A medical external preparation for inhibiting proliferation of scar fibroblasts

Abstract

This invention relates to the field of medical preparations technology and discloses a topical medical preparation for inhibiting the proliferation of scar fibroblasts. The preparation comprises a thermosensitive phase change matrix and nanomicelles distributed therein. The thermosensitive phase change matrix undergoes a phase transition from sol to gel at 25°C to 32°C. The nanomicelles include polyethylene glycol segments, enzyme-sensitive chains, polylactic acid segments, and inhibitors linked by oxidation-responsive bonds. After the enzyme-sensitive chains sense and induce enzymatic cleavage of fibroblast-activating proteins, the nanomicelles expose a hydrophobic core and trigger oxidative cleavage of the oxidation-responsive bonds, releasing the inhibitor. This invention utilizes a thermosensitive phase change synergistic multi-level biochemical signal sensing mechanism to decouple the preparation's penetration depth from its biocompatibility. The preparation triggers targeted drug release only in the scar activation area, avoiding the toxic effects of the inhibitor on normal tissue and improving drug utilization at dermal lesions.

Description

Technical Field

[0001] This invention belongs to the field of medical preparations technology, and particularly relates to a medical topical preparation for inhibiting the proliferation of scar fibroblasts. Background Technology

[0002] Currently, excessive proliferation of fibroblasts and abnormal accumulation of extracellular matrix are the core factors inducing pathological scars during the healing process after skin tissue damage. Clinical interventions for such lesions primarily utilize medical gels or ointments containing inhibitory components. These formulations construct a drug-containing film on the lesion surface, allowing active molecules to penetrate the stratum corneum and dermal barrier, thereby acting on fibroblasts at the target site to regulate collagen metabolism balance. Due to the high physical resistance of the stratum corneum and scar tissue composed of dense collagen fibers, the transdermal migration of active molecules is strictly limited by Fick's diffusion law. The diffusion flux depends on the concentration gradient established between the application surface and the deeper tissue layers. This means that a high dosage intensity must be maintained on the skin surface to drive sufficient inhibitors to overcome the dense matrix resistance and reach the target depth.

[0003] Existing technologies mostly focus on improving the permeability of the formulation matrix. Even with optimization of the physical carrier delivery efficiency, the lack of precise drug release logic control still makes it difficult to resolve the fundamental contradiction between insufficient deep drug dosage and toxicity to surrounding tissues. For example, Chinese invention patent CN103002903B discloses a method for treating keloids, which suspends L-alanyl-L-glutamine dipeptide in an organic gel, utilizing the thermoplasticity and solubility of the organic gel to break through the skin barrier. This type of approach is a non-specific release; the drug remains free and active throughout its migration from the stratum corneum to the dermis, failing to recognize the differences between the lesion area and the microenvironment of healthy tissue. This single delivery mode, lacking pathological signal response, causes biological interference of the active ingredient in non-target areas. In highly fibrotic scars, it is difficult to achieve pulsed concentration accumulation in the core area, which restricts the expansion of the clinical treatment window. However, under this passive diffusion-based design architecture, a physicochemical conflict arises between the penetration efficiency and biosafety of the formulation. When the inhibitor concentration on the application surface is increased to ensure an effective therapeutic dose to the deep tissues, the free-state active molecules produce significant non-specific cytotoxicity during the penetration of the normal epidermis and the edge area of ​​the lesion, thereby inducing atrophy of normal skin tissue or stagnation of wound healing. If the drug concentration is reduced to avoid tissue damage, the inhibitor cannot generate sufficient diffusion pressure to penetrate the highly fibrotic scar matrix, resulting in the drug concentration in the core area of ​​the lesion being lower than the effective treatment threshold.

[0004] Therefore, the technical problem to be solved by this invention is how to construct a composition system that is independent of simple concentration gradient dependence and has microenvironment recognition and release characteristics, so that the active components can efficiently penetrate dense barriers while maintaining biological inertness to healthy tissues. Summary of the Invention

[0005] This invention proposes a topical medical preparation for inhibiting the proliferation of scar fibroblasts, comprising: Thermosensitive phase change matrix, the components of thermosensitive phase change matrix include poloxamer 407 and poloxamer 188 in a weight ratio of 4:1. The thermosensitive phase change matrix undergoes a phase transition from sol to gel at 25°C to 32°C. A responsive carrier, distributed within a temperature-sensitive phase change matrix, comprises nanomicelles of an amphiphilic block copolymer. The amphiphilic block copolymer includes: a polyethylene glycol segment; and an enzyme-sensitive chain, one end of which is attached to the polyethylene glycol segment. This enzyme-sensitive chain is responsive to fibroblast activation proteins. The property of undergoing enzymatic cleavage; polylactic acid segments, connecting the other end of the enzyme-sensitive chain; The oxidative response bond is a chemical bond structure containing a thioketal bond. One end of the oxidative response bond is connected to a polylactic acid segment. The oxidative response bond has the property of responding to the oxidative cleavage of reactive oxygen species. And the inhibitor, which is covalently bonded to the hydrophobic core composed of polylactic acid segments via oxidation-responsive bonds; The responsive carrier is defined as follows: after enzymatic cleavage of the enzyme-sensitive chain leads to the release of the polyethylene glycol segment, it exposes the hydrophobic core and triggers the oxidative cleavage of the oxidative response bond, releasing the inhibitor.

