Download ISSN 1608-2281 2006 6(3):179-181

Asian Journal of Pharmacodynamics and Pharmacokinetics
Copyright by Hong Kong Medical Publisher
ISSN 1608-2281
2006 6(3):179-181
Paper ID 1608-2281-2006-06030179-03
Received May 30, 2006
Accepted July 30, 2006
Role of drug transporter studies in the drug discovery and development
Yuichi Sugiyama
Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033,
Japan
General introduction
Quantitative
prediction
transporter-mediated hepatic removal
drugs from in vitro data
Drug transporters are expressed in many tissues, such
as the intestine, liver, kidney, and the brain, and play key
roles in drug absorption, distribution and excretion. The
information on the functional characteristics of drug
transporters provides important information to allow
improvements in drug delivery or drug design by targeting
specific transporter proteins. In this presentation, I will
summarize the significant role played by drug transporters
in drug disposition, focusing particularly on their potential
use during the drug discovery and development process.
The use of transporter function offers the possibility of
delivering a drug to the target organ, avoiding distribution
to other organs (thereby reducing the chance of toxic
side-effects), controlling the elimination process, and/or
improving oral bioavailability. It is useful to select a lead
compound that may or may not interact with transporters,
depending on whether such an interaction is desirable. The
expression system of transporters is an efficient tool for
screening the activity of individual transport processes. The
changes in pharmacokinetics due to genetic polymorphisms
and drug-drug interactions involving transporters can often
have a direct and adverse effect on the therapeutic safety
and efficacy of many important drugs.In future, the in silico
prediction of the affinity of drug candidates for the
transporters may become possible. We have also
constructed a comprehensive database for membrane
transport
proteins
called
“TP-Search”
(URL:
http://www.TP-Search.jp/).
Each record has been
extracted from approx. 3500 articles published from 1968
to the present. TP-Search contains information about
more than 90 transporters in humans and rodents, including
substrate/inhibitor/inducers,
tissue
distribution,
pathophysiology, knockout animals, gender differences and
drug-drug interactions. The database also gives a brief
description of the experimental methods and all
information available in this database is linked to the
original references in PubMed.
_____
*Correspondence
to
Yuichi
[email protected]
Sugiyama
of
of
Relatively high bioavailability of orally administered
drugs is important for achieving effective drug
concentrations in the target tissues. Extensive first-pass
intestinal and hepatic elimination should be avoided to
obtain high bioavailability. It has been established that
metabolic enzymes and efflux transporters act
synergistically to reduce the oral absorption of many
different types of drugs. Benet and his coworkers initially
proposed that the synergistic effects of CYP3A4-mediated
metabolism and P-gp-mediated efflux in the intestine may
result in an unexpectedly high first-pass metabolism.. In the
new drug development, recombinant drug metabolizing
enzymes have been widely used for predicting drug
clearances and drug-drug interactions, and for carrying out
the high throughput screening of new drug candidates of
potential therapeutic use. The recombinant transporters for
drugs may be similarly used for the drug screening. Here in
this presentation, I will focus on the role of transporters in
the in the hepatic uptake/excretion and its prediction from
in vitro studies using isolated cells, plasma membrane
vesicles and/or cDNA-transfected cells. The role of
transporters in drug disposition is also summarized in our
review articles.
Vectorial transport across epithelial cells is involved in
the absorption/uptake and elimination of drugs in the small
intestine, liver and kidney. The vectorial transport of a large
number of organic anions is achieved by uptake and efflux
systems. Organic anion transporting polypeptides (OATPs)
and organic anion transporters (OATs) have been shown to
account for the hepatic and renal uptake of organic anions,
respectively, while MRPs are involved in the excretion of
their substrates from cells. Our recent studies of these
transporters will be summarized below. Transport studies
using membrane vesicles enable us to obtain the intrinsic
kinetic parameters for excretion process.
