Article
Journal of Medicinal Chemistry, 2009, Vol. 52, No. 14 4147
(total injection volume of 0.5 mL) to the rats, and the catheter
was rinsed with 0.9% NaCl. An approximately 200 μL aliquot of
blood was collected via the jugular vein at 0, 10, 20, 30, 60, 90,
120, 180, 240, and 300 min after the start of the intravenous
administration to micro test tubes containing 20 μL of 3%
EDTA in 0.7% NaCl solution. The drawn blood volume
was substituted by 0.9% NaCl immediately after each blood
sampling.
Metformin hydrochloride was dissolved in 0.9% NaCl solu-
tion at a dose of 140 mg/kg and administered orally (total
injection volume of 1.0 mL) to the rats using a feeding tube.
An approximately 200 μL aliquot of blood was collected via the
jugular vein at 0, 15, 30, 45, 60, 90, 120, 180, 240, and 300 min
after the start of the oral administration to micro test tubes
containing 20 μL of 3% EDTA in 0.7% NaCl solution. Met-
formin prodrug 2a was dissolved in 10% HP-β-CD in 0.6%
NaCl solution at a dose of 100 mg/kg and administered orally
(total injection volume of 1.0 mL) to the rats using a feeding
tube. An approximately 200 μL aliquot of blood was collected
via the jugular vein at 0, 30, 45, 60, 90, 120, 180, 240, 300, and
360 min after the start of the oral administration to micro test
tubes containing 20 μL of 3% EDTA in 0.7% NaCl solution.
The drawn blood volume was substituted by 0.9% NaCl
immediately after each blood sampling.
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Blood samples were centrifuged 5 min at 14 000 rpm imme-
diately after each blood sampling, and 100 μL aliquot of each
plasma sample and 20 μL of 5.2 mg/mL 1,1,3,3-tetramethylgua-
nidine as an internal standard were vortexed with ice-cold ACN
(1:4, v/v) to precipitate proteins and quench the degradation
reaction. The samples were centrifuged 5 min at 14 000 rpm and
kept on ice until injected into the HPLC system. The pharma-
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The area under the plasma concentration-time curve (AUC)
was calculated using the linear trapezoidal method. The max-
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maximum plasma concentration (tmax) were read directly from
the plasma concentration-time data. The clearance and the
bioavailability were calculated from the following equations:
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dose
AUCpo doseiv
F ¼
AUCiv dosepo
Cl ¼
;
AUC
Acknowledgment. We thank Tiina Koivunen for skillful
technical assistance with synthesis. We also thank Markus
Forsberg, Ph.D., and Mikko Gynther for irreplaceable assis-
tance with the animals, and Jari Ratilainen, Ph.D., and Tycho
Heimbach, Ph.D., for great scientific contribution. The work
was financially supported by the National Graduate School of
Organic Chemistry and Chemical Biology, the Finnish Fund-
ing Agency for Technology and Innovation (Tekes), the
Academy of Finland (Grants 108569 and 214334 to K.L.),
the Research and Funding Foundation of Farmos, the Dia-
betes Research Funding Foundation, the Emil Aaltonen
Foundation, the Alfred Kordelin Foundation (the Gust.
Komppa Fund), the Finnish Konkordia Foundation, and
Jenny and Antti Wihuri Foundation.
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Jarvinen, T.; Savolainen, J. Prodrugs: Design and Clinical Appli-
cations. Nat. Rev. Drug Discovert 2008, 7, 255–270.
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N,N0-Disubstituted Acylguanidines. Tetrahedron Lett. 2001, 43,
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