[0006] Preferably, the temperature-sensitive phase change matrix consists of 18% to 22% (w / v) poloxamer 407, 4% to 6% (w / v) poloxamer 188, and the balance being a phosphate buffer solution; the temperature-sensitive phase change matrix is ​​at 37°C. The viscosity ranges from 150 Pa·s to 220 Pa·s.

[0007] Preferably, the number average molecular weight of the polyethylene glycol segment is 2,000 to 5,000; the number average molecular weight of the polylactic acid segment is 5,000 to 15,000; and the polydispersity index of the amphiphilic block copolymer is not higher than 1.2.

[0008] Preferably, the enzyme-sensitive chain is a pentapeptide chain containing the Gly-Pro-Ala-Gly-Pro sequence, wherein the pentapeptide chain is linked to the carboxyl group at the end of the polyethylene glycol segment by forming an amide bond through its amino terminus.

[0009] Preferably, the oxidation-responsive bond is synthesized by the condensation reaction of thiol and acetone, and the other end of the oxidation-responsive bond is bonded to the hydroxyl site of the inhibitor via an ester bond.

[0010] Preferably, the inhibitor is fluorouracil, dexamethasone, paclitaxel or colchicine; the amount of the inhibitor loaded in the responsive carrier is 5% to 12%.

[0011] Preferably, the responsive carrier has an average particle size of 80 nm to 120 nm, and its surface... The potential ranges from -5mV to -15mV.

[0012] Preferably, the storage modulus of the formulation at 4°C is lower than the loss modulus; after the formulation is maintained at 37°C for 60 seconds, its storage modulus is more than 10 times the loss modulus.

[0013] Preferably, the amphiphilic block copolymer comprises a copolymer chain prepared by ring-opening polymerization initiated by maleic anhydride, wherein the enzyme-sensitive chain is linked to the polylactic acid segment via a Michael addition reaction product between its terminal cysteine ​​residue and the maleimide group at the end of the polylactic acid segment.

[0014] Compared with existing technologies, the medical topical preparation of the present invention for inhibiting the proliferation of scar fibroblasts has the following advantages: 1. In topical medical formulations, the structured coupling of a thermosensitive hydrogel matrix and dual-responsive nanomicelles achieves deep synergy between overall physical phase change and surface biochemical release. When the formulation comes into contact with the body surface temperature from ambient temperature, the hydrophobic segments inside the matrix undergo thermodynamic association, causing the system to rapidly transform from a sol state to a high-viscosity gel state within the range of 32 to 37°C. The surface network contraction force generated during this process, together with the in-situ formed hydration sealing layer, creates a continuous directional permeation potential for the nanophase encapsulating the drug. This mechanism breaks away from the passive diffusion mode of traditional topical formulations that rely solely on increasing the drug concentration to overcome the blockage of the dense extracellular matrix in pathological scars, enabling the inhibitor to penetrate the collagen fiber barrier and migrate to the deep dermal tissue without increasing the initial drug dosage.

[0015] 2. By utilizing specific polypeptide sequences and thioketal bonds in amphiphilic block copolymers to construct a logical threshold recognition system targeting the pathological microenvironment, the permeability and biosafety of the formulation are effectively decoupled. The prepared nanomicelles covalently lock the active component in a hydrophobic core. When penetrating normal skin tissue or in the region of inactive fibroblasts, the micelle structure maintains its physicochemical integrity, and the active component is in a biologically inert state. When the nanomicelles enter the scar activation region and simultaneously recognize two specific biochemical signals—highly expressed fibroblast activation protein and high concentration of reactive oxygen species—the connecting arms undergo stepwise degradation, inducing the release of the active component. This dual-gating mechanism avoids the non-specific toxic damage of broad-spectrum inhibitors to normal keratinocytes and surrounding healthy tissues during cross-spatial diffusion pathways, eliminating the risk of skin atrophy and delayed wound healing caused by conventional topical formulations. Attached Figure Description

