Quantification of docetaxel and its main metabolites in human plasma by liquid chromatography/tandem mass spectrometry

Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) methods for the therapeutic drug monitoring of cytotoxic anticancer drugs: An update

In the era of precision medicine, there is increasing evidence that conventional cytotoxic agents may be suitable candidates for therapeutic drug monitoring (TDM)- guided drug dosage adjustments and patient's tailored personalization of non-selective chemotherapies. To that end, many liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) assays have been developed for the quantification of conventional cytotoxic anticancer chemotherapies, that have been comprehensively and critically reviewed. The use of stable isotopically labelled internal standards (IS) of cytotoxic drugs was strikingly uncommon, accounting for only 48 % of the methods found, although their use could possible to suitably circumvent patients' samples matrix effects variability. Furthermore, this approach would increase the reliability of cytotoxic drug quantification in highly multi-mediated cancer patients with complex fluctuating pathophysiological and clinical conditions. LC-MS/MS assays can accommodate multiplexed analyses of cytotoxic drugs with optimal selectivity and specificity as well as short analytical times and, when using stable-isotopically labelled IS for quantification, provide concentrations measurements with a high degree of certainty. However, there are still organisational, pharmacological, and medical constraints to tackle before TDM of cytotoxic drugs can be more largely adopted in the clinics for contributing to our ever-lasting quest to improve cancer treatment outcomes.

Abdulbaqi I, Parumasivam T, Mohtar N, A. Wahab H. Advances in Nanocarriers for Effective Delivery of Docetaxel in the Treatment of Lung Cancer: An Overview

Docetaxel (DCX) is a highly effective chemotherapeutic drug used in the treatment of different types of cancer, including non-small cell lung cancer (NSCLC). The drug is known to have low oral bioavailability due to its low aqueous solubility, poor membrane permeability and susceptibility to hepatic first-pass metabolism. To mitigate these problems, DCX is administered via the intravenous route. Currently, DCX is commercially available as a single vial that contains polysorbate 80 and ethanol to solubilize the poorly soluble drug. However, this formulation causes short- and long-term side effects, including hypersensitivity, febrile neutropenia, fatigue, fluid retention, and peripheral neuropathy. DCX is also a substrate to the drug efflux pump P-glycoprotein (P-gp) that would reduce its concentration within the vicinity of the cells and lead to the development of drug resistance. Hence, the incorporation of DCX into various nanocarrier systems has garnered a significant amount of attention in recent years to overcome these drawbacks. The surfaces of these drug-delivery systems indeed can be functionalized by modification with different ligands for smart targeting towards cancerous cells. This article provides an overview of the latest nanotechnological approaches and the delivery systems that were developed for passive and active delivery of DCX via different routes of administration for the treatment of lung cancer.

An improved LC-MS/MS method for determination of docetaxel and its application to population pharmacokinetic study in Chinese cancer patients

Because of its unpredictable side effects and efficacy, the anticancer drug docetaxel (DTX) requires improved characterisation of its pharmacokinetic profiles through population pharmacokinetic studies. A sensitive and rugged LC-MS/MS method for the detection of DTX in human plasma was developed and optimised using paclitaxel as an internal standard (IS). The plasma samples underwent rapid extraction using hybrid solid-phase extraction-protein precipitation. The analyte and IS were separated with an isocratic system on a Zorbax Eclipse Plus C₁₈ column using water containing 0.05% acetic acid along with 20 μM of sodium acetate and methanol (30/70, v/v) as the mobile phase. Quantification was performed using a triple quadrupole mass spectrometer through multiple reaction monitoring in positive mode, using the m/z 830.3 → 548.8 and m/z 876.3 → 307.7 transitions for DTX and paclitaxel, respectively. The range of the calibration curve was 1-500 ng/mL for DTX, and the linear correlation coefficient was >0.99. The accuracies ranged from -4.6 to 4.2%, and the precision was no higher than 7.0% for the analytes. No significant matrix effect was observed. Both DTX and the IS showed considerable recovery. This method was finally applied to the establishment of a population pharmacokinetic model to optimise the clinical use of DTX.

