Gastric retention shape memory composite membrane

Abstract

The invention relates to a gastric retention shape memory composite membrane. The gastric retention shape memory composite membrane is prepared by the following method: (1) mixing a polymer with dichloromethane to obtain a solution 1; (2) preparing a solution 2 by taking water as a solvent, wherein the solution 2 contains hydroxypropyl methyl cellulose and NaHCO3; and (3) mixing the solution 1 and the solution 2, stirring, adding the luteolin phospholipid complex, continuously stirring, and volatilizing dichloromethane and water. The gastro-retention shape memory composite membrane provided by the invention has a good in-vivo expansion effect, the deformation temperature of the gastro-retention shape memory composite membrane is closer to the temperature of a human body, and the gastro-retention shape memory composite membrane can enhance penetration of luteolin to a biological membrane, improve the gastrointestinal absorption effect of the luteolin, reduce stomach discomfort of a patient and improve the bioavailability of a medicine.

Description

[0001] This invention is a divisional application. The original Chinese invention patent application number was 202310847774.7, the application date was July 12, 2023, and the patent title at the time of application was: A method for preparing a gastric retention shape memory composite membrane. Technical Field

[0002] This invention belongs to the field of pharmaceutical technology, and in particular relates to a gastric retention shape memory composite membrane. Background Technology

[0003] Luteolin is a natural flavonoid widely found in plants, especially fruits and vegetables such as celery, chrysanthemum, bell peppers, carrots, onion leaves, and broccoli. Its chemical formula is C632-C ... 15 H 10 O6. The structure is shown below.

[0004]

[0005] Luteolin can form chelates with metal ions and is not oxidized during the chelation process. Luteolin has a variety of biological activities, including anticancer, antioxidant, anti-inflammatory, immunomodulatory, and cardioprotective effects.

[0006] Conventional oral medications for treating gastric cancer suffer from limitations such as failing to achieve the desired efficacy, poor oral effect, and difficulty in preservation, severely restricting their application. Luteolin exhibits good anti-tumor activity in gastric cancer and is a promising anti-cancer drug. However, direct application of luteolin to the human body has certain drawbacks, including poor oral absorption, poor water solubility, short retention time in the body, and low bioavailability. Especially in the treatment of gastric diseases, the short residence time in the stomach prevents the achievement of a sustained-release effect.

[0007] In order to effectively utilize luteolin, increase its oral absorption, and enhance its therapeutic potential, especially for the treatment of human gastric cancer, there is an urgent need to study a new dosage form of luteolin. Summary of the Invention

[0008] In view of the problems existing in the prior art, the present invention provides a gastric retention shape memory composite membrane, which is a novel gastric retention shape memory composite membrane loaded with luteolin phospholipid complex (LPC).

[0009] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0010] The method for preparing the gastric retention shape memory composite membrane provided by the present invention includes the following steps:

[0011] (1) The polymer was mixed with dichloromethane to obtain solution 1;

[0012] (2) Solution 2 is prepared using water as a solvent. Solution 2 contains hydroxypropyl methylcellulose and NaHCO3.

[0013] (3) Mix solution 1 and solution 2, stir, add luteolin phospholipid complex, continue stirring, and evaporate dichloromethane and water.

[0014] The beneficial effects of adopting the above technical solutions include: Addressing the issue of high polymer brittleness, this invention adds hydroxypropyl methylcellulose (HPMC) for modification, making it more suitable for oral administration and reducing gastric discomfort in patients. To increase the residence time of the gastric shape memory composite membrane, a foaming agent, NaHCO3, is added to the composite membrane. When the composite membrane reaches the stomach, the acidic gastric environment causes the composite membrane to generate bubbles, resulting in stronger buoyancy. The shape memory membrane prepared by this invention exhibits good in vivo unfolding performance, with a deformation temperature closer to human body temperature. This enhances the penetration of luteolin into biological membranes, improves the gastrointestinal absorption of luteolin, and increases drug bioavailability. This invention increases the water solubility of luteolin, resulting in better drug release behavior, increased residence time, and improved patient compliance. It possesses suitable glass transition temperature, drug release rate, and composite membrane deformation rate, exhibiting good stability. This allows for effective control of dosing frequency, reduction of drug toxicity to organs, increased patient compliance, and reduced medication costs. It also shows a significant inhibitory effect on gastric cancer cells.

[0015] Furthermore, the mass ratio of the polymer to dichloromethane is 1:7.

[0016] Furthermore, the mass of hydroxypropyl methylcellulose is 5% of the polymer mass, the mass of NaHCO3 is 5% of the polymer mass, and the total mass of hydroxypropyl methylcellulose and NaHCO3 is in a mass ratio of 1:10 to water.

[0017] Furthermore, the mass of the luteolin phospholipid complex is 30% of the total mass of the polymer, hydroxypropyl methylcellulose, and NaHCO3.

[0018] The beneficial effects of adopting the above technical solution include: a uniform composite membrane can be prepared using the above method. The addition of hydroxypropyl methylcellulose and NaHCO3 can effectively reduce the hardness and brittleness of the polymer, making the composite membrane easier to fold and more suitable for oral use.

[0019] Furthermore, the preparation method of the luteolin phospholipid complex includes the following steps: dissolving soybean lecithin and luteolin in tetrahydrofuran, stirring, and recovering under reduced pressure to obtain the luteolin phospholipid complex.

[0020] The beneficial effects of adopting the above technical solution include: addressing the problems of poor water solubility and low bioavailability of the main drug luteolin, the present invention modifies it by coating it with soybean lecithin, thereby increasing the water solubility of luteolin, making it easier for the human body to absorb, and increasing the bioavailability of luteolin.

[0021] Furthermore, the mass ratio of luteolin to soybean lecithin was 1:1.2; after dissolving in tetrahydrofuran, the concentration of luteolin was 10 mg / mL; the stirring time was 6 h, and the stirring temperature was 50℃.

[0022] The beneficial effects of adopting the above technical solution include: the luteolin phospholipid complex prepared by the above method can achieve a composite rate of 91.45%, which is beneficial for the subsequent preparation of gastric retention shape memory composite membranes. Furthermore, it can improve the water solubility of the original luteolin, making it more easily absorbed by the human body.

[0023] Furthermore, the polymer is selected from one or a combination of polylactic acid (PLA), polycaprolactone (PCL), and polyethylene glycol (PEG).

[0024] Preferably, the polymer comprises polylactic acid (PLA). The polymer may be selected solely from polylactic acid (PLA). Alternatively, the polymer may include, in addition to polylactic acid (PLA), one or more combinations of polycaprolactone (PCL) and polyethylene glycol (PEG). Most preferably, the polymer comprises both polylactic acid (PLA) and polyethylene glycol (PEG), with a better effect when the mass ratio of PLA to PEG is 7:3.

[0025] The beneficial effects of adopting the above technical solution include: This invention prepares a novel thermoresponsive gastric retention shape memory composite membrane carrying natural drugs for the treatment of gastric cancer. This membrane can be used for oral chemotherapy in patients, increasing the cure rate of gastric cancer patients. This invention uses luteolin, which has anti-cancer effects, as the main drug, and PLA as the main material. PCL and PEG are added to modify PLA, lowering the glass transition temperature of the composite membrane and making the shape memory temperature more suitable for the human body. The prepared gastric retention shape memory composite membrane is folded and placed in a capsule. After oral administration to the stomach, it deforms back to its original shape at gastric temperature, increasing the area larger than the pylorus and extending the drug's retention time in the stomach.

[0026] Furthermore, in step (3), after stirring for 3.5 h, the luteolin phospholipid complex is added, and stirring is continued for another 0.5 h.

[0027] Furthermore, after evaporating the dichloromethane and water, a molding step is also included; the molding process produces a sheet with a thickness of 1 mm and a pressure of 10 MPa.

[0028] The beneficial effects of adopting the above technical solution include: uniformly loading the phospholipid complex onto the film agent; and ensuring that the prepared composite film has a consistent thickness and controlling variables through compression molding.

[0029] This invention provides the application of a gastric retention shape memory composite membrane in the preparation of drugs for treating gastric cancer, wherein the gastric retention shape memory composite membrane is prepared by the above-described preparation method.

[0030] This invention provides a PLA-based gastric retention shape memory composite membrane loaded with a luteolin-phospholipid complex (LPC). First, luteolin is complexed with soybean lecithin to prepare LPC, increasing the water solubility of luteolin. Then, a PLA-based gastric retention shape memory composite membrane loaded with LPC is prepared, using PLA, PCL, and PEG as polymer materials, and HPMC and NaHCO3 are added to modify PLA. This allows the prepared gastric retention shape memory composite membrane to better rely on in vivo temperature to induce its shape memory response in the stomach, increasing gastric retention time. This system represents a pioneering new drug delivery system and can be used for the development and preparation of novel gastric cancer drugs in the future. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the gastric drug retention system. Figure 2 This is a UV absorption spectrum. Figure 3 This is the standard curve for luteolin. Figure 4 This is a diagram of LPC solution irradiated by laser. Figure 5 This is a picture of the finished LPC product. Figure 6 This is a morphological image of LPC under an optical microscope. Figure 7 The image shows the ultraviolet spectra. In the curves corresponding to 400 nm, from bottom to top, they are Phospholipid, LPC, and Luteolin. Figure 8 The image shows infrared spectra, with curves for LPC, Phospholipid, and Luteolin arranged from bottom to top. Figure 9 The images show the appearance of the drug-loaded gastric retention shape memory composite membrane, where: (A) LPC-PLA; (B) LPC-PLA / PCL(9 / 1); (C) LPC-PLA / PCL(8 / 2); (D) LPC-PLA / PCL(7 / 3); (E) LPC-PLA / PEG(9 / 1); (F) LPC-PLA / PEG(8 / 2); (G) LPC-PLA / PEG(7 / 3); (H) LPC-PLA / PCL / PEG(8 / 2 / 1); (I) LPC-PLA / PCL / PEG(8 / 2 / 2); (J) LPC-PLA without HPMC and NaHCO3 loading; (K) LPC-PLA / PCL / PEG(8 / 2 / 3). Figure 10The results of infrared spectral analysis of gastric retention shape memory composite membranes are as follows: (A) From top to bottom, LPC-PLA, LPC-PLA / PCL (9 / 1), LPC-PLA / PCL (8 / 2), LPC-PLA / PCL (7 / 3); (B) From top to bottom, LPC-PLA / PEG (9 / 1), LPC-PLA / PEG (8 / 2), LPC-PLA / PEG (7 / 3); (C) From top to bottom, LPC-PLA / PCL / PEG (8 / 2 / 1), LPC-PLA / PCL / PEG (8 / 2 / 2), LPC-PLA / PCL / PEG (8 / 2 / 3). Figure 11 Differential scanning calorimetry (DSC) curves for each composite membrane are shown below: (A) DSC plots of LPC-PLA, LPC-PLA / PCL(9 / 1), LPC-PLA / PCL(8 / 2), and LPC-PLA / PCL(7 / 3); (B) Curves at 150℃, from top to bottom: LPC-PLA / PEG(9 / 1), LPC-PLA / PEG(8 / 2), and LPC-PLA / PEG(7 / 3); (C) Curves at 175℃, from top to bottom: LPC-PLA / PCL / PEG(8 / 2 / 1), LPC-PLA / PCL / PEG(8 / 2 / 3), and LPC-PLA / PCL / PEG(8 / 2 / 2). Figure 12 The thermogravimetric curves of each composite membrane are shown below: (A) Curves at 300℃, from top to bottom: PLA, LPC-PLA / PCL (7 / 3), LPC-PLA / PCL (8 / 2), LPC-PLA / PCL (9 / 1), LPC-PLA; (B) Curves at 300℃, from top to bottom: LPC-PLA / PEG (7 / 3), LPC-PLA / PEG (8 / 2), LPC-PLA / PEG (9 / 1); (C) Curves at 300℃, from top to bottom: LPC-PLA / PCL / PEG (8 / 2 / 3), LPC-PLA / PCL / PEG (8 / 2 / 2), LPC-PLA / PCL / PEG (8 / 2 / 1). Figure 13The results are from optical microscopy observations of the composite films, where: (A) PLA; (B) LPC-PLA; (C) LPC-PLA / PCL(9 / 1); (D) LPC-PLA / PCL(8 / 2); (E) LPC-PLA / PCL(7 / 3); (F) LPC-PLA / PEG(9 / 1); (G) LPC-PLA / PEG(8 / 2); (H) LPC-PLA / PEG(7 / 3); (I) LPC-PLA / PCL / PEG(8 / 2 / 1); (J) LPC-PLA / PCL / PEG(8 / 2 / 2); (K) LPC-PLA / PCL / PEG(8 / 2 / 3). Figure 14 The drifting behavior of the gastric retention shape memory composite membrane at different times. Figure 15 The floating behavior of shape memory composite membranes retained in the stomach at different times. Figure 16 This is a schematic diagram of the shape recovery angle. Figure 17 The results show the shape memory properties of the composite membranes observed at 50℃, where: (A) PLA; (B) LPC-PLA; (C) LPC-PLA / PCL(9 / 1); (D) LPC-PLA / PCL(8 / 2); (E) LPC-PLA / PCL(7 / 3); (F) LPC-PLA / PEG(9 / 1); (G) LPC-PLA / PEG(8 / 2); (H) LPC-PLA / PEG(7 / 3); (I) LPC-PLA / PCL / PEG(8 / 2 / 1); (J) LPC-PLA / PCL / PEG(8 / 2 / 2); (K) LPC-PLA / PCL / PEG(8 / 2 / 3). Figure 18 The results of shape memory performance observation of composite membranes at a temperature of 37℃ are shown, where: (A) PLA; (B) LPC-PLA; (C) LPC-PLA / PCL(9 / 1); (D) LPC-PLA / PCL(8 / 2); (E) LPC-PLA / PCL(7 / 3); (F) LPC-PLA / PEG(9 / 1); (G) LPC-PLA / PEG(8 / 2); (H) LPC-PLA / PEG(7 / 3); (I) LPC-PLA / PCL / PEG(8 / 2 / 1); (J) LPC-PLA / PCL / PEG(8 / 2 / 2); (K) LPC-PLA / PCL / PEG(8 / 2 / 3). Figure 19 This is the drug release curve of luteolin. Figure 20To illustrate the effect of different material ratios on the in vitro release of luteolin from the composite membrane, the curves corresponding to 24 h are as follows, from top to bottom: LPC-PLA / PEG (7 / 3), LPC-PLA / PCL / PEG (8 / 2 / 3), LPC-PLA / PCL / PEG (8 / 2 / 2), LPC-PLA / PEG (8 / 2), LPC-PLA / PCL (7 / 3), LPC-PLA / PEG (9 / 1), LPC-PLA / PCL (8 / 2), LPC-PLA, LPC-PLA / PCL / PEG (8 / 2 / 1), and LPC-PLA / PCL (9 / 1). Figure 21 The effects of HPMC addition on the in vitro release of luteolin from LPC-PLA / PEG(7 / 3) are shown from top to bottom as 5%, 3%, and 1%. Figure 22 The effects of NaHCO3 addition on the in vitro release of luteolin from LPC-PLA / PEG(7 / 3) are shown from top to bottom as 5%, 3%, and 1%. Figure 23 The effect of luteolin content in the composite membrane on the in vitro release of luteolin from LPC-PLA / PEG(7 / 3) is shown in the order of 30%, 20%, and 10% from top to bottom. Figure 24 Cell viability of SGC-7901 gastric cancer cells inoculated with non-drug-loaded composite membrane extracts of the same concentration gradient; results are expressed as mean ± standard deviation; (A) PLA; (B) PLA / PCL (7 / 3); (C) PLA / PEG (7 / 3); (D) LPC-PLA / PCL / PEG (8 / 2 / 3); in each group, from left to right, the values ​​are 24h, 48h, and 72h respectively. Figure 25 The inhibition rate of 100% drug-loaded composite membrane extract on the proliferation of SGC-7901 gastric cancer cells was shown. From left to right, the groups were LPC-PLA, LPC-PLA / PCL (9 / 1), LPC-PLA / PCL (8 / 2), LPC-PLA / PCL (7 / 3), LPC-PLA / PEG (9 / 1), LPC-PLA / PEG (8 / 2), LPC-PLA / PEG (7 / 3), LPC-PLA / PCL / PEG (8 / 2 / 1), LPC-PLA / PCL / PEG (8 / 2 / 2), and LPC-PLA / PCL / PEG (8 / 2 / 3). Figure 26 The images show the morphology of cells in the control group under an inverted microscope, where: A 24 h; B 48 h; C 72 h. Figure 27 Morphological images of SGC-7901 gastric cancer cells cultured in 100% extracts of PLA, PLA / PCL, PLA / PEG (7 / 3), and PLA / PCL / PEG (8 / 2 / 3) under an inverted microscope. Figure 28Morphological images of SGC-7901 gastric cancer cells cultured in 100% extracts of LPC-PLA, LPC-PLA / PCL(9 / 1), LPC-PLA / PCL(8 / 2), LPC-PLA / PCL(7 / 3), LPC-PLA / PEG(9 / 1), LPC-PLA / PEG(8 / 2), LPC-PLA / PEG(7 / 3), LPC-PLA / PCL / PEG(8 / 2 / 1), LPC-PLA / PCL / PEG(8 / 2 / 2), and LPC-PLA / PCL / PEG(8 / 2 / 3) under an inverted microscope. Figure 29 Specificity assessment chromatograms, where: A is blank plasma; B is blank plasma + luteolin standard + internal standard; C is plasma after administration. Figure 30 The standard curve for luteolin / geraniol (n=6). Figure 31 The curves for luteolin, LPC, and LPC-PLA / PEG(7 / 3) composite membrane in rats are shown. The curves corresponding to 8 h are LPC-PLA / PEG(7 / 3), LPC, and luteolin, respectively, from top to bottom. Detailed Implementation

