Ionic Liquid Dispersive Liquid-Liquid Microextraction Method for the Determination of Irinotecan, an Anticancer Drug, in Water and Urine Samples Using UV-Vis Spectrophotometry.

A new, simple, efficient, and environmentally friendly ionic liquid dispersive liquid-liquid microextraction method was developed for the determination of irinotecan, an anticancer drug, in water and urine samples using UV-Vis spectrophotometry. The ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate was used as the extraction solvent, and ethanol was used as the disperser solvent. The main parameters affecting the extraction efficiency, including sample pH, volume of the ionic liquid, choice of the dispersive solvent and its volume, concentration of NaCl, and extraction and centrifugation times, were investigated and optimized. The effect of interfering species on the recovery of irinotecan was also examined. Under optimal conditions, the LOD (3σ) was 48.7 µg/L without any preconcentration. Because the urine sample was diluted 10-fold, the LOD for urine would be 487 µg/L. However, this could be improved 16-fold if preconcentration using a 40 mL aliquot of the sample is used. The proposed method was successfully applied to the determination of irinotecan in tap water, river water, and urine samples spiked with 10.20 mg/L for the water samples and 8.32 mg/L for the urine sample. The average recovery values of irinotecan determined were 99.1% for tap water, 109.4% for river water, and 96.1% for urine.

The development of a quantitative and qualitative method based on UHPLC-QTOF MS/MS for evaluation paclitaxel-tetrandrine interaction and its application to a pharmacokinetic study.

Paclitaxel is a broad-spectrum anti-cancer drug by targeting microtubulin. However, multidrug resistant (MDR) makes its clinical application more difficult and results in failure of chemotherapy. Tetrandrine as a potential multidrug resistant modulator could be combined with other anti-cancer drugs. In this study, ultra-performance liquid chromatography (UHPLC) combined with quadrupole time-of-flight mass spectrometry (QTOF) was applied to simultaneously qualitative and quantitative analysis of paclitaxel for the pharmacokinetic studies while combined with tetrandrine. This method was developed based on non-target screening mode IDA (Information Dependent Acquisition). As a result, the validated range was 0.25-64ng/ml (30µl plasma) for paclitaxel. Totally 33 metabolites of paclitaxel and tetrandine were identified in vivo and in vitro. The main metabolites of PTX were dose-dependent decreased with different amounts of tetrandine co-administration no matter in vivo and in vitro, the exposure of PTX increased in pharmacokinetic study. The verified method is sensitive accurate and effective for the simultaneous determination of paclitaxel and its metabolites in blood, urine and live microsome incubation samples and it was successfully applied to evaluate the pharmacokinetics and drug-drug interaction between paclitaxel and tetrandine. Furthermore, a biosensor technology, surface plasmon resonance (SPR) analysis was applied to preliminary evaluate the competitive protein binding of multiple components. The SPR analysis indicated that the affinity between 6-hydroxy-paclitaxel and micotubulin is similar to that between paclitaxel and micotubulin, and tetrandrine also does not form a competitive combination with paclitaxel. For human, 6-hydroxy-paclitaxel is the one of main metabolites of paclitaxel, so the results suggested that tetrandine has an influence on the metabolite of paclitaxel, but tetrandine and the main metabolites of PTX probably do not affect PTX's biological targeting, the effect of its pharmacological action needs to be further studied.

Pharmacokinetics and excretion of (14)C-omacetaxine in patients with advanced solid tumors.

