著者

Xiachu ZHANG Feng LIU Xin CHEN Xu ZHU Jack UETRECHT

出版者

The Japanese Society for the Study of Xenobiotics

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.26, no.1, pp.47-59, 2011 (Released:2011-03-03)

参考文献数

135

被引用文献数

39

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There is strong evidence that most idiosyncratic drug reactions (IDRs) are immune-mediated and are caused by reactive metabolites of a drug rather than by the drug itself. Several hypotheses have been proposed by which a drug could induce an immune response. The major hypotheses are the hapten hypothesis and the danger hypothesis; however, the characteristics and spectrum of IDRs are different with different drugs, and this likely reflects mechanistic differences; therefore, no one hypothesis is likely to explain all IDRs. Some IDRs appear to involve epigenetic effects, direct activation of antigen-presenting cells, or disturbing the normal balance of the immune system. It has been suggested that many cases of idiosyncratic liver injury are not immune-mediated, and other mechanisms such as mitochondrial injury may be involved. It is essential that any hypothesis be consistent with the clinical characteristics of the IDR. Although the characteristics of most idiosyncratic liver injury do not suggest that mitochondria are the major target, it is quite possible that milder mitochondrial injury could stimulate an immune-mediated reaction. The observation that IDRs can vary widely among different drugs and different patients is most easily explained by an immune mechanism in which the target of the immune response is different.

著者

Takeshi AKIYOSHI Marie ITO Saori MURASE Mitsue MIYAZAKI F. Peter GUENGERICH Katsunori NAKAMURA Koujirou YAMAMOTO Hisakazu OHTANI

出版者

日本薬物動態学会 会長/日本薬物動態学会 DMPK編集委員長

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.28, no.5, pp.411-415, 2013 (Released:2013-10-25)

参考文献数

31

被引用文献数

21

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Inhibition of cytochrome P450 (CYP) 3A4 is the major cause of drug-drug interactions (DDI). We have previously reported that the genetic variation of CYP3A4 significantly affected the inhibitory profiles of typical competitive inhibitors. In addition to competitive inhibition, some clinically significant DDI are attributable to mechanism-based inhibition (MBI). However, the differences in the MBI kinetics among CYP3A4 genetic variants remain to be characterized. In this study, we quantitatively investigated the inhibition kinetics of MBI inhibitors, erythromycin and clarithromycin, on the CYP3A4 variants CYP3A4.1, 4.2, 4.7, 4.16, and 4.18. The activity of CYP3A4 was assessed using testosterone 6β-hydroxylation with recombinant CYP3A4. Both erythromycin and clarithromycin decreased the activity of CYP3A4 in a time-dependent manner. The maximum inactivation rate constants, kinact,max, of erythromycin for CYP3A4.2 and CYP3A4.7 were 0.5-fold that for CYP3A4.1, while that for CYP3A4.16 and CYP3A4.18 were similar to that for CYP3A4.1. The KI values of erythromycin for CYP3A4.2, 4.7, 4.16, and 4.18 were 1.2-, 0.4-, 2.2- and 0.72-fold those of CYP3A4.1, respectively. Similar results were obtained for clarithromycin. In conclusion, the inhibitory profiles of MBI inhibitors, as well as competitive inhibitors, may possibly differ among CYP3A4 variants. This difference may contribute to interindividual differences in the extent of DDI based on MBI.

著者

Rongrong JIANG Satoshi YAMAORI Yasuka OKAMOTO Ikuo YAMAMOTO Kazuhito WATANABE

出版者

The Japanese Society for the Study of Xenobiotics

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.28, no.4, pp.332-338, 2013 (Released:2013-08-25)