Mass spectrometry in the pharmacokinetic studies of anticancer natural products

In the history of medicine, nature has represented the main source of medical products. Indeed, the therapeutic use of plants certainly goes back to the Sumerian and Hippocrates and nowadays nature still represents the major source for new drugs discovery. Moreover, in the cancer treatment, drugs are either natural compounds or have been developed from naturally occurring parent compounds firstly isolated from plants and microbes from terrestrial and marine environment. A critical element of an anticancer drug is represented by its severe toxicities and, after administration, the drug concentrations have to remain in an appropriate range to be effective. Anyway, the drug dosage defined during the clinical studies could be inappropriate for an individual patient due to differences in drug absorption, metabolism and excretion. For this reason, personalized medicine, based on therapeutic drug monitoring (TDM), represents one of most important challenges in cancer therapy. Mass spectrometry sensitivity, specificity and fastness lead to elect this technique as the Golden Standard for pharmacokinetics and drug metabolism studies therefore for TDM. This review focuses on the mass spectrometry-based methods developed for pharmacokinetic quantification in human plasma of anticancer drugs derived from natural sources and already used in clinical practice. Particular emphasis was placed both on the pre-analytical and analytical steps, such as: sample preparation procedures, sample size required by the analysis and the limit of quantification of drugs and metabolites to give some insights on the clinical practice applicability. © 2015 Wiley Periodicals, Inc. Mass Spec Rev. 36:213-251, 2017.

Revisiting dosing regimen using PK/PD modeling: the MODEL1 phase I/II trial of docetaxel plus epirubicin in metastatic breast cancer patients

The MODEL1 trial is the first model-driven phase I/II dose-escalation study of densified docetaxel plus epirubicin administration in metastatic breast cancer patients, a regimen previously known to induce unacceptable life-threatening toxicities. The primary objective was to determine the maximum tolerated dose of this densified regimen. Study of the efficacy was a secondary objective. Her2-negative, hormone-resistant metastatic breast cancer patients were treated with escalating doses of docetaxel plus epirubicin every 2 weeks for six cycles with granulocyte colony stimulating factor support. A total of 16 patients were treated with total doses ranging from 85 to 110 mg of docetaxel plus epirubicin per cycle. Dose escalation was controlled by a non-hematological toxicity model. Dose densification was guided by a model of neutrophil kinetics, able to optimize docetaxel plus epirubicin dosing with respect to pre-defined acceptable levels of hematological toxicity while ensuring maximal efficacy. The densified treatment was safe since hematological toxicity was much lower compared to previous findings, and other adverse events were consistent with those observed with this regimen. The maximal tolerated dose was 100 mg given every 2 weeks. The response rate was 45 %; median progression-free survival was 10.4 months, whereas 54.6 months of median overall survival was achieved. The optimized docetaxel plus epirubicin dosing regimen led to fewer toxicities associated with higher efficacy as compared with standard or empirical densified dosing. This study suggests that model-driven dosage adjustment can lead to improved efficacy-toxicity balance in patients with cancer when several anticancer drugs are combined.

DEFENS - Drug Exposure Feedback and Education for Nurses' Safety: study protocol for a randomized controlled trial

BACKGROUND

Three decades of research findings have documented the health effects of handling hazardous drugs. Oncology nurses are vulnerable due to frequent administration of antineoplastics, low adherence to equipment use, reported barriers to use, and perceived low risk of health effects. No interventions have been tested in a controlled, multi-site trial to increase nurses' use of protective equipment when handling hazardous drugs. The Drug Exposure Feedback and Education for Nurses' Safety (DEFENS) study will compare the efficacy of education (control) versus an audit and feedback intervention (treatment) on nurses' self-reported use of personal protective equipment when handling hazardous drugs. The treatment intervention will include tailored messages based on nurses' reported barriers to protective equipment use.

METHODS/DESIGN

The DEFENS Study is a cluster randomized controlled trial. We are enrolling cancer centers and will recruit nurse participants in April 2015. Eligible cancer centers employ at least 20 eligible registered nurses in the chemotherapy infusion setting and have on-site phlebotomy resources. Eligible participants are nurses who work at least 0.40 full-time equivalent hours in the chemotherapy infusion setting and have not received an antineoplastic drug for a health problem in the past year. An encrypted, user-authenticated website will administer surveys and deliver control and treatment interventions. The primary endpoint is the change in score on nurses' reports of the Revised Hazardous Drug Handling Questionnaire between baseline and approximately 18 months later. A baseline survey is completed after informed consent and is repeated 18 months later. Nurses in all sites who experience a drug spill will also report incidents as they occur; these reports inform the treatment intervention. Plasma will be obtained at baseline, approximately 18 months later (the primary endpoint), and with drug spill occurrences to measure hazardous drugs levels and to inform the treatment intervention. Potential mediators include knowledge of hazardous drug handling and perceived risk of drug exposure. We will examine whether personal factors and organizational factors moderate the intervention effects.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02283164 , registered 31 October 2014.

