Mitigation of cardiovascular toxicity in a series of CSF-1R inhibitors, and the identification of AZD7507

Article abstract of DOI:10.1016/j.bmcl.2013.06.031

The potent and selective 3-amido-4-anilinoquinoline CSF-1R inhibitor AZ683 suffered from cardiovascular liabilities, which were linked to the off-target activities of the compound and ion channel activity in particular. Less basic and less lipophilic examples from both the quinoline and cinnoline series demonstrated cleaner secondary pharmacology profiles. Cinnoline 31 retained the required potency and oral PK profile, and was progressed through the safety screening cascade to be nominated into development as AZD7507.

Full text of DOI:10.1016/j.bmcl.2013.06.031

Bioorganic & Medicinal Chemistry Letters 23 (2013) 4591–4596
Contents lists available at SciVerse ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Mitigation of cardiovascular toxicity in a series of CSF-1R inhibitors,
and the identification of AZD7507
a
a
a
a
a
David A. Scott a, , Les A. Dakin , Kevin Daly , David J. Del Valle , R. Bruce Diebold , Lisa Drew ,
Jayachandran Ezhuthachan a, Thomas W. Gero a, Claude A. Ogoe a, Charles A. Omer a, Sean P. Redmond b,
Galina Repik a, Kumar Thakur a, Qing Ye a, Xiaolan Zheng a
⇑
a AstraZeneca R&D Boston, Oncology iMED, 35 Gatehouse Drive, Waltham, MA 02451, USA
b AstraZeneca R&D Boston, Global Safety Assessment, 35 Gatehouse Drive, Waltham, MA 02451, USA
a r t i c l e i n f o
a b s t r a c t
Article history:
The potent and selective 3-amido-4-anilinoquinoline CSF-1R inhibitor AZ683 suffered from cardiovascu-
lar liabilities, which were linked to the off-target activities of the compound and ion channel activity in
particular. Less basic and less lipophilic examples from both the quinoline and cinnoline series demon-
strated cleaner secondary pharmacology profiles. Cinnoline 31 retained the required potency and oral
PK profile, and was progressed through the safety screening cascade to be nominated into development
as AZD7507.
Received 24 April 2013
Revised 3 June 2013
Accepted 11 June 2013
Available online 20 June 2013
Keywords:
CSF-1R
Ó 2013 Elsevier Ltd. All rights reserved.
Kinase
Inhibitor
The tyrosine kinase CSF-1R (also called c-FMS) helps regulate
the growth, differentiation, function and survival of macrophages.
High levels of macrophages are present at sites of inflammation,
and inhibitors of CSF-1R are under evaluation for the treatment
of inflammatory conditions such as rheumatoid arthritis. Tumor-
associated macrophages have been associated with poor prognosis
in various cancers and are involved in the promotion of angiogen-
esis, invasion and metastasis, and this suggests that CSF-1R may
also be an attractive oncology target. The biology of CSF-1R and
development of selective inhibitors has been reviewed,1 along with
a recent overview of the patent literature.2 Several multi-targeted
kinase inhibitors have activity against CSF-1R,3 including
sunitinib,4 dasatinib,5 and sorafenib,6 but more selective agents
(JNJ-28312141,7 PLX5622,8 ARRY-3829) have also entered the
clinic.
The 3-amido-4-anilinoquinoline AZ683 (1, Fig. 1) was reported
to be a potent and highly selective inhibitor of CSF-1R.10 This com-
pound has an attractive overall profile, with good physical proper-
ties and oral bioavailability. Upon oral dosing in mice, the
compound reduced levels of tumor-associated macrophages
(TAMs) in two breast xenograft models (MDA-MB231 and
MCF7).11 However, in a dog cardiomyocyte assay,12 AZ683 showed
a concentration-dependent decrease in action potential duration at
10 and 30 M. (Fig. 4). This result was more consistent with an
inhibitor of the L-type calcium and sodium channels than a com-
l
pound with activity against the hERG channel (AZ683 hERG IC50
23
the action potential duration. Indeed, AZ683 was found to have
an IC50 of 3.5 M in a canine cardiac myocyte L-type Ca channel
current assay, and also inhibited the human cardiac NaV1.5 chan-
nel (IC50 14 M).
lM), which would have been expected to show an increase in
l
l
The cardiac electrophysiology of AZ683 was also assessed in a
guinea pig monophasic action potential duration (GP-MAPD)
assay13 in which dose-dependent increases in AV conduction time
and QRS duration were observed up to a free plasma concentration
of 4.5 lM (Fig. 2). When progressed into pivotal toxicology and
safety pharmacology studies, further liabilities emerged, including
elevated troponin levels and cardiomyocyte degeneration in the
rat, and dose-related ECG (PR interval and QRS duration increases)
changes in the dog. As a result of these toxicology and pharmacol-
ogy findings, the compound was not progressed into clinical devel-
opment, as the profile was inconsistent with the intended breast
cancer patient population, who may previously have received
known cardiotoxins as part of their initial treatment regimen.
