AMPHIPHILIC LIPID INCLUDING TERTIARY AMINE N-OXIDE GROUP, LIPOSOMAL DRUG-DELIVERY SYSTEM, AND USE OF AMPHIPHILIC LIPID

Abstract

An amphiphilic lipid including a tertiary amine N-oxide group, a liposomal drug-delivery system, and a use of the amphiphilic lipid are provided. The amphiphilic lipid is a compound shown in a formula I, where R and R each are independently selected from C.sub.1-C.sub.4 alkyl and X is a hydrophobic unit. The amphiphilic lipid can be used alone or together with the traditional phospholipid to prepare a liposomal drug-delivery system. The liposomal drug-delivery system can significantly prolong the blood circulation time of a drug and increase the accumulation and penetration of a drug in target tissues, resulting in a significantly-improved therapeutic effect.

Claims

1. An amphiphilic lipid comprising a tertiary amine N-oxide group, wherein the amphiphilic lipid is a compound shown in a formula I: ##STR00008## wherein R and R each are independently selected from C.sub.1-C.sub.4 alkyl and X is a hydrophobic unit.

2. The amphiphilic lipid comprising the tertiary amine N-oxide group according to claim 1, wherein when the hydrophobic unit X is a hydrophobic aliphatic chain, the amphiphilic lipid is a compound shown in a formula II or a formula III: ##STR00009## wherein R.sub.1 is one or more of C.sub.5-32 alkyl, cholesterol, and cholic acid; and Y is one or more of an ester group, a carbonate group, amido, a carbamate group, ureido, an ether group, sulfonyl, sulfinyl, and aryl.

3. The amphiphilic lipid comprising the tertiary amine N-oxide group according to claim 2, wherein an amphiphilic lipid comprising the hydrophobic aliphatic chain comprises the following compounds: ##STR00010##

4. The amphiphilic lipid comprising the tertiary amine N-oxide group according to claim 1, wherein the hydrophobic unit X comprises two hydrophobic chains.

5. The amphiphilic lipid comprising the tertiary amine N-oxide group according to claim 4, wherein an amphiphilic lipid comprising the two hydrophobic chains is a compound shown in a formula IV, a formula V, a formula VI, or a formula VII: ##STR00011## wherein R.sub.1 is one or more of C.sub.5-32 alkyl, cholesterol, and cholic acid; R.sub.2 is one or more of C.sub.5-32 alkyl, cholesterol, and cholic acid; Y is one or more of an ester group, a carbonate group, amido, a carbamate group, ureido, an ether group, sulfonyl, sulfinyl, and aryl; and Z is a tertiary amine N-oxide structural unit.

6. The amphiphilic lipid comprising the tertiary amine N-oxide group according to claim 5, wherein the tertiary amine N-oxide structural unit is selected from one of the following: ##STR00012## wherein R.sub.3 and R.sub.4 each are independently selected from one or more of C.sub.1-C.sub.4 alkyl, substituted alkyl, aryl, and substituted aryl; R.sub.5 is selected from one or more of C.sub.1-C.sub.4 alkyl, substituted alkyl, aryl, substituted aryl, and a heteroatomic group; and the heteroatomic group comprises a halogen, hydroxyl, and cyano.

7. The amphiphilic lipid comprising the tertiary amine N-oxide group according to claim 6, wherein a substituent on the tertiary amine N-oxide structural unit is dimethyl or diethyl.

8. The amphiphilic lipid comprising the tertiary amine N-oxide group according to claim 4, wherein the amphiphilic lipid is an N-oxide-N,N-dimethyl or N-oxide-N,N-diethyl-based amphiphilic lipid synthesized with 2,2-bis(hydroxymethyl)propionic acid (BHP) as a linker unit, and has a structural formula as follows: ##STR00013## wherein R.sub.1 is C.sub.5-32 alkyl.

9. The amphiphilic lipid comprising the tertiary amine N-oxide group according to claim 8, wherein R.sub.1 is C.sub.18 alkyl, and the amphiphilic lipid has a structural formula as follows: ##STR00014##

10. A liposome prepared from an amphiphilic lipid comprising a tertiary amine N-oxide group, wherein the liposome is prepared from one or more amphiphilic lipids comprising the tertiary amine N-oxide group; or the liposome is prepared from one or more amphiphilic lipids comprising the tertiary amine N-oxide group and a lipid without the tertiary amine N-oxide group.

11. The liposome according to claim 10, wherein the lipid without the tertiary amine N-oxide group is selected from one or more of cholesterol, a phospholipid, D--tocopheryl polyethylene glycol succinate, and a cationic lipid.

