A rapid reversed phase high performance liquid chromatographic method for the determination of docetaxel (Taxotere) in human plasma using a column switching technique

Development of a RP-HPLC method for analysis of docetaxel in tumor-bearing mice plasma and tissues following injection of docetaxel-loaded pH responsive targeting polymeric micelles

Background and purpose:

A simple, rapid, and sensitive reversed-phase high performance liquid chromatography (RP-HPLC) method based on liquid-liquid extraction was developed and validated for determination of docetaxel (DTX) in plasma and homogenate tissues of tumor-bearing mice.

Experimental approach:

Samples were spiked with celecoxib as the internal standard and separation was achieved on a μ-Bondapak C18 HPLC column. The mobile phase consisted of a mixture of acetonitrile/water (40/60 v/v) at flow rate of 1.2 mL/min and the effluent was monitored at 230 nm.

Results:

Calibration curves were linear over the concentration range of 0.1-10 μg/mL of DTX in plasma and 0.25-50 μg/mL in tissue homogenates with acceptable precision and accuracy. The mean recoveries of the drug from plasma extraction was 94.6 ± 1.44% while those of tissue homogenates ranged from 73.5 ± 3.2 to 85.3 ± 2.8% depending on the type of tissues examined. DTX was stable in biological samples with no evidence of degradation during 3 freeze-thaw cycles and two months of storage at -70 ± 15 °C. The developed HPLC method was applied to quantify DTX in the mouse plasma and tissues after intravenous administration of 7.5 mg equivalent DTX/kg dose of DTX-loaded folic acid-polyethylene glycol-heparin-tocopherol (FA-PEG-HEP-CA-TOC) micelle formulation to female Balb/c mice.

Conclusion:

A simple, sensitive, rapid, accurate, and prudent RP-HPLC method was developed, validated, and applied for DTX determination in plasma and tissues.

Preparation, characterization, and pharmacokinetics of liposomal docetaxel for oral administration

A docetaxel (DTX) liposomal formulation composed of egg phosphatidylcholine, sodium deoxycholate, and stearylamine was developed. Eudragit (0.5%) was coated to deliver the drug to the region between the distal small intestine and the colon. Lyophilized trehalose and mannitol were used as cryoprotectants because they preserve the particle integrity and good appearance. In vitro release studies showed that the amount of drug released from the coated liposomes was low in solution 1, which simulated the pH condition of the stomach. Especially during the average gastric emptying time, the amount of drug released decreased when Eudragit was added. The plasma DTX concentration was evaluated in pharmacokinetic studies. The plasma drug concentration after intravenous (i.v.) administration decreased rapidly within 120 min. Free DTX formulated using Tween 80 and the lyophilized Eudragit-coated liposomal formulation were compared after oral administration. The oral liposomal formulation had a longer half-life (t_1/2) and three-fold higher oral bioavailability. Thus, lyophilized Eudragit-coated liposomal DTX could be a promising therapy for various solid tumors to improve patient convenience and quality of life.

Development of RP-HPLC method for simultaneous determination of docetaxel and curcumin in rat plasma: Validation and stability

The purpose of the present research was to develop a suitable, simple, precise, accurate, robust, and reproducible RP-HPLC method for a reliable simultaneous quantification of docetaxel (DTX) and curcumin (CCM) in rat plasma samples using paclitaxel (PTX) as an internal standard. The samples were assayed by the Agilent 1260 Infinity HPLC instrument using a Capcell Pak C₈ column (4.6 mm × 150 mm, 5 µm) under isocratic conditions. The mobile phase consisted of acetonitrile and triple distilled water (40/60, v/v) with a flow rate of 1.0 ml/min. The eluent was monitored at 230 nm for simultaneous measurement of curcumin and docetaxel. The method was validated by determining system suitability, selectivity, sensitivity, linearity, inter-day and intra-day precision, accuracy, robustness, and stability in accordance with the guidelines of the United States Food and Drug Administration (FDA). The developed chromatographic method proved to be simple, precise, accurate, robust and reproducible. Moreover, the samples showed stability at room temperature over a period of 48 h. Thus, this method would be employed for routine simultaneous quantification of docetaxel and curcumin in rat plasma samples.

