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Present work describes the development of a liquid chromatography tandem mass spectrometry-based bioanalytical method for the reliable simultaneous quantification of docetaxel (DXL) and carvacrol (CVL) in the mice plasma. A rapid and sensitive bioanalytical method was developed and optimized in mice plasma using Paclitaxel as an internal standard. Validation of the bioanalytical method was performed according to the ICH M10 guideline covering the range of 9.62-1923.08 ng/mL in the mice plasma milleu at the low, mid, and high-quality control concentrations of 28.86 ng/mL, 961.54 ng/mL, and 1346.15 ng/mL, respectively for both the analytes. Validation parameters such as accuracy, precision, carryover-test, matrix effect, and reinjection reproducibility were carried out and were found in limits. Stability studies (Benchtop, autosampler, freeze-thaw, and long-term) were performed and found to be within limits. The developed bioanalytical method was found to be suitable for the simultaneous quantification of DXL and CVL in the mice plasma., Competing Interests: Author contributionsGogikar Shiva Kumar and Sibu Sen: conceptualization, methodology, investigation, formal analysis, data curation, writing—data compilation, and initial draft; Sandeep Daravath: analysis and data curation; Mayur Aalhate, Srushti Mahajan, and Mohd Amaan Mohd Ateeq: formulation development and methodology, and sample preparation; Amol G. Dikundwar and Pankaj K. Singh: conceptualization, supervision, and writing—original draft and editing. Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

A precise, sensitive, accurate, and validated reverse-phase high-performance liquid chromatography (RP-HPLC) method with a bioanalytical approach was utilized to analyze Cabazitaxel (CBZ) in rat plasma. Comparative research on extraction recoveries was performed between traditional liquid-liquid extraction (LLE) and synthesized graphene oxide (GO) based magnetic solid phase extraction (GO@MSPE). The superparamagnetic hybrid nanosorbent was synthesized using the combination of iron oxide and GO and subsequently applied for extraction and bioanalytical quantification of CBZ from plasma by (HPLC-PDA) analysis. Fourier- transform infrared spectroscopy (FT-IR), particle size, scanning electron microscopy (SEM), and x-ray diffraction (XRD) analysis were employed in the characterization of synthesized GO@MSPE nanosorbent. The investigation was accomplished using a shim pack C18 column (150 mm×4.6 mm, 5 µm) with a binary gradient mobile phase consisting of formic acid: acetonitrile: water (0.1:75:25, v/v/v) at a 0.8 mL/min flow rate, and a λ max of 229 nm. The limits of detection (LOD) and quantitation (LOQ) have been determined to be 50 and 100 ng/mL for both LLE and SPE techniques. The linearity range of the approach encompassed from 100 to 5000 ng/mL and was found to be linear (coefficient of determination > 0.99) for CBZ. The proposed method showed extraction recovery of 76.8-88.4% for the synthesized GO@MSPE and 69.3-77.4% for LLE, suggesting that the proposed bioanalytical approach was robust and qualified for all validation parameters within the acceptable criteria. Furthermore, the developed hybrid GO@MSPE nanosorbent with the help of the proposed RP-HPLC method, showed a significant potential for the extraction of CBZ in bioanalysis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The effect of poly(2-ethyl-butyl cyanoacrylate) nanoparticles containing the cytotoxic drug cabazitaxel was studied in three breast cancer cell lines and one basal-like patient-derived xenograft model grown in the mammary fat pad of immunodeficient mice. Nanoparticle-encapsulated cabazitaxel had a much better efficacy than similar concentrations of free drug in the basal-like patient-derived xenograft and resulted in complete remission of 6 out of 8 tumors, whereas free drug gave complete remission only with 2 out of 9 tumors. To investigate the different efficacies obtained with nanoparticle-encapsulated versus free cabazitaxel, mass spectrometry quantification of cabazitaxel was performed in mice plasma and selected tissue samples. Nanoparticle-encapsulated drug had a longer circulation time in blood. There was approximately a three times higher drug concentration in tumor tissue 24 h after injection, and two times higher 96 h after injection of nanoparticles with drug compared to the free drug. The tissue biodistribution obtained after 24 h using mass spectrometry analyses correlates well with biodistribution data obtained using IVIS® Spectrum in vivo imaging of nanoparticles labeled with the fluorescent substance NR668, indicating that these data also are representative for the nanoparticle distribution. Furthermore, immunohistochemistry was used to estimate infiltration of macrophages into the tumor tissue following injection of nanoparticle-encapsulated and free cabazitaxel. The higher infiltration of anti-tumorigenic versus pro-tumorigenic macrophages in tumors treated with the nanoparticles might also contribute to the improved effect obtained with the nanoparticle-encapsulated drug. Tumor infiltration of pro-tumorigenic macrophages was four times lower when using nanoparticles containing cabazitaxel than when using particles without drug, and we speculate that the very good therapeutic efficacy obtained with our cabazitaxel-containing particles may be due to their ability to reduce the level of pro-tumorigenic macrophages in the tumor. In summary, encapsulation of cabazitaxel in poly(2-ethyl-butyl cyanoacrylate) nanoparticles seems promising for treatment of breast cancer., (Copyright © 2018 Oslo University Hospital. Published by Elsevier B.V. All rights reserved.)

A family of five water-soluble Gd 3+ :1,4,7,10-tetraazacyclododecane-1,4,7-tetraacetic acid-modified polyrotaxane (PR) magnetic resonance contrast agents bearing mixtures of 2-hydroxypropyl-β-cyclodextrin and 4-sulfobutylether-β-cyclodextrin macrocycles threaded onto Pluronic cores were developed as long circulating magnetic resonance contrast agents. Short diethylene glycol diamine spacers were utilized for linking the macrocyclic chelator to the PR scaffold prior to Gd 3+ chelation. The PR products were characterized by 1 H NMR, gel permeation chromatography/multiangle light scattering, dynamic light scattering, and analytical ultracentrifugation. Nuclear magnetic relaxation dispersion and molar relaxivity measurements at 23 °C revealed that all the PR contrast agents displayed high spin-spin T 1 relaxation and spin-lattice T 2 relaxation rates relative to a DOTAREM control. When injected at 0.05 mmol Gd/kg body weight in BALB/c mice, the PR contrast agents increased the T 1 -weighted MR image intensities with longer circulation times in the blood pool than DOTAREM. Excretion of the agents occurred predominantly via the renal or biliary routes depending on the polyrotaxane structure, with the longest circulating L81 Pluronic-based agent showing the highest liver uptake. Proteomic analysis of PR bearing different β-cyclodextrin moieties indicated that lipoproteins were the predominant component associated with these materials after serum exposure, comprising as much as 40% of the total protein corona. We infer from these findings that Gd(III)-modified PR contrast agents are promising long-circulating candidates for blood pool analysis by MRI.

In this study, a LC-MS/MS method for the measurement of docetaxel in Dried Blood Spots (DBS) samples was developed and validated. Docetaxel was extracted from 8 mm DBS punch with a mixture of methanol and acetonitrile (9:1, v/v). The chromatographic separation occurred in an Acquity ® C18 column (150 × 2.1 mm, 1.7 μm) eluted with a mixture of water and acetonitrile plus 0.1% formic acid (45:55, v/v). Total analytical run time was 7 min. The method was linear from 50 to 3000 ng ml -1 . Precision assays showed CV% < 9.8% and accuracy between 99 and 103%, mean recovery was 81%. The method was applied in the determination of the docetaxel in 31 patients, after collection of two paired venous blood and DBS samples, following a limited sampling strategy protocol. The analyte was stable in DBS for 18 days at 25 °C and 9 days at 45 °C. The interval of docetaxel concentrations measured in DBS collected before the end of the infusion was 756-3047 ng ml -1 and 60 ± 10 min after the end of the infusion was 57-331 ng ml -1 . AUC values calculated from DBS-derived estimated plasma concentrations (EPC) represented on average 100% of those obtained in plasma samples of 3.1 mgh/l (2.4-4.9 mg h/l). There was a 93% agreement between the classification of patients as within or without the therapeutic range by plasma and EPC AUC. These findings support the clinical use of DBS sampling for routine therapeutic drug monitoring of docetaxel., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Opportunistic fungal infections are common in immunocompromised cancer patients, especially patients undergoing chemotherapy. Because antitumor agents are possible to combine with antifungal agents in clinical, it is necessary to study drug-drug interaction between antitumor agents and antifungal agents. The aim of the study was to explore a method for the simultaneous determination of voriconazole and docetaxel in plasma and investigate pharmacokinetic interaction of voriconazole and docetaxel in rats. A precise and reliable method using liquid chromatography tandem mass spectrometry (LC-MS/MS) was established for the simultaneous measure of docetaxel and voriconazole in rat plasma after liquid-liquid extraction with ethyl acetate. The method was fully validated and successfully applied to a pharmacokinetic interaction study of docetaxel and voriconazole in rats after single or combined administration. We found that the AUC of each drug after coadministration increased compared with that after the single administration, which might be caused by interaction at the absorption stage or the competitive inhibition on the metabolic enzymes. This established method can be utilized to study the detailed mechanism of the drug-drug interaction and guide rational drug use in the clinic., (Copyright © 2018 John Wiley & Sons, Ltd.)