12. A liposomal drug-delivery system comprising the liposome according to claim 10 and a drug, wherein the liposome serves as a carrier to encapsulate the drug.

13. The liposomal drug-delivery system according to claim 12, wherein a mass ratio of the drug to the liposome is (0.01-0.5):1, and the drug comprises an anti-tumor drug.

14. The liposomal drug-delivery system according to claim 13, wherein the anti-tumor drug is one or more of doxorubicin, epirubicin, camptothecin, 7-ethyl-10-hydroxycamptothecin, irinotecan, paclitaxel, oxaliplatin, gemcitabine, and curcumin.

15. A preparation method of a liposomal drug-delivery system, comprising using the amphiphilic lipid comprising the tertiary amine N-oxide group according to claim 1.

16. The preparation method according to claim 15, wherein when the hydrophobic unit X is a hydrophobic aliphatic chain, the amphiphilic lipid is a compound shown in a formula II or a formula III: ##STR00015## wherein R.sub.1 is one or more of C.sub.5-32 alkyl, cholesterol, and cholic acid; and Y is one or more of an ester group, a carbonate group, amido, a carbamate group, ureido, an ether group, sulfonyl, sulfinyl, and aryl.

17. The preparation method according to claim 16, wherein an amphiphilic lipid comprising the hydrophobic aliphatic chain comprises the following compounds: ##STR00016##

18. The preparation method according to claim 15, wherein in the amphiphilic lipid, the hydrophobic unit X comprises two hydrophobic chains.

19. The preparation method according to claim 18, wherein an amphiphilic lipid comprising the two hydrophobic chains is a compound shown in a formula IV, a formula V, a formula VI, or a formula VII: ##STR00017## wherein R.sub.1 is one or more of C.sub.5-32 alkyl, cholesterol, and cholic acid; R.sub.2 is one or more of C.sub.5-32 alkyl, cholesterol, and cholic acid; Y is one or more of an ester group, a carbonate group, amido, a carbamate group, ureido, an ether group, sulfonyl, sulfinyl, and aryl; and Z is a tertiary amine N-oxide structural unit.

20. The preparation method according to claim 19, wherein in the amphiphilic lipid, the tertiary amine N-oxide structural unit is selected from one of the following: ##STR00018## wherein R.sub.3 and R.sub.4 each are independently selected from one or more of C.sub.1-C.sub.4 alkyl, substituted alkyl, aryl, and substituted aryl; R.sub.5 is selected from one or more of C.sub.1-C.sub.4 alkyl, substituted alkyl, aryl, substituted aryl, and a heteroatomic group; and the heteroatomic group comprises a halogen, hydroxyl, and cyano.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG. 1 shows a synthetic reaction for 18-BHP-ODMA in Example 1;

[0040] FIG. 2 shows proton nuclear magnetic resonance spectroscopy characterization results of 18-BHP-ODMA and 18-BHP-ODEA in Example 1;

[0041] FIG. 3 shows a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) spectrum of 18-BHP-ODMA in Example 1;

[0042] FIG. 4 shows an MALDI-TOF-MS spectrum of 18-BHP-ODEA in Example 1;

[0043] FIG. 5 shows particle size distributions of liposomes in Example 2;

[0044] FIG. 6 shows particle sizes of liposomes after being incubated in different media for 24 h in Test Example 1;

[0045] FIG. 7 shows particle size changes of liposomes after being stored in a 4 C. freezer for different time periods in Test Example 1;

[0046] FIG. 8 shows results of cytotoxicity tests of liposomal formulations in Test Example 2;

[0047] FIG. 9 shows the comparison of .sup.DiIODML and .sup.DiIODEL in a HepG2 cell line with an endoplasmic reticulum dye in Test Example 3;

[0048] FIG. 10 shows the comparison of .sup.DiIODML and .sup.DiIODEL in a HepG2 cell line with a Golgi apparatus dye in Test Example 3;

[0049] FIG. 11 shows results of transcellular transport tests of .sup.DiIODML and .sup.DiIODEL in Test Example 4;

[0050] FIG. 12 shows in vivo imaging results of blood of mice at 48 h after .sup.DiRODML or .sup.DiRODEL is injected in Test Example 5;

[0051] FIG. 13 shows in vivo imaging results of major tissues of mice at 48 h after .sup.DiRODML or .sup.DiRODEL is injected in Test Example 5;

[0052] FIG. 14 shows tumor inhibition curves of liposomal formulations for a HepG2 tumor-bearing mouse model in Test Example 6; and

[0053] FIG. 15 shows body weight change curves of HepG2 tumor-bearing mice in Test Example 6.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0054] The technical solutions of the present disclosure will be described in further detail below with reference to specific embodiments.

