A pH-sensitive curcumin nanoliposome, its preparation method and uses

Abstract

This invention discloses a pH-sensitive curcumin nanoliposome, its preparation method, and its applications. The preparation method includes the following steps: dissolving 1,2-dioleoyl-SN-glycerol-3-phosphoethanolamine, cholesterol succinate monoester, cholesterol, pH-sensitive material, and curcumin in an alcohol solvent to obtain an inner-phase alcohol solution; dissolving a lyophilization protectant in water to obtain an outer-phase aqueous solution; the inner-phase alcohol solution is compressed by the outer-phase aqueous solution to form a laminar flow and diffuses into the aqueous phase to form a narrow mixed solvent region. When the ethanol content in the mixed solvent region is lower than the ethanol content required for the original substances to dissolve in the ethanol phase, the lipids will self-assemble to form liposomes. The liposomes prepared by this invention have a spherical morphology, controllable size, and sustained-release properties in vitro, showing good application prospects as anti-tumor drug carriers in the field of drug delivery.

Description

Technical Field

[0001] This invention relates to a nanoliposome, its preparation method and uses, specifically to a pH-sensitive curcumin nanoliposome, its preparation method and uses. Background Technology

[0002] Curcumin (CUR) is a yellow polyphenolic compound derived from the turmeric plant. It is widely used to treat many types of diseases; however, its effectiveness is limited due to poor water solubility and low bioavailability. Liposomes have been extensively studied for many years and show considerable promise in the in vivo delivery of CUR. Studies have shown that liposomal CUR formulations have greater growth-inhibiting and apoptosis-promoting effects on cancer cells. Liposomes have been used for the delivery of anticancer drugs and can alter the biodistribution and clearance of drug molecules to improve therapeutic efficiency and reduce side effects. Due to the high-permeability long-retention (EPR) effect, nanoliposomes are more likely to accumulate at tumor sites, improving antitumor efficiency and reducing systemic toxicity. Therefore, the combination of CUR and liposomes should enhance the stability, bioavailability, targeting, and anticancer efficacy of CUR.

[0003] Microfluidic hydrodynamic focusing (MHF) involves introducing a lipid solution into the central channel of a microfluidic device and focusing the central flow using the flow of aqueous solutions in the side channels. Studies have shown that precise control of liposome size can be achieved by changing parameters such as the two-phase flow rates. Currently, there is no existing method for preparing curcumin liposomes that combines microfluidics, highlighting the urgent need for new ideas and methods for developing drug delivery systems. Summary of the Invention

[0004] Objectives of the invention: The present invention aims to provide a method for preparing pH-sensitive curcumin nanoliposomes that are uniform in size, controllable in size, biocompatible, and capable of targeted drug delivery; the second objective of the present invention is to provide pH-sensitive curcumin nanoliposomes prepared by the aforementioned method; the third objective of the present invention is to provide the application of the aforementioned pH-sensitive curcumin nanoliposomes in the preparation of curcumin targeted delivery sustained-release dosage forms.

[0005] Technical solution: The preparation method of pH-sensitive curcumin nanoliposomes according to the present invention includes the following steps:

[0006] (1) 1,2-dioleoyl-SN-glycerol-3-phosphorylethanolamine, cholesterol succinate monoester, cholesterol, pH-sensitive material, and curcumin are dissolved in an alcohol solvent to prepare an internal phase alcohol solution, wherein the 1,2-dioleoyl-SN-glycerol-3-phosphorylethanolamine, cholesterol succinate monoester, and cholesterol are lipid materials.

[0007] (2) Dissolve the freeze-drying protectant in water to prepare an external aqueous solution;

[0008] (3) An inner phase alcohol solution is introduced into the middle channel of the microfluidic chip device, and an outer phase aqueous solution is introduced into the outer channel of the microfluidic chip device. The middle alcohol solution is squeezed by the aqueous solutions on both sides to form a laminar flow and diffuses into the aqueous phase to form a narrow mixed solvent region. The alcohol content in the mixed solvent region decreases. When the ethanol content in the mixed solvent region is lower than the ethanol content required for the original substance to dissolve in the ethanol phase, the lipid environment changes from a soluble environment to an insoluble environment, which promotes the self-assembly of lipid molecules into bilayer growth and bending until it is completely closed and forms a spherical structure, forming a liposome. At the same time, the pH-sensitive material and curcumin are wrapped in the lipid bilayer.