[0032] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0033] This invention provides a novel gastric retention drug delivery system, which uses a shape memory polymer combined with modified excipients to prepare a drug-loaded gastric retention shape memory composite membrane, and explores its development and application potential in gastric retention drug delivery systems. Gastric retention drug delivery systems have significant advantages, such as sustained-release and controlled-release properties, which can increase the drug retention time in the stomach and maintain stable blood drug concentrations, reducing the frequency of drug administration, thus showing promising clinical application prospects.

[0034] During the research process, the inventors tried various preparation methods and unexpectedly discovered that the preparation method provided by this invention was more effective. For example, they tried first laying the non-drug-loaded composite membrane and then adding the drug, but found that this method was ineffective and could not guarantee uniform drug distribution on the composite membrane. Furthermore, the research revealed that the drug content should not be too high (not exceeding 30%), as an excessively high drug content makes the composite membrane brittle, difficult to fold, and unusable.

[0035] This invention successfully designed and prepared 10 polylactic acid (PLA)-based gastric retention shape memory composite membranes with different polymer ratios, each loaded with a luteolin phospholipid complex (LPC). The polymer materials of the composite membranes included PLA, polycaprolactone (PCL), and polyethylene glycol (PEG). Appropriate amounts of hydroxypropyl methylcellulose (HPMC) and sodium bicarbonate (NaHCO3) were added to modify the composite membranes, further enhancing the gastric retention effect, prolonging their in vivo duration of action, and improving drug bioavailability. The results of this invention will lay a theoretical foundation for the development and application of novel gastric retention drug systems.

[0036] (1) LPC was prepared, and the luteolin content in LPC was determined by high performance liquid chromatography (HPLC). The LPC with the best composite rate was screened through orthogonal experiments, and the formulation with the highest composite rate was selected for the next step of preparing a gastric retention shape memory composite membrane. The phospholipid complex with the best composite rate was observed by optical microscopy, UV-Vis spectrophotometry, infrared spectroscopy, and its solubility was analyzed. Based on the orthogonal experiment results, the optimal preparation conditions for LPC were determined as follows: luteolin and soybean lecithin were weighed at a mass ratio of 1:1.2, and an appropriate amount of tetrahydrofuran was added to make the luteolin concentration 10 mg / mL. The mixture was stirred at 50℃ for 6 h, the organic solvent was removed by rotary evaporation under reduced pressure, and the mixture was dried overnight in a vacuum drying oven at 40℃. The average composite rate was calculated to be 91.45%. The quality evaluation of LPC was carried out through optical microscopy, ultraviolet testing, infrared testing and solubility testing. The experimental results showed that luteolin can be well encapsulated by soybean lecithin, and the water solubility of LPC is 2.29 times that of luteolin.

[0037] (2) Ten groups of drug-loaded gastric retention shape memory composite membranes were prepared, namely: LPC-PLA, LPC-PLA / PCL(9 / 1), LPC-PLA / PCL(8 / 2), LPC-PLA / PCL(7 / 3), LPC-PLA / PEG(9 / 1), LPC-PLA / PEG(8 / 2), LPC-PLA / PEG(7 / 3), LPC-PLA / PCL / PEG(8 / 2 / 1), LPC-PLA / PCL / PEG(8 / 2 / 2), and LPC-PLA / PCL / PEG(8 / 2 / 3). The drug-loaded gastric retention shape memory composite membranes were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The morphology of the drug-loaded gastric retention shape memory composite membranes was observed by optical microscopy. The shape memory performance, floating performance, and drug release behavior of the prepared drug-loaded gastric retention shape memory composite membranes were tested and evaluated. Characterization results showed that the drug-loaded gastric retention shape memory composite membranes all exhibited good thermodynamic properties, and the materials did not undergo denaturation during preparation. Optical microscopy revealed that the prepared gastric retention shape memory composite membranes were relatively uniformly mixed. Drug release tests showed that the composite membranes exhibited good drug release behavior, which was related to the polymer ratio, excipient ratio, and drug content. Shape memory performance tests showed that the recovery rates of the 10 types of gastric retention shape memory composite membranes prepared in this invention were all between 70-80% at 50℃ and between 60-70% at 37℃, enabling large-size deformation. Floating tests showed that the composite membranes possessed good floatability, with floating times all exceeding 8 h, and some reaching 48 h. Comprehensive characterization and evaluation revealed that LPC-PLA / PEG(7 / 3) exhibited superior performance, and further pharmacokinetic studies will be conducted on it.

[0038] (3) The in vitro inhibitory effects of the 10 drug-loaded composite membranes on SGC-7901 gastric cancer cells were evaluated by the MTT assay. The non-drug-loaded composite membranes were also subjected to the same MTT assay to study the toxicity of PLA, PLA / PCL(7 / 3), PLA / PEG(7 / 3), and PLA / PCL / PEG(8 / 2 / 3) composite membrane extracts on SGC-7901 gastric cancer cells. The effects of drug-loaded and non-drug-loaded PLA, PLA / PCL(7 / 3), PLA / PEG(7 / 3), and PLA / PCL / PEG(8 / 2 / 3) composite membranes on the number and morphology of SGC-7901 gastric cancer cells were observed directly under an inverted microscope after 72 h. The results showed that PLA, PLA / PCL (7 / 3), PLA / PEG (7 / 3), and PLA / PCL / PEG (8 / 2 / 3) composite membrane extracts did not exhibit cytotoxic effects on SGC-7901 gastric cancer cells after incubation for 24h, 48h, and 72h. The 100% drug-loaded composite membrane extract showed a significant inhibitory effect on SGC-7901 gastric cancer cells. When the composite membrane was LPC-PLA / PEG (7 / 3), its 100% composite membrane extract showed a stronger inhibitory effect on SGC-7901 gastric cancer cells than the other drug-loaded composite membrane groups, which is related to its optimal drug release. Inverted microscopy observations also confirmed this: the non-drug-loaded composite membrane extract showed no significant toxicity to SGC-7901 gastric cancer cells, and the cells maintained normal morphology; the drug-loaded composite membrane extract significantly increased the number of dead SGC-7901 gastric cancer cells and caused significant morphological changes, demonstrating significant cytotoxicity to SGC-7901 gastric cancer cells.

[0039] (4) A method for determining the content of luteolin in plasma was established using HPLC. The pharmacokinetics of luteolin, LPC, and LPC-PLA / PEG (7 / 3) in rats were studied. The pharmacokinetic results were analyzed using DAS 2.0 pharmacokinetic analysis software, and the pharmacokinetic parameters were analyzed using IBM SPSS Statistics 26.0. The results showed that the HPLC method established in this invention is simple and stable to operate, has good specificity, and the recovery rate, precision, and repeatability all meet the determination requirements. It can be used to determine the content of luteolin in rat plasma. The pharmacokinetic test results showed that LPC-PLA / PEG (7 / 3) can effectively improve the pharmacokinetic characteristics of luteolin in rats, and its bioavailability is the highest compared with luteolin and LPC.

[0040] A schematic diagram of the gastric retention drug system provided by this invention is shown below. Figure 1 As shown, the preparation of the luteolin-phospholipid complex with the optimal composite ratio is included; the preparation of the drug-free composite membrane; the preparation of the luteolin-phospholipid complex-loaded composite membrane; the loading of the drug-loaded composite membrane into capsules; and the enema administration of the capsules to rats to allow them to expand to their original shape and achieve gastric retention.

[0041] This invention uses luteolin, a relatively inexpensive drug with anticancer effects, as a model drug. It encapsulates soybean lecithin to improve its water solubility. The prepared phospholipid complex is loaded onto a PLA-based thermoresponsive gastric retention shape memory composite membrane, creating a multifunctional gastric retention drug delivery system with expandability and buoyancy. This system can prolong drug retention time in the stomach, increase drug release time in the body, improve drug bioavailability, and increase patient compliance. It offers advantages such as effectively controlling the frequency of administration, reducing drug toxicity and organ damage, increasing patient adherence, and reducing medication costs, making it more convenient for more patients to use the gastric retention system for adjuvant anticancer therapy. This system provides a novel drug delivery method for common gastric diseases and lays the foundation for the research of highly effective and low-toxicity new drug formulations for treating gastric diseases. The combined application of the novel gastric retention drug delivery system and shape memory polymers can be used to treat gastric cancer.

[0042] The following is a description through specific embodiments. Unless otherwise specified, the experimental methods used in each embodiment are conventional experimental methods in the art. Unless otherwise specified, the materials, reagents, and instruments used are conventional materials, reagents, and instruments in the art, which can be obtained through commercial channels or prepared by conventional methods.

[0043] Experimental reagents: MTT was purchased from Sigma-Aldrich (USA); PBS solution was purchased from Gibco (USA); luteolin (pharmaceutical grade, PC > 98%) was purchased from Chengdu Mansite Biotechnology Co., Ltd.; DMEM culture medium was purchased from Beijing Solarbio Co., Ltd.

[0044] Experimental instrument: High performance liquid chromatograph (Waters 1525) purchased from Waters Corporation, USA.

[0045] Human gastric cancer cells SGC-7901, provided by the School of Pharmacy (Pharmaceutical Engineering Technology Research Center) of Harbin University of Commerce, are available to the public for non-commercial purposes only to repeat the embodiments described in this invention.

[0046] Eighteen healthy male SD rats, weighing 200±10 g, were purchased from Changchun BCHT Biotechnology Co., Ltd. During the rearing process, suitable temperature and humidity, good lighting, and regular bedding changes were maintained.

[0047] Example 1: Preparation and quality evaluation of luteolin-phospholipid complex

[0048] This embodiment prepared a luteolin-phospholipid complex (LPC) to increase the water solubility of luteolin, improve its oral absorption, enhance its bioavailability, and allow the LPC-loaded gastric retention shape memory composite membrane to exert better efficacy. An orthogonal experimental design was used to obtain the phospholipid complex with the optimal luteolin-phospholipid complex ratio, and the quality of the LPC with the optimal complex ratio was evaluated. The prepared phospholipid complex was irradiated with a laser pointer to observe the presence of the Tyndall effect; the morphology and structure of the phospholipid complex were observed using an optical microscope; the spectroscopic characteristics of the prepared LPC were measured using a UV-Vis spectrophotometer; changes in the composition of the phospholipid complex were analyzed using infrared spectroscopy; and the solubility of the phospholipid complex was measured to observe whether the solubility of luteolin coated with soybean lecithin was improved.

[0049] 1.1 Determination of luteolin content

[0050] LPC was prepared by solvent evaporation method, including the following steps: weigh appropriate amounts of soybean lecithin and luteolin (mass ratio of luteolin to soybean lecithin is 1:1.2), dissolve in appropriate amount of tetrahydrofuran to make the concentration of luteolin 10 mg / mL, stir at constant temperature at 50℃ for 6 h, remove organic solvent by rotary evaporation under reduced pressure to recover the sample, dry overnight in vacuum drying oven at 40℃, and store for later use.

[0051] Preparation of reference solution: Weigh 0.004 g of luteolin, place it in a 10 mL vial, dissolve and dilute to volume with 40% methanol, and sonicate for 20 min to obtain the reference solution. Preparation of test solution: Weigh an appropriate amount of LPC, place it in a 10 mL vial, dissolve and dilute to volume with 40% methanol, and sonicate for 20 min to obtain the test solution. Preparation of negative control sample solution: Weigh 0.006 g of soybean lecithin, place it in a 10 mL volumetric flask, dissolve and dilute to volume with methanol, and sonicate for 20 min to obtain the negative control sample solution.

[0052] The luteolin content in LPC was determined using a high-performance liquid chromatography (Waters 1525) instrument. 4 mg of LPC was weighed and dissolved in 10 mL of acetonitrile, filtered through a 0.22 μm microporous membrane, and the filtrate was collected. The content of luteolin in the LPC was then determined (X1 is the mass of luteolin in the LPC, X0 is the total mass of the LPC, and the calculation formula is: composite rate = X1 / X0 × 100%).

[0053] Chromatographic conditions

[0054] Mobile phase: water containing 0.1% H3PO4:methanol (volume ratio 30:70); flow rate: 1 mL / min; injection volume: 20 μL; detection wavelength: 348 nm; column: Agilent ZORBAX SB-C18 (4.6 × 250 mm, 5 μm); column temperature: 25℃.

[0055] (1) Selection of wavelength for measurement: A UV-Vis spectrophotometer (UV-5200PC) was used to scan the maximum UV absorption wavelength of luteolin in the range of 200-400 nm. To determine the maximum absorption wavelength of luteolin and facilitate the establishment of a luteolin methodology, a UV-Vis spectrophotometer was used to scan luteolin in the range of 200-400 nm. The results are as follows: Figure 2 As shown, the maximum absorption wavelength of luteolin is 348 nm, therefore the detection wavelength of luteolin is determined to be 348 nm.

