Synthesis and biological evaluation of technetium-99m labeled galactose derivatives as potential asialoglycoprotein receptor probes in a hepatic fibrosis mouse model

Article abstract of DOI:10.1016/j.bmcl.2013.09.012

Two galactose derivatives, a monovalent ^99mTc-MAMA-MGal galactoside and a divalent ^99mTc-MAMA-DGal galactoside, were synthesized and radiolabeled in high radiochemical purity (>98%). Dynamic microSPECT imaging and biodistribution stu

Full text of DOI:10.1016/j.bmcl.2013.09.012

Bioorganic & Medicinal Chemistry Letters 23 (2013) 6486–6491
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Synthesis and biological evaluation of technetium-99m labeled
galactose derivatives as potential asialoglycoprotein receptor probes
in a hepatic fibrosis mouse model
Wen-Yi Chang a, Hao-Wen Kao a, Hsin-Ell Wang a, Jenn-Tzong Chen b, Wuu-Jyh Lin b, Shyh-Jen Wang c,
Chuan-Lin Chen a,
⇑
a Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, 155, Sec.2, Linong St., Taipei 11217, Taiwan
b Institute of Nuclear Energy Research, Department of Isotope Application, Taoyuan, Taiwan
c Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
a r t i c l e i n f o
a b s t r a c t
Two galactose derivatives, a monovalent 99mTc-MAMA-MGal galactoside and a divalent 99mTc-MAMA-
DGal galactoside, were synthesized and radiolabeled in high radiochemical purity (>98%). Dynamic mic-
roSPECT imaging and biodistribution study of two traces in normal and liver fibrosis mice showed that
the 99mTc-MAMA-DGal revealed higher specific binding to asialoglycoprotein receptors in liver and then
rapidly excreted via both hepatobiliary system and renal clearance. The results suggest that 99mTc-
MAMA-DGal may be used as SPECT probes for noninvasive evaluation of asialoglycoprotein receptor-
related liver dysfunction.
Article history:
Received 3 April 2013
Revised 31 August 2013
Accepted 5 September 2013
Available online 13 September 2013
Keywords:
Galactose
Asialoglycoprotein
Technetium-99m
SPECT
Crown Copyright Ó 2013 Published by Elsevier Ltd. All rights reserved.
Liver function
The chronic liver disease and cirrhosis, not including hepatoma,
were the 8th leading cause of death for men and the 10th for wo-
men in Taiwan in 2010.1 It is very important to ensure people
health by monitoring liver function.
Both modalities can combine with computed tomography (CT) and
magnetic resonance imaging to achieve detailed anatomic co-regis-
tration. By employing appropriate probes to target the correspond-
ing biomarkers,7,8 PET/SPECT imaging would have potential for
monitoring specific liver function and disease noninvasively.
Technetium-99m, having appropriate physical properties (a de-
cay energy of 0.140 MeV and a physical half life of 6 h), high avail-
ability and low cost9,10, is a most widely used radionuclide for
diagnostic purpose in nuclear medicine.
Stages of liver damage include inflammation, fibrosis, cirrhosis
and liver failure. Cirrhosis is the third stage of liver damage, resulting
from untreated hepatic fibrosis. Cirrhosis occurs after the liver has
become so scarred that it cannot heal itself.2,3 The patients with hep-
atitis B or C infection, diabetes, alcoholism, obesity or drug abuse
would be the high-risk groups that may suffer from cirrhosis.4 If re-
mained untreated, cirrhosis may lead to liver failure or liver cancer.4
A noninvasive method for diagnosis of liver damage at early stage
may be beneficial to patients to prevent progress to cirrhosis.
In clinical, biopsy is regarded as the gold standard for the diagno-
sis of liver disease, but not without risks (e.g., samplingerror, inflam-
mation, bleeding, etc.). Scientists keep developing new targets or
techniques for non-invasive monitoring of liver function or
disease.5,6
Asialoglycoprotein receptors (ASGPRs) were found on the sur-
face of hepatocyte. ASGPRs can recognize those glycoproteins with
terminal galactose or N-acetyl-galactosamine moieties and take
them into cells by endocytosis.11,12 Two 99mTc-labeled albumin-
based radiopharmaceuticals, 99mTc-labeled neoglycoalbumin
(
99mTc-NGA)13,14 and 99mTc-labeled galactosyl-human serum
albumin (99mTc-GSA)15, have been developed as ASGPR probes
and applied for liver SPECT scan. However, the long retention of
99mTc-NGA and 99mTc-GSA in systemic circulation, especially in
NGA and GSA blocking studies, significantly interfere the quantita-
tive assay of liver uptake based on SPECT imaging. In recent years,
polymer backbone radiotracers derivatives were also reported as
ASGPR targeting agents, such as 99mTc-GMC (Galactosyl-methyl-
Positron emission tomography (PET) and single-photon emission
computed tomography (SPECT) are widely used in clinical for brain,
heart and tumor scans to provide functional imaging information.