[0009] Preferably, the liposome solution obtained in step (3) is rotary evaporated to remove the organic solvent ethanol in the solution to obtain a liposome suspension. The liposome suspension is then freeze-dried to obtain liposome lyophilized powder.

[0010] Preferably, the molar ratio of 1,2-dioleoyl-SN-glycerol-3-phosphoethanolamine, cholesterol monosuccinate, and cholesterol in step (1) is 6-8:3-5:1-3.

[0011] Preferably, the mass concentration of 1,2-dioleoyl-SN-glycerol-3-phosphoethanolamine, cholesterol monosuccinate, and cholesterol in the inner phase alcohol solution in step (1) is 1% to 2%.

[0012] Preferably, the pH-sensitive material in step (1) is poly(4-vinylpyridine) with a mass concentration of 0.05% to 0.15% in the inner phase alcohol solution.

[0013] Preferably, the mass concentration of curcumin in the inner phase alcohol solution in step (1) is 0.05% to 0.15%.

[0014] Preferably, the freeze-drying protectant in step (2) is sucrose, and the mass ratio of sucrose to the lipid material used in the inner phase alcohol solution in step (1) is 1:1 to 7.5:1.

[0015] Preferably, the microfluidic chip device in step (3) is self-made, and the components include: an inner phase capillary, a collecting capillary, a square capillary, a dispensing needle, a stainless steel tube, and a glass slide.

[0016] The method for assembling the device is as follows:

[0017] Cylindrical capillaries with an inner diameter of 0.55 mm and an outer diameter of 0.96 mm were selected and drawn using a needle puller. The resulting fracture point formed a conical constriction. The drawn capillaries were then ground to a conical diameter of 60–200 μm using a needle grinder to create the inner phase capillaries, and further ground to a diameter of 450–500 μm to create the collecting capillaries. Finally, the capillaries were ultrasonically cleaned in an ethanol solution for later use. A square capillary with an inner diameter of 1.02 mm and an outer diameter of 1.5 mm was selected and fixed in the center of a glass slide. The inner phase capillaries were then... The inner phase capillary and the collecting capillary are inserted into the square capillary with their conical ends facing each other. Observation under a microscope is performed to ensure that the distance between the two conical ends is 100 μm and that they are located in the center of the square capillary. A stainless steel tube is fitted onto the part of the capillary extending out of the glass slide at both ends, so that the stainless steel tube extends beyond the edge of the glass slide and is fixed. An 18G dispensing needle is selected and fixed at the interface between the inner phase capillary and the square capillary as the inner phase inlet. AB glue is used to seal all positions except the inner phase inlet, outer phase inlet, and outlet to ensure that the device does not leak.

[0018] Preferably, in the microfluidic chip device described in step (3), the total flow rate of the inner phase alcohol solution and the outer phase aqueous solution is 100 to 1000 μL / min, and the flow rate ratio of the inner phase alcohol solution to the outer phase aqueous solution is 1:1 to 1:30.

[0019] The pH-sensitive curcumin nanoliposomes prepared by the method described in this invention have a particle size of 150–170 nm, a particle size polydispersity index of 0.1–0.25, and a potential of -31.2–-26.9 mV.

[0020] The curcumin nanoliposomes described in this invention can be used in the preparation of curcumin targeted delivery sustained-release formulations.

[0021] Preferably, the nanoliposomes can maintain structural stability under the pH conditions of normal tissues and blood, reducing drug release. Under the pH conditions of the tumor cell microenvironment, the liposome skeleton dissolves, greatly increasing drug release and allowing anticancer drugs to accumulate in the tumor, thereby achieving targeted drug delivery.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The curcumin liposomes prepared by microfluidic fluid focusing method have a particle size of 150-170 nm and uniform size. This monodisperse liposome drug carrier can significantly improve the bioavailability of the drug, reduce toxic side effects, and improve the targeting of the treatment. The size of the liposomes can be precisely controlled by changing the flow parameters of each phase fluid; (2) The curcumin liposomes prepared by microfluidic fluid focusing method have a potential of -31.2 to -26.9 mV, the solution system is stable, and the in vitro release experiment also shows that the liposomes have sustained release effect and pH sensitivity, showing great application prospects in targeting the tumor microenvironment and precise drug delivery. Attached Figure Description

[0023] Figure 1 Diagram of a microfluidic chip device;

[0024] Figure 2 Diagram of the microfluidic platform being built;

[0025] Figure 3 The figure shows the effect of the two-phase flow ratio on the liposome particle size distribution.