Cardiotoxicity has been reported for many of the tyrosine
kinase inhibitors now in use for the treatment of cancer,14 with a
trend for the less selective compounds to show increased cardio-
vascular effects.15 CSF-1R inhibition itself has been specifically
linked to cardiotoxicity, as several launched kinase inhibitors are
⇑
Corresponding author.
E-mail address: david.scott@astrazeneca.com (D.A. Scott).
0960-894X/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.bmcl.2013.06.031

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D. A. Scott et al. / Bioorg. Med. Chem. Lett. 23 (2013) 4591–4596
F
F
F
F
N
NH
O
N
NH
O
N
NH
O
N
O
N
O
N
O
NH2
NH2
NH2
N
N
N
N
N
13
Figure 3. Cinnolines 13 and 14.
14
Figure 1. 1, AZ683.
active against the target, and binding to CSF-1R was shown to cor-
relate with damage to rat cardiomyocytes for a small set of
compounds.15a
L-type Ca-channel. However, the SAR of the NaV1.5 channel did
not follow the same trends, with the most basic compounds show-
ing reduced activity relative to AZ683. We wanted to establish
whether the reduced calcium channel activity and off-target phar-
macology from less basic, less lipophilic compounds would trans-
late into meaningful improvements in the cardiac action
potential and rat toxicity profiles.
A similar approach was reported during the optimization of a
series of arylamide CSF-1R inhibitors, as part of the work that led
to the identification of JNJ-28312141.7 Early lead compounds were
active in sodium and ion channel binding assays, and also a guinea
pig right atrium assay which measured the rate and force of con-
traction. Less basic compounds within that series delivered re-
duced activity in the ion channel assays.20
While AZ683 was progressing through the pivotaltoxicity stud-
ies, the 3-amido-4-anilinocinnolines were identified as another
series of highly selective CSF-1R inhibitors with an excellent phar-
macokinetic profile and improved cellular potency relative to the
quinoline series.21 In a cell proliferation assay (3T3 cells engi-
neered to express CSF-1R and stimulated with CSF-1),22 cinnolines
In a panel of 85 kinases AZ683 showed >20% inhibition for only
two kinases (CSF-1R 96%, ARK5 51%, 1 l
M concentration).10 The
compound was also profiled in a panel of 69 enzymes, receptors,
transporters and ion channels16 and of those targets associated
with the cardiovascular system,17 it was found to have activity
against those included in Table 1. Binding data (% inhibition at
10 lM) for the alpha 1A, 1D and 2A adrenoreceptors and the L-type
Ca channel, along with hERG and NaV 1.5 ion channel IC50 data is
shown. Due to the Ca (increases in AV conduction and PR interval)
and Na (increases in QRS duration) dependent cardiac electrophys-
iology changes in the guinea-pig and dog, we suspected ion chan-
nel activities were contributing to the cardiovascular toxicity
observed with AZ683.
Therefore, as part of our efforts to deliver a safe and selective
CSF-1R inhibitor, we sought to improve the overall toxicity profile
by identifying compounds with reduced off-target activities. Addi-
tional amidoquinolines were screened in a smaller secondary phar-
macology panel, focusing on the targets in which AZ683 had shown
activity, and others associated with cardiotoxicity (Table 1). Where
possible, matched pairs were included in the selection of com-
pounds, to assess the impact of specific structural changes.