Rapid and sensitive liquid chromatography coupled with electrospray ionization tandem mass spectrometry method for the analysis of paclitaxel, docetaxel, vinblastine, and vinorelbine in human plasma

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.

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.

Quantification of docetaxel and its metabolites in human plasma by liquid chromatography/tandem mass spectrometry

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.

Combined quantification of paclitaxel, docetaxel and ritonavir in human feces and urine using LC-MS/MS

A combined assay for the determination of paclitaxel, docetaxel and ritonavir in human feces and urine is described. The drugs were extracted from 200 μL urine or 50 mg feces followed by high-performance liquid chromatography analysis coupled with positive ionization electrospray tandem mass spectrometry. The validation program included calibration model, accuracy and precision, carry-over, dilution test, specificity and selectivity, matrix effect, recovery and stability. Acceptance criteria were according to US Food and Drug Administration guidelines on bioanalytical method validation. The validated range was 0.5-500 ng/mL for paclitaxel and docetaxel, 2-2000 ng/mL for ritonavir in urine, 2-2000 ng/mg for paclitaxel and docetaxel, and 8-8000 ng/mg for ritonavir in feces. Inter-assay accuracy and precision were tested for all analytes at four concentration levels and were within 8.5% and <10.2%, respectively, in both matrices. Recovery at three concentration levels was between 77 and 94% in feces samples and between 69 and 85% in urine samples. Method development, including feces homogenization and spiking blank urine samples, are discussed. We demonstrated that each of the applied drugs could be quantified successfully in urine and feces using the described assay. The method was successfully applied for quantification of the analytes in feces and urine samples of patients.

Qualitative structure-metabolism relationships in the hydrolysis of carbamates

The aims of this review were 1) to compile a large number of reliable literature data on the metabolic hydrolysis of medicinal carbamates and 2) to extract from such data a qualitative relation between molecular structure and lability to metabolic hydrolysis. The compounds were classified according to the nature of their substituents (R³OCONR¹R²), and a metabolic lability score was calculated for each class. A trend emerged, such that the metabolic lability of carbamates decreased (i.e., their metabolic stability increased), in the following series: Aryl-OCO-NHAlkyl >> Alkyl-OCO-NHAlkyl ~ Alkyl-OCO-N(Alkyl)₂ ≥ Alkyl-OCO-N(endocyclic) ≥ Aryl-OCO-N(Alkyl)₂ ~ Aryl-OCO-N(endocyclic) ≥ Alkyl-OCO-NHAryl ~ Alkyl-OCO-NHAcyl >> Alkyl-OCO-NH₂ > Cyclic carbamates. This trend should prove useful in the design of carbamates as drugs or prodrugs.

Docetaxel-induced photolichenoid eruption

A 58-year-old man presented with complaints of blackish discoloration of forearms and face of five months duration. The lesions occurred episodically after taking anti-cancer medications, each episode lasting for two weeks. Histopathology confirmed a lichenoid eruption. Photolichenoid eruption to docetaxel is a dermatological adverse effect not reported in literature earlier.

Docetaxel: its role in current and future treatments for advanced gastric cancer

A globally accepted standard chemotherapy remains undetermined in gastric cancer, but the recent introduction of active "new-generation agents" such as taxanes, irinotecan (CPT-11), oxaliplatin, S-1, and capecitabine, offers hope for markedly improving patient outcomes. Docetaxel, as well as the other new-generation agents, plays a key role in the development of the new-era chemotherapy, and the incorporation of taxanes has provided several regimens, such as docetaxel/cisplatin/5-fluorouracil (5-FU) (DCF), that could become standard treatment. The DCF regimen is now regarded as a standard treatment option in advanced gastric cancer in selected patients in good condition. Many institutions and cooperative groups continue to study a variety of docetaxel-based combinations with "new-generation cytotoxic agents" in various treatment settings, and recent attention has been focused on the incorporation of biological agents, such as cetuximab, bevacizumab, everolimus, and sunitinib, into docetaxel-containing combinations as another innovative approach. The ongoing clinical trials of a number of new regimens will clarify their clinical benefits in gastric cancer treatment. Along with the development of more active docetaxel combination regimens, the identification of predictive biomarkers for each regimen has been intensively studied recently. This review focuses on docetaxel as a key agent in gastric cancer chemotherapy, and discusses the role of this taxane in current and future treatments for advanced gastric cancer.