[0016] Figure 1 This is a diagram illustrating the carrier structure composition and biochemical multi-level response mechanism of the present invention; Figure 2 This is a flowchart illustrating the logical process of the formulation of this invention from temperature-sensitive curing to precise drug release. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0018] It should be noted that all directional and positional terms used in this invention, such as: up, down, left, right, front, back, vertical, horizontal, inner, outer, top, bottom, transverse, longitudinal, center, etc., are only used to explain the relative positional relationship and connection between components in a specific state (as shown in the accompanying drawings). They are only for the convenience of describing this invention and do not require that this invention be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention. In addition, the descriptions of "first," "second," etc., in this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0019] In the description of this invention, unless otherwise explicitly specified and limited, the terms installation, connection, and linking should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0020] In the description of this specification, references to the terms "an embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example, and the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0021] A topical medical preparation for inhibiting the proliferation of scar fibroblasts, comprising: Thermosensitive phase change matrix, the components of thermosensitive phase change matrix include poloxamer 407 and poloxamer 188 in a weight ratio of 4:1. The thermosensitive phase change matrix undergoes a phase transition from sol to gel at 25°C to 32°C. A responsive carrier, distributed within a temperature-sensitive phase change matrix, comprises nanomicelles of an amphiphilic block copolymer. The amphiphilic block copolymer includes: a polyethylene glycol segment; and an enzyme-sensitive chain, one end of which is attached to the polyethylene glycol segment. This enzyme-sensitive chain is responsive to fibroblast activation proteins. The property of undergoing enzymatic cleavage; polylactic acid segments, connecting the other end of the enzyme-sensitive chain; The oxidative response bond is a chemical bond structure containing a thioketal bond. One end of the oxidative response bond is connected to a polylactic acid segment. The oxidative response bond has the property of responding to the oxidative cleavage of reactive oxygen species. And the inhibitor, which is covalently bonded to the hydrophobic core composed of polylactic acid segments via oxidation-responsive bonds; The responsive carrier is defined as follows: after enzymatic cleavage of the enzyme-sensitive chain leads to the release of the polyethylene glycol segment, it exposes the hydrophobic core and triggers the oxidative cleavage of the oxidative response bond, releasing the inhibitor.

[0022] Preferably, the temperature-sensitive phase change matrix consists of 18% to 22% (w / v) poloxamer 407, 4% to 6% (w / v) poloxamer 188, and the balance being a phosphate buffer solution; the temperature-sensitive phase change matrix is ​​at 37°C. The viscosity ranges from 150 Pa·s to 220 Pa·s.

[0023] Preferably, the number average molecular weight of the polyethylene glycol segment is 2,000 to 5,000; the number average molecular weight of the polylactic acid segment is 5,000 to 15,000; and the polydispersity index of the amphiphilic block copolymer is not higher than 1.2.

[0024] Preferably, the enzyme-sensitive chain is a pentapeptide chain containing the Gly-Pro-Ala-Gly-Pro sequence, wherein the pentapeptide chain is linked to the carboxyl group at the end of the polyethylene glycol segment by forming an amide bond through its amino terminus.

[0025] Preferably, the oxidation-responsive bond is synthesized by the condensation reaction of thiol and acetone, and the other end of the oxidation-responsive bond is bonded to the hydroxyl site of the inhibitor via an ester bond.

[0026] Preferably, the drug release selectivity index of the responsive carrier in a simulated pathological environment The following relationship must be satisfied: ,in, The drug release selectivity index; The formulation contains 100 nmol / L fibroblast activating protein and The cumulative mass of inhibitor released after incubation in a 1 mmol / L phosphate buffer solution for 24 h; The cumulative release mass of the inhibitor after the formulation was incubated in phosphate buffer solution for 24 hours.

[0027] Preferably, the inhibitor is fluorouracil, dexamethasone, paclitaxel or colchicine; the amount of the inhibitor loaded in the responsive carrier is 5% to 12%.

[0028] Preferably, the responsive carrier has an average particle size of 80 nm to 120 nm, and its surface... The potential ranges from -5mV to -15mV.

[0029] Preferably, the storage modulus of the formulation at 4°C is lower than the loss modulus; after the formulation is maintained at 37°C for 60 seconds, its storage modulus is more than 10 times the loss modulus.

[0030] Preferably, the amphiphilic block copolymer comprises a copolymer chain prepared by ring-opening polymerization initiated by maleic anhydride, wherein the enzyme-sensitive chain is linked to the polylactic acid segment via a Michael addition reaction product between its terminal cysteine ​​residue and the maleimide group at the end of the polylactic acid segment.