The aim of this work was to investigate the potential of pegylated poly(anhydride) nanoparticles to enhance the oral bioavailability of docetaxel (DTX). Nanoparticles were prepared after the incubation between the copolymer of methyl vinyl ether and maleic anhydride (Gantrez® AN), poly(ethylene glycol) (PEG2000 or PEG6000) and docetaxel (DTX). The oral administration of a single dose of pegylated nanoparticles to mice provided sustained and prolonged therapeutic plasma levels of docetaxel for up 48-72 h. In addition, the relative oral bioavailability of docetaxel was around 32%. The organ distribution studies revealed that docetaxel underwent a similar distribution when orally administered encapsulated in nanoparticles as when intravenously as Taxotere®. This observation, with the fact that the clearance of docetaxel when loaded into the oral pegylated nanoparticles was found to be similar to that of intravenous formulation, suggests that docetaxel would be released at the epithelium surface and then absorbed to the circulation., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Paclitaxel belongs to the taxanes family and it is used, alone or in multidrug regimens, for the therapy of several solid tumours, such as breast-, lung-, head and neck-, and ovarian cancer. Standard dosing of chemotherapy does not take into account the many inter-patient differences that make drug exposure highly variable, thus leading to the insurgence of severe toxicity. This is particularly true for paclitaxel considering that a relationship between haematological toxicity and plasma exposure was found. Therefore, in order to treat patients with the correct dose of paclitaxel, improving the overall benefit-risk ratio, Therapeutic Drug Monitoring is necessary. In order to quantify paclitaxel and its main metabolite, 6α-hydroxy-paclitaxel, in patients' plasma, we developed a new, sensitive and specific HPLC-MS/MS method applicable to all paclitaxel dosages used in clinical routine. The developed method used a small volume of plasma sample and is based on quick protein precipitation. The chromatographic separation of the analytes was achieved with a SunFire™ C18 column (3.5 μM, 92 Å, 2,1 x 150 mm); the mobile phases were 0.1% formic acid/bidistilled water and 0.1% formic acid/acetonitrile. The electrospray ionization source worked in positive ion mode and the mass spectrometer operated in selected reaction monitoring mode. Our bioanalytical method was successfully validated according to the FDA-EMA guidelines on bioanalytical method validation. The calibration curves resulted linear (R2 ≥0.9948) over the concentration ranges (1-10000 ng/mL for paclitaxel and 1-1000 ng/mL for 6α-hydroxy-paclitaxel) and were characterized by a good accuracy and precision. The intra- and inter-day precision and accuracy were determined on three quality control concentrations for paclitaxel and 6α-hydroxy-paclitaxel and resulted respectively <9.9% and within 91.1-114.8%. In addition, to further verify the assay reproducibility, we tested this method by re-analysing the incurred samples. This bioanalytical method was employed with success to a genotype-guided phase Ib study of weekly paclitaxel in ovarian cancer patients treated with a wide range of drug's dosages.

An important step in the early development of a nanomedicine formulation is the evaluation of stability and drug release in biological matrices. Additionally, the measurement of encapsulated and unencapsulated nanomedicine drug fractions is important for the determination of bioequivalence (pharmacokinetic equivalence) of generic nanomedicines. Unfortunately, current methods to measure drug release in plasma are limited, and all have fundamental disadvantages including non-equilibrium conditions and process-induced artifacts. The primary limitation of current ultrafiltration (and equilibrium dialysis) methods for separation of encapsulated and unencapsulated drug and determination of drug release is the difficulty in accurately differentiating protein bound and encapsulated drug. Since the protein binding of most drugs is high (>70%) and can change in a concentration- and time-dependent manner, it is very difficult to accurately account for the fraction of non-filterable drug that is encapsulated within the nanomedicine and how much is bound to protein. The method in this chapter is an improvement of existing ultrafiltration protocols for nanomedicine fractionation in plasma, in which a stable isotope tracer is spiked into a nanomedicine containing plasma sample in order to precisely measure the degree of plasma protein binding. Determination of protein binding then allows for accurate calculation of encapsulated and unencapsulated nanomedicine drug fractions, as well as free and protein-bound fractions.

Introduction: Two solid dispersions of docetaxel (denoted ModraDoc001 capsule and ModraDoc006 tablet (both 10 mg)) were co-administered with 100 mg ritonavir (/r) and investigated in a bi-daily once weekly (BIDW) schedule. Safety, maximum tolerated dose (MTD), pharmacokinetics (PK) and preliminary activity were explored., Methods: Adult patients with metastatic solid tumours were included in two dose-escalation arms. PK sampling was performed during the first week and the second or third week. Safety was evaluated using US National Cancer Institute's Common Terminology Criteria for Adverse Events (NCI-CTCAE) version 3.0. Antitumour activity was assessed every 6 weeks according to Response Evaluation Criteria in Solid Tumours (RECIST) version 1.0., Results: ModraDoc001 capsule/r and ModraDoc006 tablet/r were administered to 17 and 28 patients, respectively. The most common adverse events were nausea, vomiting, diarrhoea and fatigue, mostly of grade 1-2 severity. Grade 3/4 neutropenia/neutropenic fever was observed in 2 patients (4%). The MTD was determined as 20/20 mg ModraDoc001/r and 30/20 mg ModraDoc006/r (morning/afternoon dose) once weekly. The mean area under the plasma concentration-time curve (AUC 0-48 ) ± standard deviation at the MTD for ModraDoc001/r and ModraDoc006/r were 686 ± 388 ng/ml*h and 1126 ± 382 ng/ml*h, respectively. Five partial responses were reported as best response to treatment., Conclusion: Oral administration of BIDW ModraDoc001/r or ModraDoc006/r is feasible. The once weekly 30/20 mg ModraDoc006 tablet/r dose-level was selected for future clinical development. Antitumour activity is promising., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Erlotinib as a first-line drug is used in non-small cell lung cancer (NSCLC) patients with sensitive EGFR mutations, while resistance to this drug will occur after several years of treatment. Therefore, the microtubule disturber docetaxel is introduced as combined regimen in clinical trials. This report investigated the potentials and mechanisms of drug-drug interaction (DDI) between erlotinib and docetaxel using wild type (WT) and Cyp3a1/2 knockout (KO) rats. The erlotinib O-demethylation and docetaxel hydroxylation reactions in the absence or the presence of another drug were analyzed in vitro via the assay of rat liver microsomes. In whole animal studies, erlotinib and docetaxel were given to WT and KO rats individually or jointly, and the pharmacokinetic profiles of these two drugs were analyzed and compared among different groups. The results showed that docetaxel not only inhibited the CYP3A-mediated biotransformation of erlotinib in vitro, but also significantly increased the maximum concentration and systemic exposure of erlotinib in vivo in WT rats. In contrast, the DDI was significantly attenuated in KO rats. On the other hand, erlotinib did not influence docetaxel either in vitro biotransformation or in vivo pharmacokinetic behaviors. These results exhibited the potentials of erlotinib-docetaxel interaction and indicated that the CYP3A played the perpetrating role of docetaxel on erlotinib in rats. A better understanding of this DDI with CYP3A may help the regulation of the use of these two drugs, avoid potential problems, and adjust dose carefully and early in clinic., (Copyright © 2017 Elsevier Inc. All rights reserved.)

