Pharmacokinetics Of Anticancer Drugs Research Articles

Advances in Hybrid Vesicular-based Drug Delivery Systems: Improved Biocompatibility, Targeting, Therapeutic Efficacy and Pharmacokinetics of Anticancer Drugs.

Anticancer drugs and diagnostics can be transported in nanoscale vesicles that provide a flexible platform. A hybrid nanoparticle, a nano assembly made up of many types of nanostructures, has the greatest potential to perform these two activities simultaneously. Nanomedicine has shown the promise of vesicular carriers based on lipopolymersomes, lipid peptides, and metallic hybrid nano-vesicle systems. However, there are significant limitations that hinder the clinical implementation of these systems at the commercial scale, such as low productivity, high energy consumption, expensive setup, long process durations, and the current cancer therapies described in this article. Combinatorial hybrid systems can be used to reduce the above limitations. A greater therapeutic index and improved clinical results are possible with hybrid nanovesicular systems, which integrate the benefits of many carriers into a single structure. Due to their unique properties, cell-based drug delivery systems have shown tremendous benefits in the treatment of cancer. Nanoparticles (NPs) can benefit significantly from the properties of erythrocytes and platelets, which are part of the circulatory cells and circulate for a long time. Due to their unique physicochemical properties, nanomaterials play an essential role in cell-based drug delivery. Combining the advantages of different nanomaterials and cell types gives the resulting delivery systems a wide range of desirable properties. NPs are nextgeneration core-shell nanostructures that combine a lipid shell with a polymer core. The fabrication of lipid-polymer hybrid NPs has recently undergone a fundamental shift, moving from a two-step to a one-step technique based on the joint self-assembly of polymers and lipids. Oncologists are particularly interested in this method as a combinatorial drug delivery platform because of its two-in-one structure. This article addresses various preparative methods for the preparation of hybrid nano-vesicular systems. It also discusses the cellular mechanism of hybrid nano-vesicular systems and describes the thorough knowledge of various hybrid vesicular systems.

Advances in Hybrid Vesicular-based Drug Delivery Systems: Improved Biocompatibility, Targeting, Therapeutic Efficacy and Pharmacokinetics of Anticancer Drugs

Advances in Hybrid Vesicular-based Drug Delivery Systems: Improved Biocompatibility, Targeting, Therapeutic Efficacy and Pharmacokinetics of Anticancer Drugs

Coherent Raman Scattering Microscopy in Oncology Pharmacokinetic Research.

The high attrition rates of anti-cancer drugs during clinical development remains a bottleneck problem in pharmaceutical industry. This is partially due to the lack of quantitative, selective, and rapid readouts of anti-cancer drug activity in situ with high resolution. Although fluorescence microscopy has been commonly used in oncology pharmacological research, fluorescent labels are often too large in size for small drug molecules, and thus may disturb the function or metabolism of these molecules. Such challenge can be overcome by coherent Raman scattering microscopy, which is capable of chemically selective, highly sensitive, high spatial resolution, and high-speed imaging, without the need of any labeling. Coherent Raman scattering microscopy has tremendously improved the understanding of pharmaceutical materials in the solid state, pharmacokinetics of anti-cancer drugs and nanocarriers in vitro and in vivo. This review focuses on the latest applications of coherent Raman scattering microscopy as a new emerging platform to facilitate oncology pharmacokinetic research.

Pathophysiological mechanisms explaining poor clinical outcome of older cancer patients with low skeletal muscle mass.

Low skeletal muscle mass is highly prevalent in older cancer patients and affects 5% to 89% depending on the type and stage of cancer. Low skeletal muscle mass is associated with poor clinical outcomes such as post‐operative complications, chemotherapy toxicity and mortality in older cancer patients. Little is known about the mediating pathophysiological mechanisms. In this review, we summarize proposed pathophysiological mechanisms underlying the association between low skeletal muscle mass and poor clinical outcomes in older cancer patients including a) systemic inflammation; b) insulin‐dependent glucose handling; c) mitochondrial function; d) protein status and; e) pharmacokinetics of anticancer drugs. The mechanisms of altered myokine balance negatively affecting the innate and adaptive immune system, and altered pharmacokinetics of anticancer drugs leading to a relative overdosage of anticancer drugs are best‐substantiated. The effects of glucose intolerance and circulating mitochondrial DNA as a consequence of low skeletal muscle mass are topics of interest for future research. Restoring myokine balance through physical exercise, exercise mimetics, neuro‐muscular activation and adapting anticancer drug dosing on skeletal muscle mass could be targeted approaches to improve clinical outcomes in older cancer patients with low skeletal muscle mass.