参考文献数

49

被引用文献数

151

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The present study investigated the inhibitory effect of cannabidiol (CBD), a major constituent of marijuana, on the catalytic activity of cytochrome P450 2C19 (CYP2C19). (S)-Mephenytoin 4′-hydroxylase activities of human liver microsomes (HLMs) and recombinant CYP2C19 were inhibited by CBD in a concentration-dependent manner (IC50 = 8.70 and 2.51 µM, respectively). Omeprazole 5-hydroxylase and 3-O-methylfluorescein O-demethylase activities in recombinant CYP2C19 were also strongly inhibited by CBD (IC50 = 1.55 and 1.79 µM, respectively). Kinetic analysis for inhibition revealed that CBD showed a mixed-type inhibition against (S)-mephenytoin 4′-hydroxylation by recombinant CYP2C19. To clarify the structural requirements for CBD-mediated CYP2C19 inhibition, the effects of CBD-related compounds on CYP2C19 activity were examined. Olivetol inhibited the (S)-mephenytoin 4′-hydroxylase activity of recombinant CYP2C19 with the IC50 value of 15.3 µM, whereas d-limonene slightly inhibited the activity (IC50 > 50 µM). The inhibitory effect of CBD-2′-monomethyl ether (IC50 = 1.88 µM) on CYP2C19 was comparable to that of CBD, although the inhibitory potency of CBD-2′,6′-dimethyl ether (IC50 = 14.8 µM) was lower than that of CBD. Cannabidivarin, possessing a propyl side chain, showed slightly less potent inhibition (IC50 = 3.45 µM) as compared with CBD, whereas orcinol and resorcinol did not inhibit CYP2C19 activity at all. These results indicate that CBD caused potent CYP2C19 inhibition, in which one free phenolic hydroxyl group and the pentyl side chain of CBD may play important roles.

著者

Akiko MATSUI-SAKATA Hisakazu OHTANI Yasufumi SAWADA

出版者

The Japanese Society for the Study of Xenobiotics

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.20, no.5, pp.368-378, 2005 (Released:2005-11-01)

参考文献数

96

被引用文献数

140

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Objective: Among various adverse reactions of atypical antipsychotics, weight gain and impaired glucose tolerance are clinically significant. The aim of this study is to analyze quantitatively the contributions of various receptors to these antipsychotics-induced adverse reactions based on the receptor occupancy theory.    Methods: Two indices of antipsychotics-induced weight gain (the values estimated by a meta-analysis and the observed values in clinical trials) and the morbidity rate of type 2 diabetes mellitus during treatment with antipsychotics were taken from the literature. We calculated the estimated mean receptor occupancies of α1 adrenergic, α2 adrenergic, dopamine D2, histamine H1, muscarinic acetylcholine (mACh), serotonin 5-HT1A, 5-HT2A and 5-HT2C receptors by antipsychotics by using the pharmacokinetic parameters and receptor dissociation constants, and analyzed the correlation between the occupancies and the extent of adverse reactions as assessed using the aforementioned indices.    Results: There were statistically significant correlations between the estimated occupancies of H1 and mACh receptors and antipsychotics-induced weight gain estimated by meta-analysis (rs=0.81 and rs=0.83, respectively, p<0.01). There were also statistically significant correlations between these receptor occupancies and observed weight gain in clinical trials (rs=0.66 in each case, p<0.01). The morbidity rate of type 2 diabetes mellitus was highly correlated with H1, mACh, and 5-HT2C receptor occupancies (rs=0.90 in each case, p<0.05). However, H1 receptor occupancy was also highly correlated with mACh receptor occupancy among antipsychotics, so that only one of them may be critically associated with the adverse reactions. Considering that these adverse reactions have not been reported for drugs with mACh receptor antagonistic action, other than antipsychotics, the H1 receptor may contribute predominantly to the antipsychotics-induced weight gain and diabetes mellitus.    Discussion/Conclusion: Model analysis based on receptor occupancy indicates that H1 receptor blockade is the primary cause of antipsychotics-induced weight gain and diabetes mellitus.

著者

Satoshi YAMAORI Kyoko KOEDA Mika KUSHIHARA Yui HADA Ikuo YAMAMOTO Kazuhito WATANABE

出版者

The Japanese Society for the Study of Xenobiotics

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.27, no.3, pp.294-300, 2012 (Released:2012-06-25)