The synthesis of compounds 1–3, 6–7, 9 and 11, along with their
biological activity, physical properties, and pharmacokinetic pro-
files, has been described previously.10 Compounds 8, 10 and 12
were prepared by similar chemistry.18 Compounds 4 and 5 were
also prepared through a similar approach, after introducing the
piperidine substituent via pyridine installation and reduction, as
shown in Scheme 1.19
Compounds incorporating a basic amine (2–7, 11) had a similar
pattern of off-target activity to AZ683, with a trend for increased
potency of the more lipophilic dichloro examples (3 vs 1 and 5
vs 4) against the various targets. The most basic compounds
(piperidines 4 and 5, and homopiperazine 11) also tended to have
higher potency against the targets where activity was observed,
and in some cases picked up additional off-target activity (data
not included). Morpholine 8, 4-hydroxypiperidine 9 and piperazi-
none 12 showed significantly cleaner profiles. Also of note was
hydroxyethyl piperazine 10, with reduced activity against the
13 and 14 (Fig. 3) had an IC50 of 0.013 and 0.025
compared with 0.23 M for AZ683. However, when profiled in the
GP-MAPD assay up to the maximum feasible dose (free plasma
concentrations of 1.5–2.2 M), cinnolines 13 and 14 showed simi-
lM respectively,
l
l
lar dose-dependent increases in AV conduction time and QRS dura-
tion to those seen with AZ683, and the compounds were not
progressed.
It was reported previously for both the quinoline and the cinn-
oline series that potency in the cellular proliferation assay was lar-
gely determined by a combination of the aniline substitution
pattern and the 7-alkoxy group. Cyclic amines at the 6-position,
such as N-methylpiperazine, bestowed suitable physical properties
to deliver good oral PK, and modifications here typically had little
impact on in vitro potency. Therefore, this position offered a suit-
able handle to tune the overall properties of the series. The combi-
nation of 2-F, 4-Me aniline and 7-MeO had delivered good potency
and physical properties in the cinnoline series when combined
with 6-N-methylpiperazine (compound 14), and this scaffold was
selected for further work.
A variety of substituents were
introduced at the 6-position to deliver compounds with a range
Dose 1
(5mg/kg)
Dose 2
(15mg/kg)
Washout
Dose 1
(5mg/kg)
Dose 2
(15mg/kg)
Washout
vehicle
AZ683
75
50
25
0
vehicle
AZ683
120
100
80
60
40
20
0
-25
-20
0
10
20
30
40
50
60
0
10
20
30
Time (min)
40
50
60
Time (min)
Figure 2. Effects of AZ683 on AV conduction time and QRS duration in the GP-MAPD assay.

D. A. Scott et al. / Bioorg. Med. Chem. Lett. 23 (2013) 4591–4596
4593
Table 1
Selected secondary pharmacology binding data (% inhibition at 10
lM) and hERG and NaV 1.5 ion channel IC50 data for 3-amido-4-anilinoquinolines
R1
NH
N
O
R2
R3
NH2
Compound R1
R2
R3
Cell
Alpha1A
Alpha1D
Alpha2A
Calcium channel
hERG
IC50
NaV1.5
IC50
M)
(
lM) adrenoreceptor adrenoreceptor adrenoreceptor L-type,
phenylalkylamine
(l
M)
(
l
N
N
N
N
N
N
N
1, AZ683
2,4-F
EtO
EtO
EtO
EtO
EtO
0.23
0.05
0.06
0.08
0.01
59
78
95
71
94
73
78
15
69
86
91
82
93
51
71
48
84
95
92
96
97
84
92
13
41
23
15
8
14
N
N
N
2
3
4
5
6
7
8
2-F,4-Me
2,3-Cl
39
80
75
78
30
34
14
12
9
2,4-F
11
4
>30
>30
>30
>30
>30
2,3-Cl
2,4-F
MeO(CH2)2O 0.24
MeO(CH2)2O 0.14
MeO(CH2)2O 0.12
>30
>30
9
N
N
2-F,4-Me
2-F,4-Me
O
N
HO
HO
9
2,4-F
2,4-F
2,4-F
2,4-F
EtO
EtO
EtO
EtO
0.31
1.14
0.26
0.97
44
60
95
12
0
45
90
6
9
65
95
0
7
19
68
14
17
>30
—
N
N
10
11
12
>30
6
N
N
>30
>30
N
N
>30
N
O
of basicity and lipophilicity. Table 2 shows cellular potency, phys-
ical property, rat pharmacokinetic data and hERG and NaV1.5 IC50
data for these compounds.
chiral acid delivered amide 32. Piperidine compounds 33 and 34
were prepared by Suzuki coupling with the Boc-protected tetrahy-
dropyridine boronate ester to give 18, followed by deprotection
and reductive alkylations to give 20, with nitrile hydrolysis and
H-cube23 hydrogenation to complete the synthesis of those targets.
