A liquid chromatography-tandem mass spectrometric assay for the antihypertensive agent azelnidipine in human plasma with application to clinical pharmacokinetics studies.

A robust and sensitive high-performance liquid chromatographic-tandem mass spectrometric (HPLC-MS/MS) assay for the high-throughput quantification of the antihypertensive drug azelnidipine in human plasma was developed and validated following bioanalytical validation guidelines. Azelnidipine and internal standard (IS), telmisartan, were extracted from human plasma by precipitation protein and separated on a C18 column using acetonitrile-methanol-ammonium formate with 0.1% formic acid as mobile phase. Detection was performed on a turbo-spray ionization source (ESI) and mass spectrometric positive multiple reaction monitoring mode (+MRM) using the respective transitions m/z 583.3 → 167.2 for azelnidipine and m/z 515.3 → 497.2 for IS. The method has a wide analytical measuring range from 0.0125 to 25 ng/mL. For the lowest limit of quantitation, low, medium and high quality controls, intra- and interassay precisions (relative standard deviation) were 3.30-7.01% and 1.78-8.09%, respectively. The drug was sufficiently stable under all relevant analytical conditions. The main metabolite of azelnidipine, M-1 (aromatized form), was monitored semiquantitatively using the typical transition m/z 581.3 → 167.2. Finally, the method was successfully applied to a clinical pharmacokinetic study in human after a single oral administration of azelnidipine 8 mg. The assay meets criteria for the analysis of samples from large research trials.

In vitro enzyme-mimic activity and in vivo therapeutic potential of HSJ-0017, a novel Mn porphyrin-based antioxidant enzyme mimic.

Manganese (III) 5, 10, 15, 20-tetrakis [3-(2-(2-methoxy)-ethoxy) ethoxy] phenyl porphyrin chloride, designated HSJ-0017, is a novel antioxidant enzyme mimic. The aim of the present study was to investigate the enzyme-mimic activity and the therapeutic potential of HSJ-0017 in free radical-related diseases. Superoxide dismutase (SOD) mimic activity was measured by the nitroblue tetrazolium chloride monohydrate reduction assay. Catalase (CAT) mimic activity was measured based on the decomposition of hydrogen peroxide. The antitumor, radioprotective and chemoprotective effects of HSJ-0017 were evaluated in H22 or S180 tumor-bearing Kunming mice. The anti-inflammatory and hepatoprotective effects were, respectively, evaluated in histamine-induced edema model and CCl4-induced hepatic damage model in Wistar rats. HSJ-0017 over a concentration range of 0.001-10 µmol/L significantly inhibited the generation of superoxide anion. Significant hydrogen peroxide scavenging activity was observed when the concentration of HSJ-0017 was higher than 0.01 µmol/L. HSJ-0017 at a dose of 3.0 mg/kg exhibited significant antitumor effect on S180 tumor xenografts, whereas no significant antitumor effect was observed in H22 tumor xenografts. HSJ-0017 at a dose of 3.0 mg/kg enhanced the antitumor effects of radiotherapy and chemotherapy, and reduced their toxicity. However, HSJ-0017 counteracted the antitumor effects of radiotherapy when administered simultaneously with radiotherapy. HSJ-0017 showed significant anti-inflammatory and hepatoprotective effects. Our results demonstrate that HSJ-0017 exhibits antioxidant, antitumor, anti-inflammatory, radioprotective, chemoprotective, and hepatoprotective effects. It is a potent dual SOD/CAT mimic.

Pharmacokinetics, tissue distribution and excretion of manganese (III) meso-tetra [3-(2-(2-methoxy)-ethoxy) ethoxy] phenyl porphyrin chloride, a novel superoxide dismutase mimic, in Wistar rats.

