Biomedical subjects

Wim J F van der Vijgh

Publications and source records attributed to Wim J F van der Vijgh.

At least 19 recordsLinked to original sources

PubMed2007

Alpha-tocopheryl phosphate is a novel apoptotic agent.

Alpha-tocopheryl succinate (TOS) is a well-known potent and selective apoptotic agent. This apoptotic activity has been ascribed to its detergent-like property which is also shared by the structurally related compound, alpha-tocopheryl phosphate (TOP). TOP meets the structural requirements that have been described for the apoptotic activity of TO esters, i.e. the combination of three structural, one functional, one signalling and one hydrophobic domain. In this study, we have investigated the effect of TOP on the osteosarcoma cell line MG-63 using TOS as a reference compound. As compared with TOS, TOP showed a higher proliferative and apoptosis inducing activity on the MG-63 cancer cell line. The cytotoxic effect of TOP and TOS seems to be due to the effect of the intact compounds, since only a minor conversion into alpha-tocopheryl (TO) could be detected. EPR experiments showed that TOS and TOP reduced membrane fluidity, whereas TO had no effect. In addition, induction of erythrocyte hemolysis by TOP depended on the pH. These results suggest that the detergent-like activity of these compounds might be involved in their biological effect. Due to the potent biological activities, TOP might be clinically useful.

Apoptosis↗

PubMed2006

Long-term effects of 7-monohydroxyethylrutoside (monoHER) on DOX-induced cardiotoxicity in mice.

Doxorubicin (DOX) is a potent antitumor agent for different types of cancer, but the cumulative, dose-related cardiotoxicity limits its clinical use. The incidence of abnormal cardiac function after treatment with DOX appears to increase with time. Therefore, late cardiotoxicity is-especially in young surviving patients-a major concern. The aim of this study was to evaluate in mice whether the semisynthetic flavonoid 7-monohydroxyethylrutoside (monoHER) also protected against DOX-induced cardiotoxicity after a long period of follow-up. Four groups of 6 Balb/c mice were treated weekly during 6 weeks with saline, DOX alone (4 mg/kg i.v.), DOX preceded by monoHER (500 mg/kg i.p.), or DOX preceded by monoHER followed by long-term weekly monoHER injections during the observation period of 6 months. Half of the mice treated with DOX only developed DOX-induced heart failure and died within 6 months of observation. Two mice co-treated with monoHER showed weight loss and shortness of breath, whereas one mouse was found dead in its cage known with weight loss. The group receiving DOX plus long-term repeated doses of monoHER started to lose weight. Five out of six mice in this group developed shortness of breath and died before the end of the study with symptoms of cardiac failure induced by DOX. Statistical comparison of the histological heart damage between the different experimental groups was not possible, because the animals died at different time-points in the observation period and DOX-induced cardiotoxicity progressed with time. Nevertheless, it was clear that the initial cardioprotective effect of monoHER was not prolonged during the half-year observation period. It was even suggested that addition of repeated doses of monoHER tended to aggravate DOX-induced cardiotoxicity. It cannot be excluded that the dose and frequency of monoHER administration is crucial in obtaining an optimal antioxidant activity without a pro-oxidant activity of monoHER.

Animals↗

PubMed2006

The influence of the time interval between monoHER and doxorubicin administration on the protection against doxorubicin-induced cardiotoxicity in mice.

