Supercritical anti-solvent-electrostatic spraying coupling system

Abstract

The invention relates to a supercritical anti-solvent-electrostatic spray coupling system which comprises a supercritical anti-solvent generation module, a material mixing module and an electrostatic atomization module which are sequentially connected through a connecting pipeline, and a time-space synchronization control module which is in communication connection with the supercritical anti-solvent generation module and the electrostatic atomization module. The space-time synchronous control module cooperatively controls the oscillating electric field and the pressure of the supercritical anti-solvent, so that the electric field jet breaking of the material is realized by the electric field force, and the absolute value of the difference value between the Taylor cone forming time and the supercritical anti-solvent diffusion time is controlled within a set range, so that the supercritical anti-solvent permeates into liquid drops within a millisecond-level time scale; the invention discloses a preparation method of brain-targeted nano-particles, which comprises the following steps: dissolving a solvent in a solvent to trigger a sudden drop effect of polarity of the solvent, so that solute is instantaneously crystallized, and finally a nano-suspension with a particle size of less than 200nm and uniform particle size distribution (PDilt: 0.2) is formed, is suitable for preparing brain-targeted nano-particles with high drug loading capacity and small particle size, and can effectively cross a blood-brain barrier (BBB) to realize continuous and green production.

Description

Technical Field

[0001] This invention relates to the interdisciplinary field of supercritical fluid engineering and nanopharmaceutical equipment, and in particular to a supercritical antisolvent-electrostatic spray coupling system. Background Technology

[0002] The preparation of brain-targeting nanoparticles must address the issue of particle size control across the blood-brain barrier (BBB).

[0003] Existing brain-targeting nanoparticle preparation technologies mainly employ microfluidic collision technology, such as Chinese patent CN102883798B. This technology relies on temperature / flow rate to control particle size, resulting in brain-targeting nanoparticles with a minimum particle size >200 nm, which cannot meet the sub-200 nm threshold for brain-targeted delivery. At the same time, it lacks an electric field control mechanism, resulting in a wide particle size distribution (PDI > 0.3), leading to low BBB penetration efficiency. Summary of the Invention

[0004] Based on this, the purpose of the present invention is to provide a supercritical antisolvent-electrostatic spray coupling system to solve the problem that the particle size and particle size distribution of the prepared brain-targeting nanoparticles cannot meet the requirements of BBB.

[0005] A supercritical antisolvent-electrostatic spray coupling system includes: a supercritical antisolvent generation module, a material mixing module, and an electrostatic atomization module connected sequentially by connecting pipes. The electrostatic atomization module includes a resonant circuit and an insulating ceramic nozzle placed in the resonant electric field of the resonant circuit, and a spatiotemporal synchronization control module communicatively connected to the supercritical antisolvent generation module and the resonant circuit. The spatiotemporal synchronization control module includes a data acquisition unit and a controller. The data acquisition unit includes a charge density sensor and a high-speed camera installed at the material outlet of the insulating ceramic nozzle, used to collect the surface charge density of the droplets. Droplet radius r, Taylor cone formation time And pressure and temperature sensors installed at the supercritical antisolvent injection port of the insulating ceramic nozzle, used to collect the pressure of the supercritical antisolvent. The controller includes a data acquisition unit, an electric field control unit, and a pressure control unit, with respect to temperature T; wherein: The data acquisition unit is used to acquire the surface charge density of the droplets. Droplet radius r, Taylor cone formation time Density of supercritical antisolvent ; The electric field control unit is used to determine the surface charge density of the droplet. Is it greater than or equal to the set surface charge density threshold? : If not, adjust the input voltage of the resonant circuit until... ≥ ; a pressure control unit configured to calculate a difference between a Taylor cone formation time and a supercritical anti-solvent diffusion time according to a droplet radius r, a density of the supercritical anti-solvent ; and calculate the supercritical anti-solvent diffusion time an absolute value of the difference ; determine whether the absolute value of the difference is less than or equal to a set timing mismatch threshold value : : If not, adjust the pressure and flow rate of the supercritical anti-solvent until ≤ .