Effects of Cinnamon (C. zeylanicum) Bark Oil Against Taxanes-Induced Damages in Sperm Quality, Testicular and Epididymal Oxidant/Antioxidant Balance, Testicular Apoptosis, and Sperm DNA Integrity

The aim of this study was to investigate whether cinnamon bark oil (CBO) has protective effect on taxanes-induced adverse changes in sperm quality, testicular and epididymal oxidant/antioxidant balance, testicular apoptosis, and sperm DNA integrity. For this purpose, 88 adult male rats were equally divided into 8 groups: control, CBO, docetaxel (DTX), paclitaxel (PTX), DTX+PTX, DTX+CBO, PTX+CBO, and DTX+PTX+CBO. CBO was given by gavage daily for 10 weeks at the dose of 100 mg/kg. DTX and PTX were administered by intraperitoneal injection at the doses of 5 and 4 mg/kg/week, respectively, for 10 weeks. DTX+PTX and DTX+PTX+CBO groups were treated with DTX during first 5 weeks and PTX during next 5 weeks. DTX, PTX, and their mixed administrations caused significant decreases in absolute and relative weights of all reproductive organs, testosterone level, sperm motility, concentration, glutathione level, and catalase activity in testicular and epididymal tissues. They also significantly increased abnormal sperm rate, testicular and epididymal malondialdehyde level, apoptotic germ cell number, and sperm DNA fragmentation and significantly damaged the histological structure of testes. CBO consumption by DTX-, PTX-, and DTX+PTX-treated rats provided significant ameliorations in decreased relative weights of reproductive organs, decreased testosterone, decreased sperm quality, imbalanced oxidant/antioxidant system, increased apoptotic germ cell number, rate of sperm with fragmented DNA, and severity of testicular histopathological lesions induced by taxanes. In conclusion, taxanes cause impairments in sperm quality, testicular and epididymal oxidant/antioxidant balance, testicular histopathological structure, and sperm DNA integrity, and long-term CBO consumption protects male reproductive system of rats.

Quantification of taxanes in biological matrices: a review of bioanalytical assays and recommendations for development of new assays

Since the isolation of paclitaxel and its approval for the treatment of breast cancer, various taxanes and taxane formulations have been developed. To date, almost 100 bioanalytical assays have been published with the method development and optimization often extensively discussed by the authors. This Review presents an overview of assays published between January 1970 and September 2013 that described method development and validation of assays used to quantify taxanes in biological matrices such as plasma, urine, feces and tissue samples. For liquid chromatography assays, sample pretreatment, chromatographic separation and assay performance are compared. Since this Review discusses the limitations of previously developed liquid chromatography assays and gives recommendations for future assay development, it can be used as a reference for future development of liquid chromatography assays for the quantification of taxanes in various biological matrices to support preclinical and clinical studies.

Docetaxel in cationic lipid nanocapsules for enhanced in vivo activity

The usefulness of Docetaxel (DT) as an anti-cancer agent is limited to parenteral route owing to its very poor oral bioavailability. Thus, to improve its oral efficacy, DT was loaded in novel cationic lipid nanocapsules (DT CLNC). The DT CLNC possessed size of 130-150 nm, zeta potential of +72mV, adequate DT loading and over 95% encapsulation efficiency. TEM revealed capsular structure of DT CLNC. Lipolysis study indicated improved solubilization of DT by nanocapsules in comparison to DT solution. DT CLNC exhibited significantly higher release of DT in comparison to DT solution during in vitro permeation studies employing non-reverted rat-intestinal sac. Superior uptake of DT in zebra fishes exposed to DT CLNC resulted in greater apoptosis-based cell death as compared to those exposed to DT solution. This correlated well with the significantly superior (p < 0.05) anti-angiogenic activity of DT CLNC system over DT solution, in zebra fish model. DT CLNC also inhibited tumor growth in melanoma cell line induced tumors in C57BL/6 mice significantly, as compared to DT solution (p < 0.05). The DT CLNC system demonstrated adequate stability, with tremendous potential to improve oral efficacy of DT and can serve as an alternative to existing DT formulations available commercially for parenteral use.