[0056] (2) Specificity: The reference solution, test solution, and negative control solution were tested under the above chromatographic conditions, and their chromatographic behavior was examined. The liquid chromatograms of the luteolin reference solution, negative control sample solution, and test solution were compared (liquid chromatograms not shown). The results showed that luteolin eluted at 2.6 min with a good peak shape. LPC had almost no interference with the determination of luteolin, and it can be considered that the liquid chromatography detection method has good specificity.

[0057] (3) Standard Curve: Accurately pipette the luteolin reference solution into 5 mL vials and dilute to volume with methanol to obtain luteolin concentrations of 7.81, 15.63, 31.25, 62.50, 100.00, 125.00, and 200.00 μg / mL, respectively. Perform the determination using the above chromatographic conditions. The x-axis represents luteolin concentration, and the y-axis represents peak area. Establish a linear regression analysis to construct the luteolin standard curve. The luteolin standard curve is shown below. Figure 3 .Depend on Figure 3 It can be seen that luteolin exhibits good linearity in the range of 7.81-200.00 μg / mL, with the regression equation being: y=1.4085x+0.7947 (R²). 2 =0.9997).

[0058] (4) Precision: Precision was mainly assessed by the instrument. The reference standard stock solution was diluted to three concentrations: high, medium, and low, namely 31.25 μg / mL, 15.63 μg / mL, and 7.81 μg / mL. The peak area was detected under the above chromatographic conditions. Each concentration sample was tested three times within one day to assess the intra-day precision of the method. The same high, medium, and low concentration samples were prepared and tested continuously for three days, with each concentration sample tested three times to monitor the inter-day precision of the instrument. The intra-day precision analysis results showed (Table 1) that there was no significant difference in the detection of drug sample content by the instrument within one day, indicating good intra-day precision with RSD% between 0.16% and 0.26%. The inter-day precision results showed that the RSD% of the three concentrations over three days was less than 0.57%, indicating good inter-day precision of the instrument.

[0059] Table 1. Intra-day and inter-day precision of luteolin (n=3)

[0060]

[0061] (5) Repeatability: Three samples of the same batch of LPC were weighed, prepared using the above-described method for preparing the test solution, and measured under the above-described chromatographic conditions. The peak area of ​​each sample was recorded to monitor repeatability. The results of the repeatability test are shown in Table 2. The results show that the average content of luteolin in the same batch of LPC was 74.42%, with an RSD of 1.01%, indicating good repeatability.

[0062] Table 2. Repeatability of luteolin (n=3)

[0063]

[0064] (6) Recovery rate: Accurately pipette 0.4 mL of LPC test solution (luteolin concentration 48.50 μg / mL) into 2 mL EP tubes, divide into 3 groups, 3 portions per group, for a total of 9 portions. Add 0.5, 1, and 1.5 mL of luteolin standard solution (15.64 μg / mL) to each group, and add 1.1, 0.6, and 0.1 mL of methanol to ensure a total volume of 2 mL. Using the above chromatographic conditions, record the peak area of ​​each sample and monitor the recovery rate. The results of the recovery rate test are shown in Table 3. The average recovery rate of luteolin was 100.42%, and the RSD was 2.03%, indicating that the recovery rate of this method is high.

[0065] Table 3 Recovery rate of luteolin (n=9)

[0066]

[0067] (7) Stability: Take an appropriate amount of LPC (0.4 g), prepare the test solution according to the above method, and place it at room temperature for 0, 12, and 24 h. Then, determine the stability under the above chromatographic conditions. Record the peak area of ​​each sample and monitor the stability of the test solution within 24 h. The results of the stability test are shown in Table 4. The results show that the RSD is 1.79%, indicating that the LPC solution is stable within 24 h.

[0068] Table 4 Stability of luteolin

[0069]

[0070] 1.2 Orthogonal Experiment

[0071] (1) Orthogonal experimental design: Based on the preliminary experimental results, stirring time, stirring temperature, luteolin concentration, and the ratio of luteolin to soybean lecithin (mass ratio) were selected as factors for investigation and an orthogonal design was carried out. The factor levels are shown in Table 5.

[0072] Table 5 Orthogonal Factor Level Table

[0073]

[0074] Orthogonal Experiment Results: Preliminary experiments revealed that the phospholipid complex complex composite rate was mainly affected by stirring time (A), stirring temperature (B), luteolin concentration (C), and the ratio of luteolin to soybean lecithin (D). Therefore, an orthogonal experiment was designed with these four factors as influencing factors, and the composite rate was used as the evaluation index. The experimental results are shown in Tables 6 and 7. RA indicates that the order of influence of each factor on the overall result is B>A>C>D. The ANOVA table shows that factor B has a statistically significant impact on the overall result, while the differences within levels A, C, and D are not statistically significant. In factor A, K3 > K2 > K1; in factor B, K3 > K2 > K1; in factor C, K1 > K2 > K3; and in factor D, K2 > K1 > K3. Therefore, the optimal formulation for LPC preparation is determined to be A3-B3-C1-D2, which means weighing luteolin and soybean lecithin in a 1:1.2 ratio (mass ratio), adding an appropriate amount of tetrahydrofuran to make the luteolin concentration 10 mg / mL, stirring at 50℃ for 6 h, and then drying under reduced pressure by rotary evaporation.

[0075] Table 6 Experimental Design and Results

[0076]

[0077] Table 7 Analysis of Variance

[0078]

[0079] (2) Verification test: Three batches of LPC were prepared according to the optimal formulation selected by the orthogonal experiment. Each batch was measured three times in parallel, and the composite rate was used as the fitting score to examine the process stability. The average composite rate of the three batches of LPC prepared according to the optimal formulation selected by the orthogonal experiment was 91.45%, and the RSD was 1.14%, indicating that the process was stable (Table 8). The LPC used in subsequent experiments was prepared using the optimal formulation.

[0080] Table 8. Combination rate of three batches of LPC prepared with the optimal formulation

[0081]

[0082] 1.3 Quality Evaluation of LPC

[0083] (1) Tyndall effect: Weigh appropriate amounts of luteolin and soybean lecithin (the mass ratio of luteolin to soybean lecithin is 1:1.2), add appropriate amount of tetrahydrofuran to make the concentration of luteolin 10 mg / mL, and stir at a constant temperature under certain temperature conditions (stirring at 50℃ for 6 h). Observe whether the solution produces the Tyndall effect by irradiating with a laser pointer to preliminarily determine whether the LPC preparation is successful. During the LPC preparation process, the LPC solution was observed by irradiating with a laser pointer, and it was found that the solution could produce the Tyndall effect ( Figure 4 This initially determined that the LPC solution possessed colloidal properties, rather than being a mixture of liquid and particles. The LPC prepared using the solvent evaporation method was dried and sieved to obtain the finished LPC product, as shown in the image. Figure 5 As shown in the figure. Observation shows that the prepared phospholipid complex has a uniform color, full particles, and a deeper color than the luteolin standard, appearing golden yellow. It can be preliminarily judged that the phospholipid complex was successfully prepared.

[0084] (2) Optical Microscopy Observation: After drying the LPC prepared according to the above optimal formulation, the prepared phospholipid complex was diluted with a small amount of distilled water, dropped onto a glass slide, covered with a coverslip, and excess water was absorbed at the edges with absorbent paper. The slide was then placed under an optical microscope for observation and photographing. The objective lens was 100×1.25. Microscopy is often used to observe particle morphology. Morphological observation revealed that the LPC particles were intact and had a uniform spherical or near-spherical structure. A distinct and uniform halo surrounded the dispersed LPC particles, which was a soybean lecithin layer, indicating that soybean lecithin had good encapsulation properties for luteolin. Figure 6 ).

[0085] (3) Ultraviolet spectroscopy: Luteolin, phospholipids, and LPC samples were dissolved in methanol to prepare sample solutions of known concentration (20 μg / mL). Ultraviolet spectrophotometers were used to scan the samples in the wavelength range of 200-400 nm. Analysis revealed that phospholipids only exhibited terminal absorption near 210 nm. The absorption curves of luteolin and LPC were essentially the same, with two distinct characteristic absorption bands around 254 nm and 348 nm. Figure 7 The spectra of luteolin and phospholipid complexes are similar, indicating that no new chromophores were formed during the complexation process of luteolin and soybean phospholipids, i.e., no new substances were formed.

[0086] (4) Fourier Transform Infrared Spectroscopy: The major functional groups in the components were detected using a Fourier Transform Infrared Spectrometer (AVATAR360). The Fourier Transform Infrared spectra of luteolin, phospholipids, and the prepared LPC were obtained using FTIR. Potassium bromide and an appropriate amount of sample were ground into a fine powder and compressed into a disc under a hydraulic press at 10000 psi for 30 s. Each processed sample was sieved at 4000-500 cm⁻¹. -1The scan was performed within the wavenumber region. The results are as follows: Figure 8 As shown, the infrared spectrum of LPC showed no significant change compared to luteolin and phospholipids. From Figure 8 It can be seen that luteolin is present at 3425 cm. -1 There is a characteristic absorption peak of the -OH group nearby, at 1692 cm⁻¹. -1 The area near the C=C characteristic absorption peak is observed. Soybean lecithin exhibits an absorption peak at 2994 cm⁻¹. -1 The -CH2- group, representing saturated hydrocarbons, is present at these positions. LPC exhibits characteristic absorption peaks at these locations, indicating that LPC combines luteolin and soybean lecithin, thus retaining the properties of luteolin.

[0087] (5) Solubility determination: Excess luteolin, the physical mixture (a mixture of luteolin and soybean lecithin), and the phospholipid complex were placed in separate Erlenmeyer flasks, double-distilled water was added, and the mixture was magnetically stirred at room temperature for 24 h, centrifuged at 5000 r / min for 20 min, filtered, and injected under the above chromatographic conditions to determine the apparent solubility. To improve the gastric delivery efficiency of oral drugs with poor water solubility, it is necessary to improve the water solubility of the drug in the gastrointestinal tract. Improving the water solubility of the drug can be achieved by preparing the drug into a phospholipid complex. The calculation results of the apparent solubility of luteolin, the physical mixture, and LPC are shown in Table 9. The solubility of LPC in water is 2.29 times higher than that of luteolin, and the solubility of LPC in n-octanol is higher than that in water.

[0088] Table 9 Results of apparent solubility determination of samples ( ±s, n= 3)

[0089]

[0090] This embodiment obtained the optimal composite rate of LPC through orthogonal experiments, and verified the good performance of LPC through characterization experiments such as infrared and ultraviolet, laying the foundation for the combined application of LPC and gastric retention shape memory composite membrane.

[0091] Example 2: Preparation and characterization of drug-loaded gastric retention shape memory composite membrane

[0092] The gastric retention drug system provided by this invention can improve drug bioavailability, enable drugs to exert their effects locally in the stomach, reduce drug side effects, prolong dosing intervals, and improve patient compliance. This embodiment applies shape memory polymers to the gastric retention drug system, preparing a thermally responsive gastric retention shape memory composite membrane. Utilizing the deformability and buoyancy of the composite membrane, the retention time of the drug-loaded composite membrane in the stomach is prolonged, increasing drug bioavailability. First, the composite membrane is prepared using polylactic acid (PLA) as the main material. Polycaprolactone (PCL) and polyethylene glycol (PEG) are added to modify the main material, lowering the glass transition temperature (Tg) of the composite membrane and making its deformation temperature closer to human body temperature. Furthermore, excipients hydroxypropyl methylcellulose (HPCC) and sodium bicarbonate (NaHCO3) are added to the composite membrane to increase its gastric retention time. The composite membrane was then characterized using methods including Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). FTIR analysis was used to analyze the changes in material composition and stability of the composite membrane. DSC analysis was used to analyze the glass transition temperature and melting temperature of the composite membrane, observing the effects of PCL and PEG on the glass transition temperature of PLA, and investigating whether lowering the glass transition temperature of PLA would make it more suitable for deformation response at human stomach temperatures. Thermogravimetric analysis (TGA) was used to assess the thermal stability of the composite membrane and observe its thermal decomposition temperature. Optical microscopy was used to observe the effects of the addition of PCL and PEG on the surface of the PLA-based gastric retention shape memory composite membrane. The effects of shape memory on the composite membrane and the compatibility between materials were investigated. Shape memory recovery rate tests were used to observe the deformation recovery of the prepared composite membrane at human body temperature and glass transition temperature. A floating experiment was conducted to observe the floating of the prepared composite membrane in simulated gastric juice, investigating whether the floating time was suitable for a gastric retention drug system. A constant-temperature oscillator was used to study the drug release from the composite membrane, examining the effects of the HPMC addition ratio, NaHCO3 addition ratio, luteolin concentration, and composite membrane polymer ratio on luteolin release, determining the optimal excipient ratio for drug release. Based on the comprehensive analysis of the above experimental results, the optimal formulation of the LPC-loaded gastric retention shape memory composite membrane was screened, preparing for in vivo pharmacokinetic evaluation in rats.

[0093] 2.1 Preparation of drug-loaded composite membranes and drug-free composite membranes

[0094] The preparation of drug-free composite membranes includes the following steps:

[0095] (1) The polymer includes one or more of PLA, PCL and PEG, and 10 formulations are prepared according to Table 10.

[0096] Table 10 Polymer Ratio in Thermally Response Gastric Retention Shape Memory Composite Membrane

[0097]

[0098] (2) Mix the polymer with dichloromethane (CH2Cl2) at a mass ratio of 1:7 to obtain solution 1.

[0099] For formulation 1, the polymer is PLA, and the mass ratio of PLA to dichloromethane is 1:7; for formulations 2 to 4, the polymers include PLA and PCL, and the mass ratio of the sum of (PLA+PCL) to dichloromethane is 1:7; for formulations 5 to 7, the polymers include PLA and PEG, and the mass ratio of the sum of (PLA+PEG) to dichloromethane is 1:7; for formulations 8 to 10, the polymers include PLA, PCL, and PEG, and the mass ratio of the sum of (PLA+PCL+PEG) to dichloromethane is 1:7.

[0100] (3) Dissolve a fixed mass of hydroxypropyl methylcellulose (HPMC) and NaHCO3 in distilled water, (HPMC+NaHCO3):water = 1:10 (mass ratio), stir thoroughly and let stand to make a solution, and obtain solution 2.

[0101] (4) Mix solution 1 and solution 2 and stir with a mechanical stirrer for 4 h. Then, evaporate CH2Cl2 and water in the blend at room temperature and mold it to obtain a thin film with a thickness of 1 mm and a pressure of 10 MPa, thus obtaining a drug-free composite membrane.

[0102] The method for preparing the drug-loaded composite membrane is the same as the method described above, except that in step (4), when the composite membrane solution is mechanically stirred for 3.5 h, a fixed mass of LPC is added, and mechanical stirring is continued for another 0.5 h. Subsequently, the CH2Cl2 and water in the blend are evaporated, and thin sheets with a thickness of 1 mm are obtained by molding at a pressure of 10 MPa, thus obtaining the drug-loaded composite membrane. LPC-PLA, LPC-PLA / PCL(9 / 1), LPC-PLA / PCL(8 / 2), LPC-PLA / PCL(7 / 3), LPC-PLA / PEG(9 / 1), LPC-PLA / PEG(8 / 2), LPC-PLA / PEG(7 / 3), LPC-PLA / PCL / PEG(8 / 2 / 1), LPC-PLA / PCL / PEG(8 / 2 / 2), and LPC-PLA / PCL / PEG(8 / 2 / 3) drug-loaded gastric retention shape memory composite membranes were prepared by the above method.