We present a technique to rapid determine taxane in blood samples by supercritical fluid chromatography together with mass spectrometry. The aim of this study was to develop a supercritical fluid chromatography with mass spectrometry method for the analysis of paclitaxel, cabazitaxel, and docetaxel in whole-blood samples of rats. Liquid-dry matrix spot extraction was selected in sample preparation procedure. Supercritical fluid chromatography separation of paclitaxel, cabazitaxel, docetaxel, and glyburide (internal standard) was accomplished within 3 min by using the gradient mobile phase consisted of methanol as the compensation solvent and carbon dioxide at a flow rate of 1.0 mL/min. The method was validated regarding specificity, the lower limit of quantification, repeatability, and reproducibility of quantification, extraction recovery, and matrix effects. The lower limit of quantification was found to be 10 ng/mL since it exhibited acceptable precision and accuracy at the corresponding level. All interday accuracies and precisions were within the accepted criteria of ±15% of the nominal value and within ±20% at the lower limit of quantification, implying that the method was reliable and reproducible. In conclusion, this method is a promising tool to support and improve preclinical or clinical pharmacokinetic studies with the taxanes anticancer drugs., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Epidermal growth factor receptor (EGFR), upregulated in gastric cancer patients, is an oncogene of interest in the development of targeted cancer nanomedicines. This study demonstrates in silico modeling of monoclonal antibody cetuximab (CET MAb)-conjugated docetaxel (DOCT)-loaded poly(γ-glutamic acid) (γ-PGA) nanoparticles (Nps) and evaluates the in vitro/in vivo effects on EGFR-overexpressing gastric cancer cells (MKN-28). Nontargeted DOCT-γ-PGA Nps (NT Nps: 110±40 nm) and targeted CET MAb-DOCT-γ-PGA Nps (T Nps: 200±20 nm) were prepared using ionic gelation followed by 1-Ethyl-3-(3-dimethyl aminopropyl)carbodiimide-N-Hydoxysuccinimide (EDC-NSH) chemistry. Increased uptake correlated with enhanced cytotoxicity induced by targeted Nps to EGFR +ve MKN-28 compared with nontargeted Nps as evident from MTT and flow cytometric assays. Nanoformulated DOCT showed a superior pharmacokinetic profile to that of free DOCT in Swiss albino mice, indicating the possibility of improved therapeutic effect in the disease model. Qualitative in vivo imaging showed early and enhanced tumor targeted accumulation of CET MAb-DOCT-γ-PGA Nps in EGFR +ve MKN-28-based gastric cancer xenograft, which exhibited efficient arrest of tumor growth compared with nontargeted Nps and free DOCT. Thus, actively targeted CET MAb-DOCT-γ-PGA Nps could be developed as a substitute to conventional nonspecific chemotherapy, and hence could become a feasible strategy for cancer therapy for EGFR-overexpressing gastric tumors., Competing Interests: Disclosure The authors report no conflicts of interest in this work.

In spite of being a very potent and promising drug against many types of cancer, docetaxel suffers the disadvantage of low solubility and poor bioavailability rendering it unsuitable for oral administration. Also, the available marketed formulation for intravenous administration has its inherent drawbacks owing to the presence of polysorbate 80. Here, we exploited the anticancer and P-gp inhibitory potential of naturally occurring frankincense oil to fabricate a stable docetaxel loaded nanoemulsified carrier system for oral delivery. The nanoemulsion possessing desirable particle size (122±12nm), polydispersity (0.086±0.007) and zeta potential (-29.8±2.1mV) was stable against all type of physical stresses and simulated physiological conditions tested. The formulation showed higher uptake in Caco-2 cells and inhibited P-gp transporter significantly (P<0.05). In MDA-MB-231 cells, it showed less IC 50 , arrested cells in G2-M phase and exhibited higher degree of apoptosis than marketed formulation Taxotere ® . The 182.58±4.16% increment in relative oral bioavailability led to higher in vivo anti-proliferative activity manifesting 19% more inhibition than Taxotere ® . Conclusively, it is revealed that the developed nanoemulsion will be a propitious approach towards alternative docetaxel therapy., (Copyright © 2017 Elsevier B.V. All rights reserved.)

To determine the feasibility of using a nanoparticle immunoassay for clinical therapeutic drug monitoring (TDM) of docetaxel concentrations, a sensitive and simple method of liquid chromatography-tandem mass spectrometry (LC-MS/MS) was established to measure the docetaxel concentration in human plasma and the results of LC-MS/MS and the immunoassay were compared. Docetaxel and paclitaxel (the internal standard, or IS) in human plasma were extracted through protein precipitation, separated on a Diamonsil C18 column (150 mm × 4.6 mm, 5 μm), ionized with positive ions, and detected with LC-MS/MS in multi-reaction monitoring (MRM) mode. Plasma samples from 248 cancer patients were assayed with LC-MS/MS and a nanoparticle immunoassay. Data from the samples were analyzed with the statistical software SPSS and the software MedCalc. Results indicated that the calibration curve of the validated method of LC-MS/MS was linear over the range of 10-2,000 ng/mL, with an lowest limit of quantitation (LLOQ) of 10 ng/mL, and the intra- and inter- day precision and accuracy were both < ± 15%. Comparison of the two methods indicated that results of the LC-MS/MS were closely related to those of the nanoparticle immunoassay, with a correlation coefficient (R) of 0.965 and acceptable 95% confidence intervals (CI) of ‒ 231.7-331.1 ng/mL. Overall, the established method of LC-MC/MS and the nanoparticle immunoassay were both suitable for measurement of the docetaxel concentration in human plasma, and the immunoassay was far more cost-effective and better at clinical TDM of docetaxel in clinical practice.

Docetaxel is a highly potent anticancer agent being used in a wide spectrum of cancer types. There are important matters of concern regarding the drug's pharmacokinetics related to the conventional formulation. Poly(lactide- co -glycolide) (PLGA) is a biocompatible/biodegradable polymer with variable physicochemical characteristics, and its application in human has been approved by the United States Food and Drug Administration. PLGA gives polymeric nanoparticles with unique drug delivery characteristics. The application of PLGA nanoparticles (NPs) as intravenous (IV) sustained-release delivery vehicles for docetaxel can favorably modify pharmacokinetics, biofate, and pharmacotherapy of the drug in cancer patients. Surface modification of PLGA NPs with poly(ethylene glycol) (PEG) can further enhance NPs' long-circulating properties. Herein, an optimized fabrication approach has been used for the preparation of PLGA and PLGA-PEG NPs loaded with docetaxel for IV application. Both types of NP formulations demonstrated in vitro characteristics that were considered suitable for IV administration (with long-circulating sustained-release purposes). NP formulations were IV administered to an animal model, and docetaxel's pharmacokinetic and biodistribution profiles were determined and compared between study groups. PLGA and PEGylated PLGA NPs were able to modify the pharmacokinetics and biodistribution of docetaxel. Accordingly, the mode of changes made to pharmacokinetics and biodistribution of docetaxel is attributed to the size and surface properties of NPs. NPs contributed to increased blood residence time of docetaxel fulfilling their role as long-circulating sustained-release drug delivery systems. Surface modification of NPs contributed to more pronounced docetaxel blood concentration, which confirms the role of PEG in conferring long-circulation properties to NPs., Competing Interests: The authors report no conflicts of interest in this work.

Introduction: Common yew (Taxus baccata) is a common decorative evergreen shrub with potentially fatal toxicity hallmarked by seizure, arrhythmia and cardiovascular collapse if ingested. Taxine B has been identified as one of the most cardiotoxic taxine alkaloids in Taxus spp, and another alkaloid, 3,5-dimethoxyphenol (3,5-DMP), is used as a marker of ingestion. We present a fatal case of ingestion of yew with perimortem serum and gastric taxine B, and 3,5-DMP concentrations., Case Presentation: A 22-year-old woman was brought to the emergency department (ED) from a nearby botanical garden after she was found apneic and pulseless after a witnessed generalized tonic clonic seizure. The patient was found to have a wide complex rhythm with persistent cardiovascular collapse and expired despite maximal supportive care in the ED. A baggie of plant material was found on the patient, identified as Taxus baccata. Perimortem serum and gastric samples were analyzed to quantify serum and gastric taxine B and 3,5-DMP concentrations., Results: Perimortem serum showed a 3,5-DMP concentration of 86.9 ng/mL, and taxine B of 80.9 ug/mL., Conclusion: We report a perimortem serum and gastric taxine B and 3,5-DMP concentrations in a fatal case of T. baccata toxicity.