Determination of docetaxel in rat plasma and its application in the comparative pharmacokinetics of Taxotere and SID530, a novel docetaxel formulation with hydroxypropyl-β-cyclodextrin

In this study, a sensitive, simple and reliable method for the quantification of docetaxel in rat plasma was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The plasma samples were prepared by protein precipitation, and paclitaxel was used as an internal standard (IS). Chromatographic separation was achieved using a Gemini C(18) column (2.0 × 150 mm, 5 µm) with a mobile phase consisting of 0.1% formic acid-acetonitrile (30:70, v/v). The precursor-product ion pairs used for multiple reaction monitoring were m/z 808.5 → 527.5 (docetaxel) and m/z 854.2 → 286.5 (IS, paclitaxel). A calibration curve for docetaxel was constructed over the range 1-1000 ng/mL. The developed method was specific, precise and accurate, and no matrix effect was observed. The validated method was applied in a comparative pharmacokinetic study in which two docetaxel formulations, SID530, a new parenteral formulation of docetaxel with hydroxypropyl-β-cyclodextrin (HP-β-CD), and Taxotere, were administered to rats at a dose of 5 mg/kg. For SID530 and Taxotere, the mean C(0) values were 1494 and 1818 ng/mL, respectively, and the AUC(last) values were 837 and 755 h ng/mL, respectively. These two formulations did not show any statistical differences with regard to the pharmacokinetic parameters, thus establishing that the SID530 and Taxotere products are pharmacokinetically comparable in male rats.

Formulation and pharmacokinetic evaluation of a paclitaxel nanosuspension for intravenous delivery

Paclitaxel is a diterpenoid isolated from Taxus brevifolia. It is effective for various cancers, especially ovarian and breast cancer. Due to its aqueous insolubility, it is administered dissolved in ethanol and Cremophor^® EL (BASF, Ludwigshafen, Germany), which can cause serious allergic reactions. In order to eliminate Cremophor EL, paclitaxel was formulated as a nanosuspension by high-pressure homogenization. The nanosuspension was lyophilized to obtain the dry paclitaxel nanoparticles (average size, 214.4 ± 15.03 nm), which enhanced both the physical and chemical stability of paclitaxel nanoparticles. Paclitaxel dissolution was also enhanced by the nanosuspension. Differential scanning calorimetry showed that the crystallinity of paclitaxel was preserved during the high-pressure homogenization process. The pharmacokinetics and tissue distribution of paclitaxel were compared after intravenous administration of paclitaxel nanosuspension and paclitaxel injection. In rat plasma, paclitaxel nanosuspension exhibited a significantly (P < 0.01) reduced area under the concentration curve (AUC)_0–∞ (20.343 ± 9.119 μg · h · mL⁻¹ vs 5.196 ± 1.426 μg · h · mL⁻¹), greater clearance (2.050 ± 0.616 L · kg⁻¹ · h⁻¹ vs 0.556 ± 0.190 L · kg⁻¹ · h⁻¹), and shorter elimination half-life (5.646 ± 2.941 vs 3.774 ± 1.352 hours) compared with the paclitaxel solution. In contrast, the paclitaxel nanosuspension resulted in a significantly greater AUC_0–∞ in liver, lung, and spleen (all P < 0.01), but not in heart or kidney.

Evaluation of the pharmaceutical quality of docetaxel injection using new stability indicating chromatographic methods for assay and impurities

New stability indicating chromatographic methods have been developed for estimation of Assay and Impurities of Docetaxel in Docetaxel injection for evaluation of pharmaceutical quality. With this method, the process related impurities and degradants are well separated from the peaks due to placebo. The relative retention times and relative response factors of the known impurities have been established. The LOQ of the known impurities and docetaxel are found to be less than 0.2 Îg /ml and the recovery falls in the range of 90â110%. Peak purities demonstrated the stability indicating nature of the methods. The methods developed in the present study overcome the lacunae of the existing published methodologies in evaluation of the quality of Docetaxel injection. In essence, the present study provides an improved methodology for evaluation of the pharmaceutical quality of Docetaxel injection.