[0006] Compared with the prior art, the supercritical anti-solvent-electrostatic spray coupling system according to the present application utilizes crystallization kinetics, cooperatively controls the oscillating electric field and the supercritical anti-solvent pressure by using a space-time synchronization control module, so that the electric field force provided by the oscillating electric field realizes the electric field jet breakup of the material, the absolute value of the difference between the Taylor cone formation time and the supercritical anti-solvent diffusion time is within a set range, the supercritical anti-solvent penetrates into the inside of the droplet within a millisecond time scale to cause the solvent polarity to drop suddenly, the solute is instantaneously crystallized, and under the dual synergy of the oscillating electric field and the rapid diffusion of the supercritical fluid, a nanosuspension with a particle size of less than 200 nm and a uniform particle size (PDI < 0.2) is finally formed. The preparation of brain-targeting nanoparticles with high drug loading and small particle size which can cross the blood-brain barrier (BBB) can be realized. The coupling system can be used for continuous and green production, and is especially suitable for the manufacture of brain-targeting delivery systems for liposoluble drugs such as nervonic acid.

[0007] Further, the density of the supercritical anti-solvent is calculated according to the pressure and temperature of the supercritical anti-solvent by using a Peng-Robinson state equation:

[0008] In the formula, P represents the pressure of the supercritical anti-solvent, M represents the molar mass of the anti-solvent, Z represents the compressibility factor, R represents the ideal gas constant, and T represents the temperature of the supercritical anti-solvent.

[0009] Further, the supercritical anti-solvent diffusion time satisfies:

[0010] In the formula, r represents the droplet radius, and D represents the diffusion coefficient of the supercritical anti-solvent with a density of .

[0011] ​​Further, the diffusion coefficient of the supercritical anti-solvent is determined by the density of the supercritical anti-solvent The estimation is as follows:

[0012] wherein D0 represents a reference diffusion coefficient, T0 represents an absolute temperature, Tc represents a critical temperature of the anti-solvent, n represents a temperature index, A represents a constant related to the supercritical anti-solvent, represents the density of the supercritical anti-solvent.

[0013] Further, the time sequence mismatch threshold value is 0.2 ms to 0.3 ms.

[0014] Further, the supercritical anti-solvent generating module comprises a supercritical anti-solvent generating unit, the supercritical anti-solvent generating unit comprises an anti-solvent storage tank, an anti-solvent circulating tank, a first heat exchanger, a high-pressure piston pump and a second heat exchanger connected in sequence through an anti-solvent pipeline; the high-pressure piston pump is controlled to increase pressure through a PID controller, and the PID controller is in communication connection with a controller of the space-time synchronization control module.

[0015] Further, the high-pressure piston pump comprises a first high-pressure piston pump and a second high-pressure piston pump, the first high-pressure piston pump and the second high-pressure piston pump are arranged in parallel, and the high-pressure piston pump has a precision of ±0.1 mL / min.

[0016] Further, the insulating ceramic nozzle has a three-layer coaxial structure, comprising an inner channel for passing the material, a middle annular gap for passing the supercritical anti-solvent, and an outer shielding layer; wherein the inner channel is a zirconia ceramic.

[0017] Further, the resonant circuit comprises an LC oscillation circuit and a voltage feedback loop; wherein the voltage feedback loop dynamically adjusts the output voltage of the resonant circuit according to the signal of the charge density sensor.

[0018] Further, the material mixing module comprises a material tank and a reaction kettle connected with the material tank; the reaction kettle comprises a multi-stage settling tower, the multi-stage settling tower comprises a plurality of baffle plates, the gradient of each baffle plate is determined by the Stokes settling formula, and the gradient is used for separating particles with a particle size of 50 nm to 500 nm. wherein r is the droplet radius, g is the gravitational acceleration, Δp is the pressure difference, η is the material viscosity, and t is the settling time.

[0019] In order to better understand and implement, the present application is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1The schematic diagram of the supercritical anti-solvent-electrostatic spray coupling system of an embodiment of the present application; Figure 2 The cross-sectional schematic diagram of the insulating ceramic nozzle structure of the present application; Figure 3 The structural schematic diagram of the controller of the present application; Figure 4 The control flow schematic diagram of the controller of the present application. DETAILED DESCRIPTION

[0021] The technical solutions of the present application will be described in detail below with reference to the drawings of the embodiments of the present application.

