Adaptation of solid phase extraction to an automated column switching method for online sample cleanup as the basis of a facile and sensitive high-performance liquid chromatographic assay for paclitaxel in human plasma

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.

Determination of morphine, codeine, and paclitaxel in human serum and plasma by micellar electrokinetic chromatography

A micellar electrokinetic chromatography method is proposed for the determination of morphine, codeine, and paclitaxel at clinical relevant levels in human serum and plasma, which are employed in the treatment of patients with cancer. Optimal conditions for the separation were investigated. A background electrolyte solutions consisting of 20 mM borate buffer adjusted to pH 8.5, sodium dodecyl sulphate 60 mM and 15% methanol, hydrodynamic injection, and 25 kV as separation voltage were used. Detection wavelength was 212 nm for morphine and codeine and 200 nm for paclitaxel. Aspects such as stability of the solutions, linearity, accuracy, precision, and robust and ruggedness were examined in order to validate the proposed method. Detection limits obtained for all the studied compounds ranged between 26 and 52 ng/mL. Before micellar electrokinetic chromatography determination, the samples were purified and enriched by means of an extraction-preconcentration step with a preconditioned C(18) cartridge. This method was applied to the analysis of serum and plasma samples from different cancer patients undergoing treatment with paclitaxel or/and codeine.

Phase I study of the c-raf-1 antisense oligonucleotide ISIS 5132 in combination with carboplatin and paclitaxel in patients with previously untreated, advanced non-small cell lung cancer

BACKGROUND

A phase I trial was performed to evaluate the administration of carboplatin/paclitaxel in combination with ISIS-5132, a phosphorothioate antisense oligodeoxynucleotide inhibitor of c-raf-1 kinase expression, in patients with advanced non-small cell lung cancer (NSCLC).

PATIENTS AND METHODS

Previously untreated patients with stage IIIB/IV NSCLC received ISIS 5132 by continuous intravenous infusion at 2.0 mg/kg/d for 14 days. Starting doses were paclitaxel 175 mg/m(2) and carboplatin targeting an area under the free platinum plasma concentration-time curve (AUC(fp)) of 5 mg . min/ml (dose level 1). The carboplatin dose was then increased to AUC(fp) 6 mg . min/ml (dose level 2) after which the paclitaxel dose was increased to 200 mg/m(2) (dose level 3). The maximum tolerated dose was established by toxicity during the first two 21-day cycles of therapy. The pharmacokinetics of all three agents was determined before and during the ISIS 5132 infusion.

RESULTS

Thirteen patients were treated with the carboplatin/paclitaxel/ISIS 5132 combination. Dose-limiting neutropenia occurred in two patients at dose level 3. Grade 3 and 4 nonhematologic toxicities were infrequent and limited to nausea and constipation. The maximum tolerated doses were carboplatin AUC(fp) 6 mg . min/ml, paclitaxel 175 mg/m(2), and ISIS 5132 2.0 mg/kg/d for 14 days. There were no objective responses and the concurrent infusion of ISIS 5132 did not alter the plasma pharmacokinetics of paclitaxel or total platinum.

CONCLUSION

ISIS 5132 can be safely combined with standard doses of carboplatin and paclitaxel. Combining cytotoxic chemotherapeutic agents with inhibitors of aberrant signal transduction mediated by Raf proteins produced no objective responses in the dose and schedule administered in this study.

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.

Phase I trial and pharmacokinetics of escalating doses of paclitaxel and concurrent hyperfractionated radiotherapy with or without amifostine in patients with advanced head and neck carcinoma

BACKGROUND

Amifostine was developed to protect normal tissues from radiation exposure. The current study was undertaken to determine whether amifostine would allow the delivery of greater numbers of weekly paclitaxel treatments with concomitant, hyperfractionated radiotherapy in patients with advanced head and neck carcinoma.

METHODS

Patients received radiation therapy twice daily using 1.6-gray (Gy) fractions up to a total of 70.4 Gy over an elapsed time of 6.5 weeks. All patients received paclitaxel 60 mg/m(2) once weekly starting on Day 1. The number of doses of paclitaxel was escalated from three to a maximum of six in groups of three patients. For the patients who received amifostine, a dose of 400 mg/m(2) was given intravenously over 15 minutes on Days 1-5, 8, 29-33, and 36. Patients underwent surgery for persistent tumor after radiotherapy. The plasma pharmacokinetics of paclitaxel were characterized during treatment with the first weekly dose to determine the effect of concurrently administered amifostine.