参考文献数

38

被引用文献数

97

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Inhibitory effects of Δ9-tetrahydrocannabinol (Δ9-THC), cannabidiol (CBD), and cannabinol (CBN), the three major constituents in marijuana, and polycyclic aromatic hydrocarbons (PAHs) contained in marijuana smoke on catalytic activity of human cytochrome P450 (CYP) 2C9 were investigated. These phytocannabinoids concentration-dependently inhibited S-warfarin 7-hydroxylase and diclofenac 4′-hydroxylase activities of human liver microsomes (HLMs) and recombinant CYP2C9 (rCYP2C9). In contrast, none of the twelve PAHs including benz[a]anthracene and benzo[a]pyrene exerted substantial inhibition (IC50 > 10 µM). The inhibitory potentials of Δ9-THC (Ki = 0.937–1.50 µM) and CBN (Ki = 0.882–1.29 µM) were almost equivalent regardless of the enzyme sources used, whereas the inhibitory potency of CBD (Ki = 0.954–9.88 µM) varied depending on the enzyme sources and substrates used. Δ9-THC inhibited both S-warfarin 7-hydroxylase and diclofenac 4′-hydroxylase activities of HLMs and rCYP2C9 in a mixed manner. CBD and CBN competitively inhibited the activities of HLMs and rCYP2C9, with the only notable difference being that CBD and CBN exhibited mixed-type inhibitions against diclofenac 4′-hydroxylation and S-warfarin 7-hydroxylation, respectively, by rCYP2C9. None of Δ9-THC, CBD, and CBN exerted metabolism-dependent inhibition. These results indicated that the three major phytocannabinoids but not PAHs contained in marijuana smoke potently inhibited CYP2C9 activity and that these cannabinoids can be characterized as direct inhibitors for CYP2C9.

著者

Kiyoshi FUKUHARA Akiko OHNO Yosuke ANDO Takashi YAMOTO Haruhiro OKUDA

出版者

日本薬物動態学会 会長/日本薬物動態学会 DMPK編集委員長

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.26, no.4, pp.399-406, 2011 (Released:2011-09-02)

参考文献数

23

被引用文献数

18

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The widely used analgesic-antipyretic drug acetaminophen (APAP) is known to cause serious liver necrosis at high doses in man and experimental animals. For studies of toxic processes, 1H NMR spectroscopy of biofluids allows monitoring of endogenous metabolite profiles that alter characteristically in response to changes in physiological status. Herein, a 1H NMR metabolomics approach was applied to the investigation of APAP toxicity in rats and the effect of phenobarbital (PB) on APAP-induced hepatotoxicity. Metabolite differences due to hepatotoxicity were observed in 1H NMR spectra of serum and urine, and enhanced APAP hepatotoxicity by pretreatment with PB was clearly shown by a principal components analysis of the spectral data. NMR spectra of APAP-dosed rat urine provided profiles of APAP-related compounds together with endogenous metabolites. By comparison of endogenous and APAP-related metabolite spectra with those from rats pretreated with PB, it was possible to show the importance of oxidative metabolism of APAP to N-acetyl-p-benzoquinone, an essential step in APAP hepatotoxicity.

著者

David C. GAZE

出版者

日本薬物動態学会 会長/日本薬物動態学会 DMPK編集委員長

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.24, no.4, pp.333-341, 2009 (Released:2009-09-10)

参考文献数

70

被引用文献数

84

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The diagnosis of cardiac ischemia remains a challenge in contemporary emergency medicine. A blood-borne biomarker is an attractive alternative to cardiac imaging or stress testing as it would be cheaper and logistically faster to obtain. A number of candidate biomarkers have been proposed for the detection of cardiac ischemia; however, only Ischemia Modified Albumin (IMA) has been released for clinical use. IMA is a good discriminator between ischemic and non-ischemic patients. Changes in IMA concentration have shown to occur during coronary angioplasty-induced ischemia. Clinical studies indicate that IMA appears to offer on admission an early test which can be combined with electrocardiographic findings and cardiac troponin measurements for the early exclusion of acute coronary syndrome. IMA is an independent predictor of short and long term adverse outcomes in patients with acute chest pain. However, this test is relatively new and uncertainties remain. Elevations of IMA occur in conditions other than chest pain, thus questioning its specificity. The mechanism of IMA formation and the precise entity being measured are not fully known. Nevertheless, IMA measurement remains the only current clinical biomarker which may be used for the diagnosis of patients suspected of cardiac ischemia.