[0031] Example 1: In the typical repair situation of severe hypertrophic scar formation after large-area deep thermodynamic trauma, a dense collagen fiber barrier has formed on the surface of the wound, accompanied by local moisture loss. There is a highly dense cluster of activated fibroblasts in the deep dermis. This cluster area has the dual pathological microenvironmental properties of high concentration of fibroblast activating proteins and accumulation of reactive oxygen species. The edge of the lesion is embedded with newly formed keratinocytes in the proliferative phase. If conventional preparations that rely on diffusion of a single concentration gradient are to drive an effective dose of active molecules to penetrate the collagen barrier and reach the deep lesion, a high local drug concentration must be established in the epidermis. The continuously free high concentration of broad-spectrum active molecules will cause indiscriminate toxic killing of newly formed healthy cells at the edge during the migration path, causing wound ulceration or secondary atrophy.

[0032] A topical medical preparation was applied to the surface of the lesion. A thermosensitive phase change matrix composed of poloxamer 407 and poloxamer 188 in a weight ratio of 4:1 was maintained in a fluid phase at 20°C to 25°C, allowing nanomicelles composed of amphiphilic block copolymers to be uniformly dispersed within it. When the preparation came into contact with a skin surface area at 37°C, the hydrophobic blocks in the poloxamer polymer chains dehydrated and underwent intermolecular thermodynamic association, causing the matrix system to crosslink from a fluid phase to a gel network. This physical phase change process established a hydration sealing layer in situ on the scar surface, preventing water evaporation and weakening the density of the stratum corneum. During the shrinkage and curing process, this crosslinked network generated a spatial compression effect. The rheological properties of the thermodynamic phase change transformed into a continuous and directional osmotic pressure constructed by uniformly embedded nanomicelles. The gradient utilizes the physical synergy between a thermosensitive phase change matrix and nanomicelles to drive the overall migration of carrier particles encapsulated with inhibitors into the dense dermis. Because the top layer of the topical formulation is directly exposed to the air interface, forming a water-impermeable gel shell, while the bottom layer is in contact with the dense collagen matrix softened by hydration, the isotropic contractile stress caused by the thermodynamic association of polymers within the gel network cannot be released to the top boundary. This stress is physically forced downwards and transformed into a unidirectional hydraulic pump force that pushes the internal fluid into the softened lesion matrix. At the same time, the water potential difference between the water-rich state inside the formulation and the water-deficient state of the deep scar further synergizes with this unidirectional mechanical compression, causing the 100nm-scale micelle particles to be carried by the overall fluid to undergo directional convection migration into the depths where resistance is lower.

[0033] The covalent masking architecture of nanomicelles physically decouples the penetration-driven forces and tissue cytotoxicity during transdermal delivery. When nanomicelles penetrate newly formed normal epithelial cells and inactive dermal regions, the hydrophilic shell, composed of enzyme-sensitive chains and polyethylene glycol segments, maintains chemical integrity due to the lack of specific activating enzymes and baseline reactive oxygen species levels in the healthy microenvironment. The hydrophobic core, composed of polylactic acid segments, covalently locks the inhibitor inside, maintaining biological inertness. When nanomicelles migrate to the activated fibroblast microenvironment at the lesion core, highly expressed inhibitors... Fibroblast-activating proteins catalyze the cleavage of enzyme-sensitive chains, causing the polyethylene glycol segments to detach and disrupting the hydrophilic-hydrophobic balance of micelles. The micelles undergo conformational changes, exposing their hydrophobic core. High concentrations of reactive oxygen species accumulated in the microenvironment attack and oxidatively cleave the oxidative response bonds with thioketal structures. The inhibitor dissociates from the carrier backbone, releasing it and restoring its free biological activity. This multi-level biochemical signaling mechanism utilizes lesion-specific biochemical indicators to execute targeted cleavage. The physicochemical premise of this strict temporal sequence lies in the fact that the thioketal bonds are deeply embedded within the self-assembly of polylactic acid segments. Deep within the highly crystalline hydrophobic core, despite the tiny size of reactive oxygen species (ROS) molecules, a dense hydrophobic physical barrier prevents the inward diffusion of ROS-containing aqueous phases. Only when the outer hydrophilic polyethylene glycol layer detaches does the entire nanomicelle lose its amphiphilic balance in the aqueous phase, undergoing instability, disintegration, and structural swelling. The highly coiled polylactic acid segments unwind, and the previously physically concealed thioketal bonds are directly exposed to the ROS-containing body fluid environment, thus overcoming steric hindrance and activating subsequent oxidative cleavage chemical reactions. After performing the aforementioned physical-driven and biochemical cleavage actions, the free inhibitor in the topical medical formulation is released only within the activation microenvironment spatial coordinates where fibroblast activating proteins and ROS coexist. The drug concentration in the core area of ​​the target lesion meets the therapeutic indicators, simultaneously eliminating the probability of chemical toxicity of the free inhibitor to healthy tissues along the migration path. This achieves extended penetration depth and preservation of healthy cells while maintaining the initial dosing intensity. The formulation system utilizes environmental thermal energy conversion to construct a constant physical osmotic potential and incorporates a two-dimensional biochemical signal sensing mechanism to set the drug activation threshold.