PURPOSE: Despite its well-known cardiotoxicity, the anthracyclin doxorubicin (DOX) continues to be an effective and widely used chemotherapeutic agent. DOX-induced cardiac damage presumably results from the formation of free radicals by DOX. Reactive oxygen species particularly affect the cardiac myocytes because these cells seem to have a relatively poor antioxidant defense system. The semisynthetic flavonoid monohydroxyethylrutoside (monoHER) showed cardioprotection against DOX-induced cardiotoxicity through its radical scavenging and iron chelating properties. Because of the relatively short final half-life of monoHER (about 30 min), it is expected that the time interval between monoHER and DOX might be of influence on the cardioprotective effect of monoHER. Therefore, the aim of the present study was to investigate this possible effect. METHODS: Six groups of 6 BALB/c mice were treated with saline, DOX alone or DOX (4 mg/kg i.v.) preceded by monoHER (500 mg/kg i.p.) with an interval of 10, 30, 60 or 120 min. After a 6-week treatment period and additional observation for 2 weeks, the mice were sacrificed. Their cardiac tissues were processed for light microscopy, after which cardiomyocyte damage was evaluated according to Billingham (in Cancer Treat Rep 62(6):865-872, 1978). Microscopic evaluation revealed that treatment with DOX alone induced significant cardiac damage in comparison to the saline control group (P<0.001). RESULTS: The number of damaged cardiomyocytes was 9.6-fold (95% CI 4.4-21.0) higher in mice treated with DOX alone than that in animals of the control group. The ratio of aberrant cardiomyocytes in mice treated with DOX preceded by monoHER and those in mice treated with saline ranged from 1.6 to 2.8 (mean 2.2, 95% CI 1.2-4.1, P=0.019). The mean protective effect by adding monoHER before DOX led to a significant 4.4-fold reduction (P<0.001, 95% CI 2.3-8.2) of abnormal cardiomyocytes. This protective effect did not depend on the time interval between monoHER and DOX administration (P=0.345). CONCLUSION: The results indicate that in an outpatient clinical setting monoHER may be administered shortly before DOX.

Animals↗

PubMed2004

Possible (enzymatic) routes and biological sites for metabolic reduction of BNP7787, a new protector against cisplatin-induced side-effects.

Disodium 2,2'-dithio-bis-ethane sulfonate (BNP7787) is under investigation as a potential new chemoprotector against cisplatin-induced nephrotoxicity. The selective protection of BNP7787 appears to arise from the preferential uptake of the drug in the kidneys, where BNP7787 would undergo intracellular conversion into mesna (2-mercapto ethane sulfonate), which in turn can prevent cisplatin induced toxicities. In the present study, we have investigated whether the reduction of BNP7787 into the reactive compound mesna is restricted to the kidney or whether it can also occur in other organs, cells and physiological compartments, including the cytosolic fraction of the renal cortex, plasma, red blood cells (RBCs), liver and small intestine from rats and several tumors (OVCAR-3, MRI-H-207 and WARD). We also determined whether the endogenous thiols glutathione (GSH) and cysteine and the enzyme systems glutaredoxin and thioredoxin, which are all present in the kidney, can be involved in the BNP7787 reduction. UV detection and micro-HPLC with dual electrochemical detection were used to analyze the various incubation mixtures. Our observations are that, in contrast to plasma, a very large reductive conversion of BNP7787 to mesna was measured in RBC lysate. Intact RBCs, however, did not take up BNP7787. Although BNP7787 could be reduced in cytosol of liver and several tumors, this reduction will not be relevant in vivo, since these tissues do not take up large amounts of BNP7787. Kidney cortex cytosol was, similar to the small intestine cytosol, able to substantially reduce BNP7787 to mesna. The ability to reduce BNP7787 in the presence of the endogenous thiols GSH and cysteine, the glutaredoxin system as well as the thioredoxin system, could at least in part explain the high BNP7787 reductive activity of the kidney cortex cytosol. In conclusion, the high reduction of BNP7787 into mesna in the kidney as well as our earlier observation that the distribution of BNP7787 and mesna was mainly restricted to rat kidney are strong arguments in favor of selective protection of the kidney by BNP7787.

Animals↗

PubMed2004

Lecithinized copper,zinc-superoxide dismutase as a protector against doxorubicin-induced cardiotoxicity in mice.

Production of superoxide radicals from doxorubicin is widely accepted to be the cause of the cardiotoxicity induced by this antitumor agent. Pretreatment with superoxide dismutase could improve the therapeutic application. Aim of the present study was to determine whether lecithinized superoxide dismutase (PC-SOD) can serve as a cardioprotective drug during doxorubicin treatment. The protective potential of PC-SOD on doxorubicin-induced cardiotoxicity was investigated in BALB/c mice. The possible influence of PC-SOD on the antitumor activity of doxorubicin was investigated in vitro as well as in vivo. Mice were treated intravenously with doxorubicin (4 mg x kg(-1)) or doxorubicin and PC-SOD (5000, 20000 or 80000 U x kg(-1)) weekly x 6 and appropriate controls were included. Cardiotoxicity was monitored for 8 weeks by ECG measurement. The influence of PC-SOD on the antitumor activity of doxorubicin was evaluated in three human malignant cell lines. Nude mice bearing OVCAR-3 human ovarian cancer xenografts were treated intravenously with doxorubicin (8 mg x kg(-1)) alone or preceded by PC-SOD 20000 or 80000 U x kg(-1) weekly x 2 and appropriate controls were included. PC-SOD prevented doxorubicin-induced cardiotoxicity already at 5000 U x kg(-1) whereas 20000 and 80000 U x kg(-1) were equally protective. No toxicity was observed in mice treated with PC-SOD. PC-SOD did not interfere with the antiproliferative effects of doxorubicin in vitro. In vivo, PC-SOD had no negative effect on the inhibition of xenograft growth induced by doxorubicin. It can be concluded that PC-SOD protects the heart, but not the tumor against doxorubicin. These data suggest that PC-SOD may be a suitable cardioprotector during doxorubicin treatment.