The secondary pharmacology profiles of the basic cinnolines
were similar to those of the basic quinolines, with additional off-
target activities in some cases (data not included). As was observed
for the quinolines with neutral substituents, morpholine 27 and
amide 32 were significantly cleaner across the panel than the more
basic cinnoline examples.
The synthesis of 14 from bromocinnoline nitrile 15 was de-
scribed previously,21 and related compounds were prepared in a
similar fashion (Scheme 2). Buchwald–Hartwig couplings intro-
duced the cyclic amines, with a final basic hydrolysis step to con-
vert the nitriles to the amide. Hydroxyethyl homopiperazine 26
was prepared by coupling the silyl-protected ether. Compounds
31 and 32 were prepared by derivatization of the piperazine
substituent of 17. Reductive alkylation with TBDMS-protected
hydroxyacetaldehyde followed by deprotection introduced the
hydroxyethyl side chain of 31, and a coupling reaction with the
The compounds in Table 2 were all very potent in the cell assay.
Piperazines 21 and 23, and piperidines 33 and 34 demonstrated
R1
+
N
N
N
Cl
N
I
N
NH
N
Br
( a, b)
( c)
( d, e)
( f , g)
CO2Et
CONH2
EtO
NO2
EtO
NO2
EtO
NH2
EtO
EtO
4- 5
Scheme 1. Reagents and conditions: (a) pyridin-4-ylboronic acid, Pd(Ph3P)4, K2CO3, 10:1 DMA:H2O, 90 °C; (b) CH3I, CH3CN 40 °C; (c) 50 psi H2, PtO2, MeOH; (d)
diethylethoxymethylene malonate, Et3N, CH3CN; (e) POCl3, reflux; (f) aniline, cat. AcOH, EtOH, 80 °C; (g) HCONH2, THF, NaOMe in MeOH, reflux.

4594
D. A. Scott et al. / Bioorg. Med. Chem. Lett. 23 (2013) 4591–4596
Table 2
Cell potency, physical property, rat PK upon iv (3mpk) and oral (10mpk) dosing and ion channel data for 3-amido-4-anilinocinnolines
F
NH
N
O
R
NH2
N
O
Compound
R
Cell (
lM)
Sol (
87
lM)
PPB (% free)
F (%)
Cl (ml/min/kg)
12
Vss (L/kg)
T1/2 (h)
hERG IC50
>30
(lM)
NaV1.5 IC50
6
(lM)
N
N
14
0.025
0.023
6.3
6.6
100
3.8
5.7
N
N
21
22
23
40
100
—
17
—
4
3.8
—
2.5
—
17
6
4
11
14
N
0.017
0.013
54
10.3
1.3
N
HN
200
61
1.6
4.4
20
N
N
24
25
0.015
0.026
340
11
15
15
3
34
21
2.2
4.3
0.9
7.6
21
23
24
28
N
MeO
N
9.6
N
HO
O
26
27
28
0.026
0.027
0.052
270
<1
2
11
4
25
21
66
60
58
2.2
1.7
1.8
0.9
0.5
0.6
14
>30
>30
27
>30
>30
N
N
2.3
1.2
N
MeO
N
O
S
29
0.069
7
12
—
—
—
—
16
>30
O
O
N
O
S
N
30
31
0.053
0.032
<1
10
9.1
17
3
22
7
1.7
2.2
1.5
3.1
>30
>30
>30
26
N
HO
HO
N
42
N
O
32
0.052
<1
17
53
24
1.3
0.9
>30
>30
N
N
N
33
34
0.014
0.011
>1000
450
9.9
100
100
14
8
2.6
3.1
3.5
6.1
11
14
7
HO
N
10.2
25
good physical properties and attractive PK profiles. Examples with
neutral 6-substituents, such as morpholine 27, methoxypiperidine
28, sulphonamide 30 and amide 32 tended to suffer from either
low solubility or poor PK, and sometimes both. Hydroxyethyl
piperazine 31 demonstrated good rat oral PK, with in vivo clear-
ance of 7 ml/min/kg and 42% bioavailability. In the canine L-type
amide 32 showed no action potential changes up to 10 lM, but
their low solubility limited the concentrations achievable in this
assay. Hydroxyethyl piperazine 31 showed no significant effects
in the dog myocyte assay up to a concentration of 30 lM. 31 was
progressed into the GP-MAPD assay, where in contrast to AZ683
and cinnolines 13 and 14, no effects were observed on either AV
conduction time or QRS duration at the maximum feasible dose
Ca channel assay, it was found to have an IC50 >20
with 3.5 M for AZ683.
lM, compared
l
(free plasma concentration of 2.3 lM). Compound 31 also showed
Examples with different properties and secondary pharmacol-
ogy profiles were screened in a dog cardiomyocyte assay (Fig. 4).