[0034] Example 2: A physical barrier model was constructed using an in vitro three-dimensional high-density cross-linked collagen biomimetic matrix with a pore size of 10nm to 50nm. Activated fibroblast culture medium was seeded at the bottom of this model, containing fibroblast-activating proteins and reactive oxygen species to recreate the pathological environment. Normal keratinocytes lacking the aforementioned biochemical factors were seeded around the culture medium, serving as a source of physiological interference. The phase transition temperature parameter was set to balance the spreadability at room temperature and the gelation rate upon contact with the body surface. An ambient temperature of 25℃ was selected as the boundary condition. If the temperature was lower than this boundary, to maintain the low-viscosity rheological characteristics of the formulation filling the wound, the weight ratio of poloxamer 407 to poloxamer 188 was required to tend towards an inhibitory cross-linking state. A constant-temperature rheometer with a temperature control accuracy of 0.1℃ was used to monitor the rheological parameters. The instrument output data showed that the formulation system with a weight ratio of 4:1 exhibited a sudden increase in output at 28.5℃. The energy storage modulus data were used to generate a hydrated, closed gel network with mechanical strength. A sample group using a 4:1 weight ratio was established, along with a partially deficient control group containing oxidative response bonds but lacking the enzyme-sensitive chain. Out-of-range control groups with poloxamer weight ratios of 5:1 and 3:1 were established, respectively. Equal amounts of the formulation were applied to the surface of each biomimetic matrix. The permeation process was driven by a 37°C temperature environment. High-performance liquid chromatography (HPLC) equipped with a fluorescence quantitative module was used to collect the cumulative concentration data of the inhibitor penetrating the collagen barrier and entering the bottom culture medium. Three gradient levels of reactive oxygen species (ROS) concentrations were set for the bottom culture medium: 20 μM for physiological baseline, 100 μM for moderate hyperplasia, and 500 μM for severe lesions. A 10 μM matrix metalloproteinase was injected into all test groups, serving as a non-specific biochemical noise disturbance source. Drug release kinetic data for each formulation under the above multi-gradient and noise environments were recorded.

[0035] Quantitative data output by high-performance liquid chromatography (HPLC) revealed the physical penetration capacity and biochemical degradation characteristics of different formulation systems. Regarding the intermediate physical quantity of penetration depth, the out-of-range control group with a poloxamer weight ratio of 5:1 prematurely emitted a gelation signal at 23°C, indicating impaired fluid penetration. Its penetration depth through the dense collagen barrier was measured to be 45.2 μm. The out-of-range control group with a weight ratio of 3:1 failed to generate effective osmotic pressure due to a loose cross-linked network, resulting in a penetration depth of stagnant at 60.5 μm. The sample group of this invention with a weight ratio of 4:1 triggered a phase transition at 37°C, and its nanometer value was measured. The micelle penetration depth reached 150.3 μm. In the drug release rate test, the sample group of this invention, in a physiological baseline model containing matrix metalloproteinase noise interference and a reactive oxygen species concentration of 20 μM, output a drug release rate of 4.1%. This confirms that the hydrophilic shell maintains chemical inertness in a noisy environment. When the substrate reactive oxygen species concentration jumped from 100 μM to 500 μM, the concentration of the targeted release inhibitor output by the sample group of this invention increased from 15.6 μg / mL to 68.3 μg / mL. The partially deleted control group lacking the enzyme-sensitive chain, in the absence of fibroblast activating protein... Under catalytic conditions, non-specific off-target release rates greater than 40.5% were output in each gradient environment. By comparing the cumulative free drug mass obtained in a simulated severe lesion release model containing 100 nmol / L fibroblast activator protein α and reactive oxygen species concentration of 1 mmol / L with the leaked release mass in a baseline leakage model with simple phosphate buffer, statistical analysis of experimental data from 50 independent batches showed that the ratio of the two was distributed in the range of 15.2 to 18.4. Based on the above large sample distribution boundary, the [missing information] was established. The lower limit of the drug release selectivity index S is greater than or equal to 15, which serves as an engineering access benchmark for judging whether the formulation has sufficient targeting tolerance. The concentration detection data simultaneously shows the nonlinear physical boundary. When the reactive oxygen species concentration in the culture medium exceeds the critical point of 800 μM, the slope of the drug release rate curve of the sample group of this invention decreases and tends to flatten, and the highest release concentration stops at 72.1 μg / mL. The inflection point data corresponds to the stoichiometric saturation state of the oxidative response bond cleavage sites inside the nanomicelles, which defines the pathochemical concentration response range applicable to this formulation.