RESULTS

Thirty-six patients were evaluable for this study. In the absence of amifostine, a maximum of four doses of paclitaxel were tolerated in combination with the radiotherapy. With amifostine, up to five doses of paclitaxel could be given. Generally, the treatment resulted in Grade 2 and 3 stomatitis. Overall, 69% of patients had a complete remission, and 29% had a partial remission. Both progression-free survival and overall survival were 66% at 30 months. Amifostine had no effect on the pharmacokinetics of paclitaxel.

CONCLUSIONS

The administration of amifostine allowed the authors to give an additional dose of paclitaxel to patients who were undergoing hyperfractionated radiotherapy for head and neck carcinoma. This treatment regimen resulted in a high frequency of complete remissions and an excellent progression-free survival pattern without compromising the plasma kinetics of paclitaxel.

Phase I trial of the matrix metalloproteinase inhibitor marimastat combined with carboplatin and paclitaxel in patients with advanced non-small cell lung cancer

PURPOSE

Marimastat is an orally bioavailable inhibitor of matrix metalloproteinases. A phase I study was initiated to determine whether conventional doses of carboplatin and paclitaxel are tolerated when combined with marimastat and to assess the influence of marimastat on paclitaxel pharmacokinetics.

EXPERIMENTAL DESIGN

Three dose levels were evaluated. Marimastat (10 or 20 mg oral administration b.i.d.) was administered continuously with paclitaxel (175 or 200 mg/m(2) as a 3-hour i.v. infusion) and carboplatin (at a dose providing an area under the free drug plasma concentration-time curve of 7 mg min/mL) administered each 3 weeks. Toxicity and response were evaluated throughout the intended four cycles of combined therapy. The plasma pharmacokinetics of paclitaxel was determined in each patient both without concurrent marimastat and after receiving marimastat for 1 week.

RESULTS

Twenty-two chemotherapy-naive patients with stage IIIb (27%) or stage IV (73%) non-small cell lung cancer were enrolled. Their median age was 56 years (range, 39-73 years), 50% were female, and their performance status (Eastern Cooperative Oncology Group) ranged from 0 to 2. Treatment was well tolerated, as 18 (82%) of the patients completed all four cycles of chemotherapy without dose-limiting toxicity. Grade 2 musculoskeletal toxicities were reported in 3 of 12 patients receiving marimastat (20 mg b.i.d.). Nine patients required dose reductions, predominantly related to low-grade myelosuppression. Partial responses occurred in 12 of 21 (57%) evaluable patients with disease stabilization in another 5 (19%). Marimastat had no effect on paclitaxel pharmacokinetics.

CONCLUSIONS

The administration of marimastat (10 mg b.i.d.) with paclitaxel (200 mg/m(2)) and carboplatin at an area under the free drug plasma concentration-time curve of 7 mg min/mL was well tolerated with no apparent pharmacokinetic interaction. Study of this drug combination in the adjuvant setting should be considered if tissue inhibition of matrix metalloproteinase activity can first be shown.

Sensitive HPLC method for quantitation of paclitaxel (Genexol in biological samples with application to preclinical pharmacokinetics and biodistribution

A sensitive, specific and reproducible HPLC method has been developed and validated for the quantitative determination of paclitaxel in plasma, tissues and tumor of mice. Tissue specimens including liver, kidneys, spleen, lungs, heart and tumor were separately homogenized in bovine serum albumin (BSA, 40 g/l) in water. Plasma or tissue homogenates (0.1 ml) containing paclitaxel and internal standard (dimethyl-4,4'-dimethoxy-5,6,5',6'-dimethylene dioxy biphenyl-2',2' dicarboxylate (DDB), I.S.) were extracted by ethyl acetate (10 ml). A 4.6 mm x 250 mm ODS column was used to separate the components in biological samples with UV detection at 227 nm and gradient system was applied to a quantitation of paclitaxel consisting of acetonitrile-deionized water. The I.S. and paclitaxel were eluted at 13.7 and 18.0 min, respectively, and no interfering peaks were observed. Linear relationships (r(2) > 0.999) were obtained between the peak height ratios and the corresponding biological sample concentrations over the range of 0.1-20 microg/ml. The average intra- and inter-day variations (% R.S.D.s and % deviations) of the assay for biological samples were less than 10%. The LOD and LOQ were 5 and 10 ng/ml, respectively, for paclitaxel using a microsample volume (100 microl) of plasma sample. This HPLC method has been successfully applied for the determination of paclitaxel in pharmacokinetic and biodistribution study in after administration of 50 mg equivalent paclitaxel/kg dose of paclitaxel-loaded polymeric micelle and 20 mg equivalent paclitaxel/kg dose of Taxol to female SPF C57BL/6 mice.