Isopropylpiperidine 33 showed effects similar to those observed
with AZ683, with decreases in action potential duration at a con-
promising activity in our PD and efficacy models, the results of
which will be reported elsewhere.
Compound 31 was progressed into a 14 day rat dose-ranging
finding study, and in the absence of cardiac pathology changes,
the pivotal toxicology and safety pharmacology studies were then
conducted. In contrast to AZ683, there was no significant cardio-
centration of 10
lM. Hydroxyethyl piperidine 34 showed action
potential duration decreases from 30
l
M. Morpholine 27 and

D. A. Scott et al. / Bioorg. Med. Chem. Lett. 23 (2013) 4591–4596
4595
F
F
F
(a)
(b)
NH
NH
NH
R1
R1
CONH2
CN
Br
CN
N
N
N
MeO
N
MeO
N
MeO
N
15
16
14, 21-30
(c, b)
(g)
F
F
F
R2
HN
NH
BocN
NH
N
NH
(d, e)
or (f)
CONH2
N
CN
CONH2
N
N
N
N
MeO
N
MeO
N
MeO
N
18
17
31-32
(h)
F
F
F
R3
R3
N
NH
HN
NH
N
NH
(b, j)
(i) or (d)
CN
CN
CONH2
N
N
N
N
MeO
MeO
N
MeO
N
33-34
20
19
Scheme 2. Reagents and conditions: (a) amine, Pd2(dba)3, BINAP, Cs2CO3 (or XPHOS, NaOtBu), DMA, reflux; (b) KOH, tBuOH, reflux; (c) piperazine, Pd(OAc)2, BINAP, NaOtBu,
DMA, reflux; (d) TBDMSOCH2CHO, Na(OAc)3BH, CH2Cl2; (e) HCl (aq); (f) (R)-2-hydroxypropanoic acid, PyBOP, EtNiPr2, 4:1 CH2Cl2:MeOH; (g) tert-butyl 4-(4,4,5,5-tetramethyl-
1,3,2-dioxaborolan-2-yl)-3,6-dihydropyridine-1(2H)-carboxylate, Pd(Ph3P)4, K2CO3, 10:1 DMA:H2O, 90 °C; (h) 1:1 TFA:CH2Cl2; (i) acetone, Na(OAc)3BH, AcOH, dichloroeth-
ane, 55 °C; (j) Pd(OH)2, H2 at 10 bar, MeOH, concd HCl.
60
the inhibition of CSF-1R, with a reduced risk of cardiotoxicity rela-
tive to AZ683.
40
20
0
1, AZ683
27
-20
-40
-60
-80
-100
Acknowledgments
31, AZD7507
32
33
34
We thank Heather Blanchette for PK studies, Michael Rolf for
the secondary pharmacology data and Paul Lyne for assistance
with the manuscript.
0.1
1
10
100
1000
Compound concentraꢀon, μM
References and notes
Figure 4. Effects on action potential duration in dog cardiomyocytes.
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vascular toxicity, with no treatment-related elevation of troponin
levels or cardiac pathology in the 1 month rat and dog toxicology
studies. No effects on ECG parameters were observed in the dog
telemetry study, following a single oral dose. The absence of car-
diotoxicity, in conjunction with the overall compound profile,
and PD and efficacy data, led to the nomination of 31 as
AZD7507. Biological data for the compound will be reported
shortly.
In summary, the objective of delivering CSF-1R inhibitors with
reduced Ca and Na ion-channel and other off-target activity was
achieved through the modulation of the lipophilicity and basicity
of the amidocinnoline series. Trends were observed between cer-
tain off-target activities and compound basicity, and this was also
reflected in the dog cardiomyocyte data. However, examples with a
neutral substituent suffered from poor physical properties or less
than optimal oral PK. Hydroxyethyl piperazine 31 demonstrated
both a cleaner off-target profile and good oral exposure. While
no specific and definitive links were established between the sec-
ondary pharmacology and cardiac pathologies, the data does not
support the hypothesis that activity against CSF-1R was the pri-
mary cause of the cardiovascular liabilities of AZ683. Instead, a
reduction in ion channel activities corresponded to an absence of
in-vivo ECG changes, and our package of in vitro and in vivo safety
studies supported the nomination of 31 as a clinical candidate for
8. Plexxikon press release 27th Jan, 2011.
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Taylor, M.; Woods, A. J.; Valentin, J.-P.; Abi-Gerges, N. J. Pharmacol. Toxicol.
