MANNOSE DERIVATIVE AND APPLICATION THEREOF

Abstract

A mannose derivative is an isonitrile-containing mannose derivative of formula (I), including different linking groups X:

##STR00001##

A radioactive preparation is provided, including a radiolabeled compound formed by radiolabeling the mannose derivative with a radionuclide. An application of the radioactive preparation in the diagnosis and treatment of tumors is also provided.

Claims

1. A mannose derivative with a structure of formula (I): ##STR00011## wherein X is ##STR00012## n represents an integer equal to or larger than 2; a represents an integer equal to or larger than 0; and b represents an integer equal to or larger than 0.

2. A radioactive preparation, comprising: a radiolabeled compound; wherein the radiolabeled compound is formed by labelling the mannose derivative of claim 1 with a radionuclide.

3. The radioactive preparation of claim 2, wherein the radionuclide is selected from the group consisting of .sup.99mTc, .sup.99Tc, .sup.94mTc, .sup.94Tc, .sup.52Mn, .sup.186Re and .sup.188Re.

4. The radioactive preparation of claim 3, wherein the radiolabeled compound has a structure of formula (II): ##STR00013## wherein X is ##STR00014## n represents an integer equal to or larger than 2; a represents an integer equal to or larger than 0; and b represents an integer equal to or larger than 0.

5. A method for diagnosing and/or treating a tumor in a subject in need thereof, comprising: administering a therapeutically-effective amount of the radioactive preparation of claim 2 to the subject.

Description

DETAILED DESCRIPTION OF EMBODIMENTS

[0018] A mannose derivative and an application thereof are provided in the present disclosure. An embodiment of the disclosure provides a radioactive preparation with a structural general formula of .sup.99mTc-CNDM, as shown in the following formula:

##STR00006##

[0019] In the above formula, n represents an integer equal to or larger than 2; a represents an integer equal to or larger than 0; and b represents an integer equal to or larger than 0.

[0020] The radioactive preparation was prepared as follows.

Step (1) Synthesis of Ligand

[0021] An appropriate amount of D-mannosamine hydrochloride, NaOH and anhydrous methanol were sequentially added to a 25 mL round-bottomed flask. The reaction mixture was stirred at room temperature until the solid was completely dissolved, dropwise added into a methanol solution of a compound 1a, 1b or 1c, and reacted at room temperature for 24 h. The resultant reaction solution was distilled off under reduced pressure and purified by column chromatography (dichloromethane:methanol=5:1) to obtain the ligand CNDM.

[0022] The specific synthesis route is shown in Reaction Schemes 1-3.

##STR00007##

[0023] In Reaction Scheme 1, n represents an integer of 2 or more.

##STR00008##

[0024] In Reaction Scheme 2, a represents an integer of 0 or above, and b represents an integer of 0 or above.

##STR00009##

[0025] In Reaction Scheme 3, a represents an integer of 0 or above, and b represents an integer of 0 or above.

Step (2) Preparation of .SUP.99m.Tc-CNDM

[0026] An appropriate amount of sodium citrate and L-cysteine were dissolved in an appropriate amount of normal saline. The mixture was sequentially added with an appropriate amount of SnCl.sub.2.2H.sub.2O, adjusted to pH 6.0, sequentially added with an appropriate amount of the ligand CNDM and freshly-washed Na .sup.99mTcO.sub.4, and reacted at 100? C. for 20 min to obtain the .sup.99mTc-CNDM complex.

[0027] The .sup.99mTc-CNDM complex prepared by the above method has a radiochemical purity of greater than 90% and excellent in vitro and in vivo stability, and has high uptake and promising retention at the tumor site of tumor-bearing mice with a promising target-to-non-target ratio, which facilitates the promotion and application as a new tumor imaging agent.

[0028] The following embodiments are used to illustrate the invention but are not intended to limit the scope of the disclosure. If specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in literature in the field shall be followed, or the product instructions shall be followed.

[0029] In the present disclosure, if the manufacturer is not indicated for the instruments used, they are all conventional products that can be purchased through regular channels. Unless otherwise stated, the methods are conventional methods, and the raw materials can be obtained from public commercial sources unless otherwise stated.

