Degradable fat-reducing line and preparation method thereof

Abstract

The invention relates to the technical field of fat reduction, in particular to a degradable fat reduction line and a preparation method thereof. The degradable fat reducing line is prepared from the following raw materials in parts by weight: 1.5 to 2 parts of L-carnitine (PDA) microspheres, 10 to 15 parts of lysozyme-copolymer and 6 to 9 parts of betulinic acid-polymer. The prepared degradable fat reducing line is good in fat reducing effect and high in biocompatibility.

Description

Technical Field

[0001] This invention relates to the field of fat reduction technology, specifically to a biodegradable fat reduction thread and its preparation method. Background Technology

[0002] With the improvement of people's living standards, obesity has received increasing attention. Obesity not only affects appearance but is also closely related to the development of various chronic diseases, such as cardiovascular disease and diabetes. Currently, there are many weight loss methods available, among which thread embedding, a method combining traditional Chinese medicine acupoint theory, has gained popularity due to its effectiveness and relatively minimal invasiveness. However, traditional thread embedding methods have several problems. For example, early catgut sutures, while inexpensive and readily available, have poor absorbability and slow degradation in the body, easily leading to adverse reactions such as local redness, swelling, pain, and even infection. Collagen sutures, made from high-grade animal bone glue, while having high collagen purity and relatively low tissue reaction, lack precise regulation of absorption rate, making it difficult to meet the diverse needs of different individuals and treatments. Artificially synthesized absorbable polymer sutures, such as poly(glycolic acid-lactide) (PGLA) copolymers, while possessing good biocompatibility and controllable degradation properties, require steel needles for embedding. These needles pierce the skin, leading to bleeding and infection, and frequent embedding increases the probability of infection for patients. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention proposes a biodegradable slimming thread and its preparation method.

[0004] This invention is achieved through the following technical solution: A biodegradable fat-reducing line is prepared from the following components in parts by weight: 1.5-2 parts of L-carnitine@PDA microspheres, 10-15 parts of lysozyme-polymer, and 6-9 parts of betulinic acid-polymer.

[0005] Furthermore, the preparation method of the L-carnitine@PDA microspheres includes the following steps: L1. Mix deionized water and anhydrous ethanol, add dodecylamine, stir and dissolve in a 40°C water bath, add tetraethyl orthosilicate (TEOS), triethyl phosphate and calcium nitrate tetrahydrate sequentially every 30 min, stir and react for 3 h, let stand for 18-24 h, centrifuge at 10000 rpm for 10-15 min, wash the precipitate with deionized water and ethanol, dry at 60°C, calcine at 650°C for 3 h, cool in the furnace, grind into fine powder to obtain porous microspheres; L2. Add dopamine hydrochloride to Tris-HCl buffer at pH 8.5 to obtain a dopamine hydrochloride solution. Add the porous microspheres obtained in step L1 and L-carnitine sequentially to deionized water, sonicate for 30 min, stir magnetically for 24 h, centrifuge at 10000 rpm for 8-12 min, wash the precipitate with deionized water, dry at 50℃, add to the dopamine hydrochloride solution, stir for 24 h, centrifuge, wash the precipitate with deionized water and ethanol, and vacuum dry to obtain L-carnitine@PDA microspheres.

[0006] Furthermore, in step L1, the volume ratio of deionized water to anhydrous ethanol is 1:3.2.

[0007] Furthermore, in step L1, the ratio of dodecaneamine to anhydrous ethanol is 1 g: 20 mL.

[0008] Further, in step L1, the volume ratio of anhydrous ethanol, tetraethyl orthosilicate, and triethyl phosphate is 50:10:1.

[0009] Furthermore, in step L1, the mass ratio of calcium nitrate tetrahydrate to dodecaneamine is 2.5:1.

[0010] Furthermore, in step L1, the calcium nitrate tetrahydrate is dissolved in deionized water at a mass concentration of 0.5 g / mL.

[0011] Further, in step L2, the mass concentration of dopamine hydrochloride in Tris-HCl buffer is 4-6 mg / mL.

[0012] Furthermore, in step L2, the mass ratio of the porous microspheres to dopamine hydrochloride is 1:2-3.

[0013] Furthermore, in step L2, the mass ratio of L-carnitine to porous microspheres is 1:4-5.

[0014] Furthermore, in step L2, the mass concentration of the porous microspheres in deionized water is 1 mg / mL.