The Influence of Pharmacogenetics in Cancer Chemotherapy

Pharmacogenomics is an upcoming field that focusing on the genetic variations related to drug action. The cellular abnormalities arise from the inter individual genetic modifications, through the variation in genetic sequences or due to the modification in gene activation or DNA-related proteins. The pharmacogenomics study deals with the variation that provides the therapy more effective and safer by determining selection and dosing of drugs for an inter individuals and the medication demonstrates unpredictable efficacy and toxicity linked to the medication in the individual patients. Genetic polymorphisms in phase I and phase II enzymes may explain part of the inter-individual variation observed in anticancer drug pharmacokinetics and pharmacodynamics. There are numerous therapy choices for many kinds of cancer. The selection of the most suitable treatment would benefit from guidelines to enable the initiation of effective treatment as soon as possible. Failed therapy or unacceptable toxicity can considerably decrease the ideal therapeutic window resulting in a change in medication or dose. Consequently, it will be crucial to elucidate the role of pharmacogenomics in individualizing treatment in the near future research including genotype-driven clinical trials. Furthermore, trials involving gene/SNP detection approaches will be crucial for chemotherapy where there are no known validated markers to identify fresh prospective markers.

D-a-Tocopheryl Polyethylene Glycol 1000 Succinate and a small-molecule Survivin suppressant synergistically induce apoptosis in SKBR3 breast cancer cells

Breast cancer is the second in mortality rate malignancy among women. Despite the many advances in breast cancer treatment, there is still a need to improve drug efficacy and reduce non-specific effects. D-alpha-tocopheryl polyethylene glycol succinate (TPGS) is frequently used in the development of drug delivery systems to improve the pharmacokinetics of anti-cancer drugs and reduce multi-drug resistance. We have previously shown that TPGS not only acts as a carrier molecule but also exerts anti-cancer effects. As part of this study, we investigated the effect of TPGS with YM155, a small molecule suppressant of Survivin, in various breast cancer cell lines representing different subtypes of the disease. We aimed to evaluate the presumed synergistic effect of the TPGS-YM155 combination and reveal its mechanism of action. Our results show that the TPGS-YM155 combination acts synergistically to reduce specifically the viability of SKBR3 cells. The combination of these agents reduced activation of the AKT pathway, decreased Survivin and Bcl-2 levels, and induced caspase-dependent and independent apoptosis via the mitochondrial pathway. Importantly, the TPGS-YM155 combination did not significantly affect the viability of MCF-10A normal immortalized cells. In conclusion, the combination of YM155 and TPGS could be a promising approach against SKBR3-type breast cancer.

Pharmacokinetics of Anticancer Drugs Used in Treatment of Older Adults With Colorectal Cancer: A Systematic Review.

Older adults with cancer experience more toxicity from anticancer therapy, possibly because of age-related changes in the pharmacokinetic (PK) profile of anticancer drugs. We aimed to evaluate studies investigating the effect of aging on the PK of anticancer therapies used in the treatment of colorectal cancer (CRC). A systematic literature search of EMBASE and PubMed was performed to find eligible studies that assessed the effect of age on the PK of anticancer therapies used in the treatment of CRC. The 21 eligible studies included 17 prospective studies and 4 pooled analyses of prospective studies. Of these, PK of 5-fluorouracil (5-FU) was determined in 7 studies, oxaliplatin in 2 studies, capecitabine in 3 studies, irinotecan in 4 studies, bevacizumab in 1 study, cetuximab in 3 studies, and panitumumab in 1 study. Studies included a median of 44 patients and had varying definitions for older adults: 65 years or older (3 studies), older than 70 years (3 studies), or older than 75 years (1 study). Increasing age significantly affected the PK parameters of irinotecan with a 7%-8% reduction in CL (P < 0.001) for every 10 years in patients older than 60 years and an increase in area under the curve (r = 0.44, P = 0.007) and Cmax (r = 0.42, P = 0.009). Older age mainly influences PK of irinotecan and, to some extent, that of capecitabine, 5-FU, and panitumumab, but there is limited evidence for age-related changes in PK of other anticancer therapies used in the management of older adults with CRC. Factors other than PK may be responsible for the greater toxicity of these agents experienced by older adults.