[0036] Measurement indicators and quantitative test data verified the correlation between component interaction behavior and rheological and chemical kinetic mechanisms in an in vitro biomimetic environment. The 4:1 polymer ratio in the thermosensitive phase change matrix outputs the mechanical driving force to cross the collagen physical barrier. The covalent bond structure of the dual biochemical response linker outputs the chemical constraint that restricts the non-target free diffusion behavior. In a substrate environment containing non-specific enzyme noise and multi-level reactive oxygen species fluctuations, the formulation system integrates phase change osmotic pressure energy and dual-source gated molecular cleavage logic, so that the drug release spatial coordinates of the inhibitor converge to the target area of ​​scar fibroblast activation. The experimental data confirmed that the formulation solved the engineering contradiction between deep penetration efficiency and avoidance of toxicity to healthy cells.

[0037] Example 3: In this example, the preparation of a topical medical formulation for inhibiting the proliferation of scar fibroblasts requires determining the encapsulation structure of the active components and the phase transition critical point of the temperature-sensitive phase transition matrix. Polyethylene glycol segment materials containing fibroblast-activating proteins are selected. An amphiphilic block copolymer was synthesized using a chemical condensation process with enzyme-sensitive chain material that specifically recognizes the recognition sequence and polylactic acid (PLA) segment material as reaction substrates. In this specific synthetic process, polyethylene glycol monomethyl ether with terminal hydroxyl groups was used as a macromolecular initiator, mixed with maleic anhydride and lactide monomers in anhydrous toluene solvent. 0.1% (w / w) of stannous octoate was added dropwise as a catalyst. The reaction was carried out under a closed nitrogen atmosphere at 130°C for 24 hours. Under the action of the catalyst, the maleic anhydride underwent ring-opening and... The continuous growth of lactide segments was initiated. The resulting crude polymer was precipitated by washing with ice-cold diethyl ether and purified by vacuum drying. The amphiphilic block copolymer was dissolved in deionized water to form an aqueous system. The inhibitor was chemically coupled with a compound containing a thioketal structure to generate an inhibitor precursor carrying an oxidation-responsive bond. In the coupling process, 3-mercaptopropionic acid and acetone were mixed at a molar ratio of 2:1 and condensed at room temperature in the dark for 12 hours under acidic catalysis of dry hydrogen chloride gas to synthesize a dicarboxylated thioketal intermediate containing an oxidation-responsive bond. C2O2 was added. Using imine as a condensing agent and 4-dimethylaminopyridine as a catalyst, the carboxyl group of the intermediate undergoes an esterification reaction with the hydroxyl site of an inhibitor molecule such as dexamethasone or fluorouracil in anhydrous dimethylformamide, achieving covalent locking. The inhibitor precursor is dissolved in dichloromethane solvent to form an organic phase system. The reaction vessel temperature is set to 45℃, and the stirrer speed is set to 300 rpm. The organic phase system is uniformly added to the aqueous phase system at a flow rate of 2 mL / min using a micro-injection pump. The amphiphilic block copolymer in the aqueous phase system... In the process of self-assembly, the polylactic acid segment molecular chains contract inward to form a hydrophobic core, while the polyethylene glycol segment molecular chains extend outward to form a hydrophilic shell. During the assembly process, the hydrophobic core physically encapsulates and covalently locks the inhibitor precursor carrying the oxidation response bond, producing a dual-response nanomicelle suspension. The dual-response nanomicelle suspension is dialyzed using a dialysis membrane with a molecular weight cutoff of 3500 Da. The dichloromethane solvent is separated by dialysis in deionized water for 48 hours. The dialyzed dual-response nanomicelle suspension is then freeze-dried in a freeze dryer to produce solid nanomicelle powder.