[0015] Furthermore, the method for preparing the lysozyme-copolymer includes the following steps: V1. Under nitrogen protection, p-dioxanone and 1,4-butanediol were mixed and stirred in an oil bath at 80°C for 5-10 min. A toluene solution of Sn(Oct)2 was added, and the reaction was carried out for 12 h. The mixture was rapidly cooled to room temperature, dissolved in chloroform, and precipitated in cold methanol. The precipitate was filtered, the filter cake was washed with cold methanol, and dried under vacuum to obtain HPPDO. V2. Mix the toluene solution of HPPDDO, L-lactide and Sn(Oct)2 obtained in step V1, react at 200 rpm and 70 °C for 1 h under nitrogen atmosphere, react at 110 °C for 3 h, cool to room temperature, dissolve in chloroform, precipitate in cold methanol, filter, wash the filter cake with cold methanol, and dry under vacuum to obtain the copolymer. V3. Under a nitrogen atmosphere, the copolymer obtained in step V2, toluene and Sn(Oct)2 were mixed, hexamethylene diisocyanate (HDI) was added, and the mixture was stirred at 70-75°C for 7 h. Toluene was removed by rotary evaporation, dissolved in dichloromethane, precipitated with cold methanol, filtered, washed, and dried under vacuum. V4. Take the product obtained in step V3 and add it to toluene and mix well. Under N2 atmosphere, add succinic anhydride and dibutyltin dilaurate, stir magnetically at 70°C for 3 h, filter, wash, and vacuum dry. V5. The product obtained in step V4 was added to the MES buffer of EDC and NHS, stirred at 40 r / min for 2 h at room temperature, filtered, washed with deionized water, added to 5 mg / mL lysozyme solution, stirred at 40 r / min for 3 h at room temperature, filtered, washed with deionized water, and dried under vacuum to obtain the lysozyme-copolymer.

[0016] Further, in step V1, the molar ratio of p-dioxanone and 1,4-butanediol is 15:1.

[0017] Further, in step V1, the Sn(Oct)2 concentration in the toluene solution of Sn(Oct)2 is 0.5 mol / L.

[0018] Furthermore, in step V1, the molar ratio of Sn(Oct)2 to 1,4-butanediol is 1:250.

[0019] Further, in step V2, the molar ratio of HPPDO, L-lactide, and Sn(Oct)2 is 1:20:0.02.

[0020] Further, in step V2, the Sn(Oct)2 concentration in the toluene solution of Sn(Oct)2 is 0.02 mol / L.

[0021] Further, in step V3, the mass ratio of the copolymer, toluene, Sn(Oct)2 and hexamethylene diisocyanate is 40 mg:1 mL:2 mg:1 mg.

[0022] Further, in step V4, the ratio of the product obtained in step V3, toluene, succinic anhydride, and dibutyltin dilaurate is 1 g:50 mL:0.1 g:0.2 g.

[0023] Further, in step V5, the MES buffer of EDC and NHS uses 0.1 M pH 5.5 MES buffer as the base component, and adds 0.1 M EDC and 50 mM NHS.

[0024] Further, in step V5, the ratio of the product obtained in step V4, the MES buffer of EDC and NHS, and the 5 mg / mL lysozyme solution is 1 g:50 mL:50 mL.

[0025] Furthermore, the preparation method of the betulinic acid-polymer includes the following steps: X1. Add propane-2,2-dimethylbis(sulfadiyl)diethylamine and triglycidyl isocyanurate to DMSO and stir to dissolve. Purge with high-purity nitrogen for 10 min, seal, add triethylamine, react at 40℃ for 4-5 h, add ethylenediamine and continue reaction for 1 h, cool to room temperature, dialyze in deionized water (MWCO=1000), and freeze dry. X2. Under nitrogen atmosphere, take the product obtained in step X1, add it to DMF and stir to dissolve, add betulinic acid, DMAP and DCC, stir at room temperature for 24 h, dialyze, and vacuum dry to obtain betulinic acid-polymer.

[0026] Further, in step X1, the ratio of propane-2,2-dimethylbis(sulfadiyl)diethylamine, triglycidyl isocyanurate, DMSO, triethylamine and ethylenediamine is 1.2:1.5:15-20 mL:0.3 mL:1.2 mL.

[0027] Furthermore, in step X2, the mass concentration of the product obtained in step X1 in DMF is 20-30 mg / mL.