[0103] When HPMC is 5% (by mass) of the polymer, NaHCO3 is 5% (by mass) of the polymer, and LPC is 30% (by mass) of the mixture (total mass of polymer, HPMC, and NaHCO3), the appearance of the drug-loaded composite membranes obtained is shown in the figure. Figure 9 The dried composite membranes were uniformly golden in color. Small particle protrusions were present on the surface of the composite membrane, indicating LPC. This contrasts with LPC-PLA without HPMC and NaHCO3 (i.e., without added HPMC and NaHCO3). Figure 9 As shown in Figure J, it can be observed that the addition of HPMC and NaHCO3 can promote a more uniform surface of the composite membrane.

[0104] 2.2 Characterization Experiment of Gastric Retention Shape Memory Composite Membrane

[0105] (1) Fourier Transform Infrared Spectroscopy: The chemical structure of polymer materials can be studied by FTIR. Based on the characteristic absorption peaks shown in the results, the special chemical bonds and functional groups contained in the polymer materials can be analyzed. At the same time, it can be detected whether the chemical bonds and chemical structure of the material change before and after mixing. FTIR is used to evaluate the molecular properties of different samples. This invention uses an FTIR instrument to determine the characteristic functional groups of materials. The sample is ground into a fine powder, potassium bromide is added and compressed to prepare a 5×5 mm transparent sheet. At 4500-300 cm⁻¹ -1 The spectral range was scanned. Figure 10 The specific FTIR analysis results for LPC-PLA, LPC-PLA / PCL(9 / 1), LPC-PLA / PCL(8 / 2), LPC-PLA / PCL(7 / 3), LPC-PLA / PEG(9 / 1), LPC-PLA / PEG(8 / 2), LPC-PLA / PEG(7 / 3), LPC-PLA / PCL / PEG(8 / 2 / 1), LPC-PLA / PCL / PEG(8 / 2 / 2), and LPC-PLA / PCL / PEG(8 / 2 / 3) are presented. Figure 10 As shown in (A), the stretching vibration peak of PLA at C=O is at 1749 cm⁻¹. -1 At this point, the stretching vibration peak of COC appears at 1081 cm⁻¹. -1 1132 cm -1 1184 cm -1 Location; 1454cm -1 and 1381 cm -1 The peaks for the stretching and bending vibrations of -CH are located at 1749 cm⁻¹. The peak for the C=O stretching vibrations of PCL appears at 1749 cm⁻¹. -1 At this point, the stretching vibration peak of COC appears at 1083 cm⁻¹.-1 1128 cm -1 1181 cm -1 The stretching and bending vibration peaks of -CH are at 1448 cm⁻¹. -1 and 1374 cm -1 The C=O stretching vibration peak of PLA / PCL material appears at 1749 cm⁻¹. -1 At this point, the stretching vibration peak of COC appears at 1081 cm⁻¹. -1 1132 cm -1 and 1184 cm -1 The stretching and bending vibration peaks of -CH are at 1455 cm⁻¹. -1 and 1386 cm -1 The characteristic peaks of PLA and PCL molecules did not change significantly in position, nor were any new characteristic peaks generated, indicating that no denaturation occurred between them. The C=O stretching vibration peak of PEG appeared at 1742 cm⁻¹. -1 At this point, the stretching vibration peak of COC appears at 1073 cm⁻¹. -1 1113 cm -1 1204 cm -1 Location; 1465 cm -1 and 2876 cm -1 The peaks at 1378 cm⁻¹ are the bending vibration peak and the symmetrical stretching vibration peak of -CH₂-. -1 The peak at 844 cm⁻¹ is a symmetrical deformation vibration peak of -CH₃. -1 The peak at this location is an in-plane deformation peak of -CH2CH2O-. Through analysis... Figure 10 (B) It was found that the characteristic peaks of PLA / PEG materials at these locations are basically consistent. Through analysis... Figure 10 (C) It was found that the stretching vibration peak of C=O in PLA / PCL / PEG material appears at 1750 cm⁻¹. -1 At this point, the stretching vibration peak of COC appears at 1081 cm⁻¹. -1 1130 cm -1 1182 cm -1Based on the above analysis, it can be seen that the characteristic peaks of PLA, PCL, and PEG molecules in the PLA / PCL / PEG composite film are consistent with the characteristic peaks of the individual materials. In summary, it can be determined that LPC-PLA, LPC-PLA / PCL(9 / 1), LPC-PLA / PCL(8 / 2), LPC-PLA / PCL(7 / 3), LPC-PLA / PEG(9 / 1), LPC-PLA / PEG(8 / 2), LPC-PLA / PEG(7 / 3), LPC-PLA / PCL / PEG(8 / 2 / 1), LPC-PLA / PCL / PEG(8 / 2 / 2), and LPC-PLA / PCL / PEG(8 / 2 / 3) are all physically blended. After observation... Figure 10 It can also be found that these drug-loaded materials were present in 1692. -1 2994 -1 and 3425 -1 Characteristic peaks were found nearby, which corresponded to the positions of LPC characteristic peaks obtained from the FTIR analysis above, indicating that LPC in the blend material was not modified.

[0106] (2) Differential Scanning Calorimetry (DSC): DSC analysis is a common method for evaluating the thermal properties of materials. The powder on the prepared sample plate was filed into sample powder using a file. The DSC curves were obtained under a nitrogen flow and tested using a two-stage heating method. The temperature range was selected within 25-200℃, and the temperature was slowly increased and decreased at a rate of 10℃ / min. The glass transition temperature (Tg) and melting point (Tm) of the ten thermally responsive drug-loaded composite films were determined using a differential scanning calorimeter (DSC-500L) to analyze the changes in thermal performance parameters of the composite films during temperature changes. Figure 11 The table shows the secondary heating curves for PLA, LPC-PLA, LPC-PLA / PCL(9 / 1), LPC-PLA / PCL(8 / 2), LPC-PLA / PCL(7 / 3), LPC-PLA / PEG(9 / 1), LPC-PLA / PEG(8 / 2), LPC-PLA / PEG(7 / 3), LPC-PLA / PCL / PEG(8 / 2 / 1), LPC-PLA / PCL / PEG(8 / 2 / 2), and LPC-PLA / PCL / PEG(8 / 2 / 3). Table 11 provides detailed Tg and Tm values ​​for the ten composite membranes. The results show that the Tg of PLA is around 56℃, and the Tm is around 171℃. The Tg of LPC-PLA is 56.77℃. The addition of LPC, HPMC, and NaHCO3 does not affect the Tg. The Tm of LPC-PLA is 162.06℃, which is lower than that of PLA. This may be because the addition of excipients and drugs reduces the crystalline regions in the polymer matrix material, thereby lowering the Tm value. Analysis Figure 11(A) It can be seen that after adding PCL to the composite membrane, the Tg of the material decreased by about 10℃, indicating a significant modification effect. However, the melting temperature of the material remained around 160℃, without significant change. Analysis Figure 11 (B) It can be seen that the Tg value of LPC-PLA / PEG (7 / 3) is about 10℃ lower than that of LPC-PLA, indicating that the addition of PEG also has a certain modifying effect on the composite material. We were unable to measure the Tg of LPC-PLA / PEG (9 / 1) and LPC-PLA / PEG (8 / 2), which may be related to multi-peak overlap. We speculate that the reason for the decrease in Tg value due to the blending of PEG and PLA may be that PEG can enter between polylactic acid macromolecules during melt mixing and can establish physical interactions such as hydrogen bonds or dipole-dipole interactions between atoms. Therefore, some rigid and uniform PLA-PLA interactions will be replaced by non-uniform PLA-PEG interactions. This phenomenon may provide better macromolecular motion and reduce Tg by reducing the energy during the glass transition process. The addition of PEG has an effect on the melting temperature of the composite material. Within our addition ratio range, the Tm of the composite material decreases with the increase of PEG ratio. The reason may be that the addition of PEG causes the PLA and PCL to exhibit crystalline disorder and defects, resulting in a decrease in the melting point of the composite material. The intergroup test results for LPC-PLA / PCL / PEG(8 / 2 / 1), LPC-PLA / PCL / PEG(8 / 2 / 2), and LPC-PLA / PCL / PEG(8 / 2 / 3) are as follows: Figure 11 As shown in (C), in LPC-PLA / PCL, the Tg and Tm values ​​decrease sequentially with the increase of PEG ratio, and in the LPC-PLA / PCL / PEG (8 / 2 / 3) group, the Tg and Tm values ​​are the lowest among the ten test groups.

[0107] Table 11 Thermal performance parameters of composite membranes

[0108]

[0109] (3) Thermogravimetric analysis: Thermogravimetric analysis is a common method for testing the thermal properties of materials. A thermogravimetric analyzer was used for testing. During the test, powder was scraped from the prepared sample plate using a file, which served as the test sample. The sample was placed in an aluminum crucible and heated from 25°C to 800°C at a heating rate of 10°C / min under a nitrogen atmosphere. The mass loss curves of the 10 drug-loaded gastric retention shape memory composite membranes prepared in this invention under heating conditions are shown below. Figure 12As shown, the TGA curve of the gastric retention shape memory composite membrane exhibits three stages of mass loss. The first stage is attributed to the loss of water molecules (below 250℃); the second stage involves the thermal degradation of the polymer in the gastric retention shape memory composite membrane between 250-400℃; and the third stage involves the carbonization of the polymeric material (400-550℃). Figure 12 The curves show that all materials prepared in the experiment underwent thermal decomposition under heating. The temperature at which the materials were completely decomposed was around 450℃, and the residual carbon rate was 0. The degradation initiation temperature of PLA material was around 350℃, and the degradation peak temperature was around 360℃, indicating that PLA has no water content. Comparison of LPC-PLA and PLA curves reveals that ( Figure 12 (A) The addition of LPC, HPMC, and NaHCO3 significantly reduced the degradation initiation temperature of PLA, with the initial decomposition temperature of the material appearing at around 200℃. Furthermore, the addition of LPC, HPMC, and NaHCO3 significantly reduced the peak degradation temperature of PLA, with the peak degradation temperature appearing at around 250℃. This indicates that HPMC increased the water retention capacity of the composite material, enabling it to degrade significantly before 250℃. Compared to LPC-PLA, the research results for different ratios of the same material (LPC-PLA / PCL (9 / 1), LPC-PLA / PCL (8 / 2), and LPC-PLA / PCL (7 / 3) showed that with increasing PCL content, the degradation initiation temperature and peak degradation temperature increased slightly. Compared to LPC-PLA, the heat resistance of the material was slightly increased. The addition of PCL to PLA increased the initial decomposition temperature of the composite material, indicating improved heat resistance. Furthermore, the initial decomposition temperature showed an upward trend with increasing PCL content. This can be attributed to the improved heat resistance of the material due to the addition of PCL. Figure 12 (B) Figure 12 (C) The results show that the initial decomposition temperature of the material decreased after the addition of PEG, indicating that the material is more easily decomposed than before modification. Furthermore, the initial decomposition temperature increased with increasing PEG content, while the complete decomposition temperature of the composite material was earlier than that of the PLA / PCL blend group. Therefore, it can be inferred that the heat resistance of the material decreased slightly after the addition of PEG. In summary, the ten groups of gastric retention shape memory composite membranes prepared exhibited good thermal stability and maintained stable properties below 200℃.

[0110] (4) Optical Microscopy Observation: The microstructure of the composite material samples was observed using an optical microscope. Optical images of the composite material were taken at room temperature, focusing on areas with good light transmittance. A 20×0.5 objective lens was used. The experimental results are as follows: Figure 13 As shown, shape memory gastric retention smart materials all possess typical optical microstructures. Figure 13(A) indicates that the microstructure of PLA is relatively simple, containing only PLA particles, and these particles are closely arranged, which is a characteristic of good compatibility between monomers. Figure 13 (B)-(K) indicate that the surface of the drug-loaded gastric retention shape memory composite membrane is pale yellow and the color distribution is uniform, indicating that LPC is well distributed in the gastric retention shape memory composite membrane. Compared with PLA, LPC-PLA exhibits slight phase separation, which is due to the addition of excipients HPMC and NaHCO3. Figure 13 (B)). Through observation Figure 13 Studies (C)-(E) revealed that the higher the proportion of PCL added, the more uneven the surface of the composite membrane became, and bubbles were generated, indicating that the separation between PLA and PCL phases was more significant. This is because PCL and PLA form a multiphase structure with poor interfacial adhesion. Through observation... Figure 13 (F)-(H) found that PEG has better material compatibility with PLA than PCL with PLA. The higher the proportion of PEG added, the more uniform the surface of the composite film. The addition of PEG is conducive to the formation of pores in PLA material, thereby changing the distribution of material pore size. Figure 13 The results shown in (I)-(K) further validate the above viewpoint. The addition of PEG can effectively improve the uniformity of the PLA-PCL composite film surface. Compared with PCL, PEG has better compatibility with PLA.

[0111] (5) Floating Test: The in vitro floating ability of the gastric retention shape memory composite membrane was observed by the floating time. Ten groups of drug-loaded composite membranes were placed in 50 mL beakers containing simulated gastric fluid, and were pressed to the bottom of the beaker with the assistance of a glass rod. The floating time and the floating state of the composite membrane were recorded. In addition, the floating state of the drug-loaded composite membranes was recorded at 0, 0.5, 1, 2, 4, 6, 8, 12, 24 and 48 h at 37.0±0.5℃. The results of the in vitro simulated floating experiment of the 10 groups of gastric retention shape memory composite membranes are as follows: Figure 14 and Figure 15As shown in Table 12, the floating time results are as follows. The experimental results show that the initial floating time of all 10 groups of composite membranes is within 1 second. This may be because the blending of materials transforms the dense structure of PLA into an overall loose and porous structure. During the process of solvent evaporation into the composite membrane, this porous structure forms closed bubble spaces, which allows the drug-loaded composite membrane to float in the simulated gastric fluid. Therefore, it can quickly float above the gastric fluid when initially placed. As time increases, it can be observed that the gastric retention shape memory composite membrane releases LPC, turning the solution yellow, and bubbles are generated on the cup wall. This is because NaHCO3 in the gastric retention shape memory composite membrane reacts with hydrochloric acid to generate CO2, producing small bubbles that promote the release of LPC. Between 0 and 8 hours, all ten groups of drug-loaded composite membranes remained floating above the simulated gastric fluid. Between 8 and 12 hours, LPC-PLA / PCL / PEG (8 / 2 / 3) changed from a floating state to a sinking state, while the remaining drug-loaded composite membranes continued to float. Between 12 and 24 hours, LPC-PLA, LPC-PLA / PCL(7 / 3), LPC-PLA / PEG(7 / 3), and LPC-PLA / PCL / PEG(8 / 2 / 2) precipitated. This suggests that the NaHCO3 in the composite membrane reacted completely, with no further bubble generation, and that water molecules penetrated most of the pores of the composite membrane after immersion in the liquid, leading to precipitation. Between 24 and 48 hours, LPC-PLA / PEG(9 / 1) precipitated, while LPC-PLA / PCL(9 / 1), LPC-PLA / PCL(8 / 2), LPC-PLA / PEG(8 / 2), and LPC-PLA / PCL / PEG(8 / 2 / 1) did not precipitate within 48 hours. In summary, all 10 drug-loaded composite membranes prepared by this invention remained in a floating state within 8 hours, with some of the drug-loaded composite membranes floating for more than 48 hours, indicating that the prepared drug-loaded gastric retention shape memory composite membranes have good floating performance.