[0055] In the present disclosure, unless otherwise specified, all raw materials and devices adopted are commercially available or are commonly used in the art. All methods in the following embodiments are the conventional methods in the art, unless otherwise specified. The compounds in the present disclosure can be prepared by a variety of synthetic methods well known to those skilled in the art, including the specific embodiments listed below, the embodiments produced by combining these embodiments with other compound synthesis methods, and equivalent alternatives well known to those skilled in the art, and are also commercially available. Preferred embodiments include, but are not limited to, the embodiments of the present disclosure. It will be apparent to those skilled in the art that various changes and modifications can be made to the specific embodiments of the present disclosure without departing from the spirit and scope of the present disclosure.

Example 1 Synthesis of 18-BHP-ODMA and 18-BHP-ODEA (FIG. 1)

1.1 Synthesis of 18-BHP

[0056] BHP (10.05 g, 75 mmol), 4-dimethylaminopyridine (DMAP, 0.3 g, 2.5 mmol), and triethylamine (23.6 mL, 170 mmol) were added to a round-bottomed flask with 200 mL of anhydrous THF. In an ice bath, stearyl chloride (49.98 g, 165 mmol) was slowly added dropwise. After the dropwise addition was completed, warming was conducted to room temperature, and stirring was conducted for 24 h. After the reaction was completed, the THF in the system was removed through rotary evaporation. A residue was dissolved with 250 mL of dichloromethane, washed with 1 M dilute hydrochloric acid (80 mL2), deionized water (80 mL3), and a saturated sodium chloride solution (80 mL3), and dried with anhydrous magnesium sulfate. All solvents were removed through rotary evaporation. Recrystallization was conducted with acetone as a solvent to produce a white solid. The white solid was placed overnight in a vacuum chamber. The white solid was the product 18-BHP (49.64 g, yield: 89.7%).

1.2 Synthesis of 18-BHP-DMA

[0057] 18-BHP (3 g, 4 mmol), DMAP (49 mg, 0.4 mmol), and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC, 1.53 g, 8 mmol) were added to a round-bottomed flask, 50 mL of dichloromethane was added, and stirring was conducted for 15 min. N,N-dimethylethanolamine (357 mg, 4 mmol) was added, and stirring was conducted overnight. After a reaction was completed, a reaction solution was washed with deionized water (50 mL 2) and a saturated sodium chloride solution (50 mL 2), dried with anhydrous magnesium sulfate, concentrated through rotary evaporation, and subjected to separation through silica gel-based column chromatography with an n-hexane solution including 50% of ethyl acetate as a mobile phase. An eluate was spin-dried and concentrated, and placed overnight in a vacuum chamber to produce a white solid, which was the product 18-BHP-DMA (1.93 g, yield: 58.1%).

1.3 Synthesis of 18-BHP-DEA

[0058] 18-BHP (3 g, 4 mmol), DMAP (49 mg, 0.4 mmol), and EDC (1.53 g, 8 mmol) were added to a round-bottomed flask, 50 mL of dichloromethane was added, and stirring was conducted for 15 min. N,N-diethylethanolamine (468 mg, 4 mmol) was added, and stirring was conducted overnight. After the reaction was completed, the reaction solution was washed with deionized water (50 mL2) and a saturated sodium chloride solution (50 mL2), dried with anhydrous magnesium sulfate, concentrated through rotary evaporation, and subjected to separation through silica gel-based column chromatography with an n-hexane solution including 30% of ethyl acetate as a mobile phase. An eluate was spin-dried and placed overnight in a vacuum chamber to produce a white solid, which was the product 18-BHP-DEA (2.11 g, yield: 61.5%).

1.4 Synthesis of 18-BHP-ODMA or 18-BHP-ODEA

[0059] 18-BHP-DMA (1.11 g, 1.5 mmol) or 18-BHP-DEA (1.15 g, 1.5 mmol) was added to a round-bottomed flask with 5 mL of dichloromethane. Then meta-chloroperoxybenzoic acid (0.31 g, 1.8 mmol) was dissolved in 5 mL of dichloromethane and slowly added dropwise to a solution produced above in an ice bath. After the dropwise addition was completed, the ice bath was removed, and the reaction was further allowed for 3 h. After the reaction was completed, the reaction solution was subjected to separation through basic aluminum oxide-based column chromatography with a dichloromethane solution including 10% of methanol as a mobile phase. An eluate was spin-dried and placed overnight in a vacuum chamber to produce a white solid, which was the product 18-BHP-ODMA (1.04 g, yield: 92.0%) or 18-BHP-ODEA (1.12 g, 95.1%).