Embodiment 1

[0030] The embodiment provides a .sup.99mTc-labeled mannose derivative (abbreviated as .sup.99mTc-CN7DM), with the following formula:

##STR00010##

[0031] The .sup.99mTc-CN7DM was prepared as follows.

Step (1) Synthesis of CN7DM

[0032] 0.088 g (2.2 mmol) of NaOH was added to a 25 mL round-bottomed flask and dissolved with 20 mL of methanol, and then 0.431 g (2.0 mmol) of D-mannosamine hydrochloride and 0.761 g of the compound 1a (n=7, 2.4 mmol) were added to the flask. The reaction mixture was reacted at room temperature overnight, distilled under vacuum and purified by column chromatography (dichloromethane:methanol=5:1) to obtain 0.248 g of the ligand with a yield of 38%.

[0033] .sup.1H NMR (400 MHz, Methanol-d.sub.4): ? 4.96 (d, J=1.6 Hz, 1H), 4.89-4.84 (m, 1H), 4.30-4.21 (m, 1H), 3.98 (dd, J=9.7, 4.7 Hz, 1H), 3.80 (dd, J=3.9, 2.5 Hz, 1H), 3.78-3.70 (m, 2H), 3.56(t, J=9.6 Hz, 1H), 3.44 (ddt, J=6.6, 3.8, 2.0 Hz, 3H), 2.25 (td, J=7.3, 2.1 Hz, 2H), 1.67-1.60 (m,4H), 1.45-1.31 (m, 8H); .sup.13C NMR (101 MHz, Methanol-d.sub.4): ? 176.78, 175.64, 153.90 (t, J=6.3 Hz), 93.68, 76.91, 73.25, 72.11, 69.27, 67.17, 66.79, 60.94, 60.75, 54.45, 53.71, 41.06 (t, J=6.0 Hz), 35.70, 35.53, 28.81, 28.72, 28.68, 28.19, 25.95, 25.49, 25.45; IR (KBr)/cm.sup.?1 2150.72 (N?C); HR-MS (ESI) for C.sub.15H.sub.27N.sub.2O.sub.6[M+H].sup.+: found 331.1861, calcd 331.1863.

Step (2) Synthesis of .SUP.99m.Tc-CN7DM

[0034] 2.6 mg of sodium citrate and 1 mg of L-cysteine were dissolved in an appropriate amount of normal saline. The mixture was sequentially added with 0.10 mg of SnCl.sub.2.2H.sub.2O, adjusted to pH 6.0, sequentially added with 0.5 mg of CN7DM and 1 mL of freshly-washed Na.sup.99mTcO.sub.4, and reacted at 100? C. for 20 min to obtain the .sup.99mTc-CNDM described in this embodiment.

EXPERIMENTAL EXAMPLE

1. Chromatographic Identification of the Radioactive Preparation Provided in Embodiment 1

(1) Thin-Layer Chromatography (TLC)

[0035] The radiochemical yield and radiochemical purity of the radiolabeled compound were determined by TLC, where the developing system was polyamide film-ammonium acetate (1 M)/methanol in a volume ratio of 2:1. Retention factor (R.sub.f) values of radioactive components were shown in Table 1.

TABLE-US-00001 TABLE 1 R.sub.f value of radioactive components in polyamide film-ammonium acetate (1M)/methanol (volume ratio of 2:1) system .sup.99mTcO.sub.4.sup.? .sup.99mTcO.sub.2nH.sub.2O .sup.99mTc-CN7DM R.sub.f 0-0.1 0-0.1 0.7-1.0

[0036] The radiochemical yield and radiochemical purity of the .sup.99mTc-CN7DM complex measured by TLC were both greater than 90%, and the complex was directly used in subsequent experiments without further purification.

(2) High-Performance Liquid Chromatography (HPLC)

[0037] The radiochemical purity of the radiolabeled compound was identified by HPLC, where the HPLC parameters were listed as follows: SHIMADZU HPLC System (CL-20AVP); Kromasil C18 reversed-phase column (5 ?m, 250?4.6 mm); Gabi raytest radioactivity detector; the elution gradient was shown in Table 2; flow rate: 1 mL/min; phase A: pure water containing 0.1% by volume of trifluoroacetic acid; and phase B: acetonitrile containing 0.1% by volume of trifluoroacetic acid.

