phenanthrenes and Hypotension

The main objective of the present study was to evaluate the reduction in halofantrine (Hf) toxicity, an antimalarial drug frequently associated with QT interval prolongation in electrocardiogram, by its entrapment in poly-epsilon-caprolactone nanocapsules (NC). The acute lethal dose (LD(100)) of Hf.HCl experimentally observed was 200 mg/kg whereas the calculated LD(50) was 154 mg/kg. In contrast, the LD(100) for Hf-NC was 300 mg/kg with a longer mean time to death than Hf.HCl. The calculated LD(50) was 249 mg/kg for Hf-NC. The Hf entrapped in PCL NC presented a greater efficacy than PLA-PEG NC and than Hf solution in P. berghei-infected mice at 1 mg/kg. The cardiovascular parameters, ECG and arterial blood pressure, were evaluated in anaesthetized Wistar rats after the IV administration of a single, especially high dose (100 and 150 mg/kg) of halofantrine base loaded-nanocapsules (Hf-NC) or halofantrine chlorhydrate (Hf.HCl) solution. It was observed that Hf solution caused prolongation of the QT and PR intervals of the ECG; however, this effect was significantly (P<0.001) reduced when Hf was administered entrapped in nanocapsules. The treatment with Hf.HCl induced a pronounced bradycardia and severe hypotension leading to death. The effect of Hf-NC upon heart rate was reduced from 58 to 75% for 100 and 150 mg/kg, respectively, when compared with Hf.HCl solution. These findings show that the encapsulation of halofantrine reduces the QT interval prolongation of ECG in rats and suggest that a modification of drug distribution was possible by using nanocapsules. Hf encapsulation was the main factor responsible for the significant reduction in cardiac toxicity observed.

Topics: Animals; Antimalarials; Bradycardia; Disease Models, Animal; Dose-Response Relationship, Drug; Electrocardiography; Heart; Hypotension; Lethal Dose 50; Long QT Syndrome; Malaria; Male; Mice; Nanocapsules; Phenanthrenes; Plasmodium berghei; Rats; Rats, Wistar

A phase II evaluation of bruceantin was carried out in 15 patients with refractory metastatic breast cancer. All patients had received extensive prior therapy including adriamycin, cytoxan, 5-FU, methotrexate, and a vinca alkaloid. Except for two patients with stable disease, no complete or partial response was observed. Drug toxicity, mainly nonhematologic, was severe, with nausea, vomiting, mild hypotension, and fever being the most frequently encountered.

Topics: Adult; Aged; Antineoplastic Agents, Phytogenic; Breast Neoplasms; Drug Evaluation; Female; Glaucarubin; Humans; Hypotension; Leukocyte Count; Middle Aged; Nausea; Neoplasm Metastasis; Phenanthrenes; Quassins; Vomiting

During the phase I clinical trial of a new antitumor agent, bruceantin, the pharmacology was studied in 18 cancer patients. The drug was infused intravenously (IV) for 3 h at doses ranging from 1 to 3.6 mg/m2 per day for 5 days. The plasma drug disappearance curves were biphasic, with a fast initial half-life of less than 15 min. The second half-life (t1/2 beta) varied from 0.7 to 38 h among different patients and was not dose-related. The difference between the t1/2 beta on day 1 and that on day 5 was not significant. In patients with normal liver function, the mean plasma concentration at the end of infusion was 22 ng/ml, and the value of the area under the concentration X time curve (AUC) was 111 (ng/ml)h. In contrast, in patients with abnormal liver function the corresponding values were 115 ng/ml and 830 (ng/ml)h, respectively. In addition, these patients had a slower elimination half-life of 10.9 h and a decreased total clearance of 157 ml/min/m2, as compared with 2.6 h and 671 ml/min/m2, respectively, for the normal group. All these differences were statistically significant. Patients with abnormal liver function developed more severe toxicity, including fever, severe nausea, vomiting, and hypotension. Two patients with severe hepatic dysfunction received a reduced dose and developed no toxicity. These results demonstrated the importance of the effects of liver dysfunction on drug disposition and showed that the dosage should be reduced in patients with hepatic dysfunction.

Topics: Antineoplastic Agents, Phytogenic; Drug Evaluation; Glaucarubin; Half-Life; Humans; Hypotension; Infusions, Parenteral; Liver; Neoplasms; Phenanthrenes; Quassins; Radioimmunoassay