Normal phase high performance liquid chromatography for determination of paclitaxel incorporated in a lipophilic polymer matrix

A normal phase (NP) high performance liquid chromatography (HPLC) method was developed for analysis of paclitaxel incorporated in poly(sebacic-co-ricinoleic acid), a lipophilic polymer matrix utilized for preparation of an injectable formulation for the localized delivery of paclitaxel. Thin layer chromatography experiments revealed that separation of paclitaxel from the polymer is dependent on the eluting strength (solvent strength) of the mobile phase. The HPLC system consists of a Purospher STRAR Si analytical HPLC column (5 microm, 250mm x 4mm, Merck), and 1-2.5% (v/v) methanol in dichloromethane as the mobile phase. Detection was by UV absorbance at 240 and 254 nm. The effect of the mobile phase composition on paclitaxel retention, peak shape and column efficiency, and the influence of the sample loading on the shape of the paclitaxel peak were studied. The mobile phases used for the chromatography consisted of 1.5% (v/v) methanol in dichloromethane. Paclitaxel was determined in the formulation and in the samples from degradation studies using UV detection at a wavelength of 254 nm. UV detection at 240 nm has advantages for following polymer matrix degradation products due to higher detector response at this wavelength. The utility of the proposed NP HPLC approach was demonstrated by assessment of intra- and inter-batch content uniformity, and by the determination of paclitaxel content after 7 and 60 days exposure of the paclitaxel-loaded polymer matrix to in vitro and in vivo degradation.

Determination of paclitaxel in mouse plasma and brain tissue by liquid chromatography-mass spectrometry

Paclitaxel is an anticancer agent extracted from the bark of the yew tree and is widely used in chemotherapy for solid tumors, including non-small cell lung cancer and ovarian carcinoma. Most assays to measure paclitaxel in plasma require a large amount of sample (0.4-1 ml) to achieve the necessary sensitivity, and are not suitable when only small sample sizes are available. To circumvent this latter limitation, we developed a sensitive liquid chromatography-mass spectrometry (LC-MS) method for the determination of paclitaxel in plasma based on the use of small sample volumes (50 microl plasma). A solid phase extraction procedure was employed that enabled the eluent to be directly injected onto a reversed phase chromatographic HPLC system using positive electrospray ionization followed by mass spectrometric detection. The extraction recoveries of paclitaxel were 98 and 83% from plasma and brain tissues, respectively. The mobile phase consisted of 50% acetonitrile in 0.1% formic acid that was pumped at 0.2 ml/min to yield a retention time for paclitaxel of 6.2 and 5.4 min for cephalomannine, the internal standard. The method has been validated at paclitaxel plasma concentrations from 0.036 to 9.9 microg/ml, and from 0.054 to 1.96 microg/ml in brain homogenates. A sensitive and specific assay for paclitaxel has been developed that has the advantages of using small sample sizes, and a single extraction step without solvent evaporation.

Phase II study of liposomal doxorubicin and weekly paclitaxel for recurrent Müllerian tumors

OBJECTIVE

Pegylated liposomally encapsulated doxorubicin (Doxil. Ortho-Biotech) and paclitaxel (Taxol, Bristol Myers Squibb) are both active against Müllerian malignancies. A phase II trial was performed to determine the toxicity and efficacy of these agents when administered in combination.

METHODS

Patients were initially treated with 30 mg/m(2) of liposomal doxorubicin every 21 days and 70 mg/m(2) of paclitaxel every week for 18 weeks. The plasma pharmacokinetics of paclitaxel was determined when administered alone and concurrently with liposomal doxorubicin.

RESULTS

Forty women with recurrent gynecologic malignancies of Müllerian origin including 34 with ovary and primary peritoneal cancer (85%) were enrolled. Toxicity was evaluated for all 508 cycles of therapy. Paclitaxel and liposomal doxorubicin were delivered at 95% (66.4 mg/m(2)/week) and 77% (7.65 mg/m(2)/week) of their intended weekly dose intensities, respectively. Reductions in the dose of liposomal doxorubicin were frequently required for palmar plantar erythrodysesthesia during the latter cycles of therapy. There were 4 patients with a complete response and 7 with partial responses, for an overall objective response rate of 29%, among the 38 evaluable patients. Response rates for the subset of 13 women with tumor recurrence occurring at least 6 months after prior platinum-based therapy was 54%. The concurrent administration of liposomal doxorubicin did not alter the pharmacokinetic disposition of paclitaxel.

CONCLUSION

Liposomal doxorubicin with weekly paclitaxel is active in Müllerian malignancies. The concurrent delivery of the weekly paclitaxel with liposomal doxorubicin may increase liposomal doxorubicin skin toxicity. Liposomal doxorubicin does not alter the pharmacokinetics of paclitaxel.