著者

Kyoko FUKUMOTO Takashi KOBAYASHI Kazuo KOMAMURA Shiro KAMAKURA Masafumi KITAKAZE Kazuyuki UENO

出版者

日本薬物動態学会 会長/日本薬物動態学会 DMPK編集委員長

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.20, no.6, pp.423-427, 2005 (Released:2006-01-11)

参考文献数

30

被引用文献数

13 11

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We investigated whether there was a stereoselective effect of amiodarone on the pharmacokinetics of carvedilol. Among a series of 106 inpatients with heart failure, 52 received carvedilol monotherapy (carvedilol group) and 54 received carvedilol plus amiodarone (carvedilol+amiodarone group). The serum carvedilol concentration administered/dose ratio was compared between the two groups based on HPLC measurement of the serum levels of carvedilol, amiodarone, and desethylamiodarone. In 6 patients from the carvedilol group, serum carvedilol levels were compared before and after coadministration of amiodarone. There was no significant between-group difference of the serum concentration to dose (C/D ratio) for the R-enantiomer carvedilol, however, the C/D ratio for the S-enantiomer and the serum S-carvedilol to R-carvedilol (S/R) ratio were both significantly lower in the carvedilol group than in the carvedilol+amiodarone group(47.8±56.7 versus 95.3±105 ng/mg/kg, P=0.0048 and 0.460±0.207 versus 0.879±0.377 ng/mg/kg, P<0.001), respectively. Furthermore, the mean S-carvedilol concentration over 14 days of coadministration with amiodarone was higher than that before coadministration (6.54±1.73 ng/mL versus 3.03±0.670 ng/mL, P<0.001). These results suggest that metabolism of S-carvedilol was markedly inhibited by coadministration of amiodarone.

著者

Yuki Kondo Sachimi Yoshihashi Kayo Mimori Ruri Ogihara Yoshinori Kanehama Yoshiyuki Maki Shin Enosawa Kouichi Kurose Takahiro Iwao Katsunori Nakamura Tamihide Matsunaga

出版者

日本薬物動態学会 会長/日本薬物動態学会 DMPK編集委員長

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

pp.DMPK-14-RG-022, (Released:2014-04-29)

参考文献数

22

被引用文献数

9

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This study aimed to establish culture conditions which are able to give the differentiation of induced pluripotent (iPS) cells to the hepatocytes. To this end, we examined the usefulness of culture medium containing the components involved in the intermediary metabolism in the liver. More specifically, we examined the effect of the 'modified L-15 medium' containing galactose, phenylalanine and ornitine, but deprived of glucose, tyrosine, arginine and pyruvic acid. The medium was altered according to changes in the expression of enzymes that participate in liver-specific pathways. After 25 days of differentiation, the differentiated cells expressed hepatocyte markers and drug-metabolizing enzymes. These expression levels were increased using modified L-15 medium. The survival of human fetal liver cells and the death of human fibroblasts were observed during culture in modified L-15 medium. Most of the cells that differentiated from human iPS cells using modified L-15 medium were stained by anti-human albumin antibody. These results suggest that iPS cells can be converted to high purity-differentiated hepatocytes by cultivating them in modified L-15 medium.

著者

Jahye KIM Hisakazu OHTANI Masayuki TSUJIMOTO Yasufumi SAWADA

出版者

The Japanese Society for the Study of Xenobiotics

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.24, no.2, pp.167-174, 2009 (Released:2009-05-10)

参考文献数

41

被引用文献数

12

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Concomitant administration of certain fluoroquinolone antimicrobials and nonsteroidal antiinflammatory agents (NSAIDs) induces serious convulsion in humans. There are differences in convulsive activity among fluoroquinolones and in the potentiation of fluoroquinolone-induced convulsion among NSAIDs, but a comprehensive, quantitative comparison has not been carried out. This study evaluates the inhibitory effects of twelve fluoroquinolones (ciprofloxacin, enoxacin, fleroxacin, gatifloxacin, levofloxacin, lomefloxacin, norfloxacin, ofloxacin, pazufloxacin, prulifloxacin, sparfloxacin, and tosufloxacin) alone or in the presence of an NSAID (4-biphenylacetic acid, diclofenac sodium, loxoprofen, lornoxicam or zaltoprofen) on the GABAA receptor binding of [3H]muscimol in an in vitro study using mice synaptic plasma membrane. The rank order of inhibitory effects of the fluoroquinolones was prulifloxacin ≈ norfloxacin > ciprofloxacin ≥ enoxacin > gatifloxacin ≥ ofloxacin ≈ tosufloxacin ≈ lomefloxacin > levofloxacin ≥ sparfloxacin ≥ pazufloxacin ≈ fleroxacin. 4-Biphenylacetic acid most potently enhanced the inhibitory effects of the fluoroquinolones, while zaltoprofen, loxoprofen, lornoxicam and diclofenac had essentially no effect. The clinical risk of convulsion for each combination was estimated using a pharmacodynamic model based on receptor occupancy using the in vitro data set obtained and pharmacokinetic parameters in humans collected from the literature. The combinations of 4-biphenylacetic acid with prulifloxacin and enoxacin were concluded to be the most hazardous.