[0022] The terms used in the embodiments of the present application are merely for the purpose of describing specific embodiments and are not intended to limit the embodiments of the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that "a plurality of" means two or more, unless otherwise specified. The term "and / or" used herein means and includes any or all possible combinations of one or more associated listed items. The present application proposes a supercritical anti-solvent-electrostatic spray coupling system, which uses the crystallization kinetics to adopt a space-time synchronous control module to cooperatively control the diffusion time of the supercritical anti-solvent to make the solvent polarity change suddenly, control the electric field force provided by the oscillating electric field to realize the electric field jet breakup, and realize the preparation of brain-targeting nanoparticles with high drug loading and small particle size that can cross the blood-brain barrier (BBB). The coupling system can be continuously and greenly produced, and is especially suitable for manufacturing brain-targeting delivery systems for liposoluble drugs such as nervonic acid.

[0023] Please refer to Figure 1 The supercritical anti-solvent-electrostatic spray coupling system of the present application includes a supercritical anti-solvent generation module 1, a material mixing module 2, an electrostatic atomization module 3, a material collection module 4, and a space-time synchronous control module 5. The supercritical fluid generated by the supercritical anti-solvent generation module 1 is injected into the material mixing module 2 and mixed with the prepared material for adjustment. The adjusted supercritical fluid carrying the material is injected into the electrostatic atomization module 3 for solvent polarity change and electric field jet breakup. The generated nanosuspension is collected by the physical collection module 40. The space-time synchronous control module 5 adjusts the flow rate of the supercritical anti-solvent and the oscillating electric field of the electrostatic atomization module 3 by monitoring the process of generating nanoparticles in the electrostatic atomization module 3 to make the generated nanosuspension meet the particle size requirements.

[0024] Specifically, the supercritical anti-solvent generation module 1 includes a supercritical anti-solvent generation unit 10 and an anti-solvent recovery unit 12.

[0025] The supercritical anti-solvent generating unit 11 comprises an anti-solvent tank 101, an anti-solvent circulating tank 102, a first heat exchanger 103, a high-pressure plunger pump 104, and a second heat exchanger 105 connected in sequence through an anti-solvent pipeline. The liquid anti-solvent in the anti-solvent tank 101 is mixed with the liquid anti-solvent recovered by the anti-solvent recovery unit 12, cooled and supercooled by the first heat exchanger 103, pressurized to a set pressure by the high-pressure plunger pump 104, and heated to a set temperature by the second heat exchanger 105, thereby forming supercritical anti-solvent.

[0026] The high-pressure plunger pump 104 is controlled by a PID controller to increase the pressure. Specifically, the PID controller obtains the pressure in the material mixing module 2 and controls the pressure adjustment of the high-pressure plunger pump 104 to ensure that the density of the supercritical anti-solvent in the material mixing module 2 meets the requirements. In an embodiment, the PID controller maintains the pressure in the material mixing module 2 to be 10 MPa±0.1 MPa, and the corresponding anti-solvent CO2 density is 0.75 g / cm3. The accuracy of the high-pressure plunger pump 104 meets ±0.1 mL / min.

[0027] Further, a gas supplement pump 106 is arranged on the anti-solvent pipeline between the anti-solvent tank 101 and the anti-solvent circulating tank 102, which is used to automatically increase the pressure of the liquid anti-solvent when the pressure of the liquid anti-solvent provided by the anti-solvent tank 101 is lower than a set threshold.

[0028] Further, the high-pressure plunger pump 104 comprises a first high-pressure plunger pump 104A and a second high-pressure plunger pump 104B, which are arranged in parallel to ensure the continuous, pulse-free, pulsatile, switchable, constant-pressure / constant-flow fluid supply capability of the supercritical anti-solvent generating unit 11.

[0029] Further, an anti-solvent adjusting tank 107 is arranged on the anti-solvent pipeline between the high-pressure plunger pump 104 and the second heat exchanger 105, which is used to store and supplement the high-pressure liquid anti-solvent.

[0030] The anti-solvent recovery unit 12 comprises a first recovery flow path 120 and a second recovery flow path 122.

[0031] The first recovery flow path 120 comprises a recovery buffer tank 1201, a third heat exchanger 1202, and a recovery pump 1203 connected in sequence through a recovery anti-solvent pipeline. The waste supercritical anti-solvent discharged from the material mixing module 2 is cooled and condensed into liquid anti-solvent by the third heat exchanger 1202 through the recovery buffer tank 1201, and is pumped into the anti-solvent circulating tank 102 by the recovery pump 1203.

[0032] The second recovery flow path 122 includes a fourth heat exchanger 1221. The gaseous antisolvent discharged through the material collection module 4 enters the fourth heat exchanger 1221 to cool and condense into liquid antisolvent before entering the antisolvent circulation tank 102.