[0026] Figure 4 The graph shows the effect of total flow rate of the two phases on the liposome particle size distribution.

[0027] Figure 5 Figure 1 shows the effect of the inner phase capillary outlet pore size on the liposome particle size distribution.

[0028] Figure 6 Figure showing the effect of curcumin dosage on liposome encapsulation efficiency and drug loading.

[0029] Figure 7 The graph shows the effect of sucrose dosage on liposome formulations.

[0030] Figure 8 This is a particle size distribution diagram of nanoliposomes;

[0031] Figure 9 Zeta potential diagram of nanoliposomes;

[0032] Figure 10 FTIR comparison images of curcumin, blank liposomes, physical mixtures, and curcumin nanoliposomes;

[0033] Figure 11 DSC comparison images of curcumin, blank liposomes, physical mixtures and curcumin nanoliposomes;

[0034] Figure 12 TEM image of curcumin nanoliposomes;

[0035] Figure 13This is a diagram showing the in vitro release results of curcumin nanoliposomes. Detailed Implementation

[0036] The technical solution of the present invention will be further explained below with reference to specific examples.

[0037] Example 1: Construction of a Microfluidic Platform

[0038] (1) Fabrication of a microfluidic chip device using fluid focusing method

[0039] Cylindrical capillaries with an inner diameter of 0.55 mm and an outer diameter of 0.96 mm were selected and drawn using a needle puller. The resulting fracture point formed a conical constriction. The drawn capillaries were then ground to a conical diameter of 60–200 μm using a needle grinder to create the inner phase capillaries, and further ground to a diameter of 450–500 μm to create the collecting capillaries. Finally, the capillaries were ultrasonically cleaned in an ethanol solution for later use. Square capillaries with an inner diameter of 1.02 mm and an outer diameter of 1.5 mm were selected and fixed to the center of a glass slide using AB glue. The inner phase capillaries were then... The conical ends of the tube and the collecting capillary are aligned and inserted into the square capillary from both sides. Microscopic observation is used to ensure the distance between the two conical ends is 100 μm and they are centered inside the square capillary. A stainless steel tube is fitted over the portion of the capillary extending beyond the slide, extending beyond the edge of the slide and secured with AB glue. An 18G dispensing needle is fixed above the interface between the inner phase capillary and the square capillary, serving as the inner phase inlet. AB glue is used to seal all areas except the inner phase inlet, outer phase inlet, and outlet to ensure the device is leak-proof. Thus, the fluid focusing microfluidic chip device is complete. The chip device is shown below. Figure 1 As shown.

[0040] (2) Building a microfluidic platform

[0041] After the AB adhesive has cured, place the microfluidic chip on the microscope stage and connect the microscope to a high-speed camera for observation in computer software. Aspirate the internal phase solution into a 1 mL sterile syringe and the external phase solution into a 10 mL sterile syringe. Secure the two syringes to two identical syringe pumps. Connect the syringe needles to the corresponding inlets of the microfluidic chip using PTFE tubing. Input the syringe model, flow rate, and other parameters into the syringe pump control panel. Collect the generated liposome solution using a conical flask. This completes the construction of the microfluidic platform. The microfluidic platform is as follows: Figure 2 As shown.

[0042] Example 2: Preparation of liposomes

[0043] (1) Preparation of two-phase solutions

[0044] Internal phase solution: Accurately weigh 1,2-dioleoyl-SN-glycerol-3-phosphoethanolamine, cholesterol succinate monoester, and cholesterol using an analytical balance. The molar ratio of the three lipids is 7:4:2, and the total mass concentration is 1% (w / v). Weigh poly(4-vinylpyridine) with a mass concentration of 0.1% (w / v) and a certain amount of curcumin with a mass concentration of 0.05%–0.15% (w / v). Dissolve the above substances in anhydrous ethanol, and complete dissolution can be achieved using ultrasound assistance to obtain the internal phase solution.