著者

Eriko SATO Ikuko YANO Masahiro SHIMOMURA Satohiro MASUDA Toshiya KATSURA Shin-ichi MATSUMOTO Teru OKITSU Yasuhiro IWANAGA Shinji UEMOTO Ken-ichi INUI

出版者

The Japanese Society for the Study of Xenobiotics

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.24, no.2, pp.175-179, 2009 (Released:2009-05-10)

参考文献数

20

被引用文献数

3

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We attempted a switch of mammalian target of rapamycin (mTOR) inhibitors from sirolimus to everolimus, a derivative of sirolimus and now on the market in Japan, in two pancreatic islet transplant patients. Both patients were administered tacrolimus with sirolimus or everolimus. They had been administered 5 or 9 mg sirolimus once a day and had maintained a trough concentration of about 15 ng/mL as measured by high performance liquid chromatography with ultraviolet detection. After the switch from sirolimus to everolimus, they were given 10 or 12 mg/day of everolimus twice a day to maintain a trough concentration of 12-15 ng/mL as measured by a fluorescence polarization immunoassay (FPIA) method. Afterward, the blood concentrations of everolimus and sirolimus after the conversion were measured by high performance liquid chromatography with mass spectrometry and everolimus concentrations were found to be 5-10 ng/mL. These data show that a larger dosage is needed for everolimus than sirolimus to maintain the same trough blood concentration. Data obtained by the FPIA for everolimus should be carefully evaluated after switching from sirolimus to everolimus because of the cross-reactivity of the antibody with sirolimus.

著者

Keiko MAEKAWA Masaya ITODA Kimie SAI Yoshiro SAITO Nahoko KANIWA Kuniaki SHIRAO Tetsuya HAMAGUCHI Hideo KUNITOH Noboru YAMAMOTO Tomohide TAMURA Hironobu MINAMI Kaoru KUBOTA Atsushi OHTSU Teruhiko YOSHIDA Nagahiro SAIJO Naoyuki KAMATANI Shogo OZAWA Jun-ichi SAWADA

出版者

The Japanese Society for the Study of Xenobiotics

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.21, no.2, pp.109-121, 2006 (Released:2006-05-10)

参考文献数

35

被引用文献数

36

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The ATP-binding cassette transporter, ABCG2, which is expressed at high levels in the intestine and liver, functions as an efflux transporter for many drugs, including clinically used anticancer agents such as topotecan and the active metabolite of irinotecan (SN-38). In this study, to elucidate the linkage disequilibrium (LD) profiles and haplotype structures of ABCG2, we have comprehensively searched for genetic variations in the putative promoter region, all the exons, and their flanking introns of ABCG2 from 177 Japanese cancer patients treated with irinotecan. Forty-three genetic variations, including 11 novel ones, were found: 5 in the 5′-flanking region, 13 in the coding exons, and 25 in the introns. In addition to 9 previously reported nonsynonymous single nucleotide polymorphisms (SNPs), 2 novel nonsynonymous SNPs, 38C>T (Ser13Leu) and 1060G>A (Gly354Arg), were found with minor allele frequencies of 0.3%. Based on the LD profiles between the SNPs and the estimated past recombination events, the region analyzed was divided into three blocks (Block -1, 1, and 2), each of which spans at least 0.2 kb, 46 kb, and 13 kb and contains 2, 24, and 17 variations, respectively. The two, eight, and five common haplotypes detected in 10 or more patients accounted for most (>90%) of the haplotypes inferred in Block -1, Block 1, and Block 2, respectively. The SNP and haplotype distributions in Japanese were different from those reported previously in Caucasians. This study provides fundamental information for the pharmacogenetic studies investigating the relationship between the genetic variations in ABCG2 and pharmacokinetic/pharmacodynamic parameters.