[0033] The material mixing module 2 includes a material tank 20, a reaction vessel 22 connected to the material tank 20, and a waste storage tank 24.

[0034] The material tank 20 is used to store the prepared emulsion, which includes a highly lipid-soluble drug and its carrier.

[0035] The reactor 22 is used to mix, constrain, and settle the emulsion output from the material tank 20 and the supercritical antisolvent generated by the supercritical antisolvent generation unit 11.

[0036] Specifically, the reactor 22 includes an electrostatic focusing ring (not shown) and a multi-stage settling tower (not shown). The supercritical antisolvent carrying the material is atomized by the electrostatic focusing ring under a -5kV bias. The atomized beam enters the multi-stage settling tower under the influence of gravity and drag, separating the particles according to their size. The multi-stage settling tower includes multiple baffles, the gradient of which is determined by the Stokes sedimentation formula. It is used to separate particles with a size of 50 nm to 500 nm. The specific gradient spacing...

[0037] In the formula, r is the droplet radius, g is the gravitational acceleration, Δp is the pressure difference, η is the material viscosity, and t is the settling time.

[0038] In this embodiment, the separation layers of the baffles are: bottom layer >200nm, middle layer 80-200nm, and top layer <80nm.

[0039] The waste storage tank 24 is used to collect waste discharged from the material tank 20 and waste discharged from the buffer tank 1201.

[0040] Furthermore, the reactor 22 includes a first reactor 22A and a second reactor 22B. The inlets of the first reactor 22A and the second reactor 22B are connected by multiple switching valves, and the outlets of the first reactor 22A and the second reactor 22B are connected by several switching valves. By controlling the switching valves at the inlet and outlet, the first reactor 22A and the second reactor 22B can be connected in parallel or in series as needed. When the first reactor 22A and the second reactor 22B are connected in parallel, it can be used for applications with large fluid volumes; when connected in series, it can be used for applications with small fluid volumes. Setting up the first reactor 22A and the second reactor 22B allows one reactor to operate while the other is on standby / cleaning / scale-up, achieving "zero-downtime switchover" and "rapid expansion of the process window."

[0041] Further, a feed pump 24 is arranged on the connecting pipeline between the material tank 20 and the reaction kettle 22, for controlling the flow rate and pressure of the emulsion entering the reaction kettle 22.

[0042] The electrostatic atomization module 3 comprises an insulating ceramic nozzle 30 and a resonant circuit 32, and the insulating ceramic nozzle 30 is arranged in the resonant electric field of the resonant circuit 32.

[0043] Please refer to Figure 2 , Figure 3 The insulating ceramic nozzle 30 is a three-layer coaxial structure, comprising an inner layer channel 301, a middle layer annular gap 302 and an outer layer shielding layer 303 arranged in sequence from inside to outside.

[0044] The inner layer channel 301 comprises a material inlet 3011, a mixing cavity 3012, a plurality of material column pipes 3013, an adjusting cavity 3014 and a material outlet 3015 arranged in sequence from top to bottom along the Z-axis, wherein the plurality of material column pipes 3013 are arrayed vertically in the middle layer annular gap 302. The material carried by the supercritical anti-solvent output by the material mixing module 2 enters the mixing cavity 3012 through the material inlet 3011, disperses into the plurality of material column pipes 3013, and then passes through the adjusting cavity 3014 and the material outlet 3015 to output the nanosuspension. In this embodiment, the inner layer channel 301 is made of zirconia ceramic with a pressure strength ≥ 50 MPa.

[0045] The middle layer annular gap 302 comprises a supercritical anti-solvent injection port 3021 and a plurality of spiral flow guide grooves 3022 connected to the supercritical anti-solvent injection port. The inclination angle of the supercritical anti-solvent injection port 3021 satisfies 30°-45°, and the turbulent intensity is ≤ 5% when the flow rate is 15±0.3 L / min.

[0046] The outer layer shielding layer 303 is a grounded copper mesh that covers the piezoelectric ceramic oscillation layer 303, for suppressing arc discharge.

[0047] The resonant circuit 32 is electrically connected to a high-voltage power supply, which can output a 10 kV-30 kV±5% direct current voltage to the resonant circuit 32, so that the resonant circuit 32 can provide a 0.5 kHz-5 kHz oscillation electric field to suppress Ostwald ripening.