Background Omacetaxine mepesuccinate is indicated in adults with chronic myeloid leukemia resistant and/or intolerant to ≥ 2 tyrosine kinase inhibitor treatments. This phase I study assessed the disposition, elimination, and safety of (14)C-omacetaxine in patients with solid tumors. Methods The study comprised a 7-days pharmacokinetic assessment followed by a treatment period of ≤ six 28-days cycles. A single subcutaneous dose of 1.25 mg/m(2) (14)C-omacetaxine was administered to six patients. Blood, urine, and feces were collected through 168 h or until radioactivity excreted within 24 h was <1 % of the dose. Total radioactivity (TRA) was measured in all matrices and concentrations of omacetaxine, 4'-desmethylhomoharringtonine (4'-DMHHT), and cephalotaxine were measured in plasma and urine. For each treatment cycle, patients received 1.25 mg/m(2) omacetaxine twice daily for 7 days. Results Mean TRA recovered was approximately 81 % of the dose, with approximately half of the radioactivity recovered in feces and half in urine. Approximately 20 % of the dose was excreted unchanged in urine; cephalotaxine (0.4 % of dose) and 4' DMHHT (9 %) were also present. Plasma concentrations of TRA were higher than the sum of omacetaxine and known metabolites, suggesting the presence of other (14)C-omacetaxine-derived compounds. Fatigue and anemia were common, consistent with the known toxicity profile of omacetaxine. Conclusion Renal and hepatic processes contribute to the elimination of (14)C-omacetaxine-derived radioactivity in cancer patients. In addition to omacetaxine and its known metabolites, other (14)C-omacetaxine-derived materials appear to be present in plasma and urine. Omacetaxine was adequately tolerated, with no new safety signals.

Validation of high-performance liquid chromatography-tandem mass spectrometry assays quantifying omacetaxine mepesuccinate and its 4'­des-methyl and cephalotaxine metabolites in human plasma and urine.

Omacetaxine mepesuccinate (hereafter called omacetaxine) is a modified cephalotaxine and is registered (Synribo(®)) for the treatment of adult patients with chronic myeloid leukemia (CML) with resistance and/or intolerance to two or more tyrosine kinase inhibitors (TKIs). To evaluate the pharmacokinetics of omacetaxine, sensitive high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays for the quantification of omacetaxine and its inactive 4'-des-methyl (4'-DMHHT) and cephalotaxine metabolites in human plasma and urine were developed and validated. Since omacetaxine is mainly metabolised by esterases, the plasma samples were immediately stabilised after collection with an esterase inhibitor and stored at a nominal temperature of -80°C. Urine samples were stored at -80°C immediately after collection. Protein precipitation was applied as the sample pretreatment method for the plasma samples, and urine samples were processed using solid-phase extraction (SPE). For both assays, the dried and reconstituted extracts were injected on a XBridge BEH Phenyl column for analysis of all analytes. Gradient elution was applied with 0.1% formic acid in water and methanol as mobile phases. Analytes were ionised using a turbospray ionisation source in positive mode and detected with a triple quadrupole mass spectrometer. The validated plasma assay quantifies all analytes in the concentration range of 0.1-100ng/mL and the urine assay in the range of 0.1-50ng/mL. At all concentrations, the accuracies were within ±15% of the nominal concentrations and precisions were ≤15%. The developed methods have successfully been applied in a human mass balance study of omacetaxine.

Electrochemical determination of the anticancer drug taxol at a ds-DNA modified pencil-graphite electrode and its application as a label-free electrochemical biosensor.

In this study a novel biosensor for determination of taxol is described. The interaction of taxol with salmon-sperm double-stranded DNA (ds-DNA) based on the decreasing of the oxidation signals of guanine and adenine bases was studied electrochemically with a pencil-graphite electrode (PGE) using a differential pulse voltammetry (DPV) method. The decreases in the intensity of the guanine and adenine oxidation signals after interaction with taxol were used as indicator signals for the sensitive determination of taxol. DPV exhibits a linear dynamic range of 2.0×10(-7)-1.0×10(-5) M for taxol with a detection limit of 8.0×10(-8) M. Finally, this modified electrode was used for determination of taxol in some real samples.

Safety, tolerability and pharmacokinetics of liposomal curcumin in healthy humans.