[0038] The phase transition temperature of the thermosensitive phase change matrix needs to be matched to the temperature difference between the room temperature storage fluid state and the output gel state after contact with the body surface. Poloxamer 407 and Poloxamer 188 were selected as matrix polymer raw materials. The total mass fraction of the polymer aqueous solution was set to 20%, and three groups of poloxamer mixed aqueous solutions with weight ratios of 3:1, 4:1, and 5:1 were prepared. The correlation between the storage modulus and loss modulus of each solution and temperature was monitored using a rheometer. The test temperature range of the rheometer was set to 15℃ to 40℃, and the heating rate of the test unit was set to 1℃. The rheometer output data showed that the storage modulus of the 3:1 mixed aqueous solution exceeded the loss modulus at 34.2℃, the 5:1 mixed aqueous solution exceeded the loss modulus at 21.5℃, and the 4:1 mixed aqueous solution exceeded the loss modulus at 28.5℃. Based on the engineering boundary of the sol-to-gel phase transition of medical topical preparations in the 25℃-32℃ range, 28.5℃ was selected as the target phase transition threshold, and 4:1 was locked as the target weight ratio of poloxamer 407 to poloxamer 188 for preparation. When using a thermosensitive phase change matrix containing solid nanomicelle powder, poloxamer 407 and poloxamer 188 were selected as matrix raw materials. The total mass-volume concentration of the matrix in the buffer aqueous solution system was set between 20% and 25%, and the single-component concentration threshold of poloxamer 407 was limited to 16% to 20%, while the single-component concentration threshold of poloxamer 188 was simultaneously limited to 4% to 5%. A constant weight ratio of 4:1 was maintained between the two materials when extracting any unit volume of formulation. The polymer raw materials were dispersed in a 4°C phosphate buffer solution under continuous mechanical stirring. Until the polymer segments are completely hydrated, a reference fluid phase is constructed to output a stable sol-to-gel phase transition physical mechanism in the range of 25℃ to 32℃. A set mass of solid nanomicelle powder is added to a target weight ratio of poloxamer mixed aqueous solution at a temperature maintained at 4℃. The mixture is continuously stirred at 500 rpm for 60 min using a magnetic stirrer to output a medical topical preparation. The process outputs a nanomicelle carrier with a defined physical structure and a thermosensitive phase change matrix that is solidified at a thermodynamic response point. The reaction conditions and proportioning procedures are locked to output the physical acquisition pathways of each component of the medical topical preparation.

[0039] Example 4: When faced with a situation where the phase transition temperature of different batches of poloxamer raw materials deviates from the preset threshold due to fluctuations in the molecular weight polydispersity index, multiple sets of reference aqueous solutions with a mass fraction range of 15% to 25% are prepared using the target batch of poloxamer 407 and poloxamer 188. Differential scanning calorimetry and constant temperature rheometer are used to simultaneously measure the endothermic peak and storage modulus mutation point of each solution during the heating process. Based on the extracted physical characteristic parameters, a two-dimensional mapping matrix reflecting the total polymer concentration and critical gel temperature is constructed. The target phase transition temperature of 28.5℃ is used as the reference input and substituted into the two-dimensional mapping matrix for calculation, outputting the corrected weight ratio range corresponding to the current batch of raw materials.

[0040] The verification solution was prepared according to the corrected weight ratio range and placed in a dialysis device with preset salinity and pH values. The dialysis device was immersed in a constant temperature water bath with a temperature control accuracy of 0.1℃ to measure phase change data. The fluid phase evolution sequence in the device was monitored and the gelation time was recorded simultaneously. When the gelation time was within the tolerance window of 30s to 60s in the temperature range of 25℃ to 32℃, the corrected weight ratio was used as the production ratio of the current batch of raw materials. The above calibration operation based on physical parameter mapping correlation to correct rheological deviations enabled the temperature-sensitive phase change matrix composed of the calibrated polymer to constantly output physical osmotic pressure and hydration closure network when in contact with the scar activation microenvironment.

[0041] Example 5: When faced with offline calibration conditions requiring the adaptation of nanomicelle biochemical response thresholds to different pathological stages, the molecular weight of the enzyme-sensitive chain in the amphiphilic block copolymer and the fibroblast activation protein in the microenvironment were selected. The catalytic rate mapping matrix was used as a production calibration benchmark. Interstitial fluid samples from the hypertrophic scar microenvironment at different pathological stages were extracted, and fibroblast activation proteins were measured. To determine the baseline concentration, multiple groups of enzyme-sensitive chain raw materials with gradient amino acid sequence lengths were prepared using a solid-phase peptide synthesis process. These enzyme-sensitive chain raw materials were then chemically coupled with polyethylene glycol and polylactic acid segments to generate multiple groups of nanomicelle samples with differentiated hydrophilic layer thicknesses. Fibroblast activation proteins corresponding to the aforementioned pathological cycles were then injected into each group of nanomicelle samples. The standard solution was used to continuously measure the decay slope parameter of the micelle size in each sample solution using a dynamic light scattering instrument. The particle size decay slope parameter was used to characterize the physical rate of hydrophilic shell shedding and micelle conformation deformation.

[0042] Scatter plots were generated based on the particle size attenuation slope parameter output by the dynamic light scattering instrument. The critical time points corresponding to the particle size attenuation slope reaching the fragmentation threshold of the nanomicelle structure were extracted from the plots. Comparison data indicated that when the amino acid sequence length of the enzyme-sensitive chain increases to a value that generates steric hindrance, the long-chain structure blocks fibroblast activation proteins. The proximity to the reaction site delays the critical time point. When more than 15 non-specific inert amino acid residues are added to both ends of the pentapeptide-specific sequence to form a random coiled long chain, the overfolded peptide chain forms a physical shield with a diameter larger than the opening of the catalytic pocket of the activating enzyme on a three-dimensional scale, preventing the target enzyme molecule from effectively anchoring to the cleavage site. When the amino acid sequence length of the enzyme-sensitive chain is reduced to a value that changes the hydrophilic-hydrophobic dynamic balance, the nanomicelles output a physical characteristic of premature cleavage in the physiological baseline environment. Based on the specific response interval extracted from the spectrum, the length parameter of the target enzyme-sensitive chain sequence adapted to the target pathological cycle is selected. This length parameter is set as the synthesis constraint condition of the amphiphilic block copolymer. This calibration procedure uses the measurement of the particle size deformation physical rate to establish a numerical correlation between the molecular chain length scale and the enzyme cleavage kinetic characteristics, and establishes the specific physical parameter boundary of the nanomicelle biochemical signal gating mechanism.