We have
investigated the role of MRP2 using hepatic canalicular
membrane vesicles and found a species-difference in the
intrinsic transport activity between rats and humans.
e-mail:
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Sugiyama Y. Asian Journal of Pharmacodynamics and Pharmacokinetics 2006; 6(3):179-181
We have also established double-transfected MDCK II cells
where OATP2/OATP-C and MRP2 are expressed on the
basal and apical membrane, respectively, as an in vitro
model for hepatobiliary transport. Transcellular transport
from the basal-to-apical side of the monolayer corresponds
to the biliary transfer in this system, and the basal-to-apical
transport of typical ligands, such as estradiol
17-βglucuronide, pravastatin and leukotriene C4, in the
double transfectant is significantly increased compared
with that in the opposite direction. Recently, we have also
established a double-transfected MDCK II cell monolayer
which expresses rat Oatp4 and Mrp2 on basal and apical
membranes, respectively, for the purpose of quantitative
comparison of clearance values between in vitro
transcellular transport and in vivo biliary excretion. Kinetic
analysis suggested that the uptake is the rate determining
process for the transcellular transport of pravastatin, which
is similar to the previous in vivo findings. By normalizing
the level of expression of these transporters in rat liver, it
may be possible to quantitatively predict the in vivo rat
biliary excretion via these transporters. We then can predict
the biliary excretion ability of new drug candidates with the
following three data; in vivo PK (rat), in vitro transcellular
transport (rat), and in vitro transcellular transport (human),
This system is thus useful for drug discovery and
development studies and investigating drug-drug
interactions involving hepatobiliary transport. Double
transfectants where the transporters involved in the uptake
and efflux in the barriers will provide useful tools for
evaluating the drug distribution and elimination in several
tissues.
The changes in pharmacokinetics due to genetic
polymorphisms and drug-drug interactions involving
transporters can often have a direct and adverse effect on
the therapeutic safety and efficacy of many important
drugs.In future, the in silico prediction of the affinity of
drug candidates for the transporters may become possible.
Examples of the use of double transfected cells to assess
the drug-drug interaction and the effect of genetic
polymorphism of transporters in the hepatobiliary transport
of drugs will be shown in my presentation.
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References
1.
Giacomini KM, Sugiyama Y.
2006. Membrane
transporters and drug response.In: Brunton L. 11th Edition,
McGraw-Hill Professional, New York, 2006; 41-70.
2.
Sugiyama Y.: Druggability: selecting optimized drug
candidates Drug Discovery Today 2005; 10: 1577-1579.
3.
Shitara Y, Horie T, Sugiyama Y. Transporters as a
determinant of drug clearance and tissue distribution Eur J
Pharm Sci. 2006; 27: 425-446.
4.
Mizuno N, T.Niwa T, Yotsumoto Y, Sugiyama Y. Impact of
drug transporter studies on drug discovery and development.
Pharmacol Rev 2003; 55, 425-61.
5.
Shitara Y, Sato H, Sugiyama Y. Evaluation of drug-drug
interaction in the hepatobiliary and renal transport of drugs.
S
15.
16.
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Annu. Rev Pharmacol Toxicol 2004: 689-723.
Suzuki H, Sugiyama Y. Hepatic drug transport. In "Drug
bioavailability: estimation of solubility, permeability and
bioavailability", ed. by van de Waterbeemd, H., Artursson, P.
and Lennernas, H. Wiley, 2003; 288-310.
Chiba M, Shibata Y, Takahashi H, Ishii Y, Sugiyama Y.
Prediction of hepatic clearance in humans from
experimental animals and in vitro data. In “Drug
Metabolizing Enzymes: Cytochrome P450 and Other
Enzymes in Drug Discovery and Development Ed. By
Michael B.Fisher, Ronald S.Obach and Jae S. Lee., Fontis
Media and Marcel Dekker 2003; 453-481.