Animals↗

PubMed2004

In vivo reduction of erythrocyte oxidant stress in a murine model of beta-thalassemia.

BACKGROUND AND OBJECTIVES: Oxidant damage is an important contributor to the premature destruction of erythrocytes and anemia in thalassemias. To assess the extent of oxidant damage of circulating erythrocytes and the effects of antioxidant therapy on erythrocyte characteristics and anemia, we used a mouse model of human beta-thalassemia intermedia (b1/b2 deletion). DESIGN AND METHODS: Several parameters indicative of oxidant damage were measured at baseline and following administration of the semi-synthetic flavonoid antioxidant, 7-monohydroxyethylrutoside (monoHER), to beta-thalassemic mice at a dose of either 500 mg/kg i.p. once a day (n=6) or 250 mg/kg i.p. twice a day (n=6) for 21 days. RESULTS: Significant erythrocyte oxidant damage at baseline was indicated by: (i) dehydration, reduced cell K content, and up-regulated K-Cl co-transport; (ii) marked membrane externalization of phosphatidylserine; (iii) reduced plasma and membrane content of vitamin E; and (iv) increased membrane bound IgG. MonoHER treatment increased erythrocyte K content, and markedly improved all cellular indicators of oxidant stress and of lipid membrane peroxidation. While anemia did not improve, monoHER therapy reduced reticulocyte counts, improved survival of a fraction of red cells, and reduced ineffective erythropoiesis with decreased total bilirubin, lactate dehydrogenase and plasma iron. INTERPRETATION AND CONCLUSIONS: Antioxidant therapy reverses several indicators of oxidant damage in vivo. These promising antioxidant effects of monoHER should be investigated further.

Animals↗

PubMed2003

Lipoic acid protects efficiently only against a specific form of peroxynitrite-induced damage.

The ability of the sulfur-containing compounds glutathione (GSH), glutathione disulphide (GSSG), S-methylglutathione (GSMe), lipoic acid (LA), and dihydrolipoic acid (DHLA) to protect against hypochlorous acid (HOCl)-mediated damage and peroxynitrite (ONOOH)-induced damage has been compared. Protective activity was assessed in competition assays by monitoring several detectors, i.e. dihydrorhodamine-123 (DHR-123) oxidation, alpha(1)-antiproteinase (alpha(1)-AP) inactivation, and glutathione S-transferase P1-1 (GST-P1-1) inactivation. In addition, nitration of tyrosine was measured to assess protection of the sulfur-containing compounds against ONOOH. For protection against HOCl, the efficacy of the antioxidant was controlled by the ratio of the reaction rates of the antioxidant and the detector molecule with the oxidant. The rank order of the activity of the antioxidants (GSH > DHLA approximately LA approximately GSMe > GSSG) appeared to be independent of the detector used. However, the rank order of the antioxidants against ONOOH-induced damage is strongly dependent on the detector. LA was 40 times less active than GSH in the inhibition of ONOOH-induced DHR-123 oxidation, whereas LA was 20 times more active than GSH in preventing the inhibition of GST-P1-1 by ONOOH. This points to different molecular mechanisms of ONOOH damage to DHR-123 compared with ONOOH damage to GST-P1-1. LA is a poor antioxidant in protecting against the form of ONOOH damage involved in DHR-123 oxidation. In the form of ONOOH toxicity involved in GST-P1-1 inhibition, LA is the most potent sulfur-containing antioxidant in our series. It is proposed that an intermediate product in which both sulfur atoms of LA have reacted is involved in the reaction of ONOOH with LA. The high potency of LA to protect GST-P1-1 against ONOOH might be of therapeutic interest.