Phase I trial of intravesical docetaxel in the management of superficial bladder cancer refractory to standard intravesical therapy

PURPOSE

Up to 50% of patients treated with intravesical agents for superficial bladder cancer will experience recurrence. Response rates to second-line intravesical therapies range from 20% to 40%. For these high-risk patients, novel agents are necessary to prevent recurrence. Docetaxel is a microtubule depolymerization inhibitor with unique physiochemical properties, making it an excellent candidate for investigation as an intravesical agent.

PATIENTS AND METHODS

This phase I trial included patients with recurrent Ta, T1, and Tis transitional cell carcinoma who experienced treatment failure with at least one prior intravesical treatment. Docetaxel was administered as six weekly instillations at a starting dose of 5 mg, with a dose-escalation model used until a maximum tolerated dose (MTD) was achieved. Primary end points were dose-limiting toxicity (DLT) and MTD. Efficacy was evaluated by cystoscopy with biopsy, cytology, and computed tomography imaging.

RESULTS

Eighteen patients (100%) completed the trial, and the distribution of stages included six patients with Tis, seven with Ta, and five with T1 disease. No grade 3 or 4 DLTs occurred in 108 infusions, and no patient had systemic absorption of docetaxel. Eight (44%) of 18 patients experienced grade 1 or 2 toxicities, with dysuria being the most common. Ten (56%) of 18 patients had no evidence of disease at their post-treatment cystoscopy and biopsy. None of the patients who experienced relapse had disease progression.

CONCLUSION

Intravesical docetaxel exhibited minimal toxicity and no systemic absorption in the first human intravesical clinical trial. This suggests that docetaxel is a safe agent for further evaluation of efficacy in a phase II trial.

Clinical pharmacokinetics of docetaxel : recent developments

Docetaxel belongs to the class of taxane antineoplastic agents that act by inducing microtubular stability and disrupting the dynamics of the microtubular network. The drug has shown a broad spectrum of antitumour activity in preclinical models as well as clinically, with responses observed in various disease types, including advanced breast cancer and non-small cell lung cancer. The pharmacokinetics and metabolism of docetaxel are extremely complex and have been the subject of intensive investigation in recent years. Docetaxel is subject to extensive metabolic conversion by the cytochrome P450 (CYP) 3A isoenzymes, which results in several pharmacologically inactive oxidation products. Elimination routes of docetaxel are also dependent on the presence of drug-transporting proteins, notably P-glycoprotein, present on the bile canalicular membrane. The various processes mediating drug elimination, either through metabolic breakdown or excretion, impact substantially on interindividual variability in drug handling. Strategies to individualise docetaxel administration schedules based on phenotypic or genotype-dependent differences in CYP3A expression are underway and may ultimately lead to more selective chemotherapeutic use of this agent.

Determination of Docetaxel and Paclitaxel in Human Plasma by High-Performance Liquid Chromatography

Taxanes, docetaxel and paclitaxel, represent important antineoplastic agents with broad spectra of antitumor activity. The authors developed and validated a high-performance liquid chromatography method with ultraviolet detection for quantifying both taxanes in human plasma. The assay uses liquid-liquid extraction as sample treatment and an isocratic mobile phase and reversed-phase chromatography to determine docetaxel with paclitaxel as internal standard and vice versa. The lower limit of quantification was 0.015 mg/L. The assay had good recovery (87.96+/-14.05 and 90.57+/-9.63 for docetaxel and paclitaxel respectively) and precision: the within-day and between-days relative standard deviation of the mean for docetaxel (0.015-3 mg/L) and paclitaxel was always <10%. The method presented has been fully validated following the U.S. Food and Drug Administration requirements and has been successfully applied for the pharmacokinetic investigation of docetaxel or paclitaxel.