Background: The circulatory pathway for particles deposited outside of blood capillaries has not been well characterized for non-traditionally-delivered chemotherapeutics., Materials and Methods: Blood and lymph pharmacokinetics of docetaxel (5 mg/kg) and carboplatin (14 and 28 mg/kg) following subcutaneous (s.c.) versus intravenous (i.v.) delivery were determined in a rodent model with catheterizations of both the thoracic lymphatic duct and jugular vein for prolonged synchronous blood and lymph sampling., Results: Subcutaneous docetaxel demonstrates preferential lymphatic accumulation based on the area under the time-concentration curve (AUC 0-24h ) whereas i.v. docetaxel resulted in a greater plasma maximum concentration measured (C max ). The apparent elimination half-life (t 1/2 ) in lymph for docetaxel is greater following i.v. or s.c. delivery compared to t 1/2 in blood. Carboplatin demonstrates a dose-dependent increase in plasma C max regardless of delivery route; the total carboplatin exposure over 24 h in lymph and plasma are comparable., Conclusion: Subcutaneous docetaxel achieves lymphatic accumulation greater than that of i.v. delivery., (Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Purpose: Docetaxel is frequently used in the treatment of a wide variety of solid tumors, including breast cancer. The aim of this study is to obtain the population pharmacokinetic parameters of docetaxel in Japanese female patients with breast cancer., Methods: Blood samples from 24 patients were collected sequentially before and after docetaxel infusion. Genomic DNA was isolated from the peripheral blood and genotyped for the selected polymorphisms in the candidate genes of drug transporters and metabolizing enzymes. The influence of patient characteristics on the pharmacokinetics of docetaxel was evaluated using the nonlinear-mixed-effect modeling program, NONMEM. As a basis for comparison, the pharmacokinetics of another taxane paclitaxel in 41 separate female patients with breast cancer was calculated., Results: A two-compartment model adequately described the pharmacokinetic profiles of docetaxel. The population mean estimates of the total body clearance for patients aged 58 years or less and the central volume of distribution for docetaxel were 32.6 L/h and 5.77 L, respectively. In patients over 58 years, the clearance was 24 % higher than that in the younger patients. No influences of the genotypes examined were noted on the clearance of docetaxel. The clearance of paclitaxel was not affected by patient age., Conclusions: Patients over the age of 58 years showed significantly higher clearance of docetaxel than that in patients aged 58 years or less. Since the clearance of paclitaxel was not affected by the age, it is possible that the pharmacokinetic mechanisms of docetaxel might be specifically affected by age in females.

Docetaxel is a semi-synthetic taxane with cytotoxic anti-neoplastic activity and, currently used as anticancer agent in several types of cancer. Docetaxel is highly bound to plasma proteins, and this significantly determines its clearance and activity. Therefore, measurement of free docetaxel in plasma is pharmacologically important when pharmacokinetics is investigated. We developed and validated chromatographic methods by ultra-performance liquid chromatography-tandem mass spectrometry to measure total and free docetaxel concentration in human plasma. The final validated methods involved liquid-liquid extraction followed by dryness under nitrogen evaporation. To measure free docetaxel concentration, sample preparation was preceded by ultrafiltration. Chromatographic separation was achieved using an Acquity(®) UPLC(®) BEH™ (2.1×100 mm id, 1.7 μm) reverse-phase C18 column at a flow rate of 0.4 mL/min, using isocratic elution mode containing ammonium acetate/formic acid in water/methanol (30:70 v/v) as mobile phase. Docetaxel and its internal standard (paclitaxel) were detected by electrospray ionization mass spectrometry in positive ion multiple reaction monitoring mode using mass-to-charge (m/z) transitions of 808.3→527.0 (quantifier) and 808.3→509.0 (qualifier); and 854.3→569.0 (quantifier) and 854,3→509,0 (qualifier), respectively. The run time per sample was 3.5 min. The limits of quantification were 1,95 and 0.42 μg/L and linearity was observed between 1.95 and 1000 and 0.42-100 μg/L for total and free docetaxel, respectively. Coefficients of variation and absolute relative biases were less than 13.8% and 10.0%. Recovery values were greater than 79.4%. Evaluation of the matrix effect showed ion suppression and no carry-over was observed. The validated methods could be useful for both therapeutic drug monitoring and pharmacokinetic studies. They could be applied to daily clinical laboratory practice to measure the concentration of total and free docetaxel in plasma., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Background: Delivery of drugs to brain is a subtle task in the therapy of many severe neurological disorders. Solid lipid nanoparticles (SLN) easily diffuse the blood-brain barrier (BBB) due to their lipophilic nature. Furthermore, ligand conjugation on SLN surface enhances the targeting efficiency. Lactoferin (Lf) conjugated SLN system is first time attempted for effective brain targeting in this study., Purpose: Preparation of Lf-modified docetaxel (DTX)-loaded SLN for proficient delivery of DTX to brain., Methods: DTX-loaded SLN were prepared using emulsification and solvent evaporation method and conjugation of Lf on SLN surface (C-SLN) was attained through carbodiimide chemistry. These lipidic nanoparticles were evaluated by DLS, AFM, FTIR, XRD techniques and in vitro release studies. Colloidal stability study was performed in biologically simulated environment (normal saline and serum). These lipidic nanoparticles were further evaluated for its targeting mechanism for uptake in brain tumour cells and brain via receptor saturation studies and distribution studies in brain, respectively., Results: Particle size of lipidic nanoparticles was found to be optimum. Surface morphology (zeta potential, AFM) and surface chemistry (FTIR) confirmed conjugation of Lf on SLN surface. Cytotoxicity studies revealed augmented apoptotic activity of C-SLN than SLN and DTX. Enhanced cytotoxicity was demonstrated by receptor saturation and uptake studies. Brain concentration of DTX was elevated significantly with C-SLN than marketed formulation., Conclusions: It is evident from the cytotoxicity, uptake that SLN has potential to deliver drug to brain than marketed formulation but conjugating Lf on SLN surface (C-SLN) further increased the targeting potential for brain tumour. Moreover, brain distribution studies corroborated the use of C-SLN as a viable vehicle to target drug to brain. Hence, C-SLN was demonstrated to be a promising DTX delivery system to brain as it possessed remarkable biocompatibility, stability and efficacy than other reported delivery systems.

Docetaxel is a second-generation taxane and is used clinically as an anti-neoplastic agent in cancer chemotherapy via an anti-mitotic mechanism. Its efficacy is limited to a narrow therapeutic window. Inappropriately high concentrations may cause erythema, fluid retention, nausea, diarrhea, and neutropenia. As a result, dosing recommendations have changed from high dosage loading every 3 weeks to lower dosage loading weekly. We describe a method that can be used for therapeutic drug monitoring of docetaxel levels using turbulent flow liquid chromatography electrospray tandem mass spectrometry (TFC-HPLC-ESI-MS/MS). The method is rapid, requiring only 6.3 min per analytical run following a simple protein crash. The method requires only 100 μL of serum. Concentrations of docetaxel were quantified by a calibration curve relating the peak-area ratio of docetaxel to a deuterated internal standard (docetaxel-D9). The method was linear from 7.8 to 1000 ng/mL, with imprecision ≤6.2 %.

In this study, a more rapid and more sensitive ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method is developed and validated for the pharmacokinetic study of a new lung-targeting docetaxel liposome (DTX-LP) at low dose (1 mg/kg) in rabbits. The method is reliable and reproducible with intra-day precision below 5.75 %, inter-day precision below 7.57 %, and mean extraction recovery of 84.1-91.7 %. At low dose, the validated method is successfully applied to the comparative pharmacokinetic study of docetaxel (DTX) in rabbit plasma after intravenous administration of DTX-LP and DTX injection, respectively. The results indicate that the pharmacokinetic profile of DTX is completely changed when loaded in the new type of liposome, which can make DTX quicker distribution from the circulation to the target organ and slower eliminated from the body.

Purpose: Docetaxel and gefitinib play key roles in the treatment of non-small-cell lung cancer (NSCLC), and their combination could be of interest. Both drugs are mainly metabolized by CYP3A4, and drug-drug interactions are a major concern. This phase I dose-finding study was designed to assess the tolerability and drug-drug interactions in this combination using full pharmacokinetic (PK) samplings., Methods: Docetaxel was intravenously administered on days 1 and 22 at a dose of 45 or 60 mg/m(2). Gefitinib (250 mg/day) was orally administrated starting on day 2. Ten PK samplings of docetaxel were performed on days 1 and 22. Seven PK samplings of gefitinib were performed on day 18 ± 3 and on day 22., Results: Twelve patients with advanced or metastatic NSCLC were enrolled without considering EGFR mutation status. The major toxicity was neutropenia. Two patients withdrew from this study due to dose-limiting toxicities; however, the toxicity profiles in this combination were generally acceptable. The docetaxel AUC0-24 and C max did not differ whether administered alone or with gefitinib, and the geometric mean ratios (GMRs) of AUC0-24 and C max (co-administrated/administrated alone) were 0.95 (90 % CI 0.85-1.06) and 0.95 (90 % CI 0.85-1.05), respectively. Furthermore, the GMRs of the steady state gefitinib AUC0-24 and C max were 0.93 (90 % CI 0.84-1.03) and 0.98 (90 % CI 0.88-1.09), respectively., Conclusion: The tolerability of 60 mg/m(2) docetaxel with 250 mg/day gefitinib was confirmed, and we observed no drug-drug interaction in this combination.