Antioxidants↗

PubMed2003

Tetrahydrofolate and 5-methyltetrahydrofolate are folates with high antioxidant activity. Identification of the antioxidant pharmacophore.

The presumed protective effect of folic acid on the pathogenesis of cardiovascular, hematological and neurological diseases and cancer has been associated with the antioxidant activity of folic acid. Peroxynitrite (PON) scavenging activity and inhibition of lipid peroxidation (LPO) of the physiological forms of folate and of structurally related compounds were tested. It was found that the fully reduced forms of folate, i.e. tetrahydrofolate (THF) and 5-methyltetrahydrofolate (5-MTHF), had the most prominent antioxidant activity. It appeared that their protection against LPO is less pronounced than their PON scavenging activity. The antioxidant activity of these forms of folic acid resides in the pterin core, the antioxidant pharmacophore is 4-hydroxy-2,5,6-triaminopyrimidine. It is suggested that an electron donating effect of the 5-amino group is of major importance for the antioxidant activity of 4-hydroxy-2,5,6-triaminopyrimidine. A similar electron donating effect is probably important for the antioxidant activity of THF and 5-MTHF.

Animals↗

PubMed2003

Bioavailability and pharmacokinetics of the cardioprotecting flavonoid 7-monohydroxyethylrutoside in mice.

PURPOSE: The pharmacokinetics and bioavailability of monoHER, a promising protector against doxorubicin-induced cardiotoxicity, were determined after different routes of administration. METHODS: Mice were treated with 500 mg.kg(-1) monoHER intraperitoneally (i.p.), subcutaneously (s.c.) or intravenously (i.v.) or with 1000 mg.kg(-1) orally. Heart tissue and plasma were collected 24 h after administration. In addition liver and kidney tissues were collected after s.c. administration. The levels of monoHER were measured by HPLC with electrochemical detection. RESULTS: After i.v. administration the AUC(0-120 min) values of monoHER in plasma and heart tissue were 20.5+/-5.3 micromol.min.ml(-1) and 4.9+/-1.3 micromol.min.g(-1) wet tissue, respectively. After i.p. administration, a mean peak plasma concentration of about 130 microM monoHER was maintained from 5 to 15 min after administration. The AUC(0-120 min) values of monoHER were 6.1+/-1.1 micromol.min.ml(-1) and 1.6+/-0.4 micromol.min.g(-1) wet tissue in plasma and heart tissue, respectively. After s.c. administration, monoHER levels in plasma reached a maximum (about 230 microM) between 10 and 20 min after administration. The AUC(0-120 min) values of monoHER in plasma, heart, liver and kidney tissues were 8.0+/-0.6 micromol.min.ml(-1), 2.0+/-0.1, 22.4+/-2.0 and 20.5+/-5.7 micromol.min.g(-1), respectively. The i.p. and s.c. bioavailabilities were about 30% and 40%, respectively. After oral administration, monoHER could not be detected in plasma, indicating that monoHER had a very poor oral bioavailability. CONCLUSIONS: MonoHER was amply taken up by the drug elimination organs liver and kidney and less by the target organ heart. Under cardioprotective conditions (500 mg/kg, i.p.), the Cmax was 131 microM and the AUC(infinity) was 6.3 microM.min. These values will be considered endpoints for the clinical phase I study of monoHER.

Administration, Oral↗

PubMed2003

The cardioprotector monoHER does not interfere with the pharmacokinetics or the metabolism of the cardiotoxic agent doxorubicin in mice.

PURPOSE: Monohydroxyethylrutoside (monoHER) has proved to be a good protector against doxorubicin-induced cardiotoxicity without interfering with the antitumor effect of doxorubicin. The aim of the present study was to determine whether there is a pharmacokinetic interaction between monoHER and doxorubicin which may be involved in monoHER cardioprotection. METHODS: Mice were treated with monoHER (500 mg x kg(-1) i.v.) alone, monoHER 5 min after doxorubicin (10 mg x kg(-1) i.v.), doxorubicin alone and doxorubicin 5 min after monoHER. The levels of monoHER and doxorubicin(ol) in plasma and heart tissue were measured by HPLC 24 h and 48 h after monoHER and doxorubicin administration, respectively. RESULTS: The areas under the concentration-time curves (AUCs) of monoHER and doxorubicin(ol) were not affected by the coadministered drug. No changes were observed in pharmacokinetic parameters such as initial and final half-lives, mean residence time, clearance and volume of distribution of monoHER and doxorubicin(ol) after single or combined administration. CONCLUSION: The cardioprotection of monoHER in mice is not caused by a pharmacokinetic interaction between monoHER and doxorubicin.