Liquid chromatography/tandem triple-quadrupole mass spectrometry for determination of paclitaxel in rat tissues

A liquid chromatography/tandem triple-quadrupole mass spectrometry assay to quantify paclitaxel in rat tissue homogenates containing taxol or paclitaxel nanoliposome (PTX-NLP) was developed and validated. Liquid-liquid extraction with tert-butyl methyl ether was used for tissue sample preparation and docetaxel was used as the internal standard. Paclitaxel and docetaxel were separated on a 200 mm x 4.6 mm x 5 microm C(18) column and quantified using a triple-quadrupole mass spectrometer operating in positive ion electrospray selective reaction monitoring mode (ESI(+)-SRM) with a total run time of 6.0 min. The peak area of the m/z 876.3 --> 307.9 transition of paclitaxel is measured versus that of the m/z 830.3 --> 549.1 transition of docetaxel to generate the standard curves. The standard curves were linear over the concentration range of 0.2008-2008 ng/mL for different tissues. The method had high extraction recovery (>90%) and accuracy (>90%) with the intra-day and inter-day precision <15%. Frozen stability, freeze/thaw stability, extraction stability and solution stability at ambient temperature were examined, which indicated the tissue samples should be extracted within 5 days and avoid being frozen and thawed repeatedly over 5 times. Extracted samples after evaporation could be stored at -20 degrees C for 20 days without drug degradation and no degradation was also observed after solution samples were left to stand at ambient temperature for 24 h. This assay was used to support an in vivo biodistribution study of PTX-NLP in rats.

Rapid analysis of docetaxel in human plasma by tandem mass spectrometry with on-line sample extraction

A simple, rapid, and sensitive analytical method for the measurement of docetaxel in human plasma was developed and validated. The method is based on positive electrospray ionization tandem mass spectrometry (ESI+-MS-MS) with on-line sample extraction. It uses paclitaxel as internal standard for calibration. The on-line sample extraction minimizes sample handling and is readily adopted for automation. Quantitation of plasma docetaxel was done by the multiple reaction monitoring (MRM) mode. The method had a linear calibration range of 1.00-3000 ng/mL with a correlation coefficient >0.9999. The limit of quantitation (LOQ) for docetaxel in plasma was 1.00 ng/mL. The on-line extraction recovery of docetaxel was between 86.1-94.7%, with %CV < or = 6.1%. This method has high accuracy (90.1-96.3%), and excellent intra-assay (0.6-3.8%) and inter-assay (2.0-5.7%) precision. Its applicability to clinical samples was demonstrated by measuring patient plasma samples after treatment of weekly docetaxel at 25 mg/m2 as 60-min infusion.

Simple and rapid docetaxel assay in plasma by protein precipitation and high-performance liquid chromatography–tandem mass spectrometry

A simple, rapid and low cost sample preparation method was developed for quantification of docetaxel in mouse plasma by high-performance liquid chromatography/tandem mass spectrometry with paclitaxel as the internal standard. A small volume of plasma (40 microl) and one-step protein precipitation using methanol and acetonitrile (1:1 (v/v)) were used for sample preparation. The calibration curve for docetaxel in mouse plasma was linear over the range 25-2500 nM. The detection limit was 8 nM. The lower limit of quantitation is 25 nM. The intra- and inter-day precisions (CV) of analysis were 9.5 and 9.7% for the low quality control (LQC), 5.5 and 4.9% for the medium quality control (MQC) and 3.9 and 6.3% for the high quality control (HQC), respectively. The accuracy was 102.5% for LQC, 97.9% for MQC and 108.8% for HQC. This assay has now been applied to evaluation of mouse pharmacogenetics and other clinical pharmacology applications.

Comparative pharmacokinetics of weekly and every-three-weeks docetaxel

PURPOSE

Weekly administration of docetaxel has demonstrated comparable efficacy together with a distinct toxicity profile with reduced myelosuppression, although pharmacokinetic data with weekly regimens are lacking. The comparative pharmacokinetics of docetaxel during weekly and once every 3 weeks (3-weekly) administration schedules were evaluated.