[0048] The resonant circuit 32 comprises an LC oscillation circuit and a voltage feedback loop. The voltage feedback loop dynamically adjusts the output voltage of the resonant circuit according to the signal of the charge density sensor.

[0049] In the embodiment, the parameters of the electronic elements of the LC oscillation circuit satisfy: inductance L = 10 mH, capacitance C = 2 μF, and the resonant frequency of the LC oscillation circuit satisfies f = 1.12 kHz.

[0050] The material collection module 4 comprises a crystallization kettle 41 and a gaseous anti-solvent recovery channel 42. The crystallization kettle 41 is used to collect the nanosuspension generated by the electrostatic atomization module 3. The gaseous anti-solvent recovery channel 42 passes the gaseous anti-solvent separated by the electrostatic atomization module 3 into the fourth heat exchanger 1221 of the second recovery flow path 122.

[0051] The time-space synchronous control module 5 comprises a data acquisition unit 51 and a controller 52. The controller 52 adjusts the pressure, flow rate of the supercritical anti-solvent and the input voltage of the resonant circuit 32 according to the data collected by the data acquisition unit 51, so that the particle size of the nanosuspension generated by the electrostatic atomization module 3 meets the requirements of the brain-targeting nanoparticles crossing the blood-brain barrier (BBB).

[0052] The data acquisition unit 51 comprises a charge density sensor 511, a high-speed camera 512, a pressure sensor 513 and a temperature sensor 514.

[0053] The charge density sensor 511 is arranged at the material outlet 3015 and is used to collect the surface charge density of the droplets. The charge density is transmitted to the controller 52.

[0054] The high-speed camera 512 is arranged at the material outlet 3015 and is used to collect the Taylor cone formation time , the droplet radius r, and the Taylor cone formation time , the droplet radius r are transmitted to the controller 52. The high-speed camera 512 satisfies 10 6 frames per second. The droplet radius r is obtained according to an image analysis technique. Existing machine learning models and deep learning models for calculating the size of a measured object based on image analysis can be used, such as YOLO, SSD and Mask R-CNN, etc.

[0055] The pressure sensor 513 is arranged at the supercritical anti-solvent injection port 3021 and is used to collect the pressure of the supercritical anti-solvent, and the pressure is transmitted to the controller 52.

[0056] The temperature sensor 514 is arranged at the supercritical anti-solvent injection port 3021 and is used to collect the temperature of the supercritical anti-solvent, and the temperature is transmitted to the controller 52.

[0057] The controller 52 comprises a data acquisition unit 521, an electric field control unit 522 and a pressure control unit 523.

[0058] The data acquisition unit 521 is configured to execute step S10 of acquiring the droplet surface charge density , the droplet radius r, the Taylor cone formation time , and the density of the supercritical anti-solvent .

[0059] wherein the density of the supercritical anti-solvent is calculated according to the pressure and temperature of the supercritical anti-solvent by using the Peng-Robinson equation of state

[0060] wherein P represents the pressure of the supercritical anti-solvent, M represents the molar mass of the anti-solvent, Z represents the compressibility factor, R represents the ideal gas constant, and T represents the temperature of the supercritical anti-solvent.

[0061] By controlling the temperature and pressure of the supercritical anti-solvent, the density of the supercritical anti-solvent .

[0062] The electric field force control unit 522 is configured to execute step S20A of judging whether the droplet surface charge density is greater than or equal to a set surface charge density threshold : If not, the input voltage of the resonant circuit is adjusted until ≥ .

[0063] wherein the set surface charge density threshold is determined according to the surface tension of the material droplet.

[0064] When the electric field force significantly exceeds the surface tension of the droplet , the droplet is caused to lose stability in the form of a Taylor cone and is broken into sub-micron droplets, and the diameter of the sub-micron droplets is wherein is the surface tension coefficient, is the density of the droplet, is the dielectric constant of the droplet, r is the droplet radius, is the dielectric constant in vacuum, and k is a constant.

[0065] In an embodiment, the supercritical is used as the anti-solvent, and the corresponding set surface charge density threshold = 10 -4 C / m 2 , so that the corresponding electric field force is greater than the surface tension, and the droplet loses stability in the form of a Taylor cone.