TABLE-US-00002 TABLE 2 Gradient elution program t/min A/% B/% 0 90 10 2 90 10 5 10 90 20 10 90 24 90 10 25 90 10

[0038] The HPLC identification results showed that a retention time of .sup.99mTc-CN7DM was 9.5 min.

2. Determination of Lipid-Water Partition Coefficient

[0039] To a 5 mL centrifuge tube were added 100 ?L of a .sup.99mTc-CN7DM solution with a radioactivity of 10 ?Ci, 1 mL of n-octanol and 900 ?L of phosphate buffered saline (PBS) (0.025 M and pH 7.4). The mixture was vortexed at a rotation speed of 2,500 rpm for 3 min, subjected to standing for stratification, and centrifuged at 9,000 rpm in a centrifuge for 5 min. Three samples (each for 100 ?L) were taken from each of the two phases, and determined by a ?-counter for the radioactivity counts. The lipid-water partition coefficient P was a ratio of the organic-phase radioactivity count to the aqueous-phase radioactivity count, usually expressed as log P. The log P of .sup.99mTc-CN7DM was obtained as ?3.15?0.06, indicating that .sup.99mTc-CN7DM is water-soluble.

3. Determination of Stability

[0040] The radiochemical purity of .sup.99mTc-CN7DM was determined by TLC after being placed in normal saline at room temperature and in mouse serum at 37? C. for 4 h. It was found that the radiochemical purity of .sup.99mTc-CN7DM was greater than 90% after being placed in normal saline at room temperature and in mouse serum at 37? C. for 4 h, indicating that .sup.99mTc-CN7DM has excellent in vitro stability.

4. Biodistribution Determination in Tumor-Bearing Mice

[0041] 0.1 mL of the .sup.99mTc-CN7DM labeling solution (370 kBq) was injected into mice bearing S180 tumors through the tail vein. After recording the injection time, the mice were subjected to sacrificing by cervical dissection at different time points of 30 min and 120 min (5 mice were executed at each time), dissecting, taking out tissues or organs of interest such as heart, liver, lungs, kidneys, spleen, bone, muscles, small intestine, blood and tumors. A radioactivity count of each of the tissues or organs was measured by the ?-counter, and uptake value of each of the tissues or organs in % ID/g was obtained by converting a mass of each of the tissues or organs. The biodistribution results of the radiolabeled compound in tumor-bearing mice were shown in Table 3.

TABLE-US-00003 TABLE 3 Biodistribution results of .sup.99mTc-CN7DM in S180 tumor-bearing mice (n = 5, mean ? SD, % ID/g) 30 min 120 min Heart 2.08 ? 0.26 1.40 ? 0.14 Liver 2.91 ? 0.23 2.13 ? 0.46 Lung 1.86 ? 0.19 0.76 ? 0.20 Kidney 6.22 ? 0.91 3.12 ? 0.82 Spleen 1.23 ? 0.11 0.80 ? 0.15 Bone 1.41 ? 0.17 0.76 ? 0.17 Muscle 1.88 ? 0.16 0.96 ? 0.12 Small intestine 1.05 ? 0.20 0.42 ? 0.13 Tumor 6.11 ? 0.76 5.92 ? 0.30 Blood 1.61 ? 0.17 0.09 ? 0.02 Thyroid gland (% ID) 0.04 ? 0.01 0.02 ? 0.00 Tumor/Muscle 3.25 6.18 Tumor/Blood 3.79 63.48

[0042] It can be seen from the results that .sup.99mTc-CN7DM has high uptake and excellent retention in tumors, while can be rapidly metabolized in non-target organs. After 120 min of administration, tumor-to-muscle and tumor-to-blood ratios are high. In particular, .sup.99mTc-CN7DM can be rapidly cleared from the blood, thereby greatly increasing the tumor-to-blood ratio.

[0043] Although the present disclosure has been described in detail above with reference to embodiments, those skilled in the art can still make some modifications or improvements to the technical solutions disclosed herein. It should be understood that those modifications or improvements made without departing from the spirit of the disclosure (for example, radioactive preparations obtained by radiolabeling a ligand formed by structurally modifying monosaccharides other than glucose and mannose) shall fall within the scope of the disclosure defined by the appended claims.