EXPERIMENTAL DESIGN

Forty-six patients received weekly docetaxel (35 mg/m(2)) as a 30-min infusion alone (n = 8) or in combination with irinotecan (n = 12), or in 3-weekly regimens, as a 1-h infusion at 60 mg/m(2) with doxorubicin (n = 10), 75 mg/m(2) alone (n = 9), or 100 mg/m(2) alone (n = 7). Serial blood samples were obtained immediately before and up to 21 days after the infusion. Plasma concentrations were measured by liquid chromatography-mass spectrometry and analyzed by compartmental modeling.

RESULTS

Mean +/- SD docetaxel clearance values were similar with weekly and 3-weekly schedules (25.2 +/- 7.7 versus 23.7 +/- 7.9 liter/h/m(2)); half-lives were also similar with both schedules of administration (16.5 +/- 11.2 versus 17.6 +/- 7.4 h). With extended plasma sampling beyond 24 h post-infusion, docetaxel clearance was 18% lower and the terminal half-life was 5-fold longer. At 35 mg/m(2), the mean +/- SD docetaxel concentration on day 8 was 0.00088 +/- 0.00041 microg/ml (1.08 +/- 0.51 nM) at 75 mg/m(2), concentrations on day 8, 15, and 22 were 0.0014 +/- 0.00043 microg/ml (1.79 +/- 0.53 nM), 0.00067 +/- 0.00025 microg/ml (0.83 +/- 0.31 nM), and 0.00047 +/- 0.00008 microg/ml (0.58 +/- 0.099 nM), respectively.

CONCLUSION

Docetaxel pharmacokinetics are similar for the weekly and 3-weekly regimens. Prolonged circulation of low nanomolar concentrations of docetaxel may contribute to the mechanism of action of docetaxel through suppression of microtubule dynamics and tumor angiogenesis and enhanced cell radiosensitivity in combined modality therapy.

Simultaneous analysis of docetaxel and the formulation vehicle polysorbate 80 in human plasma by liquid chromatography/tandem mass spectrometry

An analytical procedure for the simultaneous determination of the anticancer agent docetaxel (Taxotere) and its formulation vehicle polysorbate 80 (Tween 80) in human plasma samples is described. Sample pretreatment involved a double liquid-liquid extraction step with a mixture of acetonitrile/n-butyl chloride (1/4, v/v). Separation of the compounds of interest, including the internal standard paclitaxel, was achieved on a reversed-phase Waters X-Terra mass spectrometry (MS) column (50 x 2.1mm internal diameter) packed with a 3.5-microm octadecyl stationary phase, using isocratic elution. Detection of docetaxel and polysorbate 80 was performed using tandem MS detection with electrospray ionization. Validation results indicated that the method is accurate and precise and has lower limits of quantitation of 0.500 nM (approximately 0.4 ng/ml) and 1.00 microg/ml for docetaxel and polysorbate 80, respectively. The method was subsequently used to measure concentrations of docetaxel and polysorbate 80 in plasma samples in support of a project to assess the influence of polysorbate 80 concentrations on the disposition and toxicity profile of docetaxel in cancer patients receiving Taxotere.

Sensitive liquid chromatography-mass spectrometry assay for quantitation of docetaxel and paclitaxel in human plasma

We have developed a high-performance liquid chromatography-electrospray ionization mass spectrometry (LC-MS) method for quantifying docetaxel and paclitaxel in human plasma. The assay fulfills the need for defining the lower plasma concentrations of these antineoplastic agents that result from a number of changes in how these agents are used clinically. The assay uses paclitaxel as the internal standard for docetaxel, and vice versa; solid-phase extraction; a Phenomenex Hypersil ODS (5 micrometer, 100x2 mm) reversed-phase analytical column; an isocratic mobile phase of 0.1% formic acid in methanol-water (70:30, v/v); and mass spectrometric detection using electrospray positive mode electron ionization. The assay has a lower limit of quantitation (LLOQ) of 0.3 nM and is linear between 0.3 nM and 1 microM for docetaxel. For paclitaxel, the LLOQ was 1 nM, and the assay is linear between 1 nM and 1 microM. We demonstrated the suitability of this assay for docetaxel by using it to quantify the docetaxel concentrations in plasma of a patient given 40 mg/m(2) of docetaxel and comparing those results to results produced when the same samples were assayed with an HPLC assay using absorbance detection. In a similar manner, the suitability of the assay for paclitaxel was demonstrated by using it to quantify the concentrations of paclitaxel in the plasma of a patient given 15 mg/m(2) of paclitaxel and comparing those results to results produced when the same samples were assayed with an HPLC assay using absorbance detection. The LC-MS assay, which proved superior because of its greater sensitivity and relatively short (7 min) run time, should be an important tool for future pharmacokinetic analyses of docetaxel and paclitaxel.