[0028] Furthermore, in step X2, the mass ratio of betulinic acid to the product obtained in step X1 is 1:5-6.

[0029] Furthermore, in step X2, the mass ratio of betulinic acid, DMAP, and DCC is 1:0.5:0.8.

[0030] Furthermore, the present invention also provides a method for preparing the biodegradable slimming thread and its preparation method, comprising the following steps: mixing L-carnitine@PDA microspheres, lysozyme-polymer, and betulinic acid-polymer, stirring at 1000-1500 rpm for 10-15 min, drying, extruding and granulating at 120℃, melting and drawing into threads with a diameter of 0.15-0.2 mm, sterilizing in medical alcohol, and vacuum drying to obtain the biodegradable slimming thread.

[0031] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a biodegradable fat-reducing thread and its preparation method, overcoming the technical shortcomings of traditional implantable fat-reducing threads in terms of biocompatibility, fat-reducing effect, and antibacterial properties. This invention prepares L-carnitine@PDA microspheres. L-carnitine can promote fat conversion and reduce fat accumulation. By loading L-carnitine onto porous microspheres and coating their surface with a polydopamine (PDA) layer, slow release of L-carnitine can be achieved, improving the persistence of the fat-reducing effect. The polydopamine layer improves biocompatibility and bioadhesion, has bactericidal effects, enhances antibacterial properties, and the abundant amino and catechol groups can improve compatibility with other substrates and enhance the dispersibility of the L-carnitine@PDA microspheres. This invention prepares a lysozyme-copolymer. A prepolymer, HPPDO, is prepared using dioxane, and then HPPDO is used as an initiator to polymerize with L-lactide to generate a copolymer with hydroxyl groups at both ends. Isocyanate groups are then attached to these copolymers, resulting in a copolymer with isocyanate groups at both ends. Succinic anhydride is used to attach carboxyl groups at both ends, which react with the active amino groups of lysozyme to form an amide reaction, effectively attaching lysozyme to the copolymer, improving the stability of the lysozyme, and enhancing the antibacterial effect of the slimming line. This invention uses PLA-PPDO-PLA as the base material, which itself has excellent biocompatibility and is gradually degradable. Simultaneously, lysozyme, as a natural enzyme, has good biocompatibility. When combined with the copolymer, it retains the biodegradable properties of the copolymer while imparting certain biological activity to the material. This invention utilizes the ring-opening reaction of the polyamine compound propane-2,2-dimethylbis(sulfadimidine)diethylamine and the polyepoxy compound triglycidyl isocyanate to prepare a multi-hydroxyl-branched polymer. This polymer is biodegradable, and its hydroxyl groups can connect with the carboxyl groups of betulinic acid to form ester bonds, creating a betulinic acid polymer. The introduction of betulinic acid enhances its anti-inflammatory and antibacterial properties, thereby improving its fat-reducing effect. The fat-reducing thread prepared by this invention exhibits well-matched degradation rates among its components, gradually degrading during the fat-reducing effect period, resulting in a long-lasting effect, significant antibacterial properties, reduced infection risk, and guaranteed successful fat-reducing outcomes. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 Cytotoxicity tests of the fat reduction threads described in Examples 1-3 and Comparative Examples 1-3 of this invention; Figure 2 The fat reduction effect of the fat reduction lines described in Embodiment 1 and Comparative Examples 1-3 of this invention; Figure 3This demonstrates the antibacterial effect of the fat-reducing threads described in Embodiment 2 and Comparative Examples 1-3 of the present invention. Figure 4 This is a test of the biodegradability of the fat-reducing thread described in this invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. However, this invention is not limited to the following embodiments. It should be noted that, unless otherwise specified, all chemical reagents involved in this invention are purchased through commercial channels.

[0035] Example 1: A biodegradable fat-reducing line, the raw materials for which are prepared include the following components in parts by weight: 2 parts L-carnitine@PDA microspheres, 15 parts lysozyme-polymer, and 9 parts betulinic acid-polymer.