Dose recommendations for anticancer drugs in patients with renal or hepatic impairment.

Renal or hepatic impairment is a common comorbidity for patients with cancer either because of the disease itself, toxicity of previous anticancer treatments, or because of other factors affecting organ function, such as increased age. Because renal and hepatic function are among the main determinants of drug exposure, the pharmacokinetic profile might be altered for patients with cancer who have renal or hepatic impairment, necessitating dose adjustments. Most anticancer drugs are dosed near their maximum tolerated dose and are characterised by a narrow therapeutic index. Consequently, selecting an adequate dose for patients who have either hepatic or renal impairment, or both, is challenging and definitive recommendations on dose adjustments are scarce. In this Review, we discuss the effect of renal and hepatic impairment on the pharmacokinetics of anticancer drugs. To guide clinicians in selecting appropriate dose adjustments, information from available drug labels and from the published literature were combined to provide a practical set of recommendations for dose adjustments of 160 anticancer drugs for patients with hepatic and renal impairment.

Large-scale purification of functional human P-glycoprotein (ABCB1)

Human P-glycoprotein (P-gp) is an ATP-binding cassette transporter that has been implicated in altering the pharmacokinetics of anticancer drugs in normal tissues and development of multidrug resistance in tumor cells via drug efflux. There is still no definitive explanation of the mechanism by which P-gp effluxes drugs. One of the challenges of large-scale purification of membrane transporters is the selection of a suitable detergent for its optimal extraction from cell membranes. In addition, further steps of purification can often lead to inactivation and aggregation, decreasing the yield of purified protein. Here we report the large-scale purification of human P-gp expressed in High-Five insect cells using recombinant baculovirus. The purification strategies we present yield homogeneous functionally active wild type P-gp and its E556Q/E1201Q mutant, which is defective in carrying out ATP hydrolysis. Three detergents (1,2-diheptanoyol-sn-glycero-3-phosphocholine, dodecyl maltoside and n-octyl-β-d-glucopyranoside) were used to solubilize and purify P-gp from insect cell membranes. P-gp purification was performed first using immobilized metal affinity chromatography, then followed by a second step of either anion exchange chromatography or size exclusion chromatography to yield protein in concentrations of 2–12 mg/mL. Size exclusion chromatography was the preferred method, as it allows separation of monomeric transporters from aggregates. We show that the purified protein, when reconstituted in proteoliposomes and nanodiscs, exhibits both basal and substrate or inhibitor-modulated ATPase activity. This report thus provides a convenient and robust method to obtain large amounts of active homogeneously purified human P-gp that is suitable for biochemical, biophysical and structural characterization.