Purpose: Whether microdosing studies can be used to evaluate the human pharmacokinetics of new anticancer drugs remains unclear. The disposition of docetaxel in cancer patients is linear in terms of dose proportionality. We examined whether the pharmacokinetics of docetaxel in a clinically relevant therapeutic dose could be predicted from the pharmacokinetics of a microdose of docetaxel in Japanese patients with cancer., Methods: A microdose of docetaxel (100 μg/patient) was given by 5-min intravenous infusion on day 1, followed by a therapeutic dose of docetaxel (60-75 mg m(-2)), given by 1-h intravenous infusion on day 8. Plasma docetaxel was analyzed by liquid chromatography-tandem mass spectrometry. A two-compartment pharmacokinetic model was used to calculate the area under the plasma concentration-time curve from time 0 to infinity (AUC0-inf)., Results: Nine patients received both a microdose and therapeutic dose of docetaxel. The AUC0-inf after microdosing was 3640 ± 1150 ng h L(-1), while that after therapeutic dosing adjusted to 100 mg/patient was 2230 ± 757 µg h L(-1). The ratio of docetaxel clearance in therapeutic dose to that in microdose was 1.8 (P = 0.0041). Plasma α1-acid glycoprotein concentrations negatively correlated with docetaxel clearance at therapeutic dose, whereas the trend was weak at microdose., Conclusion: Docetaxel clearance showed marginal nonlinearity between microdose and therapeutic dose, presumably because of saturation of plasma protein binding; however, the magnitude was within twofold, allowing practically acceptable extrapolation.

TM-2 is a novel semi-synthetic taxane derivative, selected for preclinical development based on its greater anticancer activity and lower toxicity compared with docetaxel. In this study, a rapid and sensitive analytical method based on ultra performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for the determination of TM-2 in rat plasma. The biological samples were extracted with methyl tert-butyl ether and separated on a C18 column (50 mm × 2.1 mm, 1.7 µm) using a mobile phase consisting of acetonitrile and 2 mM ammonium acetate. The standard curves were linear over the range 5-1000 ng/mL in rat plasma. The precision (relative standard deviation, RSD, %) were within 14.5%, and the accuracy (relative error, RE, %) ranged from -1.56 to 2.36%. Recovery and matrix effect were satisfactory in rat plasma. The validated method was successfully applied to pharmacokinetic studies after intravenous administration of TM-2 to rats. The pharmacokinetics of TM-2 in rats were characterized by a large volume of distribution and a long half-life of elimination after single dose (4, 8, and 16 mg/kg), and a good correlation was observed between AUC and dose. The preclinical data will be useful for the design of subsequent trials of TM-2., (Copyright © 2014 John Wiley & Sons, Ltd.)

A rapid, sensitive and reliable method has been developed and validated for the simultaneous determination of seven taxoids including 10-deacetylbaccatin III (10-DAB III), baccatin III, 5-epi-canadensene, taxinine M, 10-deacetyltaxol (10-DAT), cephalomannine and paclitaxel in rat plasma using docetaxel as the internal standard (IS). The plasma samples were pretreated by liquid-liquid extraction with methyl tert-butyl ether. The chromatographic separation was achieved on a C18 column (50 mm × 2.1 mm, 1.8 μm, Waters, USA) with a gradient elution program consisting of methanol and water (containing 0.1% formic acid) at a flow rate of 0.2 mL/min. Detection was performed under the selected reaction monitoring (SRM) scan using an electrospray ionization (ESI) in the positive ion mode. The mass transitions were as follows: m/z 567.4→444.9 for 10-DAB III, m/z 609.0→549.3 for baccatin III, m/z 617.4→496.9 for 5-epi-canadensene, m/z 709.6→649.3 for taxinine M, m/z 834.8→307.9 for 10-DAT, m/z 854.5→285.4 for cephalomannine, m/z 876.8→307.3 for paclitaxel and m/z 830.8→549.6 for IS, respectively. All calibration curves exhibited good linearity (r(2)>0.99) over a wide concentration range for all components. The intra-day and inter-day precisions at three different levels were both less than 14.3% in terms of relative standard deviation (RSD) and the accuracies ranged from -8.3% to 14.8% in terms of relative error (RE). The extraction recoveries of the seven compounds ranged from 62.5% to 100.5%. The developed method was successfully applied to the pharmacokinetic study of the seven taxoids in rat plasma after oral administration of the crude extract of the twigs and leaves of Taxus yunnanensis., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Cabazitaxel is a semisynthetic taxane approved for the treatment of patients with hormone-refractory metastatic prostate cancer (now known as metastatic castration-resistant prostate cancer) treated previously with a docetaxel-containing treatment regimen. The human plasma pharmacokinetics of cabazitaxel have been described previously, but detailed analyses of the metabolism and excretion pathways of cabazitaxel have not yet been published. Metabolite profiling, quantification, and identification as well as excretion analyses were carried out on samples from patients with advanced solid tumors who received an intravenous infusion of 25 mg/m [C]-cabazitaxel (50 μCi, 1.85 MBq) over 1 h. In plasma, cabazitaxel was the main circulating compound. Seven metabolites were detected, but with each accounting for 5% or less of the parent drug exposure, none were considered relevant metabolites. In excreta, 76.0% of the administered dose was recovered in feces within 2 weeks and 3.7% of the dose was excreted in urine within 1 week. Approximately 20 metabolites were detected in excreta; the main metabolites corresponded to combined mono-O-demethyl or di-O-demethyl derivatives on the taxane ring, with hydroxyl or cyclized derivatives on the lateral chain. Docetaxel (di-O-demethyl-cabazitaxel) was only detected at trace levels in excreta. These results suggest an extensive hepatic metabolism and biliary excretion of cabazitaxel in humans.

A simple and sensitive method based on ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been developed for the determination of TM-2, which was a novel semi-synthetic taxane derivative in beagle dog plasma. Cabazitaxel was chosen as internal standard. Following extraction by methyl tert-butyl ether, the chromatographic separation was achieved on a Thermo Syncronis C18 column (50 × 2.1 mm, 1.7 µm) by gradient elution within a runtime of 3.5 min. The mobile phase consisted of (A) acetonitrile and (B) 2 mmol/L ammonium acetate in water. The detection was accomplished using positive ion electrospray ionization in multiple reaction monitoring mode. The MS/MS ion transitions were monitored at m/z 812.39 → 551.35 for TM-2 and 836.36 → 555.26 for IS, respectively. The method was linear for TM-2 (r = 0.9924) ranging from 2.5 to 1000 ng/mL. The intra-day and inter-day precisions (relative standard deviation) were within 8.0 and 17.6%, respectively, and the accuracy (relative error) was less than 2.3%. The extraction recovery ranged from 83.1 to 97.1%. The reliable method was successfully applied to a pharmacokinetic study of TM-2 in beagle dogs after intravenous drip with different doses of 0.6, 1.2, and 2.4 mg/kg, respectively., (Copyright © 2014 John Wiley & Sons, Ltd.)

Docetaxel lipid microsphere (DT-LM) is a novel formulation of docetaxel without Tween-80. A sensitive, robust and reproducible ultrafiltration (UF) followed by UPLC-MS/MS method was developed and validated for the quantification of unbound docetaxel in human plasma using paclitaxel as IS. Ultrafiltrate samples were chromatographed on Acquity UPLC BEH C18 column (50 mm × 2.1 mm, 1.7 μm). The mobile phase was a mixture of 10mM ammonium formate in water containing 0.2% formic acid (A) and acetonitrile containing 0.2% formic acid (B). The volume of plasma utilized was only 450 μL. The calibration curve was linear over the range of 0.2-200 ng/mL, with LLOQ of 0.2 ng/mL. The method was shown to be reliable and reproducible with intra- and inter-day precision and accuracy <±15%, and extraction recovery of 98.1-104.8%. Docetaxel was stable during stability studies, e.g., short term, post-preparation and freeze-thaw cycles. The validated method was utilized to support the pharmacological study of DT-LM in patients with advanced cancer., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The primary aim of this work was to investigate the potential of bile salt, sodium taurocholate (NaTC), in improving the bioavailability and anti-tumor efficacy of docetaxel (DCT) upon rectal administration. Poloxamer-based nanomicelles with thermosensitive and mucoadhesive properties were prepared using the cold method. The optimized nanomicellar formulation was evaluated in terms of physicochemical and viscoelastic parameters. Nanomicelles containing bile salt maintained sufficient gelation strength (234×10(2) mPa·s) and mucoadhesive force (17.3×10(2) dyne/cm(2)) to be retained in the upper part of the rectum. They significantly enhanced the DCT internalization across the rectal mucosa and showed a high plasma level during the first 4 hours of the study period, compared to nanomicelles with no bile salt. As a result, a slightly higher rectal bioavailability of ~33% was observed in nanomicelles containing bile salt, compared to ~28% from the latter system. The higher pharmacokinetic parameters for rectally administered DCT/P407/P188/Tween 80/NaTC (0.25%/11%/15%/10%/0.1% by weight, respectively) resulted in significant anti-tumor efficacy. However, the tumor regression rate for the NaTC group was not statistically different from that for nanomicelles without NaTC. Therefore, overall results suggest that thermosensitive nanomicelles could be a potential dosage form for improvement of the bioavailability and chemotherapeutic profile of DCT.