INTRODUCTION: Experimental studies have shown that liposomal curcumin can exert a reduction in tumor growth in pancreatic and colorectal cancer. In this phase I clinical trial we investigated the pharmacokinetics, safety, and tolerability of intravenously administered liposomal curcumin in healthy subjects. MATERIAL AND METHODS: 50 male and female participants were included in this randomized, placebo-controlled double-blind phase I dose escalation study. Subjects received a single dose of liposomal curcumin (10 - 400 mg/m2; n = 2 - 6 per group) or placebo over 2 hours intravenously. RESULTS: Dose-dependent increases in the plasma concentrations of curcumin and its metabolite tetrahydrocurcumin (THC) were detected. After the end of drug infusion, curcumin and THC plasma concentrations decreased within 6 - 60 minutes below the limit of quantification. Mean urinary excretion was ~ 0.1% of total systemic clearance. Liposomal curcumin was tolerated well, but a transient red blood cell echinocyte formation with concomitant increase in mean cellular volume was observed at dosages ≥ 120 mg/m2. CONCLUSION: Short-term intravenous dosing of liposomal curcumin appears to be safe up to a dose of 120 mg/m2. Changes in red blood cell morphology may represent a dose limiting sign of toxicity.

Rapid and sensitive detection of vinorelbine in the urine of tumor patients by capillary electrophoresis with tris(2,2'-bipyridyl)ruthenium(II)-based electrochemiluminescence assay.

A capillary electrophoresis method coupled with electrochemiluminescence detection for the analysis of vinorelbine (VNB) in the urine of tumor patients was established in this research. Complete determination of VNB was achieved in 8 min using a background electrolyte of 50 mmol/L phosphate buffer (pH 9.0) and a separation voltage of 15 kV. The calibration curves showed a linear range from 2.8 × 10(-10) to 1.6 × 10(-8) mol/L. The relative standard derivation for VNB was below 3.4%. The linear relationships were good and the correlation factor of VNB exceeded 0.985. The detection limits were 1.0 × 10(-11) mol/L under the optimal conditions. The developed method was applied to the sensitive determination of VNB in the urine of tumor patients.

O-acetylated N-acetylneuraminic acid as a novel target for therapy in human pre-B acute lymphoblastic leukemia.

The development of resistance to chemotherapy is a major cause of relapse in acute lymphoblastic leukemia (ALL). Though several mechanisms associated with drug resistance have been studied in detail, the role of carbohydrate modification remains unexplored. Here, we investigated the contribution of 9-O-acetylated N-acetylneuraminic acid (Neu5Ac) to survival and drug resistance development in ALL cells. A strong induction of 9-O-acetylated Neu5Ac including 9-O-acetyl GD3 was detected in ALL cells that developed resistance against vincristine or nilotinib, drugs with distinct cytotoxic mechanisms. Removal of 9-O-acetyl residues from Neu5Ac on the cell surface by an O-acetylesterase made ALL cells more vulnerable to such drugs. Moreover, removal of intracellular and cell surface-resident 9-O-acetyl Neu5Ac by lentiviral transduction of the esterase was lethal to ALL cells in vitro even in the presence of stromal protection. Interestingly, expression of the esterase in normal fibroblasts or endothelial cells had no effect on their survival. Transplanted mice induced for expression of the O-acetylesterase in the ALL cells exhibited a reduction of leukemia to minimal cell numbers and significantly increased survival. This demonstrates that Neu5Ac 9-O-acetylation is essential for survival of these cells and suggests that Neu5Ac de-O-acetylation could be used as therapy to eradicate drug-resistant ALL cells.

Direct and fast determination of paclitaxel, morphine and codeine in urine by micellar electrokinetic chromatography.

A micellar electrokinetic chromatography (MEKC) method was developed for the determination of paclitaxel, morphine and codeine in human urine from patients under cancer treatment. The background electrolyte consisted of a borate buffer (pH 9.2; 20 mM) with sodium dodecyl sulfate (60 mM) and 5% MeOH. The applied voltage was 25 kV, temperature was 20 °C and the sample injection was performed in the hydrodynamic mode. All analyses were carried out in a fused silica capillary with an internal diameter of 75 µm and a total length of 57 cm. The detection of target compounds was performed at 212 nm. Under these conditions, a complete separation of paclitaxel, morphine and codeine was achieved in less than 15 min. According to the validation study, the developed method was proved to be accurate, precise, sensitive, specific, rugged and robust. This method was applied to the analysis of six urines samples from different cancer patients undergoing treatment with paclitaxel or/and codeine. In all the urine paclitaxel determination were done.