[0060] 18-BHP could react directly with 2-(N-oxide-N,N-dimethyl) ethanol or 2-(N-oxide-N,N-dicthyl) ethanol to prepare 18-BHP-ODMA or 18-BHP-ODEA. Proton nuclear magnetic resonance spectroscopy or MALDI-TOF-MS characterization results of 18-BHP-ODMA or 18-BHP-ODEA were shown in FIG. 2 to FIG. 4.

[0061] The stearyl chloride in the step 1.1 could be replaced with an equal molar mass of palmitoyl chloride, myristoyl chloride, or lauroyl chloride to produce an intermediate X-BHP (X represents a carbon chain length) with a carbon chain length of 16, 14, or 12. Then the 18-BHP in the step 1.2 or 1.3 was replaced with an equal molar mass of X-BHP, and/or the ethanolamine in the step 1.2 or 1.3 was replaced with an equal molar mass of N,N-dibutylethanolamine (DBU) or 4-(2-hydroxyethyl) pyridine (PY). Finally, according to the step 1.4, oxidation was conducted to produce lipids X-BHP-ODMA, X-BHP-ODEA, X-BHP-ODBU, and X-BHP-OPY with different carbon chain lengths and different tertiary amine N-oxide groups.

Example 2 Preparation of Tertiary Amine N-Oxide Group-Containing Liposomes (Liposomes Prepared from Amphiphilic Lipids Including Tertiary Amine N-Oxide Groups)

[0062] 10 mg of 18-BHP-ODMA or 18-BHP-ODEA, and 2.5 mg of cholesterol and/or 2.5 mg of D--tocopheryl polyethylene glycol succinate were weighed and added to a flask, 9 mL of trichloromethane and 1 mL of methanol were added, and an ultrasonic treatment was conducted for dissolution. Rotary evaporation was conducted under reduced pressure to form a dry lipid membrane on a wall of the flask. Then 5 mL of PBS was added, and hydration was allowed at room temperature for 1 h. Finally, the resulting solution was filtered through the membrane (200 nm) to produce a blank tertiary amine N-oxide group-containing liposome, which was named ODML or ODEL.

[0063] The 18-BHP-ODMA or 18-BHP-ODEA could be replaced with other tertiary amine N-oxide group-containing lipids (at an equal molar mass) in Example 1 to produce other tertiary amine N-oxide group-containing liposomes.

Example 3 Preparation of Fluorescently-Labeled Tertiary Amine N-Oxide Group-Containing Liposomes

[0064] 10 mg of 18-BHP-ODMA or 18-BHP-ODEA, 2.5 mg of cholesterol and/or 2.5 mg of D--tocopheryl polyethylene glycol succinate, and 100 g of DiI or DiR were weighed and added to a flask, 9 mL of trichloromethane and 1 mL of methanol were added, and an ultrasonic treatment was conducted for dissolution. Rotary evaporation was conducted under reduced pressure to form a dry lipid membrane on the wall of the flask. Then 0.5 mL of the prepared 7-ethyl-10-hydroxycamptothecin/irinotecan nanoparticles and 4.5 mL of PBS were added, and hydration was allowed at room temperature for 1 h. The free fluorescent molecules were removed through the separation of a sephadex column. Accordingly, a DiI or DiR-labeled nitrogen oxide-containing liposome .sup.DiIODML, .sup.DiIODEL, .sup.DiRODML, or .sup.DiRODEL was produced.

Example 4

[0065] The preparation of tertiary amine N-oxide group-containing liposomes loaded with 7-ethyl-10-hydroxycamptothecin/irinotecan nanoparticles and the preparation of 7-ethyl-10-hydroxycamptothecin/irinotecan nanoparticles (SC) were conducted with reference to the literature (Hu et al., Journal of Controlled release, 2015, 220, 175-179).