A rapid, sensitive and selective ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed and validated for the determination and pharmacokinetic investigation of cephalomannine in rat plasma. Sample preparation was accomplished through a simple one-step deproteinization procedure with 0.2 mL of perchloric acid-methanol (1:9, v/v) to a 0.1 mL plasma sample. Plasma samples were separated by UPLC on an Acquity UPLC BEH C18 column using a mobile phase consisting of acetonitrile-0.1% formic acid in water with gradient elution. The total run time was 2.0 min and the elution of cephalomannine was at 1.60 min. The detection was performed on a triple quadrupole tandem mass spectrometer in the multiple reaction-monitoring (MRM) mode using the respective transitions m/z 832.8→264.1 for cephalomannine and m/z 812.6→286.0 for 10-DAT (internal standard), respectively. The calibration curve was linear over the range of 10-2,000 ng/mL with a lower limit of quantitation (LLOQ) of 10 ng/mL. Mean recovery of cephalomannine in plasma was in the range of 80.9-85.3%. Intra-day and inter-day precision were both <11.2%. This method was successfully applied in pharmacokinetic study after intravenous administration of 5.0mg/kg cephalomannine in rats., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The tripeptide arginine-glycine-aspartate (RGD) was conjugated with various fatty alcohols to obtain RGDOCnH2n+1 (n=8, 10, 12, 14, 16, 18), which were incorporated into the bilayer of docetaxel liposomes to improve their tumor specificity. The fatty alcohols were accepted as linking groups to insert the tetrapeptide RGDX (X=amino acid) into the bilayer of liposomes. RGDX was previously shown to be a potent ligand to target tumor cell-surface integrin receptors, whereas RGD was not shown to have this ability. We hypothesized that RGD-fatty alcohol conjugates lacking the fourth amine X can guide liposomes to tumors without reducing their binding affinity to integrins. Antitumor activity, pharmacokinetics and biodistribution studies were evaluated in mice inoculated with S180 sarcoma. Compared with unmodified liposomes, RGD-fatty alcohol-modified liposomes successfully delivered significantly more docetaxel to tumors, which led to significant tumor weight loss and increased tumor docetaxel concentrations accompanied by reduced liver accumulation. Improved affinity of RGD-fatty alcohols to integrins was also confirmed on A375 cell model. Further comparisons among the tumor-targeting capacities of liposomes containing RGD-fatty alcohols, RGDF-fatty alcohols and RGDV-fatty acids demonstrated that RGD-fatty alcohols were as effective as the other two tetrapeptide derivatives. Therefore, a simplified tumor-targeting delivery system using RGD-fatty alcohols was developed., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Background: A rapid and sensitive analytical method using liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-MS/MS) was developed for the determination of paclitaxel, docetaxel, vinblastine, and vinorelbine in human plasma., Methods: A simple liquid-liquid extraction procedure was applied using only 100-μL plasma. Chromatographic separation of these anticancer drugs was achieved with an isocratic mobile phase consisting of acetonitrile/aqueous buffer (10 mmol/L ammonium acetate and 0.1% formic acid in 70:30, vol/vol) at a flow rate of 0.25 mL/min in a short time (4.5 minutes)., Results: The calibration curves for paclitaxel, docetaxel, vinblastine, and vinorelbine in spiked human plasma ranged from 25 to 2500, 10 to 1000, 10 to 1000, and 10 to 1000 ng/mL, respectively. The squares of the linear correlation coefficients were all more than 0.99. The intraday and interday relative standard deviations across 3 validation runs over the entire concentration range were less than 9.2%., Conclusions: The established method should be helpful for the pharmacokinetic monitoring of paclitaxel, docetaxel, vinblastine, and vinorelbine in the human plasma of non-small cell lung cancer patients.

Rationale: A subset of cancer survivors demonstrates impairments in cognition long after chemotherapy completion. At present, it is unclear whether these changes are due to direct neurotoxic effects of chemotherapy., Objectives: This study examined the impact of variable docetaxel (DTX) chemotherapy dosing on brain DTX exposure via analyses of neural morphology and changes in cognition., Methods: Male CD-1 mice were treated with DTX either intermittently (8 mg/kg i.p. weekly) or via a sustained delivery system (DTX-PoLigel), which continuously releases DTX. Both groups received total DTX doses of 32 mg/kg. Mice were assessed on the novel object recognition (NOR) task and the Morris water maze (MWM) shortly after treatment., Results: Post-treatment behavioral testing demonstrated impaired NOR in mice treated with either dosing schedule relative to controls. No differences were observed between groups in MWM training and initial testing, though control mice performed better than chance while DTX-treated mice did not. Appreciable amounts of DTX were found in the brain after both treatment regimens. DTX treatment did not significantly increase levels of apoptosis within the CNS. However, some elevation in neural autophagy was observed following DTX treatment. Analysis of astrocytic activation demonstrated that intermittent DTX treatment resulted in an elevation of GFAP-positive astrocytes for 48 h after administration. Sustained chemotherapy demonstrated prolonged but lower levels of astrocyte activation over 9 days following implantation., Conclusions: DTX treatment induced cognitive impairment shortly after treatment. Further, these findings suggest an association between DTX dosing, neurotoxicity, and cognitive effects.

Purpose: This exploratory study was aimed at elucidating the pharmacogenetics of regulatory nuclear receptors (PXR, CAR, RXRα and HNF4α) and their implications on docetaxel pharmacokinetics and pharmacodynamics in local Chinese nasopharyngeal cancer patients., Methods: A total of 59 single nucleotide polymorphisms (SNPs), including tag-SNPs and functionally relevant SNPs of the genes encoding these regulatory nuclear receptors (PXR/NR1I2, CAR/NR1I3, RXRα/NR2B1 and HNF4α/NR2A1), were profiled in the patients enrolled in our study by direct sequencing (N = 50). The generalized linear model was employed to estimate the haplotypic effects on the pharmacokinetics and pharmacodynamics of the patients., Results: The pharmacokinetic profiles of docetaxel in these patients were characterized by marked interindividual variability, with approximately four- to sixfold variations observed in Cmax, AUC0-∞ and CL. Individual SNP association tests revealed that polymorphisms in NR2B1 and NR2A1 were significantly correlated with altered docetaxel pharmacokinetics. Subsequent haplotype association analysis identified the NR2B1 LD block 2 AG haplotype [*+4458G>A(rs3132291) and *+4988A>G(rs4842198)] to be significantly associated with altered pharmacokinetics, in which patients carrying two copies of the AG haplotype had approximately a 20 % decreased Cmax and AUC0-∞ and a 21 % increased CL compared to those who carried only one copy or no copies of the haplotype. A number of SNPs in NR1I2, NR1I3, NR2B1 and NR2A1 were also associated with a significant decrease in blood counts from baseline. No haplotype was found to exert any effects on the pharmacodynamics parameters., Conclusions: The present exploratory study identified several SNPs in the genes encoding regulatory nuclear receptors which may account for the interpatient variability in docetaxel pharmacokinetics and pharmacodynamics. These findings highlight the important role of regulatory nuclear receptors on the disposition of docetaxel.

A mixed micelle that comprised of monomethylol poly(ethylene glycol)-poly(D,L-lactic acid) (MPP), D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) and stearic acid grafted chitosan oligosaccharide(CSO-SA) copolymers was developed to enhance the oral absorption of docetaxel (DTX). DTX-loaded MPP/TPGS/CSO-SA mixed polymeric micelles (MPMs) were prepared with thin film hydration method and characterized in terms of morphology, size, zeta potential, encapsulation efficiency, critical micellization concentration, and in vitro stability in media modeling physiological conditions. The in vitro release of docetaxel from the mixed micelles was studied with dialysis method. The oral bioavailability studies were conducted in rats and the pharmacokinetic parameters were evaluated. The results showed that DTX-loaded MPP/TPGS/CSO-SA MPMs had a mean diameter of 34.96 nm and exhibited spherical shape under transmission electron microscopy. The drug loading of DTX in the mixed micelles was 19.15%. The critical micellization concentration of MPP/TPGS/CSO-SA copolymer was 2.11×10(-5) M, and the size of mixed micelles in gastric fluid (pH 1.6) for 2 h and simulated intestinal fluid (pH 6.5) for 6h showed no significant change. The in vitro release study showed that DTX-loaded MPP/TPGS/CSO-SA MPMs exhibited slower release characteristics compared to DTX solution. The oral bioavailability of the DTX-loaded MPP/TPGS/CSO-SA MPMs was increased by 2.52 times compared to that of DTX solution. The current results encourage further development of DTX mixed polymeric micelles as the oral drug delivery system., (Copyright © 2013 Elsevier B.V. All rights reserved.)