Wacher VJ, Wu CY, Benet LZ. Overlapping substrate
specificities and tissue distribution of cytochrom P450 3A
and P-glycoprotein: Implications for drug delivery and
activity in cancer chemotherapy. Mol. Carcinogen 1995; 13:
129-134.
Sasaki M, Suzuki H,.Ito K, Abe T, Sugiyama Y.
Transcellular transport of organic anions across
double-transfected MDCK II cell monolayer expressing both
human organic anion transporting polypeptide (OATP2) and
multidrug resistance associated protein2 (MRP2).
J.Biol.Chem 2002; 277; 6497-6503.
Sasaki M, Suzuki H, Aoki J, Ito K, Meier PJ, Sugiyama Y.
Prediction of in vivo biliary clearance from the in vitro
transcellular transport of organic anions across a
double-transfected Madin-Darby canine kidney II
monolayer expressing both rat organic anion transporting
polypeptide 4 and multidrug resistance associated protein 2.
Mol Pharmacol 2004; 66, 450-9.
Mita S, Suzuk H, Akita H, Stieger B, Meier PJ, Hofmann AF,
Sugiyama Y. Vectorial transport of bile salts across MDCK
cells expressing both rat Na+-taurocholate cotransporting
polypeptide and rat bile salt export pump. Am J Physiol
Gastrointest Liver Physiol 2005; 288:G159-167.
Kusuhara H, Sugiyama Y. Drug-drug interactions involving
the membrane transport process. In Drug-Drug Interactions
Ed. by A.D. Rodrigues. Marcel Dekker, New York. 2001;
123-188.
Suzuki M, Suzuki H, Sugimoto Y, Sugiyama Y. ABCG2
transports sulfated conjugates of steroids and xenobiotics. J
Biol Chem 2003; 278: 22644-22649.
Shitara Y, Itoh T, Sato H, Li A, Sugiyama Y. Inhibition of
transporter-mediated hepatic uptake as a mechanism for
drug-drug interaction between cerivastatin and cyclosporin
A J.Phamacol.Exp.Therap 2003; 304: 610-616.
Shitara Y, Hirano M, .Sato H, Sugiyama Y. Gemfibrozil and
its glucuronide inhibit the organic anion transporting
polypeptide
2
(OATP2/OATP1B1:SLC21A6-mediated
hepatic uptake and CYP2C8-mediated metabolism of
cerivastatin: analysis of the mechanism of the clinically
relevant drug-drug interaction between cerivastatin and
gemfibrozil. J Pharmacol Exp Ther 2004; 311: 228-36.
Nishizato H, Ieiri H, Suzuki H, Kimura M, Kawabata K,
Hirota T, Takane H, Irie S, Kusuhara H, Urasaki Y, Urae A,
Higuchi S, Otsubo K, Sugiyama Y. Polymorphisms of
OATP-C(SLC21A6)
and
OAT3(SLC22A8)
genes:
Consequences for pravastatin pharmacokinetics Clin
Pharmaco .Therap 2003; 73:554-565.
ugiyama Y. Asian Journal of Pharmacodynamics and Pharmacokinetics 2006; 6(3):179-181
17.
Iwai M, Suzuki. H, Ieiri I, Otsubo K, Sugiyama Y.
Functional analysis of single nucleotide polymorphisms of
hepatic organic anion transporter OATP1B1 (OATP-C).
Pharmacogenetics 2004; 14:749-57.