ated chitosan)16 and 99mTc-PVLA poly(vinylbenzyl-O-ß-
pyranosyl-
-gluconamide).17
D-galacto-
⇑
Corresponding author.
E-mail address: clchen2@ym.edu.tw (C.-L. Chen).
D
0960-894X/$ - see front matter Crown Copyright Ó 2013 Published by Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.bmcl.2013.09.012

W.-Y. Chang et al. / Bioorg. Med. Chem. Lett. 23 (2013) 6486–6491
6487
Recently, several galactosides and N-acteyl galactosamine
derivatives, including mono-, di-, tri- and hexa-valent ligands, have
been reported as potential substrates for ASGPR in vitro.18–20 In our
previous report, we have demonstrated that 18F-labeled monova-
lent galactoside (18F-FBHGal) is an ASGPR-specific PET probe for
monitoring hepatic fibrosis in mice.21 In clinical, SPECT imaging
is more widely available than PET imaging and the radionuclides
used for SPECT are easier to prepare and usually have a longer
half-life than those used for PET. In this study, we prepared two
new 99mTc-labeled galactosides and evaluated their ability to im-
age ASGPR in a normal and a hepatic fibrosis mouse model.
A study of Ernst et al.22 suggested that the optimal distance be-
tween the branching point and the galactose residue in a poly-va-
lent galactoside was 14–20 Å for binding with ASGPRs on the cell
membrane. This study prepared 99mTc-labeled monovalent and
divalent galactosides, 99mTc-MAMA-MGal and 99mTc-MAMA-DGal,
and performed the biological characterization as ASGPR probes in
both normal and hepatic fibrosis mouse models. The length of
spacer in our 99mTc-MAMA-DGal was 14–16 Å (based on Chem-
Draw calculation), lie in the optimal range suggested by Ernst.
Carbohydrates are generally weak ligands for technetium-99m.
Modification with chelating agents is essential for preparing radio-
metal-labeled complexes. The monoaminemonoamide dithiol
(MAMA) ligand, with strong chelating ability to 99mTc and 188Re,
has been used to conjugate with various ligands for the diagnosis
and therapy of cancers.23,24 The synthesis of the mono- and di-va-
lent galactoside ligands for technetium-99m labeling and complex-
ation with ReOÀ4 (Scheme 1) were performed following the method
previously described with some modifications. In brief, cysteamine
hydrochloride reacted with trityl chloride in dichloromethane/
dimethylformamide (1/1) to protect its thiol group and provide
compound 1. N-acylation of compound 1 with bromoacetyl
chloride in the presence of triethylamine gave compound 2.
Nucleophilic displacement of the bromide of methyl 4-(bromo-
methyl)benzoate with compound 1 provided compound 3, which
was then treated with compound 2 to produce compound 4. After
hydrolysis of the ester group, compound 5 was obtained. To pre-
pare the monovalent ligand, compound 5 was reacted with com-
pound 6 (its preparation was detailed in our previous report21
)
using 1-ethyl-3-(3-dimethylamino)carbodiimide hydrochloride
(EDC) as condensation reagent to afford compound 7 as the
monogalactosyl ligand for metal (99mTc, Re) chelation. After depro-
tecting the thio groups with trifluoroacetic acid, metal chelation
proceeded in situ without separation. Rhenium (V) oxo incorpora-
tion was achieved by incubation of the ligand in methanol/tetrahy-
drofuran (7/1) solution with tin(II) chloride and sodium perrhenate
(VII). The Re-chelated monogalactoside 8 (Re-MAMA-MGal) was
then isolated by reverse phase column chromatography (Re-MGal,
20% yield). To prepare the divalent ligand, compound 5 was mod-
ified with methylglutamate to produce compound 9. After hydroly-
sis of the ester group, compound 10 was obtained, and then
reacted with compound 6 to afford compound 11 as the digalacto-
syl ligand for metal (99mTc, Re) chelation. Re-MAMA-DGal (12, 50%
yield) was prepared following a similar procedure as that of Re-
MAMA-MGal (8). All compounds were identified by 1H NMR, 13C
NMR spectroscopy and high resolution electro-spray ionization
(ESI) mass (Supplementary data).