[0036] The preparation method of L-carnitine@PDA microspheres includes the following steps: L1. Mix 25 mL of deionized water and 80 mL of anhydrous ethanol, add 4 g of dodecaneamine, stir and dissolve in a water bath at 40 °C, add 16 mL of tetraethyl orthosilicate, 1.6 mL of triethyl phosphate and 10 g of calcium nitrate tetrahydrate (dissolved in 20 mL of deionized water) every 30 min, stir and react for 3 h, let stand for 24 h, centrifuge at 10000 rpm for 15 min, wash the precipitate with deionized water and ethanol, dry at 60 °C, calcine at 650 °C for 3 h, cool in the furnace, grind into fine powder to obtain porous microspheres; L2. Add 0.6 g of dopamine hydrochloride to 100 mL of Tris-HCl buffer at pH 8.5 to obtain a dopamine hydrochloride solution. Add 0.2 g of the porous microspheres obtained in step L1 and 40 mg of L-carnitine sequentially to 200 mL of deionized water, sonicate for 30 min, stir magnetically for 24 h, centrifuge at 10000 rpm for 12 min, wash the precipitate with deionized water, dry at 50 °C, add to the dopamine hydrochloride solution, stir for 24 h, centrifuge, wash the precipitate with deionized water and ethanol, and vacuum dry to obtain L-carnitine@PDA microspheres.

[0037] A method for preparing lysozyme-polymer includes the following steps: V1. Under nitrogen protection, 150 mmol of p-dioxanone and 10 mmol of 1,4-butanediol were mixed and stirred in an oil bath at 80°C for 10 min. Then, 80 μL of a 0.5 mol / L Sn(Oct)2 toluene solution was added, and the reaction was allowed to proceed for 12 h. The mixture was then rapidly cooled to room temperature, dissolved in chloroform, and precipitated in cold methanol. The precipitate was filtered, washed with cold methanol, and dried under vacuum to obtain HPPDO. V2. Mix 0.1 mol HPPDO, 2 mol L-lactide, and 100 mL of a 0.02 mol / L Sn(Oct)2 toluene solution obtained in step V1. Under a nitrogen atmosphere, react at 200 rpm and 70℃ for 1 h, then at 110℃ for 3 h. Cool to room temperature, dissolve in chloroform, precipitate in cold methanol, filter, wash the filter cake with cold methanol, and dry under vacuum to obtain the copolymer. V3. Under a nitrogen atmosphere, 4 g of the copolymer obtained in step V2, 100 mL of toluene and 2200 mg of Sn(Oct)2 were mixed, 100 mg of hexamethylene diisocyanate was added, and the mixture was stirred at 75 °C for 7 h. Toluene was removed by rotary evaporation, dissolved in dichloromethane, precipitated with cold methanol, filtered, washed, and dried under vacuum. V4. Take 4 g of the product obtained in step V3 and add it to 200 mL of toluene and mix well. Under N2 atmosphere, add 0.4 g of succinic anhydride and 0.8 g of dibutyltin dilaurate, stir magnetically at 70℃ for 3 h, filter, wash, and vacuum dry. V5. Add 4 g of the product obtained in step V4 to 200 mL of MES buffer containing EDC and NHS, stir at 40 r / min for 2 h at room temperature, filter, wash with deionized water, add 200 mL of 5 mg / mL lysozyme solution, stir at 40 r / min for 3 h at room temperature, filter, wash with deionized water, and vacuum dry to obtain lysozyme-copolymer; the MES buffer containing EDC and NHS uses 0.1 M pH 5.5 MES buffer as the base component, and adds 0.1 M EDC and 50 mM NHS.

[0038] A method for preparing betulinic acid-polymer includes the following steps: X1. Take 2.4 g of propane-2,2-dimethylbis(sulfadimidine)diethylamine and 3 g of triglycidyl isocyanurate and add them to 40 mL of DMSO. Stir to dissolve, purge with high-purity nitrogen for 10 min, seal, add 0.6 mL of triethylamine, react at 40 °C for 5 h, add 2.4 mL of ethylenediamine and continue the reaction for 1 h, cool to room temperature, dialyze in deionized water (MWCO=1000), and freeze dry. X2. Under nitrogen atmosphere, take 3 g of the product obtained in step X1, add it to 100 mL of DMF and stir to dissolve. Add 0.5 g of betulinic acid, 0.25 g of DMAP and 0.4 g of DCC, stir at room temperature for 24 h, dialyze, and vacuum dry to obtain betulinic acid-polymer.