Apoptotic and anti-angiogenic effects of Pulsatilla koreana extract on hepatocellular carcinoma.

Chemoprevention through the use of food and plants has emerged as a novel approach to control various malignancies including cancer. Pulsatilla koreana extract (PKE) has been used to treat malaria and dysentery. The functions and effect of PKE in cancer treatment have been reported but with less information. In this study, we investigated the effect of PKE on the progression of hepatocellular carcinoma (HCC) cells and its mechanism. PKE strongly suppressed the growth of HCC cells in a dose-dependent manner. Apoptosis by PKE was observed by DAPI and TUNEL staining and accompanied with increases of cleaved PARP and caspase-3 in Huh-7 cells. Also, PKE decreased the expression of hypoxia-inducible factor (HIF-1α) and vascular endothelial growth factor (VEGF), and inhibited tube formation and migration of human umbilical vein endothelial cells (HUVECs). In addition, PKE potently suppressed in vivo neovascularization in a mouse Matrigel plug assay. Furthermore, in vivo study showed that PKE significantly inhibited tumor growth in a mouse xenograft model, and induced apoptosis by increasing the cleaved PARP and caspase-3. The expressions of Ki-67, VEGF, and CD31 in the tumor tissue were decreased by the treatment of PKE. Taken together, our study demonstrates that PKE not only induced apoptosis but also inhibited cell growth and angiogenesis of human HCC. We suggest that PKE is an effective chemotherapeutic candidate for cancer therapy against HCC.

Development of chemiluminescence method for determination of 10-hydroxycamptothecin based on luminol-[Ag(HIO6)2]5⁻ reaction in alkaline solution.

A novel chemiluminescence (CL) method was developed for the determination of 10-hydroxycamptothecin(HCPT) based on the CL reaction between [Ag(HIO6)2]5⁻ and luminol in alkaline solution. CL emission of Ag(III) complex-luminol in alkaline medium was very different from that in acidic medium. A possible mechanism of enhanced CL emission was suggested. The enhanced effect of HCPT on CL emission of the [Ag(HIO6)2]5⁻-luminol system was found. The enhanced degree of CL emission was proportional to HCPT concentration. The effect of the reaction conditions on CL emission was examined. Under optimal conditions, the limit of detection was 6.5 × 10⁻9 g mL⁻¹. The proposed method was applied for the determination of HCPT in real samples with the recoveries of 93.2-109% with the RSD of 1.7-3.3%.

Metabolic pathways of the camptothecin analog AR-67.

7-tert-Butyldimethylsilyl-10-hydroxycamptothecin (AR-67; also known as DB-67) is a novel lipophilic camptothecin analog in early-phase anticancer clinical trials. In support of these studies, we evaluated the metabolism of AR-67 in vitro and identified potential metabolites in patient samples. The lactone form of AR-67 was found to be preferentially metabolized over AR-67 carboxylate in human microsomes. Subsequently, the lactone form was tested as a substrate in a panel of CYP450 and UDP-glucuronosyltransferase (UGT) enzymes known to metabolize the majority of clinically approved molecules. AR-67 was metabolized by CYP3A5, CYP3A4, CYP1A1, and CYP1A2, in order of activity. Extrahepatic UGT1A8 and UGT1A7 possessed at least 6-fold higher metabolizing activity than UGT1A1 and other UGT enzymes tested. CYP1A1 and UGT1A7 displayed Michaelis-Menten kinetics, whereas CYP3A4, CYP3A5, and UGT1A8 displayed kinetics consistent with substrate inhibition. Chromatographic analysis of representative patient plasma and urine samples demonstrated the presence of AR-67 glucuronides and oxidized products in the urine but only in very minimal amounts. We conclude that limited in vivo metabolism of AR-67 by UGT1A1 may partly explain the absence of AR-67 glucuronides in plasma and hypothesize that UGT1A8- and CYP3A-mediated biotransformation within the gastrointestinal epithelium may provide protective mechanisms against AR-67 gastrointestinal toxicity.