A rapid and sensitive liquid chromatography/tandem mass spectrometry method for determination of docetaxel in human plasma

A novel, rapid and sensitive isocratic liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for quantification of docetaxel in human plasma with paclitaxel as internal standard. The high sensitivity and specificity of MS/MS detection enabled the use of a small volume of plasma (0.05 mL) and a simple liquid-liquid extraction procedure. Furthermore, a very short run-time (3 min) fulfilled the need for monitoring plasma levels of docetaxel from large-scale clinical studies. The calibration curve for docetaxel was linear over the range 5-1000 ng/mL with coefficients of correlation >0.999 using only 0.05 mL plasma. The intra- and inter-day precisions (CV) of analysis were <7%, and accuracy ranged from 96 to 110%. The applicability of the method was demonstrated in a pharmacokinetic study of a 1-h infusion of docetaxel with dosages of 75 mg/m(2). Possible conjugated metabolites of docetaxel were not detected in patients' samples.

High-performance liquid chromatographic assay for the determination of the novel C-Seco-taxane derivative (IDN 5390) in mouse plasma

A HPLC assay was developed to determine IDN 5390, a new paclitaxel analogue, in mouse plasma. The method involves solid-phase extraction from cyano cartridges (recovery >80%), HPLC separation on Symmetry C(18) (4.6 x 150 mm), on isocratic mobile phase of water-acetonitrile-acetic acid (49:50:1) and detection at 227 nm. Retention times of IDN 5390 and IDN 5517 (internal standard, I.S.) were 9.1 and 10.5 min, respectively. The assay was linear from 0.05 to 5 micro g/ml (r(2)>or=0.995), showed intra- and inter-day precision within 1.0 and 6.2%, and accuracy of 94.7-106.8%. LOQ was 0.050 micro g/ml. Using this method IDN 5390 pharmacokinetics was determined in mice.

Src tyrosine kinase augments taxotere-induced apoptosis through enhanced expression and phosphorylation of Bcl-2

Activation of Src, which has an intrinsic protein tyrosine kinase activity, has been demonstrated in many human tumours, such as colorectal and breast cancers, and is closely associated with the pathogenesis and metastatic potential of these cancers. In this study, we have examined the effect of activated Src on the sensitivity to taxotere, an anticancer drug targeting microtubules, using v-src-transfected HAG-1 human gall bladder epithelial cells. As compared with parental HAG-1 cell line, v-src-transfected HAG/src3-1 cells became 5.9 and 7.0-fold sensitive to taxotere for 2 and 24-h exposure, respectively. By contrast, HAG-1 cells transfected with activated Ras, which acts downstream of Src, acquired approximately 2.5- approximately 4.8-fold taxotere resistance. The taxotere sensitivity in HAG/src3-1 cells was reversed, if not completely, by herbimycin A, a specific inhibitor of Src family protein tyrosine kinase, indicating that Src protein tyrosine kinase augments sensitivity to taxotere. Treatment of HAG/src3-1 cells with taxotere resulted in phosphorylation of Bcl-2 and subsequent induction of apoptotic cell death, whereas neither Bcl-2 phosphorylation nor apoptosis occurred in parental or c-H-ras-transfected HAG-1 cells. Interestingly, the Bcl-2 protein is overexpressed in v-src-transfected cell line, compared to those in parental or Ras-transfected cell line. Treatment of HAG/src3-1 cells with herbimycin A significantly reduced the expression and phosphorylation of Bcl-2, and abrogated taxotere-induced apoptosis, suggesting a potential role for Src protein tyrosine kinase in the taxotere-induced apoptotic events. H-7, a protein kinase C inhibitor and wortmannin, a phosphatidylinositol-3 kinase (PI-3 kinase) inhibitor, neither altered taxotere sensitivity nor inhibited taxotere-induced apoptosis in these cells. These data indicate that the ability of activated Src to increase taxotere sensitivity would be mediated by apoptotic events occurring through Src to downstream signal transduction pathways toward Bcl-2 phosphorylation, but not by activated Ras, PI-3 kinase or protein kinase C.