[0039] This embodiment also provides a method for preparing the biodegradable slimming thread and its preparation method, including the following steps: mixing L-carnitine@PDA microspheres, lysozyme-polymer, and betulinic acid-polymer, stirring at 1500 rpm for 15 min, drying, extruding and granulating at 120℃, melting and drawing into threads with a diameter of 0.2 mm, sterilizing in medical alcohol, and vacuum drying to obtain the biodegradable slimming thread.

[0040] Example 2: A biodegradable fat-reducing line, the raw materials for which are prepared include the following components in parts by weight: 1.5 parts of L-carnitine@PDA microspheres, 10 parts of lysozyme-polymer, and 6 parts of betulinic acid-polymer.

[0041] The preparation method of L-carnitine@PDA microspheres includes the following steps: L1. Mix 25 mL of deionized water and 80 mL of anhydrous ethanol, add 4 g of dodecaneamine, stir and dissolve in a 40°C water bath. Add 16 mL of tetraethyl orthosilicate, 1.6 mL of triethyl phosphate and 10 g of calcium nitrate tetrahydrate (dissolved in 20 mL of deionized water) every 30 min. Stir and react for 3 h, let stand for 18 h, centrifuge at 10000 rpm for 10 min, wash the precipitate with deionized water and ethanol, dry at 60°C, calcine at 650°C for 3 h, cool in the furnace, and grind into fine powder to obtain porous microspheres. L2. Add 0.4 g of dopamine hydrochloride to 100 mL of Tris-HCl buffer at pH 8.5 to obtain a dopamine hydrochloride solution. Add 0.2 g of the porous microspheres obtained in step L1 and 50 mg of L-carnitine sequentially to 200 mL of deionized water, sonicate for 30 min, stir magnetically for 24 h, centrifuge at 10000 rpm for 8 min, wash the precipitate with deionized water, dry at 50 °C, add to the dopamine hydrochloride solution, stir for 24 h, centrifuge, wash the precipitate with deionized water and ethanol, and vacuum dry to obtain L-carnitine@PDA microspheres.

[0042] A method for preparing lysozyme-polymer includes the following steps: V1. Under nitrogen protection, 150 mmol of p-dioxanone and 10 mmol of 1,4-butanediol were mixed and stirred in an oil bath at 80°C for 5 min. Then, 80 μL of a 0.5 mol / L Sn(Oct)2 toluene solution was added, and the reaction was allowed to proceed for 12 h. The mixture was then rapidly cooled to room temperature, dissolved in chloroform, and precipitated in cold methanol. The precipitate was filtered, washed with cold methanol, and dried under vacuum to obtain HPPDO. V2. Mix 0.1 mol HPPDO, 2 mol L-lactide, and 100 mL of a 0.02 mol / L Sn(Oct)2 toluene solution obtained in step V1. Under a nitrogen atmosphere, react at 200 rpm and 70℃ for 1 h, then at 110℃ for 3 h. Cool to room temperature, dissolve in chloroform, precipitate in cold methanol, filter, wash the filter cake with cold methanol, and dry under vacuum to obtain the copolymer. V3. Under a nitrogen atmosphere, 4 g of the copolymer obtained in step V2, 100 mL of toluene and 2200 mg of Sn(Oct)2 were mixed, 100 mg of hexamethylene diisocyanate was added, the mixture was stirred at 70 °C for 7 h, toluene was removed by rotary evaporation, the mixture was dissolved in dichloromethane, precipitated with cold methanol, filtered, washed and dried under vacuum. V4. Take 4 g of the product obtained in step V3 and add it to 200 mL of toluene and mix well. Under N2 atmosphere, add 0.4 g of succinic anhydride and 0.8 g of dibutyltin dilaurate, stir magnetically at 70℃ for 3 h, filter, wash, and vacuum dry. V5. Add 4 g of the product obtained in step V4 to 200 mL of MES buffer containing EDC and NHS, stir at 40 r / min for 2 h at room temperature, filter, wash with deionized water, add 200 mL of 5 mg / mL lysozyme solution, stir at 40 r / min for 3 h at room temperature, filter, wash with deionized water, and vacuum dry to obtain lysozyme-copolymer; the MES buffer containing EDC and NHS uses 0.1 M pH 5.5 MES buffer as the base component, and adds 0.1 M EDC and 50 mM NHS.