Quantification of free and protein-bound trans-resveratrol metabolites and identification of trans-resveratrol-C/O-conjugated diglucuronides - two novel resveratrol metabolites in human plasma.

The polyphenol trans-resveratrol (t-RES) is present as t-RES-3-O-beta-D-glycoside, termed piceid, in several plant-derived foods. Although data on the metabolism and on in vivo effects of t-RES have been reported, quantitative data on the metabolites formed after dietary intake of t-RES or piceid are still lacking. In this study, 85.5 mg of piceid per 70 kg of body weight (bw) were administered to healthy volunteers in a bolus dose. t-RES metabolites formed in plasma and urine were identified and quantified by LC-MS/MS, NMR, and HPLC-DAD analysis using chemically synthesized t-RES conjugate standards. In addition, the amount of t-RES metabolites bound noncovalently to plasma proteins was determined for the first time in humans. The metabolites identified and quantified were t-RES-3-sulfate, t-RES-3,4'-disulfate, t-RES-3,5-disulfate, t-RES-3-glucuronide and t-RES-4'-glucuronide, with t-RES-sulfates being the dominant conjugates in plasma and urine. Besides these metabolites, two novel t-RES-C/O-conjugated diglucuronides have been identified and quantified in plasma and urine. Moreover, it could be shown that up to 50% of the plasma t-RES-3-sulfate, t-RES-disulfates, and the novel t-RES-C/O-diglucuronides were bound to proteins. Total recovery of the dietary administered piceid in urine ranged between 13.6 and 35.7%.

A high performance liquid chromatography method for vinorelbine and 4-O-deacetyl vinorelbine: a decade of routine analysis in human blood.

A sensitive high performance liquid chromatographic method was developed and validated for the simultaneous quantification of vinorelbine and its active metabolite, 4-O-deacetyl vinorelbine, in human biological fluids. These two compounds together with vinblastine, used as internal standard, were extracted from blood and urine by a liquid-liquid process using diethyl ether, and followed by a back-extraction in acidic conditions. Then, they were analysed through a cyano column and detected in ultraviolet at 268 nm. The assay linearity was validated up to 2000 ng/ml. The lower limit of quantification was set at 2.5 ng/ml. The between-run precision and accuracy were always higher than 94%. Biological samples were stable when stored at -80 degrees C over 2 years. The long-term reproducibility and the suitability of this analytical method were demonstrated within the last decade through the analysis of about 7000 samples during the clinical development of i.v. and oral formulations of vinorelbine. Because vinorelbine binds mainly to platelets and blood cells and because this binding is rapidly reversible and highly influenced by environmental conditions, drug concentration in plasma may be highly influenced by the sampling conditions and the centrifugation process used to separate blood cells from plasma. Therefore, this method was developed in blood and then used for sample analyses in routine. The major benefit was that it was easy for nurses to directly collect blood instead of plasma and that reduced volume of sampling could be withdrawn from frail patients. Furthermore, the analysis in blood enabled to quantify vinorelbine and 4-O-deacetyl vinorelbine concentrations for a longer period of time, which resulted in a more accurate evaluation of pharmacokinetic parameters.

Hepatic transport, metabolism and biliary excretion of irinotecan in a cancer patient with an external bile drain.