The radioactive complexes 99mTc-MAMA-MGal (8b) and 99mTc-
MAMA-DGal (12b) were prepared in moderate yield (8b: 35%, 12b:
32%) and high radiochemical purity (>98%) by reaction of 99mTc-
pertechnetate and SnCl2 with compound 7 and 11, respectively
(Scheme 2). The chemical identity of 99mTc-MAMA-MGal and
99mTc-MAMA-DGal was determined by comparing their reverse
phase-HPLC radio peak (retention time: 8b, 16.5 min; 12b,
14.5 min) with the reverse phase-HPLC UV peak of rhenium ana-
logues Re-MAMA-MGal (8a) and Re-MAMA-DGal (12a) (retention
time: 8a, 16.4 min; 12a, 14.1 min) (Fig. 1).
The lipophilicity of 99mTc-MAMA-MGal (8b) and 99mTc-MAMA-
DGal (12b) was evaluated based on the octanol/saline partition
coefficients (log Po/s). The average log Po/s value of
Scheme 1. Synthesis of MGal and DGal precursors for 99mTc labeling and their Re-conjugated complexes. Reagents and conditions: (a) dichloromethane/dimethylformamide
(1/1), trityl chloride, 92% yield; (b) bromoacetyl chloride, triethylamine, dichloromethane, 90% yield; (c) methyl 4-(bromomethyl)benzoate, acetonitrile, K2CO3, KHCO3, 80 °C,
60% yield; (d) acetonitrile, K2CO3, KHCO3, 80 °C, 76% yield; (e) LiOH, MeOH/H2O (1/1), 25 °C, 71–75% yield; (f) compound 6, HOBt, DMF, EDC, DIPEA, 30–34% yield; (g) MeOH/
THF (7/1), SnCl2, NaReO4, 0.05 M HCl, 60 °C, 20–50% yield; (h) methylglutamate, HOBt, DMF, EDC, DIPEA, 82% yield.

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W.-Y. Chang et al. / Bioorg. Med. Chem. Lett. 23 (2013) 6486–6491
Scheme 2. MGal and DGal precursors labeled with 99mTc to produce 99mTc-conjugated complexes (8b, 12b). Reagents and conditions: (a) trifluoroacetic acid, triethylsilane;
(b) acetonitrile, 0.5 M phosphate buffer (pH 8.0), 99mTc-pertechnetate, stannous chloride dihydrate in 0.05 M HCl, potassium sodium tartrate tetrahydrate, ethylenedi-
aminetetraacetic acid (EDTA, 0.1 M), 60 °C, 1 h.
injected via a tail vein and the mice were sacrificed at 5 min,
30 min and 120 min post-injection. The reduction of ASGPR in liver
of hepatic fibrosis mouse has been demonstrated by histological
examination in our previous report.21 The results of biodistribution
of two tracers in both normal and DMN-induced liver fibrosis mice
were shown in Tables 1 and 2. At the 5 min p.i. in normal mice, the
liver uptake of 99mTc-MAMA-MGal and 99mTc-MAMA-DGal were
42.89 3.85 and 21.15 1.16 %ID/g, while that in the DMN-in-
duced hepatic fibrosis mice were significantly reduced to
30.83 2.71 and 12.44 0.48 %ID/g (P < 0.01), respectively. The
lower uptake of 99mTc-MAMA-DGal in liver might due to higher
binding affinity and faster metabolic rate than 99mTc-MAMA-MGal.
The receptor index of 99mTc-MAMA-MGal was observed similar in
normal and hepatic fibrosis mice (0.98 0.02. and 0.97 0.01,
P < 0.005). However, the receptor index of 99mTc-MAMA-DGal
was 0.95 0.01 in normal mice and remarkably higher than that
in hepatic fibrosis mice (0.87 0.01, P < 0.001). The result showed
that the distribution of 99mTc-MAMA-DGal has larger deference for
liver uptake ratio and receptor index between normal and fibrosis
mice. It may be used as a better imaging tracer for in vivo evalua-
tion of asialoglycoprotein receptor-related liver dysfunction.