[0112] Table 12 Floating behavior of composite membranes at different times

[0113]

[0114] (6) Shape Memory Performance Test: The gastric retention shape memory composite membrane prepared in this invention contains a thermosensitive shape memory polymer. The shape memory performance of the material is characterized by the recovery rate parameter. The shape memory performance of the gastric retention shape memory composite membrane was tested by a bending experiment. The sample was processed into a size of 50 mm × 4 mm × 1 mm, and a glass rod with a diameter of 5 mm was used as the core rod. The sample and the glass rod were placed in a constant temperature water bath at 50°C for 5 min. Then, the sample was bent at 180°C for 10 s with the glass rod. Then, the sample was placed in cold water at 5°C for 10 s. Finally, the sample was placed in hot water at 50°C again, and the shape recovery of the sample was recorded with a camera at 0 s, 3 s, 9 s, and 60 s. The shape recovery time refers to the time required for the molded polymer to recover to its original shape after reheating. The shape recovery rate is usually indicated by the recovery angle, which is the change in angle of the material at different times during the shape recovery process, that is, the angle between the two ends of the sample after the polymer is bent and molded. See Figure 16 t refers to the material thickness, r is the bending radius, and θ is the shape recovery angle. S0 is parallel to the fixed end of the bent sample and passes through the endpoint of the centerline of the circle. x This is the distance of the sample from the center of the circle during the recovery process. The shape recovery rate is calculated using formula (1-1).

[0115] (1-1)

[0116] The diameter of the human pylorus is 15 mm. To prevent the shape-recovery composite membrane from flowing out of the pylorus, certain requirements are placed on the folding angle and length of the membrane. Therefore, we designed and prepared a membrane with a length of 50 mm. The shape recovery process of ten different gastric retention shape memory composite membranes was recorded and calculated using a camera under stress conditions of Tg temperature (50℃) and human body temperature (37℃). The results are as follows: Figure 17 and Figure 18 As shown. At a glass transition temperature of 50°C, the addition of auxiliary materials HPMC and NaHCO3 has a certain impact on the shape recovery rate of the composite film. Compared with PLA alone, the addition of auxiliary materials prolongs the shape recovery time of the composite film and exhibits a lower recovery rate. Figure 17 A and Figure 18 B); Even so, when the shape recovery time is extended to 60 seconds, the deformation recovery rate of the LPC-PLA group can still reach 70%. Figure 17 B and Figure 18As can be seen from K, the addition of PEG and PCL to PLA has little effect on the shape memory recovery performance of the composite membrane. Within 60 seconds, the shape recovery rate of each group of composite membranes was within the range of 70-90%, indicating relatively ideal shape recovery performance. This is likely because PLA has the largest proportion, and as the stationary phase, it provides the corresponding driving force for shape recovery. Unmelted PLA macromolecules and microcrystals form some physical entanglement points, providing the deformation driving force. Considering that shape memory gastric retention smart materials will be used to treat patients with gastric cancer, this invention, based on the investigation of the composite membrane deformation process at the glass transition temperature, further studied its deformation capability under stress conditions at 37℃, in order to provide a theoretical basis for the clinical application of the composite membrane. Experimental results are as follows: Figure 18 As shown, the decrease in stress temperature does indeed affect the shape recovery ability of the ten composite membranes (by about 10%), with a deformation recovery rate of about 60%, resulting in a diagonal side length of 25 mm. This recovery rate also meets the size requirements for achieving gastric retention.

[0117] 2.3 Study on luteolin release from LPC-loaded gastric retention shape memory composite membrane

[0118] (1) Construction of the luteolin standard curve: Accurately weigh 10 mg of luteolin standard and dissolve it completely in methanol solution. Add simulated gastric fluid to a 10 mL volumetric flask and dilute to volume. Dilute to different concentrations according to the same ratio, and measure the absorbance at 348 nm using a UV-7 spectrophotometer. Plot the luteolin standard curve with concentration on the x-axis and absorbance on the y-axis. The luteolin standard curve is shown below. Figure 19 As shown, the standard curve equation for luteolin is y = 0.0067x - 0.0389, R0 2 = 0.9969, indicating a good linear relationship.

[0119] (2) Effect of polymer ratio on luteolin release from the composite membrane: The release of luteolin from the gastric retention shape memory composite membrane was studied using a constant-temperature shaker. The effect of the polymer ratio in the composite membrane on the release of luteolin was investigated. The polymer ratio is shown in Example 2.1. Based on Example 2.1, the proportion of HPMC added to the composite membrane was kept constant at 1 wt% (i.e., HPMC is 1% of the polymer), the proportion of NaHCO3 added was kept constant at 1 wt% (NaHCO3 is 1% of the polymer), and the proportion of LPC added was kept constant at 10 wt% (i.e., LPC is 10% of the total mass of polymer, HPMC, and NaHCO3). 2.73 g of the gastric retention shape memory composite membrane was placed in a glass beaker containing 500 mL of simulated gastric fluid. The beaker was placed in a constant-temperature shaker, which was continuously shaken at 100 rpm. The temperature environment was set at 37℃ ± 0.5℃. Equal volumes of test solution were collected at 1 h, 2 h, 3 h, 4 h, 6 h, 8 h, 1 d, 2 d, 3 d, 4 d, 5 d, 6 d, and 7 d, and replaced with an equal volume of release medium (simulated gastric juice) to ensure a constant total volume throughout the overall release experiment. The release of luteolin was analyzed at 348 nm using a UV-Vis spectrophotometer, and the concentration of luteolin in the samples was calculated using a standard curve. The in vitro release study was performed in triplicate, and the percentage of drug release was plotted based on the average value.

[0120] This embodiment investigated the effect of polymer ratio on the release behavior of luteolin in the composite membrane. Under the condition that the proportions of HPMC, NaHCO3, and LPC remained constant at 1%, the effect of polymer ratio on drug release from the composite membrane was as follows: Figure 20 As shown, the gastric retention shape memory composite membranes with different polymer ratios exhibited the highest drug release rate in the first 0-7 hours, and also demonstrated sustained drug release, with drug release still detectable at 24 hours. With increasing PEG ratio, the cumulative drug release increased accordingly. LPC-PLA / PEG (7 / 3) showed the highest cumulative drug release at all detection time points, reaching 31.42% at 24 hours. LPC-PLA / PCL / PEG (8 / 2 / 3) ranked second in cumulative drug release, with a 24-hour cumulative release rate of 28.95%. This indicates that PEG has a certain promoting effect on the release of luteolin from the composite membrane. The addition of PCL also has a certain promoting effect on drug release from the composite membrane, but its addition ratio needs to reach a certain value. Figure 20The results showed that the cumulative drug release of the LPC-PLA / PCL(7 / 3) composite membrane and the LPC-PLA / PCL(8 / 2) composite membrane was greater than that of LPC-PLA, while the cumulative drug release of the LPC-PLA / PCL(8 / 2) composite membrane was less than that of the LPC-PLA composite membrane. The inventors speculate that the addition of PEG and PCL promotes drug release because they disrupt the polymer network formed by PLA itself. As the ratio of PCL to PEG increases, the free voids between the structures formed by PLA itself increase, thereby promoting drug release. In contrast, PEG has a stronger effect on promoting drug release than PCL, possibly due to the different properties of PEG and PCL in the materials. The addition of PEG leads to the formation of large pores in PLA, which is beneficial for drug release. Furthermore, PCL and PLA form a multiphase structure thermodynamically with poor interfacial adhesion. The composite membrane may exhibit PCL agglomeration with other materials. The agglomerates have fewer pores, resulting in the composite membrane with added PCL having inferior drug release compared to the composite membrane with added PEG.

[0121] (3) Effect of HPMC addition ratio on luteolin release in composite membrane: The effect of HPMC addition ratios of 1%, 2%, and 3% (mass ratios of HPMC to polymer of 1%, 2%, and 3%, respectively) on luteolin release in composite membrane was investigated. Based on Example 2.1, using composite membrane LPC-PLA / PEG (7 / 3) as the research object, the addition ratio of NaHCO3 was kept constant at 1 wt% (i.e., NaHCO3 is 1% of the polymer) and the addition ratio of LPC was kept constant at 10 wt% (i.e., LPC is 10% of the total mass of polymer, HPMC, and NaHCO3). The release amount of luteolin was determined according to the above method. Using composite membrane LPC-PLA / PEG (7 / 3) as the research object, under the constant conditions of 1% NaHCO3 addition ratio and 10% LPC addition ratio, the effect of HPMC addition amount (1%, 3%, and 5%) on luteolin release was investigated. The experimental results are as follows. Figure 21As shown, at the same drug release detection time point, the cumulative drug release increased with the increase of HPMC addition ratio. At 24 h, the cumulative release rate of luteolin in LPC-PLA / PEG(7 / 3) containing 5% HPMC reached 46.85%. Based on the above examples, it is known that high HPMC content affects the deformation rate of the composite membrane. In this invention, a 5% HPMC concentration was selected as the addition ratio of luteolin as a pharmaceutical excipient. Furthermore, LPC-PLA / PEG(7 / 3) containing different proportions of HPMC exhibited a biphasic release phenomenon in vitro. The rapid drug release phenomenon in the gastric retention shape memory composite membrane in the first 7 h may be due to the fact that most of the luteolin is loaded on the surface of the composite membrane, making it unprotected by the polymer network structure, resulting in rapid release. Another reason for the rapid release of luteolin in the first 7 h may be that the NaHCO3 on the composite membrane completely reacts with the gastric hydrochloric acid within 7 h, forming pores in the composite membrane, thereby promoting the release of luteolin from within the composite membrane. The slow release phenomenon after 7 hours may be due to the formation of a rigid polymer network structure between LPC, polymer and excipient, which affects the internal porosity of the composite membrane and reduces the entry of water molecules into the composite membrane.

[0122] (4) Effect of NaHCO3 addition ratio on luteolin release in composite membrane: The effect of NaHCO3 addition ratios of 1%, 3%, and 5% (i.e., the mass percentages of NaHCO3 and polymer are 1%, 3%, and 5%, respectively) on luteolin release in gastric retention shape memory composite membranes was investigated. Based on Example 2.1, using composite membrane LPC-PLA / PEG (7 / 3) as the research object, under constant conditions of HPMC addition ratio of 5 wt% (HPMC is 5% of the polymer) and LPC addition ratio of 10 wt% (i.e., LPC is 10% of the total mass of polymer, HPMC, and NaHCO3), the luteolin release was determined according to the above method. Using composite membrane LPC-PLA / PEG (7 / 3) as the research object, under constant conditions of HPMC addition ratio of 5% and LPC addition ratio of 10%, the effect of NaHCO3 addition amount (1%, 3%, and 5%) on luteolin release in composite membranes was investigated. The experimental results are as follows. Figure 22As shown, LPC-PLA / PEG (7 / 3) with different concentrations of NaHCO3 exhibited the highest drug release rate in the first 7 hours, and the experiment revealed that the composite membrane possessed sustained drug release characteristics, with a release time reaching 24 hours. With increasing NaHCO3 concentration, the cumulative drug release rate increased. When the NaHCO3 concentration was 5%, the cumulative release rate of luteolin in LPC-PLA / PCL / PEG (8 / 2 / 3) was the highest, reaching 53.76% at 24 hours in the 5% NaHCO3 composite membrane. Based on the experimental results, the inventors inferred that the higher the NaHCO3 concentration, the less stable the polymer network structure. Considering the influence of NaHCO3 on the deformation rate of the composite membrane demonstrated in the above examples, we chose to add NaHCO3 at a concentration of 5%.

[0123] (5) Effect of luteolin concentration on luteolin release in composite membrane: The drug release of LPC-PLA / PEG(7 / 3) with added 10%, 20%, and 30% luteolin (i.e., LPC is 10%, 20%, and 30% of the total mass of polymer, HPMC, and NaHCO3, respectively) was further tested. Based on Example 2.1, the HPMC concentration was fixed at 5 wt% (HPMC is 5% of the polymer), and the NaHCO3 concentration was fixed at 5 wt% (i.e., NaHCO3 is 5% of the polymer). The release of luteolin was determined according to the above method. The drug release of LPC-PLA / PEG(7 / 3) with added 10%, 20%, and 30% luteolin (HPMC and NaHCO3 were fixed at 5%) was further tested. The results are as follows: Figure 23 It is known that the cumulative drug release rate increases with increasing luteolin concentration. When the luteolin concentration is 30%, the cumulative drug release rate in LPC-PLA / PEG (7 / 3) is the highest, reaching 75.56% after 24 hours. The inventors infer that increasing the luteolin quality in the drug-loaded composite membrane not only increases the LPC concentration on the membrane surface, but also, due to the higher concentration of LPC embedded in the rigid polymer structure, increases the free voids between the polymer structures within the composite membrane, promoting drug release. The cumulative drug release rate may be positively correlated with the drug loading; the higher the drug loading, the greater the cumulative release rate. Based on the above examples showing that the addition of luteolin affects the composite membrane deformation rate, we selected a luteolin concentration of 30%.

[0124] In this embodiment, LPC-PLA, LPC-PLA / PCL(9 / 1), LPC-PLA / PCL(8 / 2), LPC-PLA / PCL(7 / 3), LPC-PLA / PEG(9 / 1), LPC-PLA / PEG(8 / 2), LPC-PLA / PEG(7 / 3), LPC-PLA / PCL / PEG(8 / 2 / 1), LPC-PLA / PCL / PEG(8 / 2 / 2), and LPC-PLA / PCL / PEG(8 / 2 / 3) gastric retention shape memory composite membranes were prepared. Comprehensive analysis of the morphology, thermodynamic properties, thermal properties, buoyancy, deformation, and drug release properties of the 10 composite membranes showed that all ten composite membranes exhibited good performance. Among them, LPC-PLA / PEG(7 / 3) showed the best performance as a gastric retention drug system and was used in subsequent pharmacokinetic experiments.

[0125] Example 3: Evaluation of the inhibitory effect of gastric retention shape memory composite membrane on gastric cancer cells

[0126] Luteolin has excellent medicinal value and is mainly used clinically for relieving cough, expectoration, anti-inflammation, and lowering uric acid. Studies have found that it can inhibit the proliferation of various malignant tumors in gastric cancer, demonstrating significant anti-cancer potential. However, luteolin has poor solubility, which directly affects its efficacy in treating cancer. The gastric retention shape memory composite membrane we prepared loaded with LPC as the drug. This invention has shown that phospholipid complexes can improve the solubility of water-insoluble drugs, allowing tumor cells to absorb more drug molecules, thus improving the drug's therapeutic effect. This embodiment investigated the toxic effects of the unloaded composite membrane on SGC-7901 gastric cancer cells and the inhibitory effects of the loaded composite membrane on SGC-7901 gastric cancer cells. The effects of the composite membrane on the number and morphology of SGC-7901 gastric cancer cells were observed directly using an inverted microscope after 72 hours.