Analytical approaches for traditional chinese medicines exhibiting antineoplastic activity

Traditional Chinese medicines have attracted great interest in recent researchers as alternative antineoplastic therapies. This review focuses on analytical approaches to various aspects of the antineoplastic ingredients of traditional Chinese medicines. Emphasis will be put on the processes of biological sample extraction, separation, clean-up steps and the detection. The problems of the extraction solvent selection and different types of column chromatography are also discussed. The instruments considered are gas chromatography, capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC) connected with various detectors (ultraviolet, fluorescence, electrochemistry, mass, etc.). In addition, determinations of antineoplastic herbal ingredients, including camptothecin, taxol (paclitaxel), vinblastine. vincristine, podophyllotoxin, colchicine, and their related compounds, such as irinotecan, SN-38, topotecan, 9-aminocamptothecin, docetaxel (taxotere) and etoposide, are briefly summarized. These drugs are structurally based on the herbal ingredients, and some of them are in trials for clinical use. Evaluation of potential antineoplastic herbal ingredients, such as harringtonine, berberine, emodin, genistein, berbamine, daphnoretin, and irisquinone, are currently investigated in laboratories. Other folk medicines are excluded from this paper because their antineoplastic ingredients are unknown.

Simple and sensitive high-performance liquid chromatography method for the determination of docetaxel in human plasma or urine

Several methods for quantification of docetaxel have been described mainly using HPLC. We have developed a new isocratic HPLC method that is as sensitive and simpler than previous methods, and applicable to use in clinical pharmacokinetic analysis. Plasma samples are spiked with paclitaxel as internal standard and extracted manually on activated cyanopropyl end-capped solid-phase extraction columns followed by isocratic reversed-phase HPLC and UV detection at 227 nm. Using this system, the retention times for docetaxel and paclitaxel are 8.5 min and 10.5 min, respectively, with good resolution and without any interference from endogenous plasma constituents or docetaxel metabolites at these retention times. The total run time needed is only 13 min. The lower limit of quantification is 5 ng/ml using 1 ml of plasma. The validated quantitation range of the method is 5-1000 ng/ml with RSDs < or = 10%, but plasma concentrations up to 5000 ng/ml can be accurately measured using smaller aliquots. This method is also suitable for the determination of docetaxel in urine samples under the same conditions. The method has been used to assess the pharmacokinetics of docetaxel during a phase I/II study of docetaxel in combination with epirubicin and cyclophosphamide in patients with advanced cancer.

Rapid and sensitive determination of paclitaxel (Taxol(R)) in environmental samples by high-performance liquid chromatography tandem mass spectrometry

A new, rapid and sensitive method for the quantitative determination of paclitaxel (Taxol(R)) in environmental samples is developed and validated. This highly sensitive and specific method was successfully applied to an environmental monitoring study for identifying occupational exposure situations to anticancer drugs. After addition of an internal standard, 2'-methylpaclitaxel, aqueous extraction of wipe samples or air filters followed by a single-step liquid-liquid extraction with ethyl acetate was performed. Extraction efficiency averaged 90%. The method is based on analysis by liquid chromatography with tandem mass spectrometry in selected reaction monitoring mode of environmental samples from the preparation and administration of cytostatic agents. The assay is linear (r = 0.998) in the range 2-64 ng on filters (air samples), and 20-320 ng on wipe samples. The accuracy of the assay is always </=20% for both matrices, and the intra- and interday assay variability of paclitaxel ranged from 7 to 19% and 10 to 14%, respectively. The lower limit of quantification is assessed at 2 ng on filter and 10 ng on wipe samples. Copyright 2000 John Wiley & Sons, Ltd.