Abstract SY02-03: Imaging cancer metabolism in patients: FDG PET and beyond

Abstract The identification of altered energy metabolism as a hallmark of cancer (1) leads to opportunities to exploit cancer metabolism as a target for diagnosis. This has been most widely exploited using the elevated rate of glycolysis observed in most tumors as a target for imaging (2)–in particular, positron emission tomography (PET) imaging of the glucose analog 18F-fluorodeoxyglucose (FDG). FDG PET, now combined with anatomic imaging in the form of PET/CT, has become an important tool for cancer detection, staging, and response assessment, widely used in oncologic clinical practices around the world (3,4). Clinical use of FDG PET has increased our appreciation of aberrant glycolysis as a feature of more aggressive, less differentiated tumors (5,6). At the same time, the variability of tumor FDG uptake seen in clinical imaging has highlighted some of the limitations of imaging tumor glycolysis and has spurred the development of new imaging probes and novel imaging modalities designed to image other facets of cancer energy metabolism. In addition, the use of therapeutics that are targeted to and/or influenced by cancer metabolic phenotype (7) drives applications of cancer metabolic imaging to clinical challenges beyond detection to predicting and and monitoring response to targeted therapy (8). This talk highlights current uses of FDG PET/CT for cancer staging and response evaluation, as well as alternative PET probes targeted to other metabolic substrates such as amino acids, lipids, and TCA intermediates (9). It also highlights other methods for imaging cancer metabolism in patients, including magnetic resonance spectroscopy, optical imaging, chemical exchange saturation transfer (CEST), MR metabolomics, and MR imaging of hyperpolarized 13C-labeled metabolic substrates such as pyruvate (10-14). Unique features and advantages of each modality are highlighted, as are approaches to image analysis common across modalities, including quantitative imaging and kinetic analysis. Finally, the talk emphasizes the benefit of multimodality imaging as an approach to fully characterize cancer metabolism, using glutaminolysis imaging as an example of active investigation. Supported in part by Komen SAC130060, DOE DE-SE0012476, NIH P30-CA016520, and NIH R01-CA211337.

Chemotherapy for primary mediastinal yolk sac tumor in a patient undergoing chronic hemodialysis: a case report

BackgroundThe safety and efficacy of chemotherapy for patients undergoing concomitant hemodialysis have not been fully established and optimal doses of anti-cancer drugs and best timing of hemodialysis remains unclear. Although chemosensitive cancers, such as germ cell tumors, treated with chemotherapy should have sufficient dose intensity maintained to achieve the desired effect, many patients with cancer undergoing hemodialysis might be under-treated because the pharmacokinetics of anti-cancer drugs in such patients remains unknown.Case presentationWe describe a 31-year-old Japanese man with a mediastinal yolk sac tumor treated with surgery followed by five cycles of chemotherapy containing cisplatin and etoposide while concomitantly undergoing hemodialysis. The doses of these agents used in the first cycle were 50% of the standard dose of cisplatin (10 mg/m2) and 60% of the standard dose of etoposide (60 mg/m2) on days 1 through to 5; the doses were subsequently escalated to 75% with both agents. Hemodialysis was started 1 hour after infusions of these agents. Severe hematological toxicities were observed despite successful treatment. During treatment with concurrent hemodialysis, pharmacokinetic analysis of cisplatin was performed and its relationship with adverse effects was assessed. Compared with patients with normal renal function, the maximum drug concentration was higher, and concentration increased in the interval between hemodialysis and the subsequent cisplatin infusion, resulting in a higher area under the curve despite a reduction in the dose to 75% of the standard regimen.ConclusionsBecause of the altered pharmacokinetics pharmacodynamics status of patients with renal dysfunction undergoing hemodialysis, pharmacokinetics pharmacodynamics analysis is deemed to be helpful for effective and safe management of chemotherapy in patients undergoing hemodialysis.

Genotypes Affecting the Pharmacokinetics of Anticancer Drugs.

Cancer treatment is becoming more and more individually based as a result of the large inter-individual differences that exist in treatment outcome and toxicity when patients are treated using population-based drug doses. Polymorphisms in genes encoding drug-metabolizing enzymes and transporters can significantly influence uptake, metabolism, and elimination of anticancer drugs. As a result, the altered pharmacokinetics can greatly influence drug efficacy and toxicity. Pharmacogenetic screening and/or drug-specific phenotyping of cancer patients eligible for treatment with chemotherapeutic drugs, prior to the start of anticancer treatment, can identify patients with tumors that are likely to be responsive or resistant to the proposed drugs. Similarly, the identification of patients with an increased risk of developing toxicity would allow either dose adaptation or the application of other targeted therapies. This review focuses on the role of genetic polymorphisms significantly altering the pharmacokinetics of anticancer drugs. Polymorphisms in DPYD, TPMT, and UGT1A1 have been described that have a major impact on the pharmacokinetics of 5-fluorouracil, mercaptopurine, and irinotecan, respectively. For other drugs, however, the association of polymorphisms with pharmacokinetics is less clear. To date, the influence of genetic variations on the pharmacokinetics of the increasingly used monoclonal antibodies has hardly been investigated. Some studies indicate that genes encoding the Fcγ-receptor family are of interest, but more research is needed to establish if screening before the start of therapy is beneficial. Considering the profound impact of polymorphisms in drug transporters and drug-metabolizing enzymes on the pharmacokinetics of chemotherapeutic drugs and hence, their toxicity and efficacy, pharmacogenetic and pharmacokinetic profiling should become the standard of care.