[0045] External phase solution: A certain amount of sucrose was weighed using an analytical balance, and its mass ratio with that of the lipid material in the internal phase solution was 1:1 to 7.5:1. The sucrose was dissolved in ultrapure water to prepare the external phase solution.

[0046] (2) Preparation of liposomes using microfluidic technology

[0047] The flow rates of the two-phase solutions were adjusted on two syringe pumps, and the inner and outer phase solutions were ejected from the syringes, passing through PTFE tubing to the chip. In the contact area between the two phases, the inner phase alcohol solution was squeezed into a thin stream by the outer phase aqueous solution, producing a significant laminar flow phenomenon. Along the direction of liquid flow, the width of the thin stream gradually widened. The two-phase fluids fell into a collection bottle through a collecting capillary. After collection, the fluid was transferred to a round-bottom flask in a rotary evaporator. The water bath temperature was set to 30°C, the rotation speed was adjusted to 60 r / min, and the rotary evaporation time was 3 min to remove the organic solvent ethanol from the solution, obtaining a liposome suspension.

[0048] Example 3: Investigating the effect of two-phase flow ratio on liposome particle size distribution

[0049] The internal and external phase solutions from Example 2 were selected, and the total flow rate (TFR) was controlled at 100 μL / min, 200 μL / min, 300 μL / min, and 1000 μL / min. Within each total flow rate, the flow rate ratio (FRR) of the internal phase to external phase (μL / min:μL / min) was adjusted to a gradient range of 1:1, 1:5, 1:10, 1:15, 1:20, 1:25, and 1:30. With the total flow rates of both phases being the same, the effect of the flow rate ratio on the liposome particle size distribution was investigated. The results are as follows: Figure 3 As shown in the curve trend, when the TFR is constant, the liposome particle size decreases with the increase of FRR.

[0050] Example 4: Investigating the effect of total two-phase flow rate on liposome particle size distribution

[0051] The internal and external phase solutions from Example 2 were selected, and different total flow rates were chosen: 50 μL / min, 100 μL / min, 150 μL / min, 200 μL / min, 250 μL / min, 300 μL / min, and 350 μL / min. Within each total flow rate, the flow ratio of the internal and external phases was adjusted to 1:10. With the same flow ratio, the effect of the total flow rate of the two phases on the liposome particle size distribution was investigated. The results are as follows: Figure 4 As shown, combined with Figure 3 Analysis revealed that when the total liposome velocity (TFR) varies within a small range (100–300 μL / min), under the same free liposome velocity (FRR), TFR has little effect on liposome size. When FRR varies within 1–30, the resulting liposomes range from 80 to 300 nm. However, when the TFR value is higher (1000 μL / min), the effect of TFR on liposome size becomes more apparent. Compared to the case where TFR is between 100 and 300 μL / min, increasing TFR leads to an increase in liposome size. However, when FRR exceeds 20, the difference decreases, and the smaller the FRR, the more significant the difference. Furthermore, a higher TFR results in a larger and less stable range of liposome sizes. When TFR is between 100 and 300 μL / min and FRR is between 10 and 15, the resulting liposomes have a size less than 200 nm.

[0052] Example 5: Investigating the effect of the inner phase capillary outlet pore size on liposome particle size distribution

[0053] The internal and external phase solutions from Example 2 were selected, and four internal phase capillaries with conical diameters of 200 μm, 150 μm, 100 μm, and 60 μm were chosen. Except for the tip aperture, all other details of the microfluidic chip device were identical. The internal-external phase flow rate ratio was set to 1:15, and the results are as follows: Figure 5 As shown, when the tip diameter decreases from 200 μm to 60 μm, the liposome size decreases from 165 nm to 142 nm. Furthermore, when the pore size is 100 μm and 60 μm, the PDI is smaller, both below 0.1, and the particle size distribution is narrower, which better meets the requirements for liposome production.