[0127] 3.1 Experimental Methods

[0128] (1) Combination of composite membranes: Since some composite membrane groups only differ in polymer ratio but have the same polymer composition when the materials are mixed, four groups with the same material composition were selected when studying the effect of non-drug-loaded composite membranes on SGC-7901 gastric cancer cells. These groups were PLA, PLA / PCL (7 / 3), PLA / PEG (7 / 3), and PLA / PCL / PEG (8 / 2 / 3) composite membranes as non-drug-loaded cell experimental groups. The toxic effects of the four groups of non-drug-loaded composite membranes on SGC-7901 gastric cancer cells were observed. SGC-7901 gastric cancer cell proliferation inhibition assays were performed on drug-loaded composite membranes of LPC-PLA, LPC-PLA / PCL(9 / 1), LPC-PLA / PCL(8 / 2), LPC-PLA / PCL(7 / 3), LPC-PLA / PEG(9 / 1), LPC-PLA / PEG(8 / 2), LPC-PLA / PEG(7 / 3), LPC-PLA / PCL / PEG(8 / 2 / 1), LPC-PLA / PCL / PEG(8 / 2 / 2), and LPC-PLA / PCL / PEG(8 / 2 / 3).

[0129] (2) Preparation of composite membrane extract: The composite membrane was placed in an autoclave and sterilized for 20 min. After sterilization, it was transferred to an oven to dry and remove surface moisture. After thorough drying, it was placed in a clean bench for UV sterilization for 30 min and set aside. 0.5 g of the pretreated composite membrane was placed in sterilized beakers, and 250 mL of cell culture medium (DMEM high-glucose medium with added fetal bovine serum and antibiotics, with 10% fetal bovine serum and 1% antibiotics) was added to each beaker. The beakers were incubated at 37℃ and 5% CO2 for 24 h. This culture medium was considered a 100% concentration extract. 100% extracts of different groups of non-drug-loaded composite membranes were serially diluted to concentrations of 50%, 25%, 12.5%, and 6.25% for cell culture and toxicity assays against SGC-7901 gastric cancer cells were performed. The 100% concentration of the material extract from the drug-loaded composite membrane was used as the experimental group to demonstrate the effect of the drug-loaded composite membrane on SGC-7901 gastric cancer cells.

[0130] (3) Resuscitation of SGC-7901 gastric cancer cells: First, the frozen SGC-7901 gastric cancer cells were resuscitated. The water bath was preheated to 36℃. The laminar flow hood was opened, the main instruments were placed in, and ultraviolet sterilization was turned on for 30 min. The cell cryopreservation tubes were taken out of liquid nitrogen and placed in the water bath for rapid thawing. The cells were quickly taken to the laminar flow hood, aspirated, and placed in a sterile centrifuge tube. The cells were centrifuged at 1000 r / min for 5 minutes. The supernatant and culture medium were aspirated from the centrifuge tubes, 5 mL of culture medium was added to the culture flask, and the centrifuged cells were rinsed with 1 mL of culture medium. The cells were then transferred to the culture flask, observed and labeled under a microscope. The cell culture flasks were sterilized by wiping with alcohol swabs, the caps were slightly loosened, and the cells were placed in the incubator.

[0131] (4) Passaging of SGC-7901 gastric cancer cells: SGC-7901 gastric cancer cells were observed under an inverted microscope after resuscitation and showed good growth. When the cells in the cell culture flask reached 70-80% growth, adhered to the wall, and exhibited an irregular elongated spindle shape, cell passage could be performed. The reagents to be used were preheated to 37°C in a constant temperature water bath. The culture medium in the cell culture flask was discarded, and the cells were washed 2-3 times with PBS. The residual PBS was then discarded using a pipette. 1 mL of digestion solution (0.25% trypsin solution) was added to the culture flask to digest the cells. Observation was performed under an inverted microscope. Once the cells became rounded, the digestion solution was discarded. 3 mL of fresh culture medium was added, and the cells were pipetted. The fresh culture medium containing the cells was evenly distributed into two cell culture flasks, and passage was completed. The culture medium was replaced after 24 hours, and the cells were cultured for 4-5 days, with daily observation of the cell status.

[0132] (5) Seeding of SGC-7901 gastric cancer cells: SGC-7901 gastric cancer cells in good growth condition were collected. Similar to the steps described above, the cells were first washed with PBS solution, digested with trypsin, and digestion was terminated with cell culture medium to prepare a cell suspension. The cell suspension was then counted and diluted to 4 × 10⁻⁶. 5 Cells were seeded at a concentration of [number] cells / mL into 96-well plates, with 100 μL of cell suspension added to each well. A culture medium containing 10% fetal bovine serum was used as a control group. The 96-well plates were incubated in a cell culture incubator for 24 h. The supernatant was discarded, and 100 μL of each of the four groups of non-drug-loaded composite membrane extracts (6.25%, 12.5%, 25%, 50%, and 100%) and ten groups of 100% drug-loaded composite membrane extracts were added to each 96-well plate. After labeling, the plates were incubated in a cell culture incubator for 24, 48, and 72 h, respectively, before performing the MTT assay.

[0133] (6) MTT assay: After culturing SGC-7901 gastric cancer cells for 24, 48, and 72 h, 150 μL of MTT solution (MTT concentration of 5 mg / mL) was added to each well. The cells were then cultured in the dark for another 4 h. The culture medium in each well was gently aspirated with a dropper, taking care not to touch the edge or bottom of the well. Subsequently, 150 μL of dimethyl sulfoxide was added to each well, and the cells were shaken on a microplate shaker for about 10 min. The 96-well plate was then placed in a microplate reader, and the OD value of each well was measured at 570 nm. The cell viability was calculated using a formula.

[0134] (2-1)

[0135] (2-2)

[0136] (7) Effect of gastric retention shape memory composite membrane on SGC-7901 gastric cancer cells observed under an inverted microscope: The same operation as above was performed. SGC-7901 gastric cancer cells were cultured with the above 4 groups of 100% non-drug-loaded composite membrane extracts and 10 groups of 100% drug-loaded composite membrane extracts. After 24, 48 and 72 h of culture, the number and morphology of cells were observed under an inverted microscope and the cells were tracked and photographed using a camera system.

[0137] 3.2 Experimental Results

[0138] (1) Evaluation of the toxicity of non-drug-loaded gastric retention shape memory composite membranes to SGC-7901 gastric cancer cells: The toxic effects of four groups of non-drug-loaded composite membranes on SGC-7901 gastric cancer cells were investigated. The experimental results are as follows: Figure 24 As shown, after culturing SGC-7901 gastric cancer cells with 6.25%, 12.5%, 25%, 50%, and 100% non-drug-loaded composite membrane extracts for 24h, 48h, and 72h, the survival rate of SGC-7901 gastric cancer cells was greater than 78.76%, and the cytotoxicity grade was grade 1 or below. This indicates that PLA, PLA / PCL (7 / 3), PLA / PEG (7 / 3), and PLA / PCL / PEG (8 / 2 / 3) have no significant toxicity to SGC-7901 gastric cancer cells.

[0139] (2) Inhibitory effect of drug-loaded gastric retention shape memory composite membrane on SGC-7901 gastric cancer cells: The inhibitory effect of 10 groups of drug-loaded composite membranes on the proliferation of SGC-7901 gastric cancer cells was investigated. The experimental results are as follows: Figure 25As shown, after incubating SGC-7901 gastric cancer cells with 10 groups of drug-loaded composite membrane extracts at 100% concentration for 24 h, the cell proliferation inhibition rate was greater than 50%, with the maximum inhibition rate being 74.10%. The inhibition rate increased with increasing incubation time. After 72 h, LPC-PLA / PEG (7 / 3) achieved the maximum inhibition rate of 89.04% against SGC-7901 gastric cancer cells. The 100% extract of LPC-PLA / PEG (7 / 3) showed the best inhibitory effect on SGC-7901 gastric cancer cells, which is related to its superior drug release performance.

[0140] (3) Observation of the effect of the composite membrane on the proliferation of SGC-7901 cells using an inverted microscope: The effects of non-drug-loaded shape memory composite membrane and drug-loaded shape memory composite membrane extracts on the morphology of SGC-7901 gastric cancer cells were observed using an inverted microscope. Figure 26 As shown, the live cells in the negative control group had two shapes: spherical and spindle-shaped. The effects of four groups of 100% drug-free composite membrane extracts (PLA, PLA / PCL, PLA / PEG (7 / 3), and PLA / PCL / PEG (8 / 2 / 3)) on the morphology of SGC-7901 gastric cancer cells were first observed. From a morphological perspective, the SGC-7901 gastric cancer cells cultured in the four groups of 100% drug-free composite membrane extracts showed basically normal morphology, all being spherical or spindle-shaped. Furthermore, the cell number increased significantly with time, consistent with the morphology of the negative control group. Figure 27 Subsequently, the effects of 100% drug-loaded composite membrane extracts on the morphology of cultured SGC-7901 gastric cancer cells were observed. The results showed that the morphology of SGC-7901 gastric cancer cells cultured in 100% drug-loaded composite membrane extracts was significantly deformed, and the number of dead cells increased. The cell count was significantly reduced compared with the negative control group. Figure 28 The above analysis further reveals that the non-drug-loaded composite membrane extract has no cytotoxicity against SGC-7901 gastric cancer cells; the drug-loaded composite membrane extract significantly increases the number of dead SGC-7901 gastric cancer cells, exhibiting a significant inhibitory effect on SGC-7901 gastric cancer cell proliferation. The MTT assay was used to evaluate the inhibitory effects of the non-drug-loaded and drug-loaded gastric retention shape memory composite membranes on SGC-7901 gastric cancer cells. The results show that the non-drug-loaded shape memory composite membrane has no cytotoxicity against SGC-7901 gastric cancer cells, while the drug-loaded shape memory composite membrane has a significant inhibitory effect on SGC-7901 gastric cancer cells, with LPC-PLA / PEG (7 / 3) showing the strongest inhibitory effect.

[0141] Example 4: In vivo pharmacokinetic evaluation of thermoresponsive gastric retention shape memory drug-loaded composite membrane in rats

[0142] The above examples revealed that the 10 drug-loaded composite membranes, namely LPC-PLA, LPC-PLA / PCL(9 / 1), LPC-PLA / PCL(8 / 2), LPC-PLA / PCL(7 / 3), LPC-PLA / PEG(9 / 1), LPC-PLA / PEG(8 / 2), LPC-PLA / PEG(7 / 3), LPC-PLA / PCL / PEG(8 / 2 / 1), LPC-PLA / PCL / PEG(8 / 2 / 2), and LPC-PLA / PCL / PEG(8 / 2 / 3), exhibited good gastric drug retention system characteristics and significant inhibitory effects on SGC-7901 gastric cancer cells. Furthermore, a comprehensive evaluation showed that the LPC-PLA / PEG(7 / 3) drug-loaded composite membrane had the best performance as a gastric drug retention system. In addition, studying the pharmacokinetics of drug-loaded composite membranes in rats allows for a systematic observation of whether the drug in the membrane maintains a longer blood concentration, which is significant for studying the absorption and excretion processes of drug-loaded composite membranes in vivo. This embodiment uses rats as an experimental animal model, administering the drug via gavage to investigate the pharmacokinetic properties of the gastric retention composite membrane in rats. The LPC-PLA / PEG(7 / 3) drug-loaded composite membrane, which exhibited the best overall performance in the above embodiments, was selected for pharmacokinetic evaluation.

[0143] Preparation of the control solution: Accurately weigh 25.00 mg of the reference standard (luteolin) and add it to a 50 mL volumetric flask. Dissolve and dilute to volume with acetonitrile to obtain a reference solution with a mass concentration of 0.50 mg / mL. Add 5 mL of the reference solution to the 50 mL volumetric flask and dilute to volume to obtain a mass concentration of 50 μg / mL. Preparation of the internal standard solution: Accurately weigh 12.50 mg of geraniol reference standard and add it to a 50 mL volumetric flask. Dissolve and dilute to volume with acetonitrile to obtain an internal standard solution with a mass concentration of 0.25 mg / mL. Add 2 mL of the internal standard solution to the 50 mL volumetric flask and dilute to volume to obtain a mass concentration of 10 μg / mL. Then, measure 1 mL of the solution into a 10 mL volumetric flask and dilute to volume to obtain a 1 μg / mL internal standard solution. Preparation of luteolin and luteolin-phospholipid complex suspension: Luteolin and LPC were diluted with 0.5% CMC-Na solution and sonicated to prepare a suspension with a concentration of 1.50 mg / mL (calculated as luteolin). Preparation of LPC-PLA / PEG(7 / 3) capsules: LPC-PLA / PEG(7 / 3) was heated for 10 min to soften it, then folded into a size suitable for loading into rat capsules. The capsules were then fixed at approximately 5°C and finally loaded into rat capsules.

[0144] Grouping and Administration: Eighteen male SD rats were divided into three groups of six each: a luteolin group, an LPC group, and a group loaded with LPC-PLA / PEG(7 / 3) capsules. Rats were acclimatized for 7 days in an animal facility at a temperature of 25±0.5℃ and a humidity of 50±5%, with alternating light and dark periods for 12 h. The prepared luteolin suspension, LPC suspension, and LPC-PLA / PEG(7 / 3) capsules were administered to each rat by gavage at a dose of 20 mg / kg (based on luteolin content). Rats were fasted for 12 h prior to administration, but were allowed a small amount of water. Blood samples were collected at 10 min, 20 min, 30 min, 1 h, 2 h, 4 h, 8 h, and 12 h after administration, and an equal volume of physiological saline was administered after each blood sample. The blood collection process involved collecting approximately 600 µL of blood from the posterior orbital venous plexus of each rat, placing it in a 1.5 mL centrifuge tube moistened with a small amount of heparin, centrifuging at 4000 r / min for 10 min, and collecting the supernatant to obtain rat plasma.

[0145] Plasma sample pretreatment: Accurately pipette 200 μL of rat plasma sample and 20 μL of internal standard solution into a centrifuge tube. Add 100 μL of 3 mol / L HCl solution, vortex to mix, and incubate in a 65℃ water bath for 3 h. Add 150 μL of 5% HClO4 solution to the centrifuge tube, shake for 10 min, then add 3 mL of ethyl acetate for extraction, vortex for 15 min. Subsequently, centrifuge the extract at 10000 r / min for 12 min, transfer the upper organic phase to another blank centrifuge tube, add 1.0 mL of ethyl acetate for extraction again, combine the extracts, and dry under nitrogen at 45℃. Finally, add 100 µL of mobile phase to the centrifuge tube to reconstitute, and filter using a 0.45 μm microporous membrane.

[0146] An HPLC method for the analysis of luteolin was established: using geraniol as an internal standard, the concentration of luteolin in the sample was determined by the internal standard method. The chromatographic conditions for the luteolin detection method are as follows.

[0147] Chromatographic column: Inertsil ODS-3 C18 column (250 mm × 4.6 mm, 5 μm); mobile phase: acetonitrile-0.1% potassium dihydrogen phosphate water (55:45) elution; injection volume: 20 μL; flow rate: 1 mL / min; column temperature: 30 ℃.

[0148] Data processing and methods: Pharmacokinetic parameters of luteolin were calculated using the pharmacokinetic software DAS 2.1. All data are expressed as mean ± standard deviation (x ± s), and t-tests were performed using SPSS 19.0 statistical software to compare data between two groups.