[0043] A method for preparing betulinic acid-polymer includes the following steps: X1. Take 2.4 g of propane-2,2-dimethylbis(sulfadiyl)diethylamine and 3 g of triglycidyl isocyanurate and add them to 30 mL of DMSO. Stir to dissolve, purge with high-purity nitrogen for 10 min, seal, add 0.6 mL of triethylamine, react at 40 °C for 4 h, add 2.4 mL of ethylenediamine and continue the reaction for 1 h, cool to room temperature, dialyze in deionized water (MWCO=1000), and freeze dry. X2. Under nitrogen atmosphere, take 2 g of the product obtained in step X1, add it to 100 mL of DMF and stir to dissolve. Add 0.4 g of betulinic acid, 0.2 g of DMAP and 0.32 g of DCC, stir at room temperature for 24 h, dialyze, and vacuum dry to obtain betulinic acid-polymer.

[0044] This embodiment also provides a method for preparing the biodegradable slimming thread and its preparation method, including the following steps: mixing L-carnitine@PDA microspheres, lysozyme-polymer, and betulinic acid-polymer, stirring at 1000 rpm for 10 min, drying, extruding and granulating at 120℃, melting and drawing into threads with a diameter of 0.15 mm, sterilizing in medical alcohol, and vacuum drying to obtain the biodegradable slimming thread.

[0045] Example 3: A biodegradable fat-reducing line, the raw materials for which are prepared include the following components in parts by weight: 1.8 parts of L-carnitine@PDA microspheres, 12 parts of lysozyme-polymer, and 8 parts of betulinic acid-polymer.

[0046] The preparation method of L-carnitine@PDA microspheres includes the following steps: L1. Mix 25 mL of deionized water and 80 mL of anhydrous ethanol, add 4 g of dodecaneamine, stir and dissolve in a 40°C water bath. Add 16 mL of tetraethyl orthosilicate, 1.6 mL of triethyl phosphate and 10 g of calcium nitrate tetrahydrate (dissolved in 20 mL of deionized water) every 30 min. Stir and react for 3 h, let stand for 20 h, centrifuge at 10000 rpm for 12 min, wash the precipitate with deionized water and ethanol, dry at 60°C, calcine at 650°C for 3 h, cool in the furnace, and grind into fine powder to obtain porous microspheres. L2. Add 0.5 g of dopamine hydrochloride to 100 mL of Tris-HCl buffer at pH 8.5 to obtain a dopamine hydrochloride solution. Add 0.2 g of the porous microspheres obtained in step L1 and 45 mg of L-carnitine sequentially to 200 mL of deionized water, sonicate for 30 min, stir magnetically for 24 h, centrifuge at 10000 rpm for 10 min, wash the precipitate with deionized water, dry at 50 °C, add to the dopamine hydrochloride solution, stir for 24 h, centrifuge, wash the precipitate with deionized water and ethanol, and vacuum dry to obtain L-carnitine@PDA microspheres.

[0047] A method for preparing lysozyme-polymer includes the following steps: V1. Under nitrogen protection, 150 mmol of p-dioxanone and 10 mmol of 1,4-butanediol were mixed and stirred in an oil bath at 80°C for 7 min. 80 μL of a 0.5 mol / L Sn(Oct)2 toluene solution was added, and the reaction was allowed to proceed for 12 h. The mixture was then rapidly cooled to room temperature, dissolved in chloroform, and precipitated in cold methanol. The precipitate was filtered, washed with cold methanol, and dried under vacuum to obtain HPPDO. V2. Mix 0.1 mol HPPDO, 2 mol L-lactide, and 100 mL of a 0.02 mol / L Sn(Oct)2 toluene solution obtained in step V1. Under a nitrogen atmosphere, react at 200 rpm and 70℃ for 1 h, then at 110℃ for 3 h. Cool to room temperature, dissolve in chloroform, precipitate in cold methanol, filter, wash the filter cake with cold methanol, and dry under vacuum to obtain the copolymer. V3. Under a nitrogen atmosphere, 4 g of the copolymer obtained in step V2, 100 mL of toluene and 2200 mg of Sn(Oct)2 were mixed, 100 mg of hexamethylene diisocyanate was added, and the mixture was stirred at 72 °C for 7 h. Toluene was removed by rotary evaporation, dissolved in dichloromethane, precipitated with cold methanol, filtered, washed, and dried under vacuum. V4. Take 4 g of the product obtained in step V3 and add it to 200 mL of toluene and mix well. Under N2 atmosphere, add 0.4 g of succinic anhydride and 0.8 g of dibutyltin dilaurate, stir magnetically at 70℃ for 3 h, filter, wash, and vacuum dry. V5. Add 4 g of the product obtained in step V4 to 200 mL of MES buffer containing EDC and NHS, stir at 40 r / min for 2 h at room temperature, filter, wash with deionized water, add 200 mL of 5 mg / mL lysozyme solution, stir at 40 r / min for 3 h at room temperature, filter, wash with deionized water, and vacuum dry to obtain lysozyme-copolymer; the MES buffer containing EDC and NHS uses 0.1 M pH 5.5 MES buffer as the base component, and adds 0.1 M EDC and 50 mM NHS.