Animals↗

PubMed2003

Superoxide dismutase: the balance between prevention and induction of oxidative damage.

Cu,Zn-superoxide dismutase (SOD1) has been shown to be effective in several free radical mediated diseases, although some studies have pointed toward SOD1 toxicity at a high concentrations. In the present study, the balance between prevention and induction of damage by SOD1 has been investigated both in vitro and in vivo. In vitro superoxide was generated using xanthine/xanthine oxidase. In vivo superoxide was generated using the redox cycling compound doxorubicin. Furthermore, we determined the pharmacokinetics of lecithinized SOD1 (PC-SOD) in order to compare the results obtained in vivo with those obtained in vitro. It was found that in vitro high concentrations of SOD1 induce hydroxylation of coumarin 3-carboxylic acid (3-CCA). This could be caused by a peroxidative action of SOD1 or formation of the highly reactive hydroxyl radicals. Any signs of toxicity are absent in vivo because these concentrations are not reached. It can be concluded that SOD1 possesses a large therapeutic window and application of SOD1 or its derivatives for strengthening the body's defenses against oxidative stress in a variety of pathologies seems safe.

Animals↗

PubMed2003

Quantification of mesna and total mesna in kidney tissue by high-performance liquid chromatography with electrochemical detection.

A sensitive and selective assay for the determination of mesna and total mesna in tissue was developed and validated. After a simple homogenization, extraction and deproteinization step, mesna could be measured immediately by HPLC with an electrochemical detector provided with a sensitive wall-jet gold electrode. Total mesna (i.e., free mesna and mesna present in mesna disulfides and mixed mesna disulfides) could be measured after pre-column reduction with sodium borohydride to free mesna. The lower limit of quantification of mesna and total mesna was for both compounds 10 nmol/g. The assays for mesna and total mesna in tissue were linear over the ranges of 10-3000 and 10-10000 nmol/g, respectively. The within-day and between-day precisions of both methods were better than 9%. The within-day and between-day accuracy of the mesna assay ranged from 103.7 to 113.6%, whereas the accuracies of the total mesna assay ranged from 97.8 to 106.7%. Mesna in an EDTA containing tissue homogenate or in deproteinized tissue homogenate stored at -80 degrees C was stable for at least 12 weeks. Total mesna was stable under all conditions measured. The developed assays will be applied for the determination of the distribution of mesna and total mesna in tissues of the rat after administration of mesna or BNP7787.

Animals↗

PubMed2003

Pharmacokinetics and preliminary clinical data of the novel chemoprotectant BNP7787 and cisplatin and their metabolites.