[0066] The pressure control unit 523 is configured to perform step S20B: calculating a difference between the Taylor cone formation time and the supercritical anti-solvent diffusion time according to the droplet radius r and the density of the supercritical anti-solvent Calculating the supercritical anti-solvent diffusion time ; and calculating the supercritical anti-solvent diffusion time The difference between the Taylor cone formation time and the supercritical anti-solvent diffusion time The absolute value of the difference ; determining whether the absolute value of the difference is less than or equal to a set timing mismatch threshold value : If not, adjusting the pressure and flow rate of the supercritical anti-solvent until is less than or equal to .

[0067] The supercritical anti-solvent diffusion time satisfies:

[0068] In the formula, r represents the droplet radius, and D represents the diffusion coefficient of the supercritical anti-solvent with a density of .

[0069] The absolute value of the difference satisfies: .

[0070] The set timing mismatch threshold value According to the diameter of the generated sub-micron droplets, in an embodiment, the value is 0.2 ms to 0.3 ms.

[0071] The diffusion coefficient of the supercritical anti-solvent can be estimated according to the density of the supercritical anti-solvent by using an empirical formula method. Under high pressure and supercritical conditions, the diffusion coefficient of the supercritical anti-solvent is estimated according to the density of the supercritical anti-solvent by using an empirical formula method.

[0072] In the formula, D0 represents a reference diffusion coefficient, T0 represents an absolute temperature, Tc represents a critical temperature of the anti-solvent, n represents a temperature index, A represents a constant related to the supercritical anti-solvent, and represents the density of the supercritical anti-solvent.

[0073] Practical examples Carbon dioxide (CO2) is used as the anti-solvent to prepare high-drug-loading brain-targeting nanoparticles containing nervonic acid.

[0074] (I) Preparation of an emulsion containing nervonic acid ​​S1A: Preparation of oil phase solution: accurately weighed nervonic acid and phosphatidylserine (PS) are dissolved in high-purity organic solvent, the concentration is controlled at 60%~100%(v / v); the dissolution process is carried out under the protection of inert gas and in the dark, the temperature is maintained at 40℃~60℃, until a uniform transparent nervonic acid-PS complex solution is formed.

[0075] The organic solvent is selected from at least one of anhydrous ethanol, acetone or ethyl acetate.

[0076] The inert gas is, for example, nitrogen or argon.

[0077] S1B: Preparation of aqueous phase solution: chitosan (CS) and polyethylene glycol (PEG) with molecular weight specifications are dissolved in an acidic buffer solution, the concentration range is 0.05~0.5 (mol / ml), the pH value is accurately controlled between 3.0~6.0, the dissolution process is carried out under continuous magnetic stirring at a speed of 600 rpm~1000 rpm, the temperature is maintained at 35℃~5℃, to ensure complete hydration and dispersion of the polymer to form a homogeneous solution.

[0078] The buffer system is selected from one of acetic acid buffer, citric acid buffer or hydrochloric acid buffer.

[0079] S2: Under dynamic mixing conditions, the oil phase solution is injected into the water phase at a flow rate of 0.5mL / min~2 mL / min, and immediately introduced into a high-pressure homogenization device, and subjected to 3 to 7 cycles of homogenization treatment under ultra-high pressure of 80 MPa~150 MPa, to form an oil / water (O / W) emulsion with an initial particle size of about 180 nm, a dispersion index PDI<0.2 and uniform distribution, and the emulsion is stored in the material tank 20.

[0080] This step realizes the nanoscale dispersion of the nervonic acid-PS complex in the CS-PEG aqueous phase through strong shear force and cavitation effect.

[0081] (II) Preparation of high drug-loaded brain-targeted nano-suspension containing nervonic acid by using supercritical anti-solvent-electrostatic spraying coupling system S3: The emulsion is pumped into the pre-adjusted reaction kettle 22 at a constant flow rate of 1mL / min~3 mL / min, and supercritical CO2 is introduced into the reaction kettle 22 at the same time, the flow rate of supercritical CO2 is controlled at 5L / min~20 L / min; supercritical CO2 with materials is formed in the mixing axe 22. The pressure of the reaction kettle 22 is set in the range of 5MPa~25 MPa, and the temperature is maintained at 30℃~60℃.

[0082] The purity of CO2 is ≥99.99%.

[0083] S4: A DC high voltage of 10 kV~30 kV is applied to the resonance circuit 32, and the supercritical CO2 with the material is introduced into the electrostatic atomization module 3: The input voltage of the resonance circuit 32 is adjusted by monitoring the surface charge density of the droplets at the material outlet 3015 until the surface charge density of the droplets reaches 10 -4 C / m²; at the same time, the radius r of the droplets at the material outlet 3015, the Taylor cone formation time , the supercritical CO2 diffusion time , the absolute value of the difference between the Taylor cone formation time and the supercritical CO2 diffusion time , the pressure and flow of the supercritical CO2 are monitored to make the absolute value of the difference less than 0.3 ms.