BACKGROUND: Irinotecan is metabolized by various enzymes, including carboxylesterases, cytochrome P450 3A isozymes (CYP3A) and uridine-diphosphate glucuronosyltransferase 1A isoforms (UGT1A). Here we report on the disposition of irinotecan and its metabolites in plasma, urine, bile and feces of a single cancer patient with an external bile drain. METHODOLOGY: Irinotecan (450 mg) was administered during a 90-minutes continuous infusion to a cancer patient with an external bile drain. Blood samples were collected up to 55 hours after infusion, while bile, feces and urine were collected during six consecutive days after administration. Samples were analyzed using high-performance liquid chromatography (HPLC)-assays with fluorescence detection. RESULTS: Plasma pharmacokinetics were characterized by a relatively slow clearance of irinotecan and a relatively high exposure to 7-ethyl-10-[4-N-(5-aminopentanoic acid)-1-piperidino] carbonyloxycamptothecin (APC). Exposures to the other metabolites was within the normal range. Overall, 83.4% of the administered dose was recovered in the excreta, with the majority excreted during the first 24 hours. CONCLUSIONS: Enterohepatic recirculation is of minor importance for the plasma disposition of irinotecan and its metabolites. The high percentage of the dose recovered in urine, the relatively slow clearance of irinotecan and the preferential urinary over biliary excretion of APC in this particular patient are likely related to reduced functioning of ABC-transporters. Circumstantial evidence was found that APC is subject to further intestinal biotransformation indicating a role in the etiology of irinotecan-induced diarrhea. Since intra-luminal exposure to SN-38 in patients with an external bile drain is limited, neutropenia will be the dose-limiting toxicity. Based on presented data, although collected from only one patient, irinotecan therapy in patients with an external bile drain is feasible. No a priori dose adjustments are recommended, although in the absence of severe side-effects in previous courses, a higher dose may be considered.

Pharmacokinetics, tissue distribution and excretion of vinflunine.

The plasma pharmacokinetics, tissue distribution, excretion and binding to plasma proteins of vinflunine, were investigated after intravenous (iv) administration. We obtained plasma profiles after iv administration of vinflunine at the doses of 3.5, 7 and 14 mg/kg in rats. The t1/2 values for vinflunine were estimated to be 18.38+/-1.20, 17.05+/-0.77, 18.35+/-1.57 h, and the mean AUC0-t values were 3.48+/-0.38, 6.54+/-0.68, 12.79+/-2.93 microg x h/ml, respectively. Of the various tissues tested, vinflunine was widely distributed into tissues, with the highest concentrations of vinflunine being found in well perfused organs. Maximal concentration of vinflunine was reached at 0.5 h postdose in the majority of tissues. In tumor-bearing mice, the similar pattern of tissue distribution was observable, except that vinflunine can be distributed into tumor. The binding of vinflunine in human and rat plasma proteins were 39.6% and 58.4% respectively. Within 96 h after administration, 9.58%, 15.36% and 0.71% of the given dose was excreted in urine, feces and bile, respectively. In conclusion, Vinflunine had a longer terminal half-life, a wide tissue distribution and less than 25% of the given dose was excreted as unchanged drug, suggesting metabolism as a major style of elimination.

Pharmacokinetics and urinary excretion of vincristine sulfate liposomes injection in metastatic melanoma patients.

Vincristine sulfate liposomes injection (VSLI) is a liposomal formulation of vincristine encapsulated in sphingosomes composed of sphinogomyelin and cholesterol (58/42; mol/mol). The pharmacokinetics and urinary excretion of VSLI were evaluated in 12 patients with metastatic melanoma after single-dose (2.0 mg/m2 every 2 weeks = 1 cycle) and multiple-dose (cycle 3, pharmacokinetics only) administrations (intravenous infusion over 1 hour). After VSLI infusion, total (released and encapsulated) vincristine concentrations in plasma remained relatively constant for 3 to 12 hours and thereafter declined, with interpatient variability seen in the rate of decline resulting in monoexponential or biexponential profiles. The area under the plasma concentration-time curve from time zero to infinity of total vincristine in plasma ranged from 4933 to 40495 h.ng/mL and total clearance ranged from 131 to 445 mL/h. The volume of distribution at steady state was 2650 +/- 731 mL, indicating VSLI was mainly confined within the plasma. The released vincristine concentrations in plasma were below the level of quantitation in 95% of samples. The pharmacokinetic parameters were similar between cycles 1 and 3, and trough plasma levels of total vincristine were below the level of quantitation of 1 ng/mL. Approximately 8% of the injected dose was excreted in the urine as unchanged vincristine (7%) or N-desformylvincristine (0.8%). Overall, VSLI exhibited a longer circulation half-life and higher area under the plasma concentration-time curve compared to conventional vincristine, whereas its route of elimination remained unchanged.