A sensitive and reliable high-performance liquid chromatography-mass spectrometry (LC-MS/MS) method was developed and validated for determination of larotaxel (LTX) and its active metabolites (M1, M2 and M3) in rat plasma. The analytes were extracted by one-step protein precipitation and separated on a Capcell pak C18 column (2.0 mm × 100 mm; 2 μm; Shiseido) using methanol-water as mobile phase at a flow rate of 0.2 mL min(-1) in gradient mode. The method was validated over the concentration range of 2.5-1250 ng mL(-1) for LTX and 1.0-500 ng mL(-1) for M1, respectively, while M2 and M3 were monitored semi-quantitatively and quantified as M1 equivalents. Intra- and inter-day accuracy and precision were within the acceptable limits of less than 15% at all concentrations. Coefficients of correlation (r) for the calibration curves were more than 0.99 for all analytes. The quantitation method was successfully applied for simultaneous estimation of LTX and its metabolites in a pharmacokinetic study after oral administration at different doses of 10, 20, and 40 mg/kg and intravenous administration at the dose 10 mg/kg to Wistar rats, respectively. The results indicated that larotaxel has linear pharmacokinetic characteristics in rats after oral administration and its absolute bioavailability in rats was 12.24%., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Background and Objective: St John's wort (SJW), a herbal antidepressant, is commonly used by cancer patients, and its component hyperforin is a known inducer of the cytochrome P450 (CYP) isoenzyme 3A4. Here, the potential pharmacokinetic interaction between SJW and the sensitive CYP3A4 substrate docetaxel was investigated., Methods: In ten evaluable cancer patients, the pharmacokinetics of docetaxel (135 mg administered intravenously over 60 min) were compared before and after 14 days of supplementation with SJW (300 mg extract [Hyperiplant(®)] three times daily)., Results: SJW supplementation resulted in a statistically significant decrease in the mean area under the docetaxel plasma concentration-time curve extrapolated to infinity (AUC∞) from 3,035 ± 756 to 2,682 ± 717 ng · h/mL (P = 0.045). Furthermore, docetaxel clearance significantly increased from 47.2 to 53.7 L/h (P = 0.045) after SJW intake. The maximum plasma concentration and elimination half-life of docetaxel were (non-significantly) decreased after SJW supplementation. In addition, the incidence of docetaxel-related toxicities was lower after SJW supplementation., Conclusion: These results suggest that concomitant use of docetaxel and the applied SJW product should be avoided to prevent potential undertreatment of cancer patients.

A sensitive and reliable LC-MS/MS method for the determination of Lx2-32c, a novel taxane derived from cephalomannine, has been developed and validated. Plasma samples containing Lx2-32c and paclitaxel (internal standard) were prepared based on a simple protein precipitation by the addition of two volumes of acetonitrile. The analyte and internal standard were separated on a Zorbax SB-C18 column (3.5μm, 2.1mm×100mm) with the mobile phase of acetonitrile/water containing 0.1% formic acid (v/v) with gradient elution at a flow rate of 0.2ml/min. The detection was performed on a triple quadrupole tandem mass spectrometer equipped with atmospheric pressure chemical ionization (APCI) by multiple reactions monitoring (MRM) of the transitions at m/z 887.5→264.3 for Lx2-32c and 854.5→286.2 for IS. Linear detection responses were obtained for Lx2-32c ranging from 1 to 1000ng/ml. Inter- and intra-day precision (R.S.D.%) were all within 15% and the accuracy (R.E.%) was equal or lower than 8%. The lower limit of quantitation (LLOQ) was 1ng/ml and the average recovery was greater than 91.5%. The method was successfully applied to the pharmacokinetic study of Lx2-32c in rat plasma., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Background: Docetaxel (Taxotere) (DTX) is a widely used chemotherapy agent used in many regimens for the treatment of solid tumors, for example breast cancer, non-small cell lung cancer, gastric, prostate, and head and neck cancers. This drug meets the criteria for therapeutic dose management, in that it is associated with high pharmacokinetic variability and dose-limiting toxicity; it has a narrow therapeutic window, and there is a significant pharmacokinetic-pharmacodynamic relationship. Measures of exposure and area under the time-concentration curve have been associated with both toxicity and outcomes, making therapeutic dose management for this drug an unmet clinical need. The current methodologies for measuring DTX are based on physical methods, making the analysis less available and costly. An automated immunoassay has been developed to provide greater access to DTX dose management., Methods: A DTX immunoassay (MyDocetaxel) has been developed using a generic nanoparticle turbidimetric method that can be used on a wide variety of automated clinical chemistry analyzers including the Beckman Coulter AU400 and AU640 instruments, which were used in this study. The assay is based on a competitive assay format using a selective DTX monoclonal antibody. Clinical Laboratory Standards Institute protocols for establishing manufacturer's claims were used to verify performance. Testing at 3 clinical laboratories was undertaken using the same protocols for laboratory validation of precision, accuracy, and linearity. Method comparison (n = 89) was done using samples collected from patients on DTX therapy. The comparative method was LC-MS/MS validated according to Food and Drug Administration guidance on bioanalytical methods. Institutional review board approval was obtained for prospective collection of samples from patients on DTX therapy., Results: The assay on the AU400 uses 2 μL of sample, provides the first result in 9.0 minutes and can generate 400 determinations per hour. Internal studies established a lower limit of detection ≤25 ng/mL and a lower limit of quantitation ≤30 ng/mL. Additional studies demonstrated no interference from coadministered drugs, major metabolites, or related compounds. Linearity from 50 to 1000 ng/mL was validated. Method comparisons between laboratories and to the physical method gave slopes: 1 ± 0.5, intercepts: < 2.0 ng/mL, R > 0.99, with the range of DTX concentrations measured by the assay 31-9754 ng/mL, with a mean of 689 ng/mL. In all 3 laboratories, the coefficient of variation percentage for repeatability ranged from 0.8% to 6.2% and the within-laboratory precision ranged from 1.4% to 10.1%., Conclusions: This immunoassay is suitable for quantifying DTX in plasma with advantages of small sample size, no sample pretreatment, and the ability to be applied to a wide range of clinical analyzers. With the validation of this method, the application of DTX testing in clinical practice may gain wider acceptance for individualizing patient DTX dosing.

An original oral formulation of docetaxel nanocapsules (NCs) embedded in microparticles elicited in rats a higher bioavailability compared with the i.v. administration of the commercial docetaxel solution, Taxotere. In the present study, various animal studies were designed to elucidate the absorption process of docetaxel from such a delivery system. Again, the docetaxel NC formulation elicited a marked enhanced absorption compared with oral Taxotere in minipigs, resulting in relative bioavailability and Cmax values 10- and 8.4-fold higher, respectively, confirming the previous rat study results. It was revealed that orally absorbed NCs altered the elimination and distribution of docetaxel, as shown in the organ biodistribution rat study, due to their reinforced coating, while transiting through the enterocytes by surface adsorption of apoproteins and phospholipids. These findings were demonstrated by the cryogenic-temperature transmission electron microscopy results and confirmed by the use of a chylomicron flow blocker, cycloheximide, that prevented the oral absorption of docetaxel from the NC formulation in an independent pharmacokinetic study. The lipoproteinated NCs reduced the docetaxel release in plasma and its distribution among the organs. The improved anticancer activity compared with i.v. Taxotere, observed in the metastatic lung cancer model in Severe Combined Immune Deficiency-beige (SCID-bg) mice, should be attributed to the extravasation effect, leading to the lipoproteinated NC accumulation in lung tumors, where they exert a significant therapeutic action. To the best of our knowledge, no study has reported that the absorption of NCs was mediated by a lymphatic process and reinforced during their transit.