Cancer and liver cirrhosis: implications on prognosis and management

Liver cirrhosis, the end-stage of every chronic liver disease, is not only the major risk factor for the development of hepatocellular carcinoma but also a limiting factor for anticancer therapy of liver and non-hepatic malignancies. Liver cirrhosis may limit surgical and interventional approaches to cancer treatment, influence pharmacokinetics of anticancer drugs, increase side effects of chemotherapy, render patients susceptible for hepatotoxicity, and ultimately result in a competitive risk for morbidity and mortality. In this review, we provide a concise overview about the impact of liver cirrhosis on the management and prognosis of patients with primary liver cancer or non-hepatic malignancies.

Polymorphisms in the ABCB1 gene and effect on outcome and toxicity in childhood acute lymphoblastic leukemia.

The membrane transporter P-glycoprotein, encoded by the ABCB1 gene, influences the pharmacokinetics of anti-cancer drugs. We hypothesized that variants of ABCB1 affect outcome and toxicity in childhood acute lymphoblastic leukemia (ALL). We studied 522 Danish children with ALL, 93% of all those eligible. Risk of relapse was increased 2.9-fold for patients with the 1199GA variant versus 1199GG (P=0.001), and reduced 61% and 40%, respectively, for patients with the 3435CT or 3435TT variants versus 3435CC (overall P=0.02). The degree of bone marrow toxicity during doxorubicin, vincristine and prednisolone induction therapy was more prominent in patients with 3435TT variant versus 3435CT/3435CC (P=0.01/P<0.0001). We observed more liver toxicity after high-dose methotrexate in patients with 3435CC variant versus 3435CT/TT (P=0.03). In conclusion, there is a statistically significant association between ABCB1 polymorphisms, efficacy and toxicity in the treatment of ALL, and ABCB1 1199G>A may be a new possible predictive marker for outcome in childhood ALL.

Abstract 4680: Effect of various anticoagulants on the bioanalysis of drugs in rat blood: Implications for pharmacokinetic studies of anticancer drugs

Abstract Background: Pharmacokinetic studies play a vital role in the development and optimization of drugs, more so in cancer. Most often, pharmacokinetic blood samples are collected in EDTA vacutainers. Heparin is used infrequently and citrate, hardly ever. While the choice of anticoagulant is based on scientific rationale for some drugs, it is arbitrary in most others, with EDTA being the choice by convention. The purpose of this study was to evaluate the effects of anticoagulants on the bioanalysis of drugs. Methods: Six drugs used extensively in cancer therapy / care were selected. Albino wistar rats (N=6 per drug) were dosed with one of the following drugs intraperitoneally - Pemetrexed (50mg/kg), Imatinib (50mg/kg), Erlotinib (25mg/kg), Meropenem (60mg/kg), 6-Mercaptopurine (20mg/kg) and Voriconazole (6mg/kg). Animals were sacrificed 2 hours after dosing (1 hour in 6-mercaptopurine group due to short half-life) by terminal bleeding from the retro-orbital plexus. Approximately 750 µL of blood was collected in each of Na2ETDA, heparin, trisodium citrate (TSC) and plain (no anticoagulant) tubes. Blood levels of the drug were determined by HPLC assay. Results: Table below summarizes the findings of the study. Anticoagulant effect was significant for 3 out of 6 drugs. Concentration of erlotinib and meropenam were significantly underestimated when heparin was used, whereas EDTA led to underestimation of 6-mercaptopurine levels. Anticoagulants did not have any effect on the estimation of voriconazole levels. High interanimal variability in imatinib and pemetrexed levels did not allow adequate evaluation of the anticoagulant effect, although large differences in the average concentration of drugs were observed. Conclusion: Careful selection of anti-coagulant is necessary for accurate characterization of pharmacokinetics of anticancer drugs. EDTA as the anticoagulant of choice is questionable and may lead to erroneous interpretation of pharmacokinetic data. Effect of anticoagulant on the estimation of drug concentration in rat blood (Conc. in µg/mL)DrugHeparin(Mean±SD)EDTA(Mean±SD)TSC(Mean±SD)Plain(Mean±SD)P value (ANOVA)Imatinib5.74±4.406.75±5.207.37±6.946.45±4.47NSErlotinib0.85±0.841.24±0.951.97±1.081.12±0.91&amp;lt;0.056-mercaptopurine0.31±0.170.21±0.120.26±0.100.42±0.24&amp;lt;0.05Voriconazole2.19±0.872.32±0.872.14±0.842.44±1.09NSMeropenam0.37±0.130.52±0.130.49±0.110.51±0.14&amp;lt;0.05Pemetrexed8.46±5.979.08±7.038.11±5.3010.39±7.60NS Citation Format: Preeti Kulkarni, Kamal Pathak, Murari Gurjar, Sagar Dhoble, Arvind Naik, Bhaskar Gavitre, Bhaskar Vidhun, Vikram Gota. Effect of various anticoagulants on the bioanalysis of drugs in rat blood: Implications for pharmacokinetic studies of anticancer drugs. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4680. doi:10.1158/1538-7445.AM2014-4680