Quantitative determination of paclitaxel in human plasma using semi-automated liquid-liquid extraction in conjunction with liquid chromatography/tandem mass spectrometry

This paper describes a high-throughput sample preparation procedure combined with LC-MS/MS analysis to measure paclitaxel in human plasma. Paclitaxel and an internal standard were extracted from plasma by a semi-automated robotic method using liquid-liquid extraction. Thereafter compounds were separated on a RP C18 column. Detection was by a PE Sciex API 3000 mass spectrometer equipped with a TurboIonSpray interface. The compounds were detected in positive ion mode using the mass transition m/z 854.6-->286.2 and m/z 831.6-->263.2 for paclitaxel and the internal standard, respectively. The limit of quantitation for paclitaxel was 1 ng/ml with an imprecision of 5.2% following extraction of 0.1 ml of plasma. Linearity was confirmed over the whole calibration range (1-1000 ng/ml) with correlation coefficients higher than 0.99 indicating good fits of the regression models. The inter and intra-day precision was better than 9.5% and the accuracy ranged from 90.3 to 104.4%. The assay was simple, fast, specific and exhibited excellent ruggedness.

Quantitation of paclitaxel in micro-sample rat plasma by a sensitive reversed-phase HPLC assay

A sensitive high-performance liquid chromatographic (HPLC) method was developed for the determination of paclitaxel in micro-samples of rat plasma in order to study the mechanism of enhanced systemic exposure of paclitaxel co-administered with P-glycoprotein inhibitors. The assay involved solid-phase extraction procedures using 2'-methylpaclitaxel as the internal standard. Chromatographic separations were achieved using a ZORBAX ODS C18 column and mobile phase consisting of acetonitrile, methanol and ammonium acetate buffer (10 mM, pH 5.0) (48.5:16.5:35) pumped at 0.8 ml/min. The effluents were measured for UV absorption at 227 nm, with retention times of 8.5 and 11.0 min for paclitaxel and 2'-methylpaclitaxel, respectively. The chromatographic separation was excellent, with no endogenous interference. The standard curves showed a good linearity (r=0.9994) over the concentration ranges of 10-1,000 ng/ml. At 1,000 ng/ml, the absolute recoveries of paclitaxel and 2'-methylpaclitaxel are 89 and 90%, respectively. The intra- and inter-day variabilities of paclitaxel were both less than 15%. This validated method for the assay of paclitaxel in micro-sample rat plasma made it feasible to study the pharmacokinetics of the drug in a single rat.

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.

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.

A Phase I-II study of 96-hour infusional topotecan and paclitaxel for patients with recurrent Müllerian tumors

BACKGROUND

Topotecan and paclitaxel are schedule dependent chemotherapeutic agents with activity against ovarian carcinoma. A Phase I-II study in which both drugs were administered concurrently by 96-hour, continuous, intravenous infusion was performed to determine the maximum tolerated dose (MTD), toxicities, pharmacokinetics, and efficacy of the combination.

METHODS

Women with ovarian or primary peritoneal carcinoma and documented recurrent disease were eligible for the study. The dose of topotecan was escalated from 1.6 mg/m(2) while maintaining the paclitaxel dose constant at 100 mg/m(2). Plasma concentrations of both drugs were monitored daily during the first cycle of therapy.

RESULTS

Forty-five patients with a median age of 54 years (range, 42-70 years) received 181 cycles of therapy. Five patients were recruited to each of four dose levels (topotecan 1.6 mg/m(2), 2.0 mg/m(2), 2.8 mg/m(2), and 3.6 mg/m(2)), and an additional 25 patients were treated at the MTD (Phase II). Neutropenia and thrombocytopenia became dose limiting toxicities (DLT) at the fourth dose level. Emesis, mucositis, peripheral neuropathy, diarrhea, and alopecia were mild. Twenty patients (44%) had line-related occlusion, thrombosis, or infection. The mean values (+/- standard deviation) of the apparent steady-state plasma concentrations at the Phase II doses were 2.3 nM +/- 0.5 nM for topotecan lactone, 5.6 nM +/- 2.1 nM for total topotecan, and 40.1 nM +/- 16.8 nM for paclitaxel. There were seven partial responses (Phase II) contributing to an objective response rate of 28% and a median survival time of 11.7 months (range, 0.6-20.1 months).

CONCLUSIONS

Topotecan at a dose of 2.8 mg/m(2) and paclitaxel at a dose of 100 mg/m(2) administered by concurrent, 96-hour, continuous intravenous infusions shows activity against tumors of Müllerian origin.