Figure 1. HPLC chromatograms of 99mTc- and Re-conjugated galactosides. (A)
The radioactivity distribution in bile and small intestine post-
99mTc-MAMA-MGal 8b (radio peak-red) and Re-MAMA-MGal 8a (UV peak-blue). (B)
injection may indicate the rate of liver metabolism of a radiotracer.
A faster liver metabolism would result in more rapid bile and small
intestine accumulation. The radioactivity accumulation in small
intestine after intravenous administration of 99mTc-MAMA-DGal
was 162.6 52.77 and 32.81 2.62 %ID/g for the normal and the
hepatic fibrosis mice at 5 min p.i., while it was only 23.16 4.01
and 16.96 3.77 %ID/g (Tables 1 and 2) for 99mTc-MAMA-MGal.
Similar distribution profiles were also observed in bile within
120 min p.i.. The findings in biodistribution studies indicated that
the divalent galactoside, 99mTc-MAMA-DGal, exhibited a faster li-
ver metabolism than that of the monovalent, 99mTc-MAMA-MGal.
The 99mTc-GSA for the evaluation of hepatic functional reserva-
tion showed that the receptor index (liver ROI/liver-plus-heart ROI
derived from SPECT images acquired at 15 min p.i.) was 0.86 in pa-
tients with liver cirrhosis, lower than that in healthy subjects (0.95,
P = 0.0007).15 Graaf et al. also used receptor index for preoperative
assessment of total and regional liver function of patients.31 The
receptor index derived from dynamic 99mTc-GSA imaging can be
regarded as a representative measurement of ASGP receptor bio-
chemistry (including ligand concentrations, receptor density and
binding affinity).32 From the microSPECT/CT images, the receptor
index of 99mTc-MAMA-MGal and 99mTc-MAMA-DGal was
0.98 0.01 and 0.86 0.01 in hepatic fibrosis mice, respectively,
similar to or lower than that in normal mice (0.99 0.02 and
0.99 0.01, P = 0.13 and 0.002; n = 4, Fig. 2B). The findings were
consistent with those observed in biodistribution study and high
99mTc-MAMA-DGal 12b (radio peak-red) and Re-MAMA-DGal 12a (UV peak-blue).
The mobile phase was a gradient of 10–90% aqueous acetonitrile (containing 0.1%
trifluoroacetic acid) over 25 min at a flow rate of 3.0 mL/min.
99mTc-MAMA-MGal and 99mTc-MAMA-DGal determined in three
independent trials were À1.76 0.07 and À1.58 0.05, respec-
tively, indicating the high hydrophilic property of these 99mTc-la-
beled galactosylated complexes.
A competitive binding assay was conducted to evaluate the
binding affinity of Re-MGal and Re-DGal compounds using 131I-la-
beled ASF as a reference compound. ASF, containing 12.4 galactose
and 1.6 galactosamine moieties in one molecule, exhibited high
binding capacity to ASGPR.25 The IC50 value of Re-DGal
(0.47 mM) for the ASGPR on HepG2 cells was higher than that of
Re-MGal (>4 mM) (data not shown), similar to those of divalent
galactose derivatives reported in earlier literature.26–28 Other pre-
vious studies also suggested that the in vitro ASGPRs binding of
affinity of divalent galactoside was 10-fold higher than the mono-
valent ligand.29,30 The results of in vitro studies demonstrated that
divalent compound (Re-DGal) have better binding affinity to
ASGPRs than monomeric compound (Re-MGal).