[0066] 10 mg of 18-BHP-ODMA or 18-BHP-ODEA, and 2.5 mg of cholesterol and/or 2.5 mg of D--tocopheryl polyethylene glycol succinate were weighed and added to a flask, 9 mL of trichloromethane and 1 mL of methanol were added, and an ultrasonic treatment was conducted for dissolution. Rotary evaporation was conducted under reduced pressure to form a dry lipid membrane on the wall of the flask. Then 0.5 mL of the prepared 7-ethyl-10-hydroxycamptothecin/irinotecan nanoparticles and 4.5 mL of PBS were added, and hydration was allowed at room temperature for 1 h. The unloaded 7-ethyl-10-hydroxycamptothecin/irinotecan nanoparticles were removed through the separation of a sephadex column. Accordingly, a tertiary amine N-oxide group-containing liposome loaded with 7-ethyl-10-hydroxycamptothecin/irinotecan was produced, which was named ODMLSC or ODELSC.

[0067] Particle size distribution patterns of ODML, ODEL, ODMLSC, and ODELSC were shown in FIG. 5.

Test Example 1 Stability Testing for Liposomal Formulations

[0068] 1 mL of each liposome solution in Example 4 was pipetted and added to 4 mL of deionized water, PBS, HEPES, DMEM, or fetal bovine serum (FBS), and incubated under shaking at 37 C. and 100 rpm for 24 h. Then the particle size of a liposome was determined by a dynamic light scattering (DLS) particle size analyzer. For long-term stability testing, each liposome was stored in a 4 C. freezer. A sample was collected at a set time point and tested for a particle size by DLS.

[0069] Test results were shown in FIG. 6 to FIG. 7. The nitrogen oxide-containing liposomes exhibit excellent stability in deionized water, PBS, HEPES, DMEM, or FBS, and can remain stable during long-term storage.

Test Example 2 Cytotoxicity Test

[0070] Cells were added at 5,000 cells/well to a 96-well plate. 100 L of a medium was added to each well. A culture was conducted for 24 h in a 37 C. incubator with a CO.sub.2 concentration of 5% and a humidity of 95%. 100 L of a drug was added at different concentrations to each well, including SC, ODMLSC, or ODELSC. A final concentration of a drug molecule in each well was an experimental design value. 100 L of a fresh medium was added in a blank group. After a culture was conducted for 48 h, centrifugation was conducted at 1,100 rpm for 6 min, and a medium in each well was discarded. 100 L of an MTT working solution was added, and a culture was continued for 3 h. Centrifugation was conducted at 3,300 rpm for 5 min, and the MTT working solution in each well was discarded. 100 L of dimethylsulfoxide (DMSO) was added, and shaking was conducted for 5 min to make crystals in each well fully dissolved. An absorbance of a sample at 562 nm was detected by a microplate reader. Each set of data was an average of results of three independent experiments for a same sample.

[0071] Test results were shown in FIG. 8. The tertiary amine N-oxide group-containing liposomes themselves have no significant toxicity at a cellular level and exhibit prominent biocompatibility, making these liposomes perfect drug delivery vehicles. Notably, ODMLSC or ODELSC shows much greater cytotoxicity than SC itself, and has a much smaller IC.sub.50 value than SC (Table 1), indicating that the tertiary amine N-oxide group-containing liposomes can increase the toxicity of loaded drugs to cells.

TABLE-US-00001 TABLE 1 IC.sub.50 values of SC, ODMLSC, or ODELSC in different cell lines (unit: g/mL) HepG2 HCT116 BxPC3 SC 0.98 0.27 5.76 0.31 0.40 0.02 ODMLSC 0.17 0.01 0.54 0.08 0.09 0.01 ODELSC 0.22 0.03 0.74 0.12 0.10 0.01

Test Example 3 Subcellular Distribution of Tertiary Amine N-Oxide Group-Containing Liposomes

[0072] 100,000 HepG2 cells were plated in a confocal dish and incubated overnight until adherent. Then the original medium was replaced with a fresh medium. 0.2 L of an endoplasmic reticulum or Golgi apparatus fluorescent dye was added, and incubation was conducted for 30 min. Then a nuclear fluorescent dye Hoechst was added, and incubation was further conducted for 15 min. Finally, .sup.DiIODML or .sup.DiIODEL was added with a final concentration of DiI in a medium being 0.5 g/mL, and incubation was conducted for 60 min. Images were acquired by a laser scanning confocal microscope, and a colocalization rate between liposomes and cellular microsomes was calculated with imageJ.

[0073] Test results were shown in FIG. 9 to FIG. 10. The distributions of .sup.DiIODML and .sup.DiIODEL in the endoplasmic reticulum or Golgi apparatus in HepG2 cells are almost identical, and the corresponding colocalization rates both are higher than 60%, indicating that the tertiary amine N-oxide group-containing liposomes can target the endoplasmic reticulum or Golgi apparatus of cells.