Pharmacokinetics and safety of cetuximab in a patient with renal dysfunction

In the literature, data on the effect of renal impairment on the pharmacokinetics of anticancer drugs are scarce. Here, we report a 68-year-old metastatic osteosarcoma patient with impaired renal function due to prior chemotherapy, who was treated on compassionate use basis with 400 mg/m(2) cetuximab. Pharmacokinetic parameters after the first dose, including dose-normalised AUC from time zero to day 7, clearance, elimination half-life (t(1/2)), were estimated using trapezoidal non-compartmental methods and compared to pharmacokinetic data from a study population with normal kidney function. The results showed that the pharmacokinetics of cetuximab in this patient with renal failure was similar to that with adequate renal function. This study suggests that cetuximab can be safely used in cancer patients with renal impairment without dose adjustment.

To Cap or Not to Cap: Chemotherapy Dosing in Obese Adult Hematology Patients

Obesity, defined by the World Health Organization (WHO) as a body mass index (BMI) of ≥30 kg/m2, is a risk factor for many cancers and may be associated with higher cancer-related mortality.1 In comparison to solid tumors, the influence of obesity on the prevalence, pathophysiology, treatment, and disease outcomes of hematological cancers such as lymphoma, leukemia, and plasma cell disorders is less well defined. As the incidence of obesity increases (according to WHO projections, by 2015 more than 700 million adults worldwide will be obese), clinicians treating blood cancers are increasingly aware of the uncertainties and disparities with drug treatment within this group, especially in determining the most appropriate chemotherapy dosing algorithms that take into account the changes in anticancer drug pharmacokinetics and pharmacodynamics to optimize outcomes.

The effect of complementary and alternative medicines on CYP3A4-mediated metabolism of three different substrates: 7-benzyloxy-4-trifluoromethyl-coumarin, midazolam and docetaxel

Concomitant use of complementary and alternative medicine (CAM) and anticancer drugs can affect the pharmacokinetics of anticancer drugs by inhibiting the metabolizing enzyme cytochrome P450 3A4 (CYP3A4) (EC 1.14.13.157). Several in vitro studies determined whether CAM can inhibit CYP3A4, but these studies revealed contradictory results. A plausible explanation for these conflicting results is the use only of a single model CYP3A4 substrate in each study. Therefore, the objective was to determine the potential of selected CAM (β-carotene, Echinacea, garlic, Ginkgo biloba, ginseng, grape seed extract, green tea extract, milk thistle, saw palmetto, valerian, vitamin B6, B12 and C) to inhibit CYP3A4-mediated metabolism of different substrates: 7-benzyloxy-4-trifluoromethyl-coumarin (BFC), midazolam and docetaxel. The effect of CAM on CYP3A4-mediated metabolism of an anticancer drug has never been determined before in vitro, which makes this study unique. The oncolytic CYP3A4 substrate docetaxel was used to establish the predictive value of the model substrates for pharmacokinetic interactions between CAM and anticancer drugs in vitro, and to more closely predict these interactions in vivo. The inhibition of CYP3A4-mediated metabolism of 7-benzyloxy-4-trifluoromethyl-coumarin (BFC) by CAM was assessed in Supersomes, using the fluorometric CYP3A4 inhibition assay. In human liver microsomes (HLM) the inhibition of CYP3A4-mediated metabolism of midazolam and docetaxel was determined, using liquid-chromatography coupled to tandem mass spectrometry (LC-MS/MS). The results confirmed grape seed and green tea as potent inhibitors and milk thistle as moderate inhibitor of CYP3A4-mediated metabolism of BFC, midazolam and docetaxel. Clinical studies are required to determine the clinical relevance of the determined CYP3A4 inhibition by grape seed, green tea and milk thistle.