[0048] A method for preparing betulinic acid-polymer includes the following steps: X1. Take 2.4 g of propane-2,2-dimethylbis(sulfadiyl)diethylamine and 3 g of triglycidyl isocyanurate and add them to 36 mL of DMSO. Stir to dissolve, purge with high-purity nitrogen for 10 min, seal, add 0.6 mL of triethylamine, react at 40 °C for 4.5 h, add 2.4 mL of ethylenediamine and continue the reaction for 1 h, cool to room temperature, dialyze in deionized water (MWCO=1000), and freeze dry. X2. Under nitrogen atmosphere, take 2.5 g of the product obtained in step X1, add it to 100 mL of DMF and stir to dissolve. Add 0.45 g of betulinic acid, 0.225 g of DMAP and 0.36 g of DCC, stir at room temperature for 24 h, dialyze, and vacuum dry to obtain betulinic acid-polymer.

[0049] This embodiment also provides a method for preparing the biodegradable slimming thread and its preparation method, including the following steps: mixing L-carnitine@PDA microspheres, lysozyme-polymer, and betulinic acid-polymer, stirring at 1200 rpm for 12 min, drying, extruding and granulating at 120°C, melting and drawing into threads with a diameter of 0.18 mm, sterilizing in medical alcohol, and vacuum drying to obtain the biodegradable slimming thread.

[0050] The only difference between Comparative Example 1 and Example 1 is that the product obtained in step X1 is used instead of the betulinic acid-polymer.

[0051] The only difference between Comparative Example 2 and Example 1 is that a copolymer is used instead of a lysozyme-copolymer.

[0052] The only difference between Comparative Example 3 and Example 1 is that L-carnitine was used instead of L-carnitine@PDA microspheres.

[0053] Experimental Example 1: The fat-reducing threads prepared in Examples 1-3 and Comparative Examples 1-3 were immersed in complete culture medium at a ratio of m (degradable fat-reducing thread) / v (complete culture medium) = 100 mg / mL, and extracted in a 37°C water bath for 24 h to obtain the extract. Mouse mesenchymal stem cells (mBMSCs) were adjusted to a concentration of 10... 6 Cells were seeded at a rate of 100 μL / well in 96-well plates and cultured at 37°C with 5% CO2 for 24 h. Then, 100 μL of extraction medium was added to each well, and the plates were cultured for another 24 h. Finally, 10 μL of CCK-8 solution was added to each well, and the plates were cultured for 3 h. The absorbance (OD) at 450 nm was measured using a microplate reader, and the relative cell proliferation rate was calculated. The results are shown below. Figure 1 As shown.

[0054] Figure 1 The results showed that the cell proliferation rate of the fat-reducing threads prepared in Examples 1-3 and Comparative Examples 1-3 was greater than 100%, indicating that the biodegradable fat-reducing threads of the present invention have no cytotoxicity and good biocompatibility.

[0055] Experiment 2: Mice were acclimatized for one week, and their weight was recorded. Male C57BL / 6J mice were fed a high-fat diet for 10 weeks, during which all mice had free access to food and water to establish an obese mouse model. A successful model was defined as a mouse weighing more than 20% above the weight of mice fed a normal diet. Successfully modeled mice were divided into 5 groups: Example 1, Comparative Examples 1-3, and the model group. A normal control group fed a normal diet was also included, with 12 mice in each group. Acupoints were selected: Zusanli (ST36), Shenshu (BL23), Tianshu (ST25), and Pishu (BL20). After disinfecting the sites for thread embedding in the mice of Example 1 and Comparative Examples 1-3, biodegradable fat-reducing threads were embedded into the acupoints using a thread embedding guide needle, with an embedding length of 0.2 cm. Thread embedding was performed once every 3 weeks for 9 consecutive weeks, for a total of 3 treatments. All mice were fed a normal diet. After treatment, all experimental animals were fasted for 12 hours, and the weight of each group of mice was measured and recorded, and the weight loss rate was calculated. Weight loss rate (%) = [(weight before thread embedding treatment - weight after thread embedding treatment) / weight before thread embedding treatment] × 100%. Mice were immobilized, and approximately 1 mL of blood was rapidly collected using the orbital blood sampling method. The blood was allowed to stand at room temperature for 2 hours, then centrifuged at 3000 rpm for 20 minutes to separate the serum. The total cholesterol (TC) content in the serum was measured using a fully automated biochemical analyzer. Results are as follows... Figure 2 As shown.