Stereochemical differentiation of C-7 hydroxyltaxane isomers by electrospray ionization mass spectrometry

In this study, different electrospray ionization mass spectrometric (ESI-MS) methods were utilized to analyze several pairs of taxane stereoisomers including paclitaxel and 7-epi-paclitaxel. Both ESI-MS and tandem mass spectrometry (MS/MS) techniques provided stereochemically dependent mass spectra in negative-ion mode, and all studied stereoisomers could be easily distinguished based on their characteristic ions or distinct fragmentation patterns. MS/MS experiments for several taxane analogues at various collision energies were performed to elucidate potential dissociation pathways. The gas-phase deprotonation potentials were also calculated to estimate the most thermodynamically favorable deprotonation site using DFT B3LYP/6-31G(d). The results of the theoretical studies agreed well with the fragmentation patterns of paclitaxel and 7-epi-paclitaxel observed from MS/MS experiments. In addition, it was found that liquid chromatography (LC)/ESI-MS was a useful and sensitive technique for assignment of C-7 taxane stereoisomers from realistic samples.

Profiling of yew hair roots from various species using ultra-performance liquid chromatography/electrospray ionization mass spectrometry

An efficient and sensitive profiling approach to complex yew samples was developed using ultra-performance liquid chromatography/electrospray ionization mass spectrometry (UPLC/ESI-MS). The UPLC-based method displayed short analytical time and improved peak capability, as well as high sensitivity. The appropriate in-source collision-induced dissociation (CID) energy was employed to produce informative characteristic ions which could be used for stereochemical and sub-structural assignment of yew constituents. The method was successfully applied in the rapid screening of yew hair roots from various species, and 53 constituents including 47 taxoids were detected from partially purified root extract. Notably, C-7 hydroxytaxane stereoisomers could be identified based on their different fragment ions under the optimal profiling conditions. It was also observed that hair roots from different Taxus species exhibited nearly identical chemical distribution, indicating they had similar metabolic frameworks. Additionally, Taxus root resources also display benign medicinal perspective because they have relatively simple chemical profiles and possess high yields of valuable taxanes such as paclitaxel, cephalomannine, 10-deacetylpaclitaxel and 7-xylosyltaxanes.

High-performance liquid chromatography-tandem mass spectrometry in the identification and determination of phase I and phase II drug metabolites

Applications of tandem mass spectrometry (MS/MS) techniques coupled with high-performance liquid chromatography (HPLC) in the identification and determination of phase I and phase II drug metabolites are reviewed with an emphasis on recent papers published predominantly within the last 6 years (2002–2007) reporting the employment of atmospheric pressure ionization techniques as the most promising approach for a sensitive detection, positive identification and quantitation of metabolites in complex biological matrices. This review is devoted to in vitro and in vivo drug biotransformation in humans and animals. The first step preceding an HPLC-MS bioanalysis consists in the choice of suitable sample preparation procedures (biomatrix sampling, homogenization, internal standard addition, deproteination, centrifugation, extraction). The subsequent step is the right optimization of chromatographic conditions providing the required separation selectivity, analysis time and also good compatibility with the MS detection. This is usually not accessible without the employment of the parent drug and synthesized or isolated chemical standards of expected phase I and sometimes also phase II metabolites. The incorporation of additional detectors (photodiode-array UV, fluorescence, polarimetric and others) between the HPLC and MS instruments can result in valuable analytical information supplementing MS results. The relation among the structural changes caused by metabolic reactions and corresponding shifts in the retention behavior in reversed-phase systems is discussed as supporting information for identification of the metabolite. The first and basic step in the interpretation of mass spectra is always the molecular weight (MW) determination based on the presence of protonated molecules [M+H]⁺ and sometimes adducts with ammonium or alkali-metal ions, observed in the positive-ion full-scan mass spectra. The MW determination can be confirmed by the [M-H]^- ion for metabolites providing a signal in negative-ion mass spectra. MS/MS is a worthy tool for further structural characterization because of the occurrence of characteristic fragment ions, either MSⁿ analysis for studying the fragmentation patterns using trap-based analyzers or high mass accuracy measurements for elemental composition determination using time of flight based or Fourier transform mass analyzers. The correlation between typical functional groups found in phase I and phase II drug metabolites and corresponding neutral losses is generalized and illustrated for selected examples. The choice of a suitable ionization technique and polarity mode in relation to the metabolite structure is discussed as well.