The role of MDR1 (C3435T) gene polymorphism in Egyptian acute lymphoblastic leukemia

P-glycoprotein (P-gp), a membrane transporter encoded by multidrug resistance 1 (MDR1) gene, influences pharmacokinetics of anticancer drugs and contributes to multidrug resistance phenotype in acute lymphoblastic leukemia (ALL). The MDR1 (C3435T) gene polymorphism is associated with the altered expression and function of P-gp. In this study, we investigated the influence of inherited MDR1 (C3435T) gene polymorphism on the susceptibility to ALL in Egypt in 60 ALL patients (30 childhood and 30 adulthood), together with 60 healthy controls using a polymerase chain reaction–restriction fragment length polymorphism assay. The mutant homozygous T/T genotype was significantly associated with the occurrence of ALL (p = 0.02; odds ratio, 8.000 (95 % confidence interval (CI), 1.425–44.920) in childhood ALL and (p = 0.04; odds ratio, 5.455 (95 % CI, 0.937–31.746) in adulthood ALL patients. The heterozygous C/T genotype was near statistical significance in both childhood and adulthood ALL patients in comparison to controls (p = 0.06). The C/C genotype was associated with worse response to treatment than the mutant type (T/T and C/T; p = 0.009, 0.04) in childhood and adulthood ALL, respectively. These results suggest that the MDR1 T/T genotype might influence risk of development of ALL and the C/C genotype might be linked to a poor prognosis of ALL.

Development and validation of a LC‐MS/MS method for the in vitro analysis of 1‐hydroxymidazolam in human liver microsomes: application for determining CYP3A4 inhibition in complex matrix mixtures

Complementary and alternative medicines (CAM) can affect the pharmacokinetics of anticancer drugs by interacting with the metabolizing enzyme cytochrome P450 (CYP) 3A4. To evaluate changes in the activity of CYP3A4 in patients, levels of 1-hydroxymidazolam in plasma are often determined with liquid chromatography-quadrupole mass spectrometry (LC-MS/MS). However, validated LC-MS/MS methods to determine in vitro CYP3A4 inhibition in human liver microsomes are scarce and not optimized for evaluating CYP3A4 inhibition by CAM. The latter is necessary because CAM are often complex mixtures of numerous compounds that can interfere with the selective measurement of 1-hydroxymidazolam. Therefore, the aim was to validate and optimize an LC-MS/MS method for the adequate determination of CYP3A4 inhibition by CAM in human liver microsomes. After incubation of human liver microsomes with midazolam, liquid-liquid extraction with tert-butyl methyl ether was applied and dried samples were reconstituted in 50% methanol. These samples were injected onto a reversed-phase chromatography consisting of a Zorbax Extend-C18 column (2.1 × 150 mm, 5.0 µm particle size), connected to a triple quadrupole mass spectrometer with electrospray ionization. The described LC-MS/MS method was validated over linear range of 1.0-500 nm for 1-hydroxymidazolam. The results revealed good inter-assay accuracy (≥85% and ≤115%) and within-day and between-day precisions (coefficient of variation ≤ 4.43%). Furthermore, the applicability of this assay for the determination of CYP3A4 inhibition in complex matrix mixtures was successfully demonstrated in an in vitro experiment in which CYP3A4 inhibition by known CAM (β-carotene, green tea, milk thistle and St. John's wort) was determined.