[0054] Example 6: Investigating the effect of curcumin dosage on liposome encapsulation efficiency and drug loading.

[0055] A microfluidic chip device with an inner-phase capillary outlet pore size of 100 μm was selected. The inner and outer phase solutions from Example 2 were used, wherein the molar ratio of 1,2-dioleoyl-SN-glycerol-3-phosphoethanolamine, cholesterol succinate monoester, and cholesterol was 7:4:2, with a total concentration of 1% (w / v). The concentration of poly(4-vinylpyridine) was 0.1%, and the concentrations of curcumin were 0.05% (w / v), 0.08% (w / v), 0.1% (w / v), 0.13% (w / v), and 0.15% (w / v), respectively. The inner-phase flow rate ratio was set to 1:15 to investigate the effect of curcumin dosage on liposome encapsulation efficiency and drug loading. The results are as follows: Figure 6 As shown, when the curcumin concentration was 1 mg / mL, the encapsulation efficiency of the liposomes reached 85.3%, and the drug loading reached 7.2%, both of which were at a relatively high level. When the curcumin concentration exceeded 1 mg / mL, both the encapsulation efficiency and the drug loading showed a decreasing trend. Taking all factors into consideration, an concentration of 1 mg / mL was selected.

[0056] Example 7: Investigating the effect of sucrose dosage on liposome formulations

[0057] The inner phase alcohol solution used in Example 2 was selected: the total lipid concentration was 1% (w / v), the poly(4-vinylpyridine) concentration was 0.1% (w / v), and the curcumin concentration was 0.1% (w / v). The ratio of sucrose mass to total lipid mass in the outer phase aqueous solution was 1:1, 2.5:1, 3:1, 5:1, and 7.5:1, respectively. The inner and outer phase flow rate ratio was 1:15, and the inner phase capillary outlet diameter was 100 μm. The effect of sucrose dosage on the liposome formulation was investigated. The results are as follows: Figure 7 As shown, with the increase of the mass ratio of sucrose to lipid material, the liposome particle size decreases, and the encapsulation efficiency (EE%) of the liposomes first increases and then decreases, reaching its maximum when the sucrose:lipid (W / W) ratio is 3. If the sugar-lipid ratio is too small (1:1) or too large (7.5:1), the encapsulation efficiency is low, and the state of the lyophilized powder is not uniform, with particulate matter present. Therefore, a sugar-lipid ratio of 3:1 was chosen.

[0058] Example 8: Characterization analysis of liposomes

[0059] Based on the above examples, liposomes prepared under optimal conditions were selected for characterization and analysis: In Example 2, the concentrations of the inner phase solution were: total lipid concentration 1% (w / v), poly(4-vinylpyridine) 0.1% (w / v), CUR 0.1% (w / v), and the mass ratio of sucrose to lipid material in the outer phase solution was 3:1. The capillary outlet diameter of the inner phase was 100 μm, and the flow rate of the inner and outer phase solutions was 1:15. After the liposome solution was collected, the organic solvent ethanol was removed by rotary evaporation at 30°C and 60 r / min for 3 min to obtain a liposome suspension.

[0060] (1) Particle size distribution and zeta potential

[0061] Particle size distribution and zeta potential were measured using an Anton Paar laser particle size analyzer. Results are as follows: Figure 8 and Figure 9 As shown.

[0062] The liposomes had a particle size of 165 nm and a PDI of 0.099, indicating uniform size and concentrated particle size distribution. The zeta potential was -31.2 mV, demonstrating sufficiently strong electrostatic repulsion between the liposomes and a highly stable system.

[0063] (2)FTIR

[0064] The liposome suspension obtained in Example 8 was freeze-dried for 24 hours to obtain loose and fluffy lyophilized liposome powder. Curcumin raw material, blank lyophilized liposome powder, drug-loaded lyophilized liposome powder, and samples prepared directly by physical mixing of each component were prepared. An appropriate amount of the above sample powder was analyzed using Fourier transform infrared spectroscopy (FTIR) with a wavenumber range of 4000 cm⁻¹. -1 ~400cm -1 .