著者

Xiao-cong ZUO Ya-nan ZHOU Bi-kui ZHANG Guo-ping YANG Ze-neng CHENG Hong YUAN Dong-sheng OUYANG Shi-kun LIU Jeffrey S. BARRETT Pei-jiong LI Zhi LIU Hong-yi TAN Ren GUO Ling-yun ZHOU Yue-liang XIE Zuo-jun LI Jing LI Chun-jiang WANG Jiang-lin WANG

出版者

The Japanese Society for the Study of Xenobiotics

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.28, no.5, pp.398-405, 2013 (Released:2013-10-25)

参考文献数

51

被引用文献数

19

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The objective of this study was to evaluate the effect of the CYP3A5*3 allele on the pharmacokinetics of tacrolimus and amlodipine, and drug-drug interactions between them in healthy subjects. Pharmacokinetic drug interactions between tacrolimus and amlodipine were evaluated in a randomized, 3-period, 6-sequence crossover study in healthy Chinese volunteers according to CYP3A5 genotype. A single-dose and multiple-dose study were designed. A 96-h pharmacokinetic study followed either tacrolimus or amlodipine dose, and the washout periods between the study phases were 14 days. In the single-dose study, apparent oral clearance (CL/F) of tacrolimus (5 mg) in CYP3A5 expressers was 3.8-fold (p = 0.008) higher than that in CYP3A5 non-expressers. Amlodipine decreased mean tacrolimus CL/F in CYP3A5 expressers by 2.2-fold (p = 0.005), while it had no effect on that in CYP3A5 non-expressers. The CL/F of amlodipine in CYP3A5 non-expressers was 2.0-fold (p = 0.001) higher than that in CYP3A5 expressers. Tacrolimus increased mean amlodipine CL/F in CYP3A5 expressers by 1.4-fold (p = 0.016) while it had no effect on that in CYP3A5 non-expressers. Tacrolimus slightly reduced the AUC0–∞ of amlodipine in both CYP3A5 expressers and non-expressers. Dose adjustment of tacrolimus should be considered according to CYP3A5*3 genetic polymorphism when tacrolimus is coadministered with amlodipine.

著者

Ger J. van der VUSSE

出版者

The Japanese Society for the Study of Xenobiotics

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.24, no.4, pp.300-307, 2009 (Released:2009-09-10)

参考文献数

62

被引用文献数

314

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Fatty acids play critical roles in mammalian energy metabolism. Moreover, they are important substrates for the synthesis of membrane phospholipids and biologically active compounds like eicosanoids and leukotrienes. Because of their low solubility in aqueous solutions such as blood plasma and interstitial fluid, fatty acids are in need of binding proteins to increase their concentration in vascular and interstitial compartments. Albumin acts as main fatty acid binding protein in extracellular fluids. Plasma albumin possesses about 7 binding sites for fatty acids with moderate to high affinity, enhancing the concentration of fatty acids by a several orders of magnitude. Despite the high affinity of albumin for fatty acids, uptake of fatty acids by parenchymal cells such as skeletal and cardiac myocytes seems not to be hampered by albumin. In contrast, experimental findings suggest that albumin may facilitate the uptake of fatty acids by organs in need of these substrates. In the present overview the following issues will be briefly discussed: (i) transport and storage of fatty acids in the mammalian body, (ii) biosynthesis of albumin in the liver, (iii) localization and concentration of albumin in body fluids, (iv) interactions between albumin and fatty acids, (v) albumin structure and fatty acid binding sites, (vi) uptake of fatty acids by organs and roles for plasma albumin and (vii) lessons from patients and experimental animals lacking plasma albumin.

著者

Li WANG Douglas H. SWEET

出版者

The Japanese Society for the Study of Xenobiotics

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.28, no.3, pp.220-228, 2013 (Released:2013-06-25)

