydroxyellipticine also accumulated in the spleen and bone marrow. The quaternary salt was concentrated in the gastrointestinal walls and the salivary and thyroid glands; none was found in the brain. Metabolic studies after administration of these antitumor drugs to rats and mice showed that 9-hydroxyellipticine is extensively metabolized, mainly to its glucuronide. Under our experimental conditions, the ellipticinium derivative was excreted unchanged in the bile (70%) and in the urine (30%). Pharmacokinetic studies in mice using either radioactivity measurements or selective extraction followed by spectrofluorometric quantitation have shown that blood levels drop very rapidly during the distribution phase followed by a much slower disposition phase, with a half-life of about 30 hours for the quaternary salt.

Stability and preliminary pharmacokinetic studies of 1-(2-chloroethyl)-3-[1-(5'-paranitrobenzoyl-2',3'-isopropylidene)-alpha, beta-D-ribofuranosyl]-1-nitrosourea (RFCNU), a nonimmunosuppressive nitrosourea

Using high-performance liquid chromatography, the stability of RFCNU was monitored as a function of pH in aqueous buffers at 37 degrees C and as a function of temperature in plasma. The kinetics of degradation of RFCNU are apparently first-order. The log kappa-pH profile demonstrated the hydroxyl ion-catalyzed solvolysis and a maximum stability around pH 3.0. This analytic assay was reliable for quantitating intact RFCNU in biologic fluids. After administration of 400 mg of RFCNU orally to a female patient, no intact drug was excreted in the urine and plasma levels were very low.