[0065] The results are as follows Figure 10 As shown, the characteristic absorption peak of curcumin is: ① 3506 cm⁻¹ -1 ① The stretching vibration peak of the phenolic hydroxyl group (OH) of curcumin; ② 1627 cm⁻¹ -1 ③ 1509 cm⁻¹ -1 ④ 1425cm -1 ⑤ 1280cm olefin CH bending vibration peak; -1 The peak observed was the CO stretching vibration peak of aromatic hydrocarbons. The FTIR spectrum of the drug-loaded liposomes showed the main peak (2927 cm⁻¹) of the blank liposomes. -1 1051cm -1 ) and the main peak of curcumin (1733cm) -1 1510cm -1 The carbon-carbon stretching vibration peak within the benzene ring of curcumin shifted, suggesting a certain degree of interaction between curcumin and the carrier. The infrared spectrum of the drug-loaded liposomes differed from that of the physical mixture of the components, indicating that the prepared drug-loaded liposomes were not simply a mixture of the components. These results confirm the successful encapsulation of curcumin.

[0066] (3) DSC

[0067] The liposome suspension obtained in Example 8 was freeze-dried for 24 hours to obtain loose and fluffy lyophilized liposome powder. Curcumin raw material, blank lyophilized liposome powder, drug-loaded lyophilized liposome powder, and samples prepared directly by physical mixing of each component were prepared. Appropriate amounts of the above sample powders were placed in crucibles, and differential scanning calorimetry was used to detect the samples within the range of 25℃ to 325℃.

[0068] The results are as follows Figure 11 As shown, the melting point peak of curcumin active pharmaceutical ingredient is at 185℃; the blank liposome carrier exhibits a broad endothermic peak between 216℃ and 246℃; in the spectra of samples directly prepared by physical mixing of components, the characteristic peaks of both the active pharmaceutical ingredient and the carrier are present; however, the spectrum of curcumin nanoliposomes only contains the broad endothermic peak of the carrier, and the melting point peak of curcumin disappears. This indicates that curcumin is dispersed in an amorphous state within the liposomes, and that there is a certain interaction between the two.

[0069] (4) TEM

[0070] The liposome suspension obtained in Example 8 was subjected to negative staining. The suspension was dropped onto a copper grid with a supporting membrane, and after precipitation for 1 minute, the liquid was absorbed by filter paper. Uranium acetate or phosphotungstic acid was then used as the negative staining solution, dropped onto the copper grid, and after precipitation for 1 minute, the liquid was absorbed by filter paper. After drying at room temperature, electron microscopy was performed at 80 kV for imaging. The obtained electron microscopy results are as follows: Figure 12 As shown, the liposome particle size ranges from 150 to 170 nm, which is consistent with the particle size results obtained using DLS technology. It can be seen that the liposomes are regular, round vesicles with a distinct core-shell bilayer structure. The shell is composed of a lipid bilayer, and poly(4-vinylpyridine) is bound into the lipid bilayer, improving the strength and stability of the liposome structure.

[0071] Example 9: In vitro release of liposomes

[0072] (1) Establishment of the standard curve for curcumin

[0073] A certain mass of curcumin was weighed, dissolved in anhydrous ethanol, and transferred to a volumetric flask. The solution was then diluted to volume with PBS buffer (pH 7.4) to obtain a curcumin stock solution. A UV-Vis spectrophotometer was used to perform a full wavelength scan within the range of 200–800 nm to determine that the maximum absorption wavelength of curcumin in the ethanol-PBS buffer was 425 nm. The curcumin stock solution was used to prepare a series of standard solutions. The absorbance was measured at 425 nm. A standard curve was plotted with concentration on the x-axis and absorbance on the y-axis. Using the same principle, standard curves for curcumin at pH 6.8 and pH 5.0 were established to eliminate errors caused by different background solutions.

[0074] The equation of the standard curve is as follows:

[0075] pH=7.4, y=0.19386x+0.01131, R2=0.99988;

[0076] pH=6.5, y=0.18194x+0.01021, R2=0.99981;

[0077] pH=5.0, y=0.17466x+0.00756, R2=0.99998.