INTRODUCTION: BNP7787 (disodium 2,2'-dithio-bis-ethane sulfonate) is currently undergoing development as a chemoprotective agent to prevent common and serious cisplatin-induced side effects. In the kidneys, intestine, and liver, BNP7787 is believed to undergo intracellular conversion into 2-mercaptoethane sulfonate (mesna), which can locally inactivate toxic platinum species. Methods and objectives In a phase I trial, 25 patients with advanced solid tumors received a 1-hour intravenous infusion of 75 mg/m(2) cisplatin immediately preceded by a 15-minute intravenous infusion of BNP7787 every 3 weeks. For pharmacokinetic investigation of BNP7787 and mesna and a possible mutual pharmacokinetic interaction between BNP7787 and cisplatin, cisplatin and BNP7787 were also administered as single agents in 14 of 25 patients. The dose of BNP7787 was escalated from 4.1 to 41 g/m(2). Patients were also monitored for tumor response and possible side effects from BNP7787. RESULTS: The maximum plasma concentration of mesna was reached approximately 1.7 hours after the start of the BNP7787 infusion. The maximum plasma concentration and area under the curve to infinity (AUC( infinity )) of BNP7787 and mesna increased linearly with the dose. The mean volume of distribution of BNP7787 (+/-SD) was approximately 0.26 +/- 0.08 L/kg. The mean normalized AUC( infinity ) of mesna was only approximately 8% of the normalized AUC( infinity ) of BNP7787. The pharmacokinetic profile of mesna was unaffected by cisplatin and its metabolites. None of the dose levels of BNP7787 (4.1-41 g/m(2)) administered appeared to influence the pharmacokinetic profile of total platinum, unbound platinum, or monohydrated cisplatin. The observed effects regarding a possible mutual interaction between BNP7787 and intact cisplatin were minor, and none were statistically significant at BNP7787 dose levels of 18.4 to 41 g/m(2). The confidence intervals for the pharmacokinetic parameters of BNP7787 and intact cisplatin, however, were relatively broad. Overall, BNP7787 was well tolerated at all dose levels (4.1-41.0 g/m(2)). The most frequently reported event related to BNP7787 was local intravenous site discomfort; the majority of events were mild (grade 1). Side effects of BNP7787 at the highest dose level of 41 g/m(2) were more prominent and included nausea and vomiting, as well as a warm feeling or flushing (grade 2 or lower). Partial tumor responses and stable disease were measured in 12 of 25 patients. CONCLUSION: BNP7787 was relatively nontoxic at doses up to 41 g/m(2). The combination of BNP7787 with cisplatin did not alter the pharmacokinetic profiles of mesna or the cisplatin metabolites. At the higher dose levels of BNP7787 (18.4 to 41 g/m(2)), there appeared to be no mutual interaction between BNP7787 and intact cisplatin, which needs to be confirmed in a larger number of patients. The absence of a mutual interaction between BNP7787 and intact cisplatin is consistent with the observation that several patients had objective tumor responses with BNP7787 and cisplatin administration.

Adult↗

PubMed2002

The antioxidant activity of phloretin: the disclosure of a new antioxidant pharmacophore in flavonoids.

Phloretin is a dihydrochalcone flavonoid that displays a potent antioxidant activity in peroxynitrite scavenging and the inhibition of lipid peroxidation. Comparison with structurally related compounds revealed that the antioxidant pharmacophore of phloretin is 2,6-dihydroxyacetophenone. The potent activity of 2,6-dihydroxyacetophenone is due to stabilisation of its radical via tautomerisation. The antioxidant pharmacophore in the dihydrochalcone phloretin, i.e., the 2,6-dihydroxyacetophenone group, is different from the antioxidant pharmacophores previously reported in flavonoids.

Acetophenones↗

PubMed2002

Hypochlorous acid is a potent inhibitor of acetylcholinesterase.

The role of hydrogen peroxide and peroxynitrite in the induction of airway hyperreactivity has been well described. Another reactive species which is formed during airway inflammation is hypochlorous acid (HOCl). In the present investigation the effect of HOCl on cholinergic innervation of the airway was investigated. It was observed that HOCl was capable of increasing the basal tension of electrically stimulated tracheal smooth muscle. It was found that HOCl inhibits purified acetylcholinesterase with an IC50 value of 0.66 microM. Decreased acetylcholinesterase activity could allow accumulation of acetylcholine and increased airway muscle tension. The effects of HOCl on the isolated organ and the enzyme preparation could be precluded with thiol group-containing compounds such as reduced glutathione and N-acetylcysteine. The present findings indicate that HOCl can act as inhibitor of acetylcholinesterase. The implications of this finding for the induction of airway hyperreactivity are discussed.

Acetylcholinesterase↗

PubMed2002

Simultaneous determination of intact cisplatin and its metabolite monohydrated cisplatin in human plasma.

Cisplatin is a cytotoxic platinum compound, used in the treatment of several solid tumors. Cisplatin and to a greater extent its hydrolysis product monohydrated cisplatin are responsible for side-effects like nephrotoxicity. A sensitive, accurate and precise method was developed to simultaneously determine cisplatin and monohydrated cisplatin in plasma. The compounds were separated by high-performance liquid chromatography and quantified by off-line furnace atomic absorption spectrophotometry. The linear ranges for cisplatin and monohydrated cisplatin in deproteinized plasma were 60-600 and 87.5-700 nM, respectively. From plasma, the mean recovery of cisplatin was 83.2% and that of monohydrated cisplatin 79.1%. The lower limits of quantification of cisplatin and monohydrated cisplatin in deproteinized plasma were 60 and 87.5 nM, respectively. Over the whole calibration range, the within- and between-day accuracy of intact cisplatin ranged from 100.7 to 111.4 and 94.8-102.0%, respectively. The within- and between-day accuracy of monohydrated cisplatin ranged from 107.1 to 113.3 and 101.4-104.9%, respectively. The within-day and between-day precision of cisplatin ranged from 3.4 to 11.5 and 7.3-10.3%, respectively. For monohydrated cisplatin, the within-day and between-day precision ranged from 3.7 to 6.2 and 5.6-7.9%, respectively. Currently, the developed assay has been implemented in pharmacokinetic studies of patients treated with cisplatin alone or in combination with other drugs.