参考文献数

44

被引用文献数

26

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When herbal products are used in combination therapy with drugs, alterations in pharmacokinetics, pharmacodynamics, and toxicity can result. Many active components of herbal products are organic anions, and human organic anion transporter 1 (hOAT1, SLC22A6), hOAT3 (SLC22A8), and hOAT4 (SLC22A11) have been identified as potential sites of drug-drug interactions. Therefore, we assessed the effects of lithospermic acid (LSA), rosmarinic acid (RMA), salvianolic acid A (SAA), salvianolic acid B (SAB), and tanshinol (TSL), components of the herbal medicine Danshen, on the function of these transporters. Kinetic analysis demonstrated a competitive mechanism of inhibition for all five. Ki values (µM) were estimated as 20.8 ± 2.1 (LSA), 0.35 ± 0.06 (RMA), 5.6 ± 0.3 (SAA), 22.2 ± 1.9 (SAB), and 40.4 ± 12.9 (TSL) on hOAT1 and as 0.59 ± 0.26 (LSA), 0.55 ± 0.25 (RMA), 0.16 ± 0.03 (SAA), 19.8 ± 8.4 (SAB), and 8.6 ± 3.3 (TSL) on hOAT3. No significant inhibition of hOAT4 activity by TSL was observed. Using published human pharmacokinetic values, unbound Cmax/Ki ratios were calculated as an indicator of in vivo drug-drug interaction potential. Analysis indicated a strong interaction potential for RMA and TSL on both hOAT1 and hOAT3 and for LSA on hOAT3. Thus, herb-drug interactions may occur in vivo in situations of co-administration of Danshen and clinical therapeutics known to be hOAT1/hOAT3 substrates.

著者

Tatsuya YAGI Takafumi NAITO Yasuaki MINO Kazuo UMEMURA Junichi KAWAKAMI

出版者

The Japanese Society for the Study of Xenobiotics

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.27, no.2, pp.248-254, 2012 (Released:2012-04-25)

参考文献数

27

被引用文献数

13

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The aim of this open-label, randomized, and 3-period crossover study was to evaluate the influences of concomitant antacid administration on the plasma disposition, intestinal absorption, and urinary excretion of gabapentin in humans. Gabapentin (200 mg) was orally administered alone, with 1 g magnesium oxide (MgO), or with 20 mg omeprazole to 13 healthy adult subjects. Oral bioavailability (BA) of gabapentin was estimated by 24-h urine collection. The Cmax, Tmax and AUC0–∞ of gabapentin + MgO were significantly lower than that of gabapentin alone (by 33%, 36% and 43%, respectively) and gabapentin + omeprazole (by 29%, 46% and 40%, respectively). In contrast, no significant differences were observed in the plasma disposition parameters of gabapentin between the treatments with and without omeprazole. The gabapentin BA in the MgO treatment was significantly lower, by 32% and 39%, compared to the gabapentin alone and with omeprazole treatment, respectively. There was no significant difference in the gabapentin BA between the gabapentin alone and with omeprazole treatment. Concomitant MgO and omeprazole did not affect the renal clearance of gabapentin. In conclusion, concomitant MgO decreased the gabapentin exposure through the reduction of intestinal absorption extent and rate. This reduction may be independent of the suppression of gastrointestinal acidification caused by antacids.

著者

Maika KISSEI Tomoo ITOH Tomoya NARAWA

出版者

The Japanese Society for the Study of Xenobiotics

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.29, no.5, pp.367-372, 2014-10-25 (Released:2014-10-25)

参考文献数

45

被引用文献数

7

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Folic acid (FA) is a water-soluble vitamin, and orally ingested FA is absorbed from the small intestine by the proton-coupled folate transporter (PCFT). In the present study, we investigated whether epigallocatechin gallate (EGCG), one of the tea catechins, affects the transport of FA by PCFT. EGCG inhibited the uptake of FA into Caco-2 cells and human PCFT-expressing HEK293 cells (PCFT-HEK293 cells). The initial rate of uptake of FA into PCFT-HEK293 cells followed Michaelis–Menten kinetics (Km = 1.9 µM). Dixon plots revealed that PCFT-mediated FA uptake was competitively inhibited by EGCG (Ki ≒ 9 µM). The uptake of the PCFT substrate methotrexate (MTX) was competitively inhibited by EGCG as well (Ki ≒ 15 µM). In conclusion, it is suggested that when FA or MTX is ingested with tea, it is likely that the intestinal absorption of these compounds by PCFT is inhibited, which could result in insufficient efficacy.