[0078] (2) In vitro drug release studies using liposomes

[0079] Ethanol-PBS buffer solutions with pH values ​​of 5.0, 6.5, and 7.4 were used as release media. Two mL of the liposome suspension prepared in Example 8 was pipetted into a treated dialysis bag, which was then placed in one of the three release media. The entire system was placed on a constant-temperature shaker at 37°C and 100 rpm, and absorbance was measured at various time points. The results are as follows: Figure 13 As shown, the liposome release differed significantly under the three pH conditions. At pH 7.4 and 6.5, curcumin release was slow and minimal, with cumulative release rates of 21.90% and 38.90% over 24 hours, respectively. At pH 5.0, the release rate accelerated, with a cumulative release rate of 84.50% over 24 hours, while also exhibiting sustained-release characteristics. Therefore, the curcumin nanoliposomes of this invention can sustainably release drugs under specific pH conditions, achieving targeted delivery.

Claims

1. A method for preparing pH-sensitive curcumin nanoliposomes, characterized in that, Includes the following steps: (1) 1,2-Dioleoyl-SN-glycerol-3-phosphorylethanolamine, cholesterol succinate monoester, cholesterol, pH-sensitive material, and curcumin are dissolved in an alcohol solvent to prepare an internal phase alcohol solution, wherein the 1,2-dioleoyl-SN-glycerol-3-phosphorylethanolamine, cholesterol succinate monoester, and cholesterol are lipid materials. The molar ratio of 1,2-dioleoyl-SN-glycerol-3-phosphoethanolamine, cholesterol succinate monoester, and cholesterol is 6~8:3~5:1~3. The total mass concentration of 1,2-dioleoyl-SN-glycerol-3-phosphoethanolamine, cholesterol succinate monoester, and cholesterol in the inner phase alcohol solution is 1%~2%. The mass concentration of the pH-sensitive material is 0.05%~0.15%, and the mass concentration of curcumin is 0.05%~0.15%. The pH-sensitive material is poly(4-vinylpyridine). (2) Dissolve the freeze-drying protectant in water to prepare an external aqueous solution. The freeze-drying protectant is sucrose, and its mass ratio with the lipid material used in the inner phase alcohol solution is 2:1 to 4:

1. (3) An inner-phase alcohol solution is introduced into the middle channel of the microfluidic chip device, and an outer-phase aqueous solution is introduced into the outer channel of the microfluidic chip device. The middle alcohol solution is squeezed by the aqueous solutions on both sides to form a laminar flow and diffuses into the aqueous phase to form a narrow mixed solvent region. The alcohol content in the mixed solvent region decreases, and lipids self-assemble to form liposomes. At the same time, the pH-sensitive material and curcumin are encapsulated in the lipid bilayer. The microfluidic chip device includes: an inner phase capillary, a collecting capillary, a square capillary, a dispensing needle, a stainless steel tube, and a glass slide. The square capillary is fixed in the center of the glass slide. The inner phase capillary and the collecting capillary are nested inside the square capillary with their conical openings facing each other. The dispensing needle is fixed at the interface between the inner phase capillary and the square capillary as the inner phase inlet. The two ends of the inner phase capillary and the collecting capillary that extend out of the glass slide are respectively fitted with a stainless steel tube as the outer phase inlet and outlet. The total flow rate of the two-phase solution in the microfluidic chip device is 100~300 μL / min, and the flow rate ratio of the inner phase alcohol solution to the outer phase aqueous solution is 1:10~1:

15.

2. The method for preparing pH-sensitive curcumin nanoliposomes according to claim 1, characterized in that, The organic solvent in the liposome solution obtained in step (3) is removed by rotary evaporation to obtain a liposome suspension. The liposome suspension is then freeze-dried to obtain liposome lyophilized powder.

3. A curcumin nanoliposome prepared by the method according to any one of claims 1 to 2, characterized in that, The nanoliposomes have a particle size of 150~170 nm, a polydispersity index of 0.1~0.25, and a potential of -31.2~-26.9 mV.

4. The use of the curcumin nanoliposomes according to claim 3 in the preparation of a curcumin-targeted delivery sustained-release dosage form, characterized in that, The drug is used for anti-tumor purposes.

5. The use according to claim 4, characterized in that, The curcumin nanoliposomes are pH sensitive and can specifically release drugs in the tumor microenvironment, reducing the damage of drugs to normal physiological tissues.

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