Antineoplastic Agents↗

PubMed2002

Dose-finding and pharmacokinetic study of cisplatin, gemcitabine, and SU5416 in patients with solid tumors.

PURPOSE: To investigate the feasibility and pharmacokinetics of the combination cisplatin, gemcitabine, and SU5416. PATIENTS AND METHODS: Patients received cisplatin 80 mg/m(2) on day 1, gemcitabine 1,250 mg/m(2) on days 1 and 8, repeated every 3 weeks, and SU5416 (85 and 145 mg/m(2)) intravenously twice weekly. Pharmacokinetics of all three agents, side effects, and antitumor response were investigated in patients with solid tumors amenable to therapy with cisplatin/gemcitabine. RESULTS: In the first cohort of three patients entered at the 85 mg/m(2) dose, no dose-limiting toxicities were observed. In the next cohort (145 mg/m(2)), three patients developed a thromboembolic event. After entry was restricted to patients with low thromboembolic risk, three additional patients enrolled at 145 mg/m(2) developed a thromboembolic event. The dose was then reduced to 85 mg/m(2) in all patients still on the study, and three additional patients were entered on this dose level. In 19 treated patients, eight patients developed nine thromboembolic events (three transient ischemic attacks, two cerebrovascular accidents, and four deep venous thromboses). The most common toxicities observed were those previously reported for SU5416 alone (headache and phlebitis) and for this chemotherapy regimen (nausea, thrombocytopenia, and leucopenia). No significant pharmacologic interaction among the three drugs was observed. Response rates were similar to those expected in the patient population selected for this study. Analysis of variables of the coagulation cascade and of vessel wall activation was performed in three patients and showed significant increases in thrombin generation and endothelial cell perturbation in a treatment cycle-dependent manner. CONCLUSION: The incidence of thromboembolic events, possibly related to the particular regimen tested in this study, discourages further investigation of this regimen.

Adult↗

PubMed2002

Continuous administration of irinotecan by hepatic arterial infusion: a phase I and pharmacokinetic study.

PURPOSE: The main advantage of administering chemotherapy by means of hepatic arterial infusion (HAI) is the achievement of a high concentration of the drug in the liver. Irinotecan (CPT-11) is an active agent for the treatment of advanced colorectal cancer and other tumor types, which frequently metastasize in the liver. We performed a Phase I and pharmacokinetic study to investigate CPT-11 by hepatic arterial administration in patients with liver metastases. PATIENTS AND METHODS: Patients with liver metastases received CPT-11 at doses ranging from 15 to 25 mg/m(2)/day for 5 days every 3 weeks by continuous HAI. All of the patients also received one cycle CPT-11 i.v. Primary end points of the study were to define the maximum tolerated dose (MTD) of hepatic arterial CPT-11 and to study its pharmacokinetics. RESULTS: Twenty patients were included. The MTD was 25 mg/m(2)/day and the dose-limiting toxicities were neutropenia and diarrhea. The metabolic ratio was significantly increased with HAI compared with i.v. administration (P = 0.015). The steady-state concentrations of total CPT-11 and CPT-11 carboxylate and lactone were all lower than those during i.v. infusion (P = 0.008, 0.013, and 0.004, respectively), whereas the levels of total SN-38, and SN-38 carboxylate, lactone, and glucuronide were similar. The total body clearance of CPT-11 was significantly higher with HAI (P = 0.008). CONCLUSIONS: The MTD of CPT-11 given by hepatic 5-day continuous infusion was 25 mg/m(2)/day. HAI of CPT-11 resulted in a higher metabolic ratio because of increased elimination of CPT-11. We recommend 20 mg/m(2)/day for additional Phase II studies.

Adult↗