Sciences 2005 and Scientific Achievement Award 2004 from the "
Pharmaceutical Society of Japan (PSJ). According to the
information in the website of ISI Essential Science Indicators (ESI),
Thomson Scientific（USA）, Prof. Sugiyama achieved the 2nd top
position for the number of citations for the last 10 years (Jan 1,
1995 -Aug 31, 2005) in the field of “ Pharmacology &
Toxicology”. He served as the chairman of Board of
Pharmaceutical Sciences in FIP (2000-2004) and chaired the
“Pharmaceutical Sciences World Conference”, Kyoto, Japan, 2004
(organized by FIP Board of Pharmaceutical Sciences). He is
currently the president of both “International society for the study
of xenobiotics (ISSX)” and “Japanese Society for Xenobiotic
Metabolism and Disposition (JSSX)”. See details in the website
http://www.f.u-tokyo.ac.jp/~sugiyama/indexe.html
_____
Yuichi Sugiyama,Ph.D.is Professor and Chairman, Department of
“Molecular Pharamacokinetics” at the University of Tokyo since
1991. He is a coauthor of more than 450 publications in
international journals as well as 270 book chapters and review
articles (ca.60 written in English). He has received such awards:
the 1994 Pharmaceutical Scientist of the Year Award of
International Pharmaceutical Federation (FIP); Scientific
Achievement Award 1995 from the Academy of Pharmaceutical
Science and Technology, Japan (APSTJ); Takeru-Aya Higuchi
Prize 1990, AAPS Distinguished Pharmaceutical Scientist Award,
2003, John G. Wagner Pfizer Lectureship Award in Pharmaceutical
___________________________________________________________________________
Fast evaluation of ADME characteristics of the chiral series compounds
Jinglai Li, Zhenqing Zhang, Jinxiu Ruan, Keliang Liu
The Key Laboratory of Drug Metabolism and Pharmacokinetics, Academy of Military Medical Sciences, Beijing 100850
Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China
To rapidly screen the novel anti-choline compounds to
find the compounds that have good pharmacokinetics
characteristics or the enantiomer that have major
differences in pharmacokinetics characteristics and initially
explore the rule of the relationship between the structure
and pharmacokinetics characteristics , then timely give a
feedback to medicinal chemistry to modify the compounds.
Solution model 、Caco-2 model 、Protein binding model
and BBB model in Silico were used to virtually evaluate
the pharmacokinetics characteristics of the enantiomer of
the AN-R(S) and ETH-R(S) series; Microsome incubation
model was used to evaluate the stability of the Chiral Series
Compounds; The “n in one” po administration was used to
evaluate the pharmacokinetics characteristics of the
enantiomer of the novel anti-choline compounds in Wistar
rats. The findings is that absorption of the ETH-R(S) chiral
series compounds is better than that of the AN-R(S) chiral
series probably because the liposolubility of the ETH-R(S)
chiral series compounds is stronger than that of the AN-R(S)
chiral series; Substitution of hydroxymethyl for methyl in
benzene ring can enhance the polarity of the compounds
that probably make absorption become worser; The
P-substitutive group in benzene ring result in AUC of
R-enantiomer larger than that of S-enantiomer; The polar
substitutive group in the benzene ring makes MRT of
S-enantiomer shorter than that of R-enantiomer.
RP-HPLC method for determination of lovastatin in dogs plasma
Jing Gao, Chang-Xiao Liu
Tianjing Stste Key Laboratory of Pharmacokinetics and Chinical Pharmacology, Tianjing Institute of Pharmaceutical
Research, 308 An-Shan West Road, Tianjing 300193, China
93.95 ％ , respectively. The relative standard derivative of
intra-day and inter-day determination was less than 10%. The
developed bioanalytical method for determination of lovastatin
in dogs plasma possesses the characteristic with issimple,
suitable and aecurate. The validation for methodology is
indicated that this bioanalytical method is suitable for clinical
pharmacokinetics study of lovastatin formulations.
A HPLC method was used to determine the
concentration of lovastatin in dogs plasma. An analytical
C18 column (10μm，4.6×250mm，ID×L)and a variable
wavelength detector at UV 238nm. The mobile phase
containing 82% methanol, 18%water (pH=6.5), was used at
a flow 1 mL·min-1, the limit of quantitation was 5ng·mL-1.
The recovery for assay of concentration in plasma samples
at 10、50 and 250 ng·ml-1 was 95.71％、 94.10％ and
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