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on action potential parameters in dog ventricular myocytes. The myocytes

4596
D. A. Scott et al. / Bioorg. Med. Chem. Lett. 23 (2013) 4591–4596
were isolated from the left ventricular midmyocardium of the heart of a Beagle
start of each infusion and at 5.5, 10.5, 20.5 and 30.5 min during the washout
phase. Data are presented as vehicle-corrected percent change from baseline.
14. (a) Force, T.; Krause, D. S.; Van Etten, R. A. Nat. Rev. Cancer 2007, 7, 332; (b)
Dasanu, C. A.; Padmanabhan, P.; Clark, B. A., 3rd; Do, C. Expert Opin. Drug Saf.
2012, 11, 445.
dog and perfused with Tyrode solution (1.8 mM CaCl2). Action potentials were
recorded optically using di-4-ANEPPS (a fast voltage-sensitive dye) in a single-
excitation dual-emission ratiometric system, in electrically field-stimulated
myocytes at 1 Hz pacing frequency. Following exposure to Tyrode solution,
vehicle (0.1% dimethylsulphoxide) and cumulative concentration–effect curves
for each test compound were constructed over nominal concentration ranges
15. (a) Hasinoff, B. B. Toxicol. Appl. Pharmacol. 2010, 244, 190; (b) Force, T.; Kerkela,
R. Drug Discovery Today 2008, 13, 778.
of 0.3–100
l
M. The following action potential parameters were measured:
16. MDS pharma services, now Eurofins Panlabs. 2200 Rittenhouse Street, Suite
175, Des Moines, IA 50321.
17. Bowes, J.; Brown, A. J.; Hamon, J.; Jarolimek, W.; Sridhar, A.; Waldron, G.;
Whitebread, S. Nat. Rev. Drug. Disc. 2012, 11, 909.
18. Cook, D.; Dakin, L.; Del Valle, D.; Gero, T.; Scott, D.; Zheng, X. WO 2007119046,
A1 20071025; Chem. Abstr.2007, 147, 486341.
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2008056148, A1 20080515; Chem. Abstr. 2008, 148, 538091.
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Chaikin, M. A.; Manthey, C. L.; Player, M. R.; Tomczuk, B. E.; Meegalla, S. K.
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action potential duration at 50% (APD50), 70% (APD70) and 90% (APD90) of
repolarisation.
13. Guinea-pig monophasic action potential duration assay. The objective of this
assay was to evaluate compound effects on cardiac electrophysiology in the
anaesthetised guinea-pig by recording ventricular monophasic action
potentials and the surface electrocardiogram. Male guinea-pigs were
anaesthetised with sodium pentobarbitone and mechanically ventilated.
Animals were vagotomised and b-blocked with propranolol to eliminate
autonomic influences on the heart. Animals were surgically prepared for the
measurement of ventricular monophasic action potentials (MAP) and lead II
ECG. The following parameters were measured during left atrial pacing: MAP
duration at 90% of repolarisation (MAPD90), atrioventricular (AV) conduction
time, ventricular conduction velocity (MAP rise time) and lead II ECG QRS
interval. Mean arterial blood pressure and heart rate were also measured
during sinus rhythm. Animals received an infusion of vehicle followed by
infusions at low- and high-doses of each test compound. Each infusion lasted
for 17 min. Animals were monitored for a further 32-minute washout period.
Blood samples for kinetics were taken at 2.5, 5.5, 10.5 and 15.5 min after the
22. Scott, D. A.; Aquila, B. M.; Bebernitz, G. A.; Cook, D. J.; Dakin, L. A.; Deegan, T. L.;
Hattersley, M. M.; Ioannidis, S.; Lyne, P. D.; Omer, C. A.; Ye, M.; Zheng, X. Bioorg.
Med. Chem. Lett. 2008, 18, 4794.
23. http://www.thalesnano.com/products/h-cube.