Quantification of [3H]docetaxel in feces and urine: development and validation of a combustion method.

Most radiolabeled biological samples require extensive sample preparation to reduce quenching interference before quantification of radioactivity is possible. Clearly, a more rapid and simple method ensuring a constant count rate and optimal counting efficiency has important advantages. We report on the development and analytical method validation of a rapid and simple combustion method to quantify [3H]docetaxel excreted in human feces and urine. A 3-day validation procedure was performed; quality control (QC) samples, prepared in blank feces and urine, were combusted 5 times and aliquots of the produced tritiated combustion water were counted in a liquid scintillation counter. The validation runs demonstrated adequate precision (below 7.6%) across all QC levels. Sensitivity at the lowest QC level was excellent and recovery of radioactivity constant (ranging from 85 to 91.8%). Clinical applicability of the method was tested in a cancer patient receiving docetaxel and a tracer amount of [3H]docetaxel; during the first 72 h after [3H]docetaxel infusion, 60% of total radioactivity was excreted in the collected feces and urine, which is within the expected range. Combustion of tritiated feces and urine samples is a simple, rapid, sensitive, precise and reproducible method with high recovery. It can be applied to quantify [3H]docetaxel excretion after i.v. administration.

Spectrofluorimetric determination of manzamine A in spiked human urine and plasma.

The native fluorescence of manzamine A (a biologically active beta-carboline marine-derived alkaloid) has been studied under different conditions. The highest fluorescence intensity was obtained in methanol. Two wavelength settings were found to be suitable for excitation, 280 nm and 340 nm; while lambdamax emission was constant in both cases at 387 nm. The fluorescence intensity at 340/387 nm setting was 1.6 greater than that obtained at 280/387 nm settings. The calibration curves were rectilinear over the range 0.1-2.0 and 0.5-2.5 microg/ml for the two settings, respectively. The detection limits were 0.05 microg/ml (9.1 x 10(-9) M) and 0.1 microg/ml (1.82 x 10(-8) M) at 340/387 nm and 280/387 nm, respectively. The proposed method was applied to the determination of manzamine A in spiked human urine and plasma samples adopting the 340/387 nm wavelength setting, the % recoveries (n = 6) were 99.61 +/- 0.90 and 100.25 +/- 1.63, respectively.

Phase I and pharmacokinetic study of the new taxane analog BMS-184476 given weekly in patients with advanced malignancies.

PURPOSE: The study was designed to establish the maximum administered dose and maximum tolerated dose (MTD) of BMS-184476, an analogue of paclitaxel, given weekly for 3 consecutive weeks every 28 days, later amended to a regimen of weekly administration for 2 consecutive weeks every 21 days. EXPERIMENTAL DESIGN: Adult patients with solid tumors received BMS-184476 i.v. on days 1, 8, and 15 without premedication. The trial followed a modified accelerated titration design. Doses of 7, 14, 28, 40, 50, and 60 mg/m(2)/wk were investigated. Pharmacokinetics of BMS-184476 in plasma and urine were investigated by high-performance liquid chromatography assay. RESULTS: Fifty-three patients were treated; the maximum administered dose was 60 mg/m(2)/wk, and the MTD was 50 mg/m(2)/wk. Dose-limiting neutropenia was the main toxicity. Neutropenia at the higher dose levels frequently prevented administration of the day 15 dose, and a modified schedule at MTD dosing on days 1 and 8 every 21 days was evaluated and found more feasible for Phase II studies. Diarrhea was the main nonhematological toxicity; other toxicities were vomiting, cumulative fatigue, and loss of appetite. Two patients died of neutropenia-related complications. Antitumor activity was observed in patients with breast and non-small cell lung cancer, with confirmed partial responses in 22% of patients. BMS-184476 was the main species found in the plasma with <5% present as paclitaxel or sulfoxide metabolites. The PKs of BMS-184476 appeared to be linear in the dose range of 7-60 mg/m(2). CONCLUSION: The recommended dose and schedule of weekly BMS-184476 is 50 mg/m(2) on days 1 and 8 every 21 days.