[0084] When the surface charge density of the droplets reaches 10 -4 C / m², the electric field force provided by the resonance circuit 32 significantly exceeds the surface tension of the droplets, causing the droplets to lose stability and break into sub-micron droplets (diameter ); at the same time, when the absolute value of the difference between the Taylor cone formation time and the supercritical CO2 diffusion time is less than 0.3 ms, the density of the supercritical CO2 is 0.75 g / cm 3 , and the corresponding diffusion coefficient is 10 -7 m 2 / s, the supercritical CO2 will penetrate into the droplets within milliseconds (≤0.1 s), triggering the solvent polarity drop effect, making the polarity of ethanol drop from the initial 24.3 to 6.5, and the polarity of water drop from 80.1 to 15.2, with a solvent polarity drop ΔPolarity≥17.8, causing the solubility of nervonic acid to drop from 50 mg / mL to <0.1 mg / mL instantaneously, reaching a highly supersaturated state; under the dual synergy of the electric field oscillation provided by the resonance circuit 32 at a frequency of 0.5 kHz~5 kHz and the rapid diffusion of supercritical fluid, the nervonic acid molecules instantaneously and uniformly nucleate, and the crystal growth is effectively inhibited by the electric field force, ultimately forming a nanosuspension with uniform particle size (PDI<0.2) and high crystallinity. The nanosuspension is collected and further solidified by freeze-drying or spray-drying, and finally a white nanosuspension powder with good flowability is obtained.

[0085] Freeze-drying parameters: pre-freezing temperature -80°C, main drying temperature -40°C, vacuum degree <0.1 mbar.

[0086] Spray drying parameter settings: inlet temperature 100-120℃, outlet temperature 50-60℃, atomization pressure 0.3-0.5MPa.

[0087] The total process time of the high drug loading brain targeting nanoparticle powder containing nervonic acid prepared by the supercritical anti-solvent-electrospray coupling system is controlled within 2 hours, which is significantly better than the traditional method (≥24 hours), and the high temperature and oxidation environment are avoided throughout the process, and the degradation rate of the unsaturated double bond (C=C) in nervonic acid is less than 5%.

[0088] (III) Test analysis The high drug loading brain targeting nanoparticle powder containing nervonic acid is subjected to test analysis, as shown in Table 1.

[0089] In summary, the supercritical anti-solvent-electrospray coupling system proposed by the application utilizes crystallization kinetics, cooperatively controls the oscillating electric field and the supercritical anti-solvent pressure by using a time-space synchronous control module, so that the electric field force provided by the oscillating electric field realizes the electric field jet breakup of the material, the absolute value of the difference between the Taylor cone formation time and the supercritical anti-solvent diffusion time is within the set range, the supercritical anti-solvent penetrates into the droplet interior within the millisecond time scale to cause the solvent polarity to drop sharply, the solute crystallizes instantaneously, and under the dual synergy of the oscillating electric field and the rapid diffusion of the supercritical fluid, a nanosuspension with a particle size of less than 200nm and uniform particle size (PDI<0.2) is finally formed; the preparation of brain targeting nanoparticles with high drug loading and small particle size that can cross the blood-brain barrier (BBB) can be realized. The coupling system can be continuously and greenly produced, and is especially suitable for the manufacture of brain targeting delivery systems for liposoluble drugs such as nervonic acid.

[0090] Table 1

[0091] The above-described embodiments only express several embodiments of the application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the application, a number of modifications and improvements can be made, and the application also intends to include these modifications and improvements.