A phase I study of docetaxel with ketoconazole modulation in patients with advanced cancers

PURPOSE

The aims were to determine the maximum tolerable dose (MTD) of docetaxel with CYP3A inhibition by ketoconazole, and to correlate the pharmacokinetics of docetaxel with midazolam phenotyping of CYP3A activity.

METHODS

Forty-one patients with refractory metastatic cancers were treated with an escalating dose of intravenous docetaxel once in every 3 week of 10 mg/m(2), concurrently with oral ketoconazole 200 mg twice daily for 3 days starting 2 days before the administration of docetaxel. Midazolam phenotyping test with ketoconazole modulation was performed before the first cycle of docetaxel. Docetaxel and midazolam pharmacokinetics were compared to our previous study of docetaxel treatment without ketoconazole modulation.

RESULTS

Neutropenia was the dose-limiting toxicity. The maximum tolerated dose was 70 mg with mean AUC at 70 mg similar to 75 mg/m(2) of docetaxel without ketoconazole. The plasma clearances of docetaxel and midazolam were reduced by 1.7- and 6-fold, respectively. The variability of midazolam AUC was reduced from 157 to 67%, but variability of docetaxel clearance was not reduced by CYP3A inhibition. Docetaxel clearance correlated with renal function and maximum concentration of ketoconazole, but not midazolam clearance or other variables of hepatic function.

CONCLUSION

Fixed dosing was found to be feasible, without increased variability of clearance or neutrophil toxicity compared to BSA-based dosing. With ketoconazole modulation, docetaxel clearance correlated with renal function but not CYP3A phenotype.

PXR, CAR and HNF4alpha genotypes and their association with pharmacokinetics and pharmacodynamics of docetaxel and doxorubicin in Asian patients

Previously studied candidate genes have failed to account for inter-individual variability of docetaxel and doxorubicin disposition and effects. We genotyped the transcriptional regulators of CYP3A and ABCB1 in 101 breast cancer patients from 3 Asian ethnic groups, that is, Chinese, Malays and Indians, in correlation with the pharmacokinetics and pharmacodynamics of docetaxel and doxorubicin. While there was no ethnic difference in docetaxel and doxorubicin pharmacokinetics, ethnic difference in docetaxel- (ANOVA, P=0.001) and doxorubicin-induced (ANOVA, P=0.003) leukocyte suppression was observed, with Chinese and Indians experiencing greater degree of docetaxel-induced myelosuppression than Malays (Bonferroni, P=0.002, P=0.042), and Chinese experiencing greater degree of doxorubicin-induced myelosuppression than Malays and Indians (post hoc Bonferroni, P=0.024 and 0.025). Genotyping revealed both PXR and CAR to be well conserved; only a PXR 5'-untranslated region polymorphism (-24381A>C) and a silent CAR variant (Pro180Pro) were found at allele frequencies of 26 and 53%, respectively. Two non-synonymous variants were identified in HNF4alpha (Met49Val and Thr130Ile) at allele frequencies of 55 and 1%, respectively, with the Met49Val variant associated with slower neutrophil recovery in docetaxel-treated patients (ANOVA, P=0.046). Interactions were observed between HNF4alpha Met49Val and CAR Pro180Pro, with patients who were wild type for both variants experiencing least docetaxel-induced neutropenia (ANOVA, P=0.030). No other significant genotypic associations with pharmacokinetics or pharmacodynamics of either drug were found. The PXR-24381A>C variants were significantly more common in Indians compared to Chinese or Malays (32/18/21%, P=0.035) Inter-individual and inter-ethnic variations of docetaxel and doxorubicin pharmacokinetics or pharmacodynamics exist, but genotypic variability of the transcriptional regulators PAR, CAR and HNF4alpha cannot account for this variability.