The biodistribution studies of 99mTc-MAMA-MGal and 99mTc-
MAMA-DGal were conducted in both normal mice and DMN-
induced liver fibrosis C57BL/6 mice. Two tracers (3.7 MBq) was

W.-Y. Chang et al. / Bioorg. Med. Chem. Lett. 23 (2013) 6486–6491
6489
Table 1
Radioactivity distribution in normal and DMN-induced liver fibrosis C57BL/6 mice after intravenous injection of 3.7 MBq of 99mTc-MAMA-MGal
Normal mice
30 min
DMN-induced liver fibrosis mice
5 min
120 min
5 min
30 min
120 min
Blood
Heart
Lung
Stomach
SI
2.28 0.40
0.75 0.10
1.39 0.37
3.21 1.63
23.16 4.01
0.57 0.06
0.69 0.09
1.02 0.48
0.34 0.07
0.75 0.18
4.87 1.08
188.6 74.7
79.80 22.64
0.58 0.23
42.89 3.85
16.38 4.74
0.98 0.02
0.74 0.06
0.22 0.01
0.38 0.06
4.10 2.60
13.80 5.62
0.19 0.04
0.26 0.04
0.25 0.04
0.10 0.01
0.24 0.02
1.40 0.10
527.2 113.3
58.45 16.89
1.09 0.21
14.32 0.65
18.05 0.54
0.98 0.01
0.37 0.03
0.11 0.01
0.20 0.03
2.27 1.10
3.76 1.84
0.25 0.22
0.13 0.02
0.20 0.06
0.06 0.01
0.10 0.06
0.82 0.04
272.4 53.8
8.25 2.23
3.54 0.74
2.64 0.28
6.84 0.69
5.46 1.10
1.37 0.44
3.36 0.98
2.46 0.76
19.45 6.45
1.22 0.48
1.28 0.44
1.26 0.39
0.82 0.24
1.14 0.42
7.88 2.27
123.0 17.7
60.53 29.03
0.31 0.13
30.83 2.71
5.63 0.89
0.97 0.01
1.58 0.29
0.34 0.07
0.70 0.20
7.72 4.42
29.85 9.23
0.39 0.29
0.39 0.08
0.60 0.27
0.23 0.15
0.31 0.04
2.11 0.52
469.7 83.4
101.0 70.27
0.42 0.16
12.62 0.41
9.98 0.45
0.97 0.03
0.97 0.07
0.18 0.09
0.48 0.18
0.54 0.09
1.17 0.36
0.20 0.09
0.20 0.05
0.24 0.20
0.08 0.01
0.14 0.02
1.37 0.25
299.8 9.96
6.74 3.63
5.79 3.24
3.54 0.24
6.88 0.51
LI
Spleen
Pancreas
Muscle
Bone
Kidney
Bile
Urine
Feces
Liver
L/B
RI
Expressed as percentage injection dose per gram of organ (%ID/g). Each value represents the mean SD (n = 4). SI, small intestine; LI, large intestine; L/B, liver-to-blood ratio;
RI, receptor index (liver/liver-plus-heart).
Table 2
Radioactivity distribution in normal and DMN-induced liver fibrosis C57BL/6 mice after intravenous injection of 3.7 MBq of 99mTc-MAMA-DGal
Normal mice
30 min
DMN-induced liver fibrosis mice
5 min
120 min
5 min
30 min
120 min
Blood
Blood
Heart
Lung
Stomach
SI
2.81 0.68
2.81 0.68
1.10 0.35
2.87 1.12
5.38 4.27
162.6 52.77
2.49 2.27
1.32 0.43
2.75 1.72
1.30 0.66
2.33 1.83
6.23 1.69
210.6 66.6
404.1 179.9
0.61 0.54
21.15 1.16
7.09 2.41
0.95 0.01
0.89 0.28
0.89 0.28
0.23 0.03
0.70 0.46
3.43 2.59
13.81 4.21
0.36 0.23
0.23 0.04
0.42 0.19
0.10 0.01
0.29 0.11
0.93 0.07
293.9 54.0
132.5 133.9
0.55 0.39
2.94 0.39
3.63 1.42
0.93 0.02
0.35 0.04
0.35 0.04
0.10 0.02
0.20 0.03
1.80 0.59
0.61 0.18
0.14 0.10
0.28 0.13
0.19 0.09
0.06 0.01
0.18 0.07
0.59 0.14
447.5 71.3
248.1 184.6
2.14 1.06
0.87 0.10
3.43 0.42
8.52 1.67
8.52 1.67
1.72 0.18
3.70 0.70
3.79 0.67
32.87 2.62
1.76 0.31
1.27 0.65
2.51 1.15
0.91 0.08
1.40 0.20
7.18 1.92
288.0 85.7
100.4 72.0
0.30 0.08
12.44 0.48
1.53 0.26
0.87 0.01
3.24 1.91
3.24 1.91
0.41 0.02
1.38 0.21
3.80 2.78
6.79 2.46
0.73 0.52
0.55 0.14
1.01 0.45
0.23 0.03
0.42 0.04
2.21 0.17
290.6 108.9
89.85 89.36
0.58 0.25
2.81 0.23
1.48 0.12
0.87 0.01
0.63 0.09
0.63 0.09
0.18 0.03
0.52 0.14
2.80 1.14
0.89 0.30
0.41 0.28
0.25 0.04
0.38 0.11
0.09 0.02
0.20 0.03
184.0 60.34
15.13 21.59
17.35 22.42
15.13 21.59
0.88 0.04
1.40 0.12
LI
Spleen
Pancreas
Muscle
Bone
Kidney
Bile
Urine
Feces
Liver
L/B
RI
Expressed as percentage injection dose per gram of organ (%ID/g). Each value represents the mean SD (n = 4). SI, small intestine; LI, large intestine; L/B, liver-to-blood ratio;
RI, receptor index (liver/liver-plus-heart).