Test Example 4 Transcellular Transport of Liposomal Formulations

[0074] 100,000 HepG2 cells were plated in a confocal dish and incubated overnight until adherent. Then the original medium was replaced with a fresh medium. .sup.DiIODML or .sup.DiIODEL was added with a final concentration of DiI in a medium being 0.5 g/mL, and incubation was conducted for 6 h. Washing was conducted with PBS. Images were acquired by a laser scanning confocal microscope. 0.8 mL of a fresh medium was then added, and a culture was conducted for 12 h. A medium was collected to culture the second batch of cells for 12 h. Then washing was conducted with PBS (including 0.5 mg/mL of heparin). Images were acquired by a laser scanning confocal microscope. This process was repeated twice.

[0075] Test results were shown in FIG. 11. A strong DiI fluorescence signal can be observed in cells treated with .sup.DiIODML or .sup.DiIODEL in the first batch of dishes. The liposome is then partially expelled by cells and absorbed by cells in the second batch of dishes. This transcytosis continues until in the fourth batch of dishes in which a weak fluorescence signal still can be observed. It indicates that the tertiary amine N-oxide group-containing liposomes can effectively induce the transcellular transport.

Test Example 5 Plasma Clearance and Tissue Distribution of Tertiary Amine N-Oxide Group-Containing Liposomal Formulations

[0076] Female BALB/c nude mice bearing HepG2 subcutaneous tumors (about 70 mm.sup.3) were randomly divided into three groups with 3 mice in each group, and intravenously injected with DiR, .sup.DiRODML, or .sup.DiRODEL. 24 h later, blood was collected from the orbital veins of mice. 500 L of a blood sample was taken and tested by a small animal in vivo imaging instrument for a fluorescence intensity. Mice were dissected, and tissues such as a heart, a liver, a spleen, a lung, a kidney, an intestine, and a tumor were collected. Each tissue was detected by a small animal in vivo imaging instrument for a fluorescence intensity.

[0077] Test results were shown in FIG. 12 to FIG. 13. Almost no fluorescence signal is observed in the blood or tissues of mice in the DiR group. However, a strong DiR fluorescence signal can be observed in the blood or tissues of mice in the tertiary amine N-oxide group-containing liposome group. Quantitative statistics show that signal intensities of DiR in the blood, heart, liver, spleen, lung, kidney, intestine, and tumor of mice in the tertiary amine N-oxide group-containing liposome group all are much higher than those in the DiR group, indicating that the tertiary amine N-oxide group-containing liposome can prolong the blood circulation time of a loaded drug and increase the accumulation of a drug in a tumor tissue.

Test Example 6 Anti-Tumor Activity Test

[0078] Balb/c nude mice were subcutaneously injected with 210.sup.6 CT26 tumor cells. After a tumor grew to about 70 mm.sup.3, mice were divided into a blank control group, an SC group, an ODMLSC group, and an ODELSC group. The administration was conducted through tail vein injection every two days (Day 0, Day 2, Day 4, Day 6, and Day 8) at a dose of 10 mg/kg (SN38equivalent). After an administration cycle was completed, mice were further observed for 19 d.

[0079] Test results were shown in FIG. 14 to FIG. 15. FIG. 14 shows that ODMLSC or ODELSC exhibits a significantly-better anti-tumor effect than SC itself. Volumes of tumors in mice of the ODMLSC or ODELSC group increase slowly during the observation period, while tumors of mice in the SC group enter an exponential growth phase immediately after the administration is stopped. Mouse tumors collected on the day when the test was completed were weighed. Results show that a tumor inhibition rate of the tertiary amine N-oxide group-containing liposome of SN38/CPT-11 is as high as 90%, which is much higher than a tumor inhibition rate (10%) of the SN38/CPT-11 nanoparticle itself. FIG. 15 shows that there is no body weight reduction in mice of the tertiary amine N-oxide group-containing liposome group of SN38/CPT-11, indicating the high biosafety of the drug.

[0080] The tertiary amine N-oxide group-containing liposome has a clear structure, and can be synthesized through simple and efficient steps. A liposomal formulation based on the tertiary amine N-oxide group-containing liposome can significantly increase a therapeutic effect of a drug, is at a leading level in the art, and has a promising application prospect.

[0081] The above examples are merely preferred solutions of the present disclosure and are not intended to limit the present disclosure in any form, and other variations and modifications may be made without departing from the technical solutions as set forth in the appended claims.