Manganese (III) 5, 10, 15, 20-tetrakis [3-(2-(2-methoxy)-ethoxy) ethoxy] phenyl porphyrin chloride, designated HSJ-0017, is a novel superoxide dismutase mimic. It exhibits strong free-radical scavenging activities in vitro and in vivo. The aim of the present study was to investigate the pharmacokinetics, tissue distribution and excretion of HSJ-0017 in Wistar rats following a single intravenous administration. Wistar rats were given different doses of HSJ-0017 by single intravenous injection. Biological samples of rats were collected and were assayed by the HPLC method. The pharmacokinetics, tissue distribution and excretion of HSJ-0017 were investigated. The pharmacokinetic data of HSJ-0017 in rats following intravenous injection was best-fit by a two-compartment model. T max of HSJ-0017 in plasma following intravenous injection was 0.083 h. AUC and plasma drug concentration were found to increase in a dose-related fashion. The highest concentrations of HSJ-0017 were detected in the liver (82.25 ± 13.99 µg/g) of rats, followed by the kidney, small intestine, lung, plasma, heart, spleen, and stomach within 2 h postdose. No HSJ-0017 was detected in the uterus, parorchis or brain of rats during the 24-h period of examination. The total cumulative excretion of HSJ-0017 in rat bile and urine were found to be 78.85 and 67.58 %, respectively. Our study has led to the view that the HSJ-0017 can be rapidly distributed to tissues after intravenous administration, but cannot diffuse through the blood-brain barrier. The faecal and biliary excretion of unchanged HSJ-0017 are the major routes of HSJ-0017 elimination.

Systemic toxicity and toxicokinetics of a high dose of polyethylene glycol 400 in dogs following intravenous injection.

Polyethylene glycol 400 (PEG-400) has been used in injections. However, limited data are available concerning the toxicity of a high dose of PEG-400 following intravenous (i.v.) injection. The aim of the present study was to estimate the systemic toxicity and toxicokinetics of a high dose of PEG-400 in dogs following i.v. injection. Twenty-four dogs were divided into four groups: a control group receiving normal saline and three test groups receiving 4.23, 6.34, and 8.45 g/kg of PEG-400, respectively, by i.v. injection once a day for 30 days. The repeated-dose toxicity of PEG-400 was assessed. Toxicokinetic parameters of PEG-400 in dogs were estimated on days 1 and 30. Dry mouth and dry nasal mucus membrane were observed in dogs treated with 6.34 and 8.45 g/kg of PEG-400. Cloudy swelling of kidney cell and increased glomerular volume were observed in dogs treated with 8.45 g/kg of PEG-400 when the animals were sacrificed 24 hours after the last injection. No significant histological changes were found 21 days later. Repeated dosing did not affect the toxicokinetic profile of PEG-400 in dogs. This study has shown that the toxicity of a high dose of PEG-400 following repeated intravenous injections is low, and alterations produced are reversible.

Systemic toxicity of non-cell corynebacterium parvum (CP) in monkeys.

AIM: Non-cell corynebacterium parvum product (NCPP) is a new preparation of corynebacterium parvum (CP), an immunomodulator that displays anticancer activities. It is prepared by nanotechnology and is intended to minimize the side effects of CP. The aim of the present study was to evaluate the immunogenicity and systemic toxicity of NCPP compared with CP in animals. METHODS: 30 monkeys were randomly divided into 5 groups and given CP (3 mg/monkey), three doses of NCPP (9, 3, 1 mg/monkey) and 0.9% normal saline (NS, 4 ml/monkey) individually by intramuscular injection twice a week for 13 weeks. The immunogenicity and systemic toxicity of NCPP and CP were compared. RESULTS: NCCP and CP caused histopathological changes in the liver, spleen and kidney, but pathologic changes in NCCP-treated groups were slighter than that in the CP group. Only 9 mg/monkey of NCPP caused the similar damage as the CP in intensity. Deposition of immune complexes in the glomerular basement membrane was observed only in the CP group. ELISA detection showed that the anti-CP antibody was at a high level, while the anti-NCPP antibody was at low level and disappeared during the recovery period. CONCLUSION: Our study has led to the view that NCPP is safer than CP.

Role of chlorogenic acid in the toxicity induced by Chinese herbal injections.