[0043] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit of this application and the scope of protection of this invention, and all of these forms are within the protection scope of this application.

Claims

1. A medical external preparation for inhibiting proliferation of a scar fibroblast, characterized by, include: Thermosensitive phase change matrix, the components of thermosensitive phase change matrix include poloxamer 407 and poloxamer 188 in a weight ratio of 4:

1. The thermosensitive phase change matrix undergoes a phase transition from sol to gel at 25°C to 32°C. The responsive carrier is distributed in a temperature-sensitive phase change matrix. The responsive carrier is composed of nanomicelles made of amphiphilic block copolymers, including polyethylene glycol segments. The enzyme-sensitive chain has a polyethylene glycol segment attached to one end, and the enzyme-sensitive chain has the property of responding to the enzymatic cleavage of fibroblast-activating proteins; the polylactic acid segment is attached to the other end of the enzyme-sensitive chain. The oxidative response bond is a chemical bond structure containing a thioketal bond. One end of the oxidative response bond is connected to a polylactic acid segment. The oxidative response bond has the property of responding to the oxidative cleavage of reactive oxygen species. And the inhibitor is covalently bonded to the hydrophobic core composed of polylactic acid segments via oxidative response bonds; the responsive carrier is defined as follows: after the enzyme-sensitive chain undergoes enzymatic cleavage leading to the release of polyethylene glycol segments, it exposes the hydrophobic core and triggers the oxidative cleavage of oxidative response bonds, releasing the inhibitor.

2. The medical topical preparation for inhibiting the proliferation of scar fibroblasts according to claim 1, characterized in that, The thermosensitive phase change matrix consists of 18% to 22% (w / v) poloxamer 407, 4% to 6% (w / v) poloxamer 188, and the balance phosphate buffer solution; the viscosity of the thermosensitive phase change matrix at 37°C is 150 Pa·s to 220 Pa·s.

3. The medical topical preparation for inhibiting the proliferation of scar fibroblasts according to claim 1, characterized in that, The number average molecular weight of the polyethylene glycol segment is 2,000 to 5,000; the number average molecular weight of the polylactic acid segment is 5,000 to 15,000; and the polydispersity index of the amphiphilic block copolymer is not higher than 1.

2.

4. The medical topical preparation for inhibiting the proliferation of scar fibroblasts according to claim 1, characterized in that, The enzyme-sensitive chain is a pentapeptide chain containing the Gly-Pro-Ala-Gly-Pro sequence. The pentapeptide chain is linked to the carboxyl group at the end of the polyethylene glycol segment by forming an amide bond through its amino terminus.

5. A topical medical preparation for inhibiting the proliferation of scar fibroblasts according to claim 1, characterized in that, The oxidative response bond is synthesized through the condensation reaction of thiol and acetone, and the other end of the oxidative response bond is bonded to the hydroxyl site of the inhibitor via an ester bond.

6. The medical topical preparation for inhibiting the proliferation of scar fibroblasts according to claim 1, characterized in that, The inhibitors are fluorouracil, dexamethasone, paclitaxel, or colchicine; the drug loading of the inhibitors in the responsive carrier is 5% to 12%.

7. A topical medical preparation for inhibiting the proliferation of scar fibroblasts according to claim 1, characterized in that, The responsive carriers have an average particle size of 80 nm to 120 nm and a surface area of ​​[missing information]. The potential ranges from -5mV to -15mV.

8. A topical medical preparation for inhibiting the proliferation of scar fibroblasts according to claim 1, characterized in that, The storage modulus of the formulation at 4°C is lower than the loss modulus; after the formulation is maintained at 37°C for 60 seconds, its storage modulus is more than 10 times the loss modulus.

9. A topical medical preparation for inhibiting the proliferation of scar fibroblasts according to claim 1, characterized in that, The amphiphilic block copolymer includes a copolymer chain prepared by ring-opening polymerization initiated by maleic anhydride, wherein the enzyme-sensitive chain is linked to the polylactic acid segment via a Michael addition reaction product between its terminal cysteine ​​residue and the maleimide group at the end of the polylactic acid segment.

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