著者

Masoud JAMEI Gemma L DICKINSON Amin ROSTAMI-HODJEGAN

出版者

The Japanese Society for the Study of Xenobiotics

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.24, no.1, pp.53-75, 2009 (Released:2009-02-28)

参考文献数

150

被引用文献数

300

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An increasing number of failures in clinical stages of drug development have been related to the effects of candidate drugs in a sub-group of patients rather than the ‘average’ person. Expectation of extreme effects or lack of therapeutic effects in some subgroups following administration of similar doses requires a full understanding of the issue of variability and the importance of identifying covariates that determine the exposure to the drug candidates in each individual. In any drug development program the earlier these covariates are known the better. An important component of the drive to decrease this failure rate in drug development involves attempts to use physiologically-based pharmacokinetics ‘bottom-up’ modeling and simulation to optimize molecular features with respect to the absorption, distribution, metabolism and elimination (ADME) processes. The key element of this approach is the separation of information on the system (i.e. human body) from that of the drug (e.g. physicochemical characteristics determining permeability through membranes, partitioning to tissues, binding to plasma proteins or affinities toward certain enzymes and transporter proteins) and the study design (e.g. dose, route and frequency of administration, concomitant drugs and food). In this review, the classical ‘top-down’ approach in covariate recognition is compared with the ‘bottom-up’ paradigm. The determinants and sources of inter-individual variability in different stages of drug absorption, distribution, metabolism and excretion are discussed in detail. Further, the commonly known tools for simulating ADME properties are introduced.

著者

TAYAMA Yoshitaka MORIYASU Aya SUGIHARA Kazumi OHTA Shigeru KITAMURA Shigeyuki

出版者

The Japanese Society for the Study of Xenobiotics

雑誌

Drug metabolism and pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.22, no.2, pp.119-124, 2007-04-25

参考文献数

41

被引用文献数

12

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In this study, the developmental changes and variability of aldehyde oxidase in postnatal rat liver were examined. Postnatal day 1, 7 and 14 rats showed little or no liver aldehyde oxidase activity, as evaluated in terms of the activities for oxidation of benzaldehyde to benzoic acid, <i>N</i>-1-methylnicotinamide (NMN) to <i>N</i>-1-methyl-2-pyridone-5-carboxamide (2-PY) and <i>N</i>-1-methyl-4-pyridone-3-carboxamide (4-PY), and methotrexate (MTX) to 7-hydroxymethotrexate (7-OH-MTX). However, these oxidase activities were markedly increased in liver cytosol from the rats after postnatal day 14. The activity was then maintained up to 6 weeks. The amounts of 2-PY and 4-PY formed from NMN were almost the same. The development of aldehyde oxidase activity toward benzaldehyde was closely correlated with that of oxidase activity toward NMN and MTX. The expression of aldehyde oxidase at postnatal day 14 was confirmed by Western blotting analysis. The density of bands of aldehyde oxidase was closely correlated with the oxidase activity toward benzaldehyde. The developmental changes of aldehyde oxidase activities during postnatal reflected the changes in the amount of the oxidase protein. Thus, aldehyde oxidase activity in rats rapidly increases from birth, reaching a plateau within 4 weeks, and is regulated by expression of the protein.<br>

著者

Susumu NAKADE Shinya UEDA Tomoya OHNO Kazuki NAKAYAMA Yasuyuki MIYATA Eiji YUKAWA Shun HIGUCHI

出版者

The Japanese Society for the Study of Xenobiotics

雑誌

Drug Metabolism and Pharmacokinetics (ISSN:13474367)

巻号頁・発行日

vol.21, no.2, pp.133-139, 2006 (Released:2006-05-10)

参考文献数

15

被引用文献数

3

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This study aimed to assess the steady-state pharmacokinetics of pranlukast, a leukotriene receptor antagonist, in children with allergic rhinitis and bronchial asthma, and to clarify factors affecting apparent clearance (CL/F). A total of 192 plasma samples were obtained from 98 children (rhinitis 64, asthma 13, complications 21), aged 3-14 years in 2 clinical trials. Plasma concentration of pranlukast was determined by liquid chromatography connected with a tandem mass spectrometer and analyzed by a population approach using NONMEM program. The plasma concentration-time course of pranlukast was described by using a one-compartment model with the first-order absorption and lag time. The robustness of the population pharmacokinetic model was evaluated by using 200 bootstrap samples. The results of population pharmacokinetic analysis showed that only age was a factor affecting the CL/F per body weight, with CL/F decreasing with increasing age. No significant variation was seen in the CL/F between rhinitis and asthma. The interindividual variability in the CL/F and the residual variability were 19.7% and 48.4%, respectively. All the parameters fell within 10% of the bootstrapped mean. In conclusion, the results show that age is the most influential factor for explaining interindividual variability in CL/F, and the difference in diseases does not affect CL/F.