radioactivity accumulation in bile and urine was noticed, which
was probably due to rapid metabolism and elimination via liver
and kidney. In normal mice, the receptor index of both 99mTc-
MAMA-MGal and 99mTc-MAMA-DGal is close to unity, suggesting
that the radioactivity contribution from blood at 15 min p.i. is very
limited. The results also implied that, after intravenous injection,
these two radioprobes enjoyed fast binding to ASGPR on hepato-
cyte and exhibited rapid blood clearance in normal mice. The
receptor index of the di-valent ligand showed significant difference
between the normal and the hepatic fibrosis mice (0.99 0.01 and
0.86 0.01, P = 0.002), which was probably due to the lower den-
sity of ASGPR on hepatocytes of fibrotic liver. Less efficient binding
of 99mTc-MAMA-DGal to fibrotic liver results in retarded liver
metabolism and slower blood clearance in hepatic fibrosis mice.
99mTc-MAMA-DGal SPECT imaging showed potential in differenti-
ating ASGPR-related liver dysfunction. The results observed in
microSPECT imaging were consistent with those obtained in bio-
distribution studies (Tables 1 and 2).
The pharmacokinetic parameters derived from microSPECT/CT
imaging of hepatic fibrosis mice post-injection of 99mTc-MAMA-
DGal were significantly different from those of normal mice
(Table 3). The half-life of 99mTc-MAMA-DGal in hepatic fibrosis
mice was 4.9-fold longer than that in normal mice. The AUC of
99mTc-MAMA-DGal in blood of hepatic fibrosis mice was
561.05 min%ID/mL, about 30.0-fold higher than that of normal
mice (18.7 min%ID/mL). The much faster blood clearance (Cl) of
99mTc-MAMA-DGal in normal mice may reasonably account for
its much lower AUC. However, the pharmacokinetic parameters
of hepatic fibrosis mice post-injection of 99mTc-MAMA-MGal were
not significantly different from those of normal mice (Table 3).
In summary, in vitro and in vivo study we demonstrated that
the di-valent 99mTc-MAMA-DGal could display specific binding to
ASGPR and fast pharmacokinetics in normal and hepatic fibrosis
mice. The biodistribution and microSPECT/CT imaging with
99mTc-MAMA-DGal revealed clear liver images and may provide
quantitative information of ASGPR related liver dysfunction.

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W.-Y. Chang et al. / Bioorg. Med. Chem. Lett. 23 (2013) 6486–6491
Figure 2. MicroSPECT images of normal and DMN-induced liver fibrosis C57BL/6 mouse after injection of 99mTc-MAMA-MGal and 99mTc-MAMA-DGal via the tail vein (A,
n = 4). (B) The receptor index derived from microSPECT/CT images. (n = 4 per group; bars represent means SD). ⁄P <0.01, compared with normal mice by student paired t test.
Table 3
Estimated pharmacokinetic parameters derived from microSPECT images of mice after intravenous injection of 99mTc-MAMA-MGal and 99mTc-MAMA-DGal
Parameter
Unit
99mTc-MAMA-MGal
99mTc-MAMA-DGal
Normal mice
DMN-induced liver fibrosis mice
Normal mice
DMN-induced liver fibrosis mice
T1/2
Cl
AUC
min
5.39
5.78
51.93
6.05
7.80
39.91
6.68
17.76
18.7
32.91
0.56
561.05
mCi/min  (%ID/mL)
min  %ID/mL
Values were derived by data of mean (n = 4). Calculated with the WinNonlin program. T1/2, half-life; Cl, blood clearance; AUC, area under the curve.
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This study was supported by grants from the Institute of Nucle-
ar Energy Research of Taiwan (1002001INER089) and National Sci-
ence council (NSC99-2314-B-010-027-MY3) of Taiwan. We thank
the staff of the Molecular and Genetic Imaging Core/National Re-
search Program for Genomic Medicine (NSC100-2319-B010-003)
of Taiwan who kindly provided the radioisotope and excellent
technical assistance.
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