Adverse reactions induced by Chinese herbal injections have been frequently reported. However, the precise causes of these adverse reactions are not yet fully understood. The aim of the present study was to determine the role of chlorogenic acid (a ubiquitous component of Chinese herbs) in the toxicity of Chinese herbal injections. Beagle dogs were given chlorogenic acid, Yuxingcao injection, or Qingkailing injection (the latter two both containing chlorogenic acid) by intravenous (i.v.) injection, once a day for 7 or 9 days. The systemic toxicity was evaluated. An additional ultrastructural observation on liver and kidney was performed. Anaphylactoid reactions were obvious in dogs treated with Yuxingcao injection. Varying degrees of ultrastructural changes in liver and kidney were observed in the treated dogs, especially in dogs treated with Chinese herbal injections. Our study has led to the view that chlorogenic acid is not an allergen when administrated by i.v. injection, but liver and kidney injury induced by Chinese herbal injections can be partly attributed to chlorogenic acid.

Effect of route of administration on the pharmacokinetics and toxicokinetics of cinnarizine in dogs.

AIMS: Cinnarizine, a piperazine derivative, is currently used for the treatment of cerebral thrombosis, cerebral arteriosclerosis, subarachnoid hemorrhage and some other diseases. However, it exhibits variable dissolution and low bioavailability after oral administration. Cinnarizine for injection was developed in order to enhance its bioavailability and make the practice more convenient for patients suffering from dysphagia. The aim of the present study was to compare the pharmacokinetics and toxicokinetics of cinnarizine following intravenous and oral administration in dogs and provide scientific basis for the development of cinnarizine for injection. METHODS: Beagle dogs were given single- or multiple-dose of cinnarizine by oral (single-dose: 10mg/kg; multiple-dose: 21.5, 12.9, 4.3mg/kg) and intravenous (single-dose: 10mg/kg; multiple-dose: 10, 6, 2mg/kg) routes. HPLC was applied to detect the plasma concentration of cinnarizine. The pharmacokinetics and toxicokinetics parameters were calculated and compared. RESULTS: The pharmacokinetics of cinnarizine following oral administration in dogs was found to fit the one-compartment mode. That of cinnarizine following intravenous injection in dogs was found to fit the two-compartment model. The relative bioavailability of oral administration was 46.4%. Cinnarizine cumulated significantly in dogs when 10mg/kg cinnarizine was injected repeatedly. Multiple-dose of cinnarizine over 6mg/kg induced reversible kidney injury in dogs. CONCLUSION: The present study indicates that pharmacokinetics and toxicokinetics properties of cinnarizine for injection show advantages over the oral preparation. But caution should be taken with the cumulative action when cinnarizine is injected and the dose of cinnarizine should be lower than 6mg/kg.

Pharmacokinetics, methionine depletion, and antigenicity of recombinant methioninase in primates.

Pharmacokinetics, methionine depletion, antigenicity, and toxicity of recombinant methioninase (rMETase), which has shown efficacy in achieving cell kill in a broad range of human tumor models, were examined in macaque monkeys. Dose-ranging studies at 1000, 2000, and 4000 units/kg i.v. identified the 4000 units/kg dose as able to reduce plasma methionine to an undetectable level (less than 0.5 microM) by 30 min, and the level so remained for 8 h. Pharmacokinetic analysis showed that rMETase was eliminated with a T(1/2) of 2.49 h. A 2-week i.v. administration of 4000 units/kg every 8 h/day for 2 weeks resulted in a steady-state depletion of plasma methionine to less than 2 microM. The only manifest toxicity was decreased food intake and slight weight loss. Serum albumin and red cell values declined transiently during treatment, which may be related to extensive blood sampling. Re-challenge on day 28 resulted in anaphylactic shock and death in one animal. Subsequent pretreatment with hydrocortisone prevented the anaphylactic reaction, although vomiting was frequently observed. Re-challenge was carried out at days 66, 86, and 116. Anti-rMETase antibodies (at 10(-3)) were found after the first challenge, and these increased to 10(-6) after the fourth challenge and decreased to 10(-2) by 2 months post therapy. The main rMETase antibody was IgG, and although it has some in vitro features of being a neutralizing antibody, each challenge dose was effective in depleting plasma methionine levels. Thus, rMETase was able to effectively deplete plasma methionine levels with minimal toxicity in a primate model. These data provide the bases for alteration by polyethyleneglycol conjugation (PEGylation) of the enzyme to increase its duration of effect and reduce its immunogenicity.