[0149] 4.1 Specificity assessment of the luteolin detection method: Blank rat plasma was collected, and a certain amount of reference solution was added to prepare plasma samples. Separately, 200 μL of blank plasma and luteolin suspension plasma were processed according to the above method and detection conditions for analysis. The chromatographic results of the rat blank plasma sample, the blank plasma sample with added luteolin, and the plasma sample after drug administration are shown below. Figure 29 As shown, the retention time of luteolin was 6.2 min, and the retention time of geraniol was 10.6 min. Luteolin and geraniol were not affected by endogenous substances in plasma, and the method had good specificity.

[0150] 4.2 Standard Curve, Limit of Detection (LOD), and Limit of Quantification (LOQ) for the luteolin detection method: Appropriate amounts of blank plasma were taken and luteolin solutions of different dilution ratios were added to prepare plasma sample solutions containing luteolin at concentrations of 0.125 μg / mL, 0.25 μg / mL, 0.5 μg / mL, 1 μg / mL, 1.5 μg / mL, and 2.5 μg / mL. Each concentration was repeated six times. The plasma was processed and analyzed under the above methods and detection conditions. A standard curve was constructed with drug concentration on the x-axis and the ratio of the luteolin peak area to the geraniol peak area on the y-axis. The LOD of luteolin was calculated based on a signal-to-noise ratio of 3 (S / N=3), and the LOQ was calculated based on a signal-to-noise ratio of 10 (S / N=10). The regression equation for the standard curve of the luteolin detection method in rat plasma was: y = 0.3627x + 0.2018. Luteolin showed good linearity in the range of 0.125-15 μg / mL. Figure 30 The limit of detection was 0.0211 μg / mL, and the limit of quantitation was 0.1396 μg / mL.

[0151] 4.3 Recovery and Intra-day and Inter-day Precision Tests for the Late Lutein Detection Method: Accurately pipette an appropriate amount of the reference solution and add it to rat blank plasma to prepare low (0.125 μg / mL), medium (1 μg / mL), and high (2.5 μg / mL) concentration plasma sample solutions, with 6 replicates per group. Take 100 μL of each solution and process the plasma under the same detection conditions as described above. Substitute the results into the standard curve to calculate the recovery rate. Intra-day precision was calculated by injecting samples 6 times within one day. Under the same conditions, once a day for 3 consecutive days, and inter-day precision was calculated. The low, medium, and high concentration samples of luteolin were analyzed, and the results are shown in Table 13. The intra-day precision RSD was 3.43-7.71%, and the inter-day precision was 4.70-11.93%. Both recoveries were between 100.00-110.00%, indicating that the method meets the detection standards for luteolin in rat plasma.

[0152] Table 13 Evaluation of plasma precision (6 repeated measurements daily for 3 consecutive days)

[0153]

[0154] The recovery results are shown in Table 14. The recovery rate of luteolin in rat plasma was 76.36-88.15%, with an RSD of 1.33-2.67%; the recovery rate of the internal standard was 75.24-80.20%, with an RSD of 1.89-2.60%.

[0155] Table 14 Recovery rate test (n=6)

[0156]

[0157] 4.4 Stability test of luteolin in blank plasma

[0158] Accurately pipette an appropriate amount of the reference solution and add it to rat blank plasma to prepare low (0.125 μg / mL), medium (1 μg / mL), and high (2.5 μg / mL) plasma sample solutions, with 6 replicates for each group. Take 100 μL of the above solution and process the plasma according to the above method. Analyze the plasma under the above detection conditions and calculate the luteolin concentration. Freeze the test sample at -20℃ for 30 days, then take out the plasma processed according to the above method and analyze it under the above detection conditions. Substitute the results into the standard curve and calculate the luteolin concentration. Calculate the stability based on the relative standard deviation. The results of the luteolin stability experiment in rat plasma are shown in Table 15. After freezing the plasma sample with added luteolin at -20℃ for 30 days, the RSD was found to be <15%, indicating that luteolin is relatively stable in rat plasma.

[0159] Table 15 Results of stability test in rat plasma (n=6)

[0160]

[0161] 4.5 Calculation of blood drug concentration and pharmacokinetic parameters

[0162] (1) Results and analysis of luteolin blood concentration: Pharmacokinetic parameters of luteolin were calculated using the pharmacokinetic software DAS 2.0. Under the above conditions, rats in the luteolin suspension, LPC suspension, and LPC-PLA / PEG(7 / 3) composite membrane groups were administered luteolin at a concentration of 20 mg / kg by gavage. Blood samples were collected from the orbital venous plexus at fixed time points, and each experiment was repeated 6 times. The plasma drug concentration-time curve was obtained by plotting the time of blood collection from the orbital venous plexus after administration on the x-axis and the plasma luteolin concentration on the y-axis. Figure 31The results showed that the absorption and excretion patterns of luteolin differed among the three groups. Luteolin reached its peak plasma concentration 2 hours after gavage, while LPC reached its peak concentration 1.5 hours after gavage. The LPC curve was biphasic, with a sharp peak indicating rapid absorption into the systemic circulation, followed by a slower excretion phase. Compared to the luteolin group, the LPC group reached its peak concentration faster, presumably because luteolin is encapsulated by phospholipids, promoting drug release. The peak plasma concentration of the LPC group was 2.1 times that of the luteolin group, indicating that preparing luteolin as a phospholipid complex effectively improved its poor water solubility, making it easier for the body to absorb. The maximum peak plasma concentration in the LPC-PLA / PEG(7 / 3) composite membrane group was at 8 hours, and the plasma concentration was retained until 24 hours later. Compared with the luteolin group (6 h) and the LPC group (18 h), the LPC-PLA / PEG (7 / 3) composite membrane effectively prolonged the retention time of drug concentration in the blood, indicating that the LPC-PLA / PEG (7 / 3) composite membrane had a more ideal gastric retention effect. However, the maximum blood drug concentration of the LPC-PLA / PEG (7 / 3) composite membrane was lower than that of the LPC group, which may be mainly because the luteolin in the drug-loaded composite membrane was not completely released from the composite membrane.

[0163] (2) Calculation and analysis of pharmacokinetic parameters: Pharmacokinetic parameters were calculated using the pharmacokinetic software DAS 2.0. In rats, these parameters conformed to an absorbable two-compartment model with a weight of 1 / C. A non-compartmental model was used to obtain the main pharmacokinetic parameters (Table 16). The results showed that after gavage administration, the AUC in the plasma of rats in the LPC group was... (0-∞) The concentration was 5697.04 μg / L·h, which was 3.54 times higher than that of luteolin, with a relative bioavailability increased by 354%, Cmax increased by 1.14 times, and mean residence time (MRT) increased. (0-t) It also significantly prolonged. The plasma AUC in rats of the LPC-PLA / PEG(7 / 3) group was significantly increased. (0-∞) The concentration was 7155.05 μg / L·h, which was 4.70 times higher than that of luteolin (0-∞), and the relative bioavailability was increased by 470%. max The AUC of the LPC-PLA / PEG(7 / 3) composite membrane was increased by 0.58 times compared to the LPC group. (0-∞) It increased by 0.26 times, relative bioavailability increased by 26%, and mean residence time (MRT) increased. (0-t) It also significantly prolonged.

[0164] Table 16 Pharmacokinetic parameters in rat plasma after gavage administration

[0165]

[0166] This embodiment establishes a high-performance liquid chromatography (HPLC) method for the determination of luteolin content in rat plasma. Methodological evaluation demonstrated that the method is simple, stable, and has good specificity. The recovery, precision, and repeatability all meet the requirements for determination, making it suitable for the determination of luteolin content in rat plasma and the evaluation of its bioavailability in vivo. Pharmacokinetic experiments showed that the peak time T for the LPC-PLA / PEG(7 / 3) group was [not specified]. max The peak concentration (C) in the LPC group was 8 h, which was significantly longer than that in the luteolin group and the LPC group; the peak concentration (C) in the LPC group was... max The peak concentration C of the LPC-PLA / PEG(7 / 3) group was 920.00 μg / L. max The effective concentration was 680.00 μg / L, which was significantly higher than that of the luteolin group; the area under the curve (AUC) of the LPC-PLA / PEG(7 / 3) group, the LPC group, and the luteolin group was also significantly higher. (0-∞) The relative bioavailabilities of the LPC-PLA / PEG(7 / 3) group and the LPC group were 7155.05 μg / L·h, 5697.04 μg / L·h, and 1256.13 μg / L·h, respectively, which were 4.70 times and 3.54 times higher than those of the luteolin group. Among them, LPC-PLA / PEG(7 / 3) showed the highest bioavailability. Pharmacokinetic experiments showed that the bioavailability of luteolin in LPC-PLA / PEG(7 / 3) in rats was further improved compared with that of LPC, demonstrating the advantages of the gastric retention drug system. In summary, this invention combines shape memory polymers with a gastric retention drug system, using luteolin phospholipid complex as the main drug, and prepared 10 groups of shape memory gastric retention composite membranes with different materials. Ten groups of drug-loaded composite membranes were screened for performance. The best-performing LPC-PLA / PEG (7 / 3) was subjected to pharmacokinetic studies, which showed that its bioavailability was significantly higher than that of luteolin and LPC.

[0167] (1) Preparation and quality evaluation of luteolin phospholipid complex: LPC was prepared to improve the water solubility of luteolin and facilitate its oral absorption. Drug content determination methods mainly include ultraviolet spectrophotometry, high-performance liquid chromatography (HPLC), and liquid chromatography-mass spectrometry (LC-MS). This invention uses precise HPLC to determine the luteolin content. The maximum ultraviolet absorption wavelength of luteolin was determined by ultraviolet wavelength scanning; therefore, 348 nm was selected as the detection wavelength. Simultaneously, the specificity, precision, repeatability, recovery rate, and stability of the established HPLC method were tested, verifying that the method is accurate and reliable and can be used to detect the luteolin content in LPC. Preliminary experiments tested the solubility of luteolin and soybean lecithin in different solvents, finding that both were soluble in ethanol and tetrahydrofuran. Further experiments revealed that under the same conditions, LPC prepared in tetrahydrofuran exhibited a higher complexation rate. This is presumably because the -OH bonds of hydrogen bond donors in ethanol interfere with the complexation process between phospholipids and the drug, resulting in a lower complexation rate compared to tetrahydrofuran. Therefore, tetrahydrofuran was chosen as the preparation solvent in the LPC preparation process. This invention screened the LPC formulation with the optimal complexation rate, and the preparation method is reasonable, reliable, and achieves an ideal complexation rate. Using the composite rate as an indicator, four evaluation indicators were investigated: stirring time, stirring temperature, luteolin mass concentration, and the ratio of luteolin to soybean lecithin. Experimental analysis revealed that the optimal process was to weigh luteolin and soybean lecithin at a mass ratio of 1:1.2, add an appropriate amount of tetrahydrofuran to achieve a luteolin mass concentration of 10 mg / mL, stir at 50℃ for 6 h, remove the organic solvent by rotary evaporation under reduced pressure, and dry overnight in a vacuum drying oven at 40℃ or for 48 h. Verification experiments showed an average composite rate of 91.45%. The preparation scheme with the highest LPC composite rate was selected, serving as a drug preparation for the subsequent preparation of LPC-loaded gastric retention shape memory composite membranes. After LPC preparation, its quality was evaluated and its physical characterization was performed. Optical microscopy is a commonly used method for observing particle morphology, utilizing a light source and glass lenses to magnify the observed image. The morphological changes of the phospholipid complex were observed using an optical microscope. The LPC particles were found to be spherical, and the dispersed LPC particles were surrounded by a distinct halo, indicating a soybean lecithin layer, suggesting good encapsulation of luteolin by soybean lecithin. Analysis of its structural absorption characteristics using ultraviolet (UV) and infrared (IR) absorption spectroscopy revealed that it possesses the structural characteristics of both the active pharmaceutical ingredient and soybean lecithin. UV absorption peak observation showed that the absorption curves of luteolin and LPC were essentially the same, with two distinct characteristic absorption bands around 254 nm and 350 nm, indicating no fundamental change in chemical structure or formation of new substances. Infrared experiments revealed significant changes in the infrared spectrum of LPC.Improved water solubility is crucial for the oral utilization of luteolin. The water solubility of the original drug is enhanced by combining luteolin with soybean lecithin. The -OH group of luteolin can interact with phospholipid molecules to form a complex, improving the water solubility of luteolin, enhancing its penetration into biological membranes, improving gastrointestinal absorption, and increasing bioavailability. Water solubility determination of luteolin, physical mixtures, and LPC samples showed that LPC's solubility in water was more than twice that of luteolin. Besides serving as intermediates in conventional pharmaceutical dosage forms, phospholipid complexes can be combined with various new formulation technologies, such as nanoparticles, liposomes, and submicroemulsions, to accelerate drug dissolution, prolong in vivo circulation time, and improve bioavailability. This invention combines LPC with shape memory polymers to prepare a gastric retention shape memory composite membrane, combining the rapid solubility of LPC with the gastric retention properties of the composite membrane to improve the oral bioavailability of luteolin.