[0056] Figure 2 The results showed that the weight loss rate of the model group was lower than that of the normal group, and the TC content was higher than that of the normal group. The weight loss rate of Example 1 and Comparative Examples 1-3 was higher than that of the model group, and the TC content was lower. Among them, Example 1 had the best effect, indicating that the biodegradable fat reduction line of the present invention can effectively reduce the weight of obese mice and has the potential for fat reduction and weight loss applications.

[0057] Experimental Example 3: 10 mg of the biodegradable slimming line from Example 2 and Comparative Examples 1-3 was added to 1 mL of Staphylococcus aureus suspension (concentration 10). 6 In a bacterial culture medium (CFU / mL), with the control group not containing the defatted line, the culture was incubated at 37℃ for 24 h on a shaker. A certain amount of bacterial suspension was then transferred to a solid agar plate using a pipette. The bacterial suspension was spread onto the solid agar plate using a spreader, and the plate was then placed in a bacterial incubator for 24 h. After incubation, the plates were removed, and the inhibition rate of the sample against Staphylococcus aureus was calculated. The results are as follows: Figure 3 As shown.

[0058] The slimming threads of Example 2 and Comparative Examples 1-3 all showed good antibacterial effects, with antibacterial rates all exceeding 95%. The antibacterial effect of Example 2 was the best, indicating that the slimming thread of the present invention has a good antibacterial effect, can effectively inhibit bacteria, suppress inflammation, and ensure slimming effect.

[0059] Experimental Example 4: Following the method of Example 1, the copolymer obtained in step V2 was replaced with HPPDO obtained in step V1, and the remaining steps were the same as in Example 1. A control group of biodegradable slimming lines was prepared. The control group slimming lines (W0) and the slimming lines from Example 1 were weighed and immersed in PBS solution. The samples were placed in a 37°C incubator, and the PBS solution was changed every 3 days. Simultaneously, the PBS solution on the samples was cleaned off, and the samples were dried to constant weight. The weight was recorded as W1, and the degradation rate was calculated. Degradation rate (%) = [(W0-W1) / W0] × 100%. The results are as follows: Figure 4 As shown.

[0060] Figure 4 The results showed that the degradation rate of the Example 1 group was higher than that of the control group, indicating that the fat reduction thread prepared by the present invention has a better degradation effect and can be better applied to thread embedding therapy.

[0061] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A biodegradable slimming line, characterized in that, The raw materials for preparation include the following components in parts by weight: 1.5-2 parts of L-carnitine@PDA microspheres, 10-15 parts of lysozyme-polymer, and 6-9 parts of betulinic acid-polymer; The preparation method of the L-carnitine@PDA microspheres includes the following steps: L1. Mix water and ethanol, add dodecylamine, TEOS, triethyl phosphate and calcium nitrate tetrahydrate, stir, let stand, dry, calcine, grind to obtain porous microspheres; L2. Add dopamine hydrochloride to Tris-HCl buffer, add the porous microspheres obtained in step L1 and L-carnitine to water, stir, add dopamine hydrochloride solution, stir, and obtain L-carnitine@PDA microspheres; The method for preparing the lysozyme-copolymer includes the following steps: V1. Under nitrogen protection, p-dioxanone and 1,4-butanediol were mixed and stirred. Sn(Oct)2 was added and reacted to obtain HPPDO. V2. Mix the toluene solution of HPPDO, L-lactide and Sn(Oct)2 obtained in step V1, and react under a nitrogen atmosphere to obtain a copolymer; V3. Under a nitrogen atmosphere, the copolymer obtained in step V2, toluene, and Sn(Oct)2 are mixed, HDI is added, and the mixture is stirred. V4. Take the product obtained in step V3