Claims

1. A supercritical antisolvent-electrostatic spray coupling system, characterized in that, include: The supercritical anti-solvent generating module, the material mixing module and the electrostatic atomization module are connected in sequence by the connecting pipeline, wherein the electrostatic atomization module comprises a resonance circuit, an insulating ceramic nozzle placed in the resonance electric field of the resonance circuit, and a space-time synchronous control module in communication connection with the supercritical anti-solvent generating module and the resonance circuit; the space-time synchronous control module comprises a data acquisition unit and a controller; the data acquisition unit comprises a charge density sensor arranged at a material outlet of the insulating ceramic nozzle, a high-speed camera, a pressure sensor arranged at a supercritical anti-solvent injection inlet of the insulating ceramic nozzle, and a temperature sensor, which are used to acquire the surface charge density of the liquid droplets , the liquid droplet radius r, and the Taylor cone forming time , and the pressure P and the temperature T of the supercritical anti-solvent; the controller comprises a data acquisition unit, an electric field control unit and a pressure control unit, wherein: a data acquisition unit for acquiring the droplet surface charge density , the droplet radius r, the Taylor cone formation time and the density of the supercritical antisolvent ; An electric field control unit judges the surface charge density of the liquid droplet whether or not the surface charge density is greater than or equal to a set surface charge density threshold : If not, the input voltage of the resonant circuit is adjusted until ≥ ; The pressure control unit is used to adjust the pressure based on the droplet radius r and the density of the supercritical antisolvent. Calculation of supercritical antisolvent diffusion time And calculate the supercritical antisolvent diffusion time. With Taylor cone formation time absolute value of the difference Determine the absolute value of the difference. Is it less than or equal to the set timing mismatch threshold? : If not, adjust the pressure and flow of the supercritical antisolvent until ≤ .

2. The supercritical antisolvent-electrostatic spray coupling system according to claim 1, characterized in that, Density of the supercritical antisolvent According to the pressure and temperature of the supercritical antisolvent, the Peng-Robinson equation of state was used to calculate: In the formula: P represents the pressure of the supercritical antisolvent, M represents the molar mass of the antisolvent, Z represents the compressibility factor, R represents the ideal gas constant, and T represents the temperature of the supercritical antisolvent.

3. The supercritical antisolvent-electrostatic spray coupling system according to claim 1, characterized in that, The supercritical anti-solvent diffusion time satisfies: where r represents the droplet radius and D represents the diffusion coefficient of the supercritical antisolvent having a density of 0.8 g / cm3.

4. The supercritical antisolvent-electrostatic spray coupling system according to claim 3, characterized in that, The diffusion coefficient of the supercritical antisolvent is determined by the density of the supercritical antisolvent The estimated value is: wherein: D0represents a reference diffusion coefficient, To represents an absolute temperature, Tcrepresents a critical temperature of the antisolvent, n represents a temperature exponent, A represents a constant related to the supercritical antisolvent, represents the density of the supercritical antisolvent.

5. The supercritical antisolvent-electrostatic spray coupling system according to claim 1, characterized in that, the timing mismatch threshold is 0.2ms~0.3ms.

6. The supercritical antisolvent-electrospray coupled system of claim 1, wherein, The supercritical antisolvent generation module includes a supercritical antisolvent generation unit, which includes an antisolvent storage tank, an antisolvent circulation tank, a first heat exchanger, a high-pressure plunger pump, and a second heat exchanger connected in sequence through antisolvent pipelines; the high-pressure plunger pump is pressurized by a PID controller, and the PID controller is communicatively connected to the controller of the time-space synchronization control module.

7. The supercritical anti-solvent-electrostatic spray coupled system of claim 6, wherein, The high-pressure plunger pump includes a first high-pressure plunger pump and a second high-pressure plunger pump, which are connected in parallel. The high-pressure plunger pump has an accuracy of ±0.1 mL / min.

8. The supercritical antisolvent-electrospray coupled system of claim 1, wherein, The insulating ceramic nozzle has a three-layer coaxial structure, including an inner channel for introducing materials, a middle annular gap for introducing supercritical antisolvents, and an outer shielding layer; wherein the inner channel is made of zirconia ceramic.

9. The supercritical antisolvent-electrospray coupled system of claim 1, wherein, The resonant circuit includes an LC oscillation circuit and a voltage feedback loop; wherein, the voltage feedback loop dynamically adjusts the output voltage of the resonant circuit according to the signal from the charge density sensor.

10. The supercritical antisolvent-electrostatic spray coupling system according to claim 1, characterized in that, The material mixing module comprises a material tank and a reaction kettle connected with the material tank; the reaction kettle comprises a multi-stage settling tower, the multi-stage settling tower comprises multi-stage baffles, and the gradient of each stage of baffles is determined by a Stokes settling formula, so as to separate particles with a particle size of 50 nm to 500 nm, and the specific gradient interval wherein r is the droplet radius, g is the gravitational acceleration, Δp is the pressure difference, η is the material viscosity, and t is the settling time.

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