Combination therapy is increasingly being utilized for the treatment of metastatic breast cancer. However, coadministration of drugs, particularly agents that are substrates for or inhibitors of p-glycoprotein, can result in increased tissue toxicity. Unfortunately, determination of levels of chemotherapeutics in human tissues is challenging, and plasma drug concentrations are not always indicative of tissue toxicokinetics or toxicodynamics, especially when tissue penetration is altered. The aim of the present work was to determine whether concomitant administration of compounds currently being combined in clinical trials for metastatic breast cancer treatment alters plasma and tissue pharmacokinetics in mice if both agents are p-glycoprotein substrates and/or inhibitors. Accordingly, we investigated the pharmacokinetic interactions of the classic cytotoxics and p-glycoprotein substrates docetaxel and doxorubicin when administered concurrently with the targeted agent and p-glycoprotein inhibitor lapatinib. Our time-course plasma and tissue distribution studies showed that coadministration of lapatinib with doxorubicin did not appreciably alter the pharmacokinetics of this anthracycline in the plasma or six tissues evaluated in mice, presumably because, at doses relevant to human exposure, lapatinib inhibition of p-glycoprotein did not significantly alter doxorubicin transport out of these tissue compartments. However, combining lapatinib with docetaxel significantly increased intestinal exposure to this chemotherapeutic, which has clinical implications for enhancing gastrointestinal toxicity. The significant lapatinib-docetaxel interaction is likely CYP3A4-mediated, suggesting that caution should be exercised when this combination is administered, particularly to patients with compromised CYP3A activity, and recipients should be monitored closely for enhanced toxicity, particularly for adverse effects on the intestine.

Rationale: During drug development accurate quantification of metabolites in biological samples using mass spectrometry is often hampered by the lack of metabolites of chemically pure quality. However, quantification of metabolites can be useful for assessment and interpretation of (pre)clinical data. We now describe an approach to quantify docetaxel metabolites in human plasma by liquid chromatography/tandem mass spectrometry (LC/MS/MS) using docetaxel calibration standards., Methods: Metabolites (M1/M3, M2 and M4) were generated using microsomal incubations. Retention times of docetaxel and its metabolites were assessed using an LC/UV assay and peak identification was performed by LC/MS(n). Samples containing isolated metabolites from human faeces were quantified by LC/UV and used as references for spiking human plasma samples. LC/MS/MS was applied to sensitively quantify docetaxel and its metabolites in human plasma using docetaxel calibration standards in a range of 0.25-500 ng/mL., Results: Because ionisation of docetaxel and its metabolites differed, correction factors were established to quantify the metabolites using docetaxel calibration samples. During method validation, accuracy and precision of the metabolites were within ±7.7% and ≤17.6%, respectively, and within ±14.3% and ≤10.1%, respectively, for docetaxel. Metabolites were found to be unstable in human plasma at ambient temperature. After storage up to 1 year at -20 °C, recovered metabolite concentrations were within ±25%., Conclusions: Development and validation of an LC/MS/MS assay for the quantification of docetaxel and its metabolites M1/M3, M2 and M4 using docetaxel calibration standards is described. The same approach may be used for quantification of metabolites of other drugs by LC/MS/MS when chemically pure reference substances are unavailable., (Copyright © 2013 John Wiley & Sons, Ltd.)

Aims: The herbal medicine Echinacea purpurea (E. purpurea) has been shown to induce cytochrome P450 3A4 (CYP3A4) both in vitro and in humans. This study explored whether E. purpurea affects the pharmacokinetics of the CYP3A4 substrate docetaxel in cancer patients., Methods: Ten evaluable cancer patients received docetaxel (135 mg, 60 min IV infusion) before intake of a commercially available E. purpurea extract (20 oral drops three times daily) and 3 weeks later after a 14 day supplementation period with E. purpurea. In both cycles, pharmacokinetic parameters of docetaxel were determined., Results: Before and after supplementation with E. purpurea, the mean area under the plasma concentration-time curve of docetaxel was 3278 ± 1086 and 3480 ± 1285 ng ml(-1) h, respectively. This result was statistically not significant. Nonsignificant alterations were also observed for the elimination half-life (from 30.8 ± 19.7 to 25.6 ± 5.9 h, P = 0.56) and maximum plasma concentration of docetaxel (from 2224 ± 609 to 2097 ± 925 ng ml(-1) , P = 0.30)., Conclusions: The multiple treatment of E. purpurea did not significantly alter the pharmacokinetics of docetaxel in this study. The applied E. purpurea product at the recommended dose may be combined safely with docetaxel in cancer patients., (© 2013 The British Pharmacological Society.)

A rapid, simple and sensitive ultra fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method coupled with one-step protein precipitation procedure has been developed and validated for the pharmacokinetic study of docetaxel in rat plasma to investigate the influence of polyethylene glycol (PEG) molecular weights (chain length) using in the modified formulations. Separation was achieved on a Venusil MP C18 column (100 mm × 2.1 mm, 3.0 μm) with a mobile phase consisting of methanol-water, and the total running time was 3.5min. The standard curve was linear over the range of 5-5000 ng/mL, with lower limits of quantification (LLOQ) of 5 ng/mL. The method was shown to be reliable and reproducible with intra-day precision below 10.7%, inter-day precision below 11.2%, accuracy within ±5.2%, and mean extraction recovery of 84.6-90.2%. The validated method was successfully applied to the comparative pharmacokinetic study of docetaxel in rat plasma after intravenous administration of docetaxel-loaded nanostructured lipid carrier modified by copolymers consisting of series of PEG molecular weights (2000, 4000, 10,000 Da), respectively. The results indicated that PEG-4000 possessed a better and longer circulation effect, which made the modified formulation one of the promising suspensions for the delivery of docetaxel in cancer., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Background: This phase IB, open-label, dose-escalation study evaluated the safety, tolerability, and optimally tolerated regimen (OTR) of lapatinib in combination with docetaxel and trastuzumab in patients with previously untreated stage IV metastatic breast cancer (MBC) tumors overexpressing human epidermal growth factor receptor 2 (HER2)., Patients and Methods: Evaluated dose regimens included lapatinib (500-1500 mg/day), docetaxel (triweekly; 60-100 mg/m&sup2;), and trastuzumab (weekly; 2 mg/kg fixed dose); prophylactic granulocyte colony-stimulating factor was included with regimens with ≥750 mg/day lapatinib. End points included OTR and safety/tolerability (primary), overall response rate (ORR), and pharmacokinetics (secondary)., Results: None of the patients (N = 53) experienced dose-limiting toxic effects (DLTs) at the highest dose level; thus, the OTR of lapatinib with 100 mg/m(2) docetaxel was not determined. Common adverse events included diarrhea, nausea, alopecia, fatigue, and rash; grade 3/4 (≥2 patients) were neutropenia, diarrhea, leukopenia, peripheral neuropathy, and rash. Seven patients had DLTs (cycle 1). In 45 patients with measurable disease confirmed by bone scan, investigator-assessed ORR was 31%; without bone scan, confirmation was 64%; 8 patients without measurable disease were evaluated as stable. Lapatinib/docetaxel plasma concentrations were positively associated with complete response., Conclusions: Lapatinib/docetaxel/trastuzumab is a feasible and well-tolerated treatment of untreated HER2-positive stage IV MBC. Two lapatinib/docetaxel OTR doses were recommended (1250 mg/75 mg/m&sup2;; 1000 mg/100 mg/m&sup2;)., Clinical Trial Number: NCT00251433.

Purpose: Pharmacokinetics of docetaxel can be measured in vivo using positron emission tomography (PET) and a microdose of radiolabeled docetaxel ([(11)C]docetaxel). The objective of this study was to investigate whether a [(11)C]docetaxel PET microdosing study could predict tumor uptake of therapeutic doses of docetaxel., Experimental Design: Docetaxel-naïve lung cancer patients underwent 2 [(11)C]docetaxel PET scans; one after bolus injection of [(11)C]docetaxel and another during combined infusion of [(11)C]docetaxel and a therapeutic dose of docetaxel (75 mg·m(-2)). Compartmental and spectral analyses were used to quantify [(11)C]docetaxel tumor kinetics. [(11)C]docetaxel PET measurements were used to estimate the area under the curve (AUC) of docetaxel in tumors. Tumor response was evaluated using computed tomography scans., Results: Net rates of influx (Ki) of [(11)C]docetaxel in tumors were comparable during microdosing and therapeutic scans. [(11)C]docetaxel AUCTumor during the therapeutic scan could be predicted reliably using an impulse response function derived from the microdosing scan together with the plasma curve of [(11)C]docetaxel during the therapeutic scan. At 90 minutes, the accumulated amount of docetaxel in tumors was less than 1% of the total infused dose of docetaxel. [(11)C]docetaxel Ki derived from the microdosing scan correlated with AUCTumor of docetaxel (Spearman ρ = 0.715; P = 0.004) during the therapeutic scan and with tumor response to docetaxel therapy (Spearman ρ = -0.800; P = 0.010)., Conclusions: Microdosing data of [(11)C]docetaxel PET can be used to predict tumor uptake of docetaxel during chemotherapy. The present study provides a framework for investigating the PET microdosing concept for radiolabeled anticancer drugs in patients., (©2013 AACR.)