[0168] (2) Preparation and characterization of drug-loaded gastric retention shape memory composite membranes: LPC was loaded onto shape memory polymers to prepare thermally responsive drug-loaded gastric retention shape memory composite membranes. The deformability and buoyancy of the composite membranes were utilized to prolong the retention time of the drug-loaded composite membranes in the stomach. First, LPC-PLA, LPC-PLA / PCL(9 / 1), LPC-PLA / PCL(8 / 2), LPC-PLA / PCL(7 / 3), LPC-PLA / PEG(9 / 1), LPC-PLA / PEG(8 / 2), LPC-PLA / PEG(7 / 3), LPC-PLA / PCL / PEG(8 / 2 / 1), LPC-PLA / PCL / PEG(8 / 2 / 2), and LPC-PLA / PCL / PEG(8 / 2 / 3) gastric retention shape memory composite membranes were prepared. PLA was used as the main material, and the drug loaded was the LPC with the optimal composite ratio. PCL and PEG were added to the composite membrane to modify PLA, thereby reducing its brittleness and lowering its glass transition temperature, making the deformation temperature more suitable for the human body. HPMC was added to the composite membrane to increase its overall water retention. NaHCO3 was added to the composite membrane to increase bubble generation when it comes into contact with gastric acid in the stomach, which helps the composite membrane float. Subsequently, the chemical composition, thermal properties, thermal stability, apparent morphology, drug release performance, flocculation performance, and shape memory performance of LPC-PLA, LPC-PLA / PCL(9 / 1), LPC-PLA / PCL(8 / 2), LPC-PLA / PCL(7 / 3), LPC-PLA / PEG(9 / 1), LPC-PLA / PEG(8 / 2), LPC-PLA / PEG(7 / 3), LPC-PLA / PCL / PEG(8 / 2 / 1), LPC-PLA / PCL / PEG(8 / 2 / 2), and LPC-PLA / PCL / PEG(8 / 2 / 3) gastric retention shape memory composite membranes were investigated. Experimental results showed that the components in the prepared drug-loaded gastric retention shape memory composite membranes did not affect the chemical properties of the composite membrane due to physical mixing, and distinct characteristic absorption peaks of each component could be observed through infrared spectroscopy analysis. Blending PLA, PBS, and PEG polymers, infrared spectroscopy analysis revealed that the material contains characteristic functional groups of PLA, PEG, and PBS. No significant shifts or new molecular characteristic peaks were observed in the characteristic peaks of PLA, PBS, and PEG, suggesting that these three molecules have not yet undergone a chemical reaction. Thermal performance (Tg) is a fundamental parameter for thermally responsive shape memory films (SMPs), as it directly determines the application of SMPs and the extent of shape memory effect (SME). If the Tg is too high above human body temperature, the shape memory film may exhibit poor unfolding performance in vivo, or excessively high temperatures may damage human organs. Thermal performance results indicate that adding PCL and PEG to the composite film lowers the Tg, making the composite film deformation temperature closer to human body temperature.Furthermore, in the LPC-PLA / PCL / PEG (8 / 2 / 3) group, the Tg value was the lowest compared to other groups, at 44.72℃. In the study by Dong Xueming et al., the Tg of the prepared PLA-based magnetically driven bone scaffold was 64.09℃. In the study by Senatov et al., a PLA-based porous scaffold with shape memory function containing hydroxyapatite was printed by FDM, and DSC detection showed that its Tg was 57.1℃. The deformation temperature of the PLA-based composite membrane prepared in this invention is lower than the above products, and its Tg is more suitable for the human body. The thermal stability analysis results show that all materials undergo thermal decomposition under heating. At a temperature of around 450℃, the carbon residue rate of the material is 0%, and the material can be considered completely decomposed. The addition of LPC, HPMC, and NaHCO3 can significantly reduce the degradation initiation temperature of PLA. The initial decomposition temperature of the material appears at around 200℃, indicating that the addition of HPMC and NaHCO3 reduces the thermal stability of the composite material compared to PLA. The addition of PCL slightly improved the heat resistance of the composite membrane, while the addition of PEG slightly reduced it. Overall, all 10 composite membranes showed good thermal stability, remaining stable below 200℃. Optical microscopy revealed that the drug-loaded composite membrane surface was pale yellow and uniformly distributed, indicating good drug distribution. Compared to PLA, LPC-PLA exhibited slight phase separation, a result of the addition of excipients HPMC and NaHCO3. Observations showed that PEG had better compatibility with PLA than PCL, and a higher PEG ratio resulted in a more uniform composite membrane surface. In gastric retention drug systems, prolonging and controlling gastric emptying time can effectively improve drug bioavailability and reduce drug waste. Gastric retention drug systems contribute to the development of better new products, offering new therapeutic possibilities and substantial benefits to patients. Specifically, increasing the floating time and making the dosage form larger than the pylorus both contribute to extending the retention time of the dosage form in the stomach. The flotation experiment results showed that the 10 groups of drug-loaded gastric retention shape memory composite membranes exhibited good flotation performance, with all floating times within 1 second and floating times exceeding 8 hours. Among them, LPC-PLA / PCL (9 / 1), LPC-PLA / PCL (8 / 2), LPC-PLA / PEG (8 / 2), and LPC-PLA / PCL / PEG (8 / 2 / 1) could float for up to 48 hours, indicating that the prepared drug-loaded gastric retention shape memory composite membranes possessed excellent flotation performance. Shape memory testing revealed that the addition of excipients HPMC and NaHCO3 to the composite membranes had a certain impact on the shape recovery rate, prolonging the shape recovery time compared to PLA and reducing the recovery rate. At an ambient temperature of 50℃, all 10 groups of drug-loaded composite membranes achieved a 70% recovery rate within 60 seconds, demonstrating good shape memory recovery performance for each composite membrane combination.When the ambient temperature was 37℃, the deformation recovery rate of all composite membranes was around 60%, which also met the requirement that the shape memory composite membrane for gastric retention could be larger than the pyloric size when it reached the stomach. Drug release is particularly important in drug formulation design, as good drug release is related to drug bioavailability. By analyzing the effects of polymer ratio, excipients, and drug concentration on drug release in composite membranes, the proportion of excipients added to the composite membranes was optimized, and the optimal polymer combination for drug release was obtained. First, the optimal polymer combination was screened, and the drug release performance of 10 groups of composite membranes was observed while maintaining a consistent concentration of HPMC. The results showed that LPC-PLA / PEG (7 / 3) showed the highest cumulative drug release at all detection time points, indicating the best drug release performance. Subsequently, the optimal addition amount of excipients and drug concentrations was investigated based on LPC-PLA / PEG (7 / 3). The results showed that when the concentrations of HPMC, NaHCO3, and luteolin were 5%, the cumulative release rate of luteolin in LPC-PLA / PEG (7 / 3) was the highest. At 24 h, the cumulative drug release rate in the LPC-PLA / PEG(7 / 3) gastric retention shape memory composite membrane reached 75.56%. Based on the drug release data, it was concluded that the optimal excipient ratio in the drug-loaded composite membrane was 5% HPMC and 5% NaHCO3, and among different polymer material combinations, the LPC-PLA / PEG(7 / 3) composite membrane exhibited the best drug release performance.

[0169] (3) Evaluation of the inhibitory effect of gastric retention shape memory composite membrane on gastric cancer cells: This invention further analyzed the inhibitory effect of drug-loaded composite membrane on the proliferation of human gastric cancer cells SGC-7901. Since the biomaterials are prepared for oral administration, cytotoxicity must be considered first. The cytotoxicity of PLA, PLA / PCL (7 / 3), PLA / PEG (7 / 3), and PLA / PCL / PEG (8 / 2 / 3) non-drug-loaded composite membranes was detected using the MTT assay, and the morphological effects on SGC-7901 gastric cancer cells were observed using an inverted microscope, providing a preliminary basis for the application of oral formulations. The MTT experiment results generally showed that the four groups of non-drug-loaded composite membranes exhibited no cytotoxicity. Inverted microscope observation revealed no effect on the morphology of SGC-7901 gastric cancer cells. The inhibitory effect of 10 groups of drug-loaded composite membranes on SGC-7901 gastric cancer cells was evaluated using the MTT assay, and the morphological effects on SGC-7901 gastric cancer cells were observed using an inverted microscope. The results showed that the drug-loaded composite membrane had the highest inhibition rate of 89.04% against SGC-7901 gastric cancer cells. Analysis revealed that the 100% extract of the LPC-PLA / PEG(7 / 3) composite membrane had the strongest inhibitory effect on SGC-7901 gastric cancer cells, which is related to its superior drug release properties.

[0170] (4) Pharmacokinetic Evaluation of Thermally Responsive Gastric Retention Shape Memory Drug-Loaded Composite Membrane in Rats: This invention establishes a method for determining the content of luteolin in rat plasma using high-performance liquid chromatography (HPLC). Method specificity verification demonstrated that the luteolin peak was completely separated from impurity peaks in plasma, with a retention time of approximately 6.2 min. The luteolin content in plasma exhibited good linearity within the range of 0.125-15 μg / mL. The intra-day and inter-day precision recoveries were both between 100-110%, and the precision was less than 15%, indicating good injection repeatability and meeting the determination requirements. These results indicate that the method is simple and stable, with good specificity, recovery rate, repeatability, and precision, making it suitable for determining the luteolin content in rat plasma and studying its pharmacokinetic properties in rats. Pharmacokinetic parameters reflect the pharmacokinetic characteristics of drugs. Analyzing these parameters can provide a basis for developing scientific dosing regimens in clinical practice and is an important indicator for evaluating drug quality. We compared and analyzed the drug elimination half-life (T0) of the luteolin group, LPC group, and LPC-PLA / PEG(7 / 3) composite membrane group. 1 / 2 ), peak concentration (C) max Peak time (T) max The differences in area under the curve (AUC) and mean residence time (MRT) among the three groups indicated that some parameters differed among them. The T value of LPC-PLA / PEG (7 / 3) was also examined. 1 / 2 Compared with the luteolin group and the LPC group, there was a certain prolongation, indicating that the elimination time of luteolin loaded in PLA / PEG(7 / 3) in rats was longer. Because the drug is loaded in PLA / PEG(7 / 3), the folded PLA / PEG(7 / 3) reverts to its original form at gastric temperature, making its drug carrier size larger than the pylorus, achieving a retention effect and prolonging the sustained drug release time, thus exhibiting a longer T... 1 / 2 It has a relatively long effective blood drug concentration, which can be maintained in animals for a relatively long time. Peak drug concentration C max This refers to the highest concentration of a drug reached in plasma after administration to animals, used to evaluate the rate and extent of drug absorption. (LPC group C) max The concentration was 920.00 μg / L, compared to group C of luteolin. max The concentration of luteolin in the LPC group was significantly higher than that in the 430.00 μg / L group, indicating that the LPC group could maintain a higher blood drug concentration. This may be due to the effective binding of soybean lecithin and luteolin in LPC, which improves the water solubility of luteolin and facilitates drug absorption by the body. LPC-PLA / PEG(7 / 3) composite membrane C maxThe concentration was 680.00 μg / L, lower than that of the LPC group, which may be due to the incomplete release of luteolin loaded in the LPC-PLA / PEG(7 / 3) composite membrane. The peak time T of the LPC-PLA / PEG(7 / 3) composite membrane was... max The mean residence time (MRT) was significantly prolonged compared to the luteolin group and the LPC group, indicating that the LPC-PLA / PEG(7 / 3) composite membrane can achieve sustained drug release in rats and prolong the duration of drug action. The peak time of the LPC-PLA / PEG(7 / 3) group was 8 h, which was significantly delayed compared to the luteolin group and the LPC group. The peak concentrations of the LPC-PLA / PEG(7 / 3) group and the LPC group were also significantly higher than those of the luteolin group. The area under the curve (AUC) was also significantly increased. (0-∞) It is t0-t ∞ The area under the drug-time curve within a given time frame is an important indicator for evaluating drug absorption. The AUC of the LPC group... (0-∞) The AUC of the LPC-PLA / PEG(7 / 3) composite membrane was 5697.04 μg / L·h. (0-∞) The AUC of the luteolin group was 7155.05 μg / L·h. (0-∞) The relative bioavailability (RBA) of luteolin was 1256.13 μg / L·h, indicating that preparing luteolin into LPC or LPC-PLA / PEG(7 / 3) composite membranes effectively improved the drug's absorption in rats. Bioavailability refers to the rate and extent to which a drug is absorbed into the systemic circulation and is an important parameter determining the dose-effect relationship. When drug formulations are administered via non-intravenous routes, the AUC of the oral reference standard drug is often used for comparison, i.e., relative bioavailability is evaluated. The relative bioavailability of LPC was 3.54 times higher than that of the luteolin group, and the relative bioavailability of LPC-PLA / PEG(7 / 3) was 4.70 times higher than that of the luteolin group, indicating that the LPC-PLA / PEG(7 / 3) composite membrane had the best bioavailability. LPC-PLA / PEG(7 / 3) can effectively improve the pharmacokinetic characteristics of luteolin in rats.

[0171] Luteolin exhibits extremely poor solubility and low bioavailability in water, thus limiting its clinical use. Phospholipid complexes, by encapsulating the drug with phospholipids, can improve drug solubility and bioavailability, and delay its clearance rate in vivo. Furthermore, the addition of phospholipids enhances the drug's stability, reduces interfacial tension with gastrointestinal fluids, promotes drug translocation within membranes and tissues, and effectively prolongs the drug's half-life in the blood. This invention prepares the drug into a gastric retention drug delivery system, extending the drug carrier's retention time in the stomach, which can also effectively improve the drug's gastric retention time and bioavailability. This invention uses high-performance liquid chromatography (HPLC) to study the pharmacokinetic characteristics of luteolin, LPC, and LPC-PLA / PEG(7 / 3) in rats. The results show that oral administration of LPC-loaded PLA / PEG(7 / 3) prolonged the drug's action time and improved its bioavailability. The findings of this invention will provide a basis for the clinical application of modified drug-loaded shape memory polymers. This invention prepares a novel gastric retention shape memory composite membrane using soybean lecithin-coated luteolin as a drug model and shape memory PLA as the matrix material. Different proportions of PEG and PCL are added to modify the matrix material, and HPMC and NaHCO3 are used to modify the polymer material. LPC-PLA, LPC-PLA / PCL(9 / 1), LPC-PLA / PCL(8 / 2), LPC-PLA / PCL(7 / 3), LPC-PLA / PEG(9 / 1), LPC-PLA / PEG(8 / 2), LPC-PLA / PEG(7 / 3), LPC-PLA / PCL / PEG(8 / 2 / 1), LPC-PLA / PCL / PEG(8 / 2 / 2), and LPC-PLA / PCL / PEG(8 / 2 / 3) gastric retention shape memory composite membranes are prepared. The optimal composite ratio preparation scheme for LPC (Lactobacillus polymorphum) was investigated, along with the preparation and performance of the drug-loaded shape memory composite membrane, its cytotoxicity, and pharmacokinetics in rats. This invention provides a novel gastric retention shape memory composite membrane that effectively improves the bioavailability of luteolin and can be better applied as a shape memory polymer in gastric drug retention systems.

[0172] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A gastro-retentive shape memory composite film, characterized in that, The gastric-retention shape memory composite film is prepared by the following method: (1) mixing the polymer with dichloromethane at a mass ratio of 1:7 to obtain solution 1; the polymer is selected from any one of the following mixtures: PLA and PCL mixture and the weight ratio of PLA and PCL is 9:1; PLA and PCL mixture and the weight ratio of PLA and PCL is 8:2; PLA and PEG mixture and the weight ratio of PLA and PEG is 9:1; PLA and PEG mixture and the weight ratio of PLA and PEG is 8:2; PLA, PCL and PEG mixture and the weight ratio of PLA, PCL and PEG is 8:2:1; (2) preparing solution 2 with water as the solvent, solution 2 containing hydroxypropyl methyl cellulose and NaHCO3; the mass of hydroxypropyl methyl cellulose is 5% of the mass of the polymer, and the mass of NaHCO3 is 5% of the mass of the polymer; the mass ratio of the total mass of hydroxypropyl methyl cellulose and NaHCO3 to the mass of water is 1:10; (3) mixing solution 1 and solution 2, stirring, adding luteolin phospholipid complex, the mass of luteolin phospholipid complex being 30% of the total mass of the polymer, hydroxypropyl methyl cellulose and NaHCO3; continuing to stir and evaporating dichloromethane and water; The preparation method of luteolin phospholipid complex comprises the following steps: dissolving soybean lecithin and luteolin with tetrahydrofuran, stirring, recovering under reduced pressure, and drying to obtain luteolin phospholipid complex; (4) molding to obtain the gastric-retention shape memory composite film.

2. The gastro-retentive shape memory composite film of claim 1, wherein, In the preparation method of luteolin phospholipid complex, the mass ratio of luteolin to soybean lecithin is 1:1.

2.

3. The gastro-retentive shape memory composite film according to claim 1 or 2, wherein, In the preparation method of luteolin phospholipid complex, the concentration of luteolin is 10 mg / mL after dissolving with tetrahydrofuran.

4. The gastro-retentive shape memory composite film according to claim 1 or 2, wherein, In the preparation method of luteolin phospholipid complex, the stirring time is 6 h and the stirring temperature is 50℃.

5. The gastro-retentive shape memory composite film according to claim 1 or 2, wherein, In the preparation method of luteolin phospholipid complex, vacuum drying at 40℃.

6. The gastro-retentive shape memory composite film according to claim 1 or 2, wherein, In step (3), after stirring for 3.5 h, luteolin phospholipid complex is added and stirring is continued for 0.5 h.

7. The gastro-retentive shape memory composite film according to claim 1 or 2, wherein, In step (4), the molding is performed to obtain a sheet with a thickness of 1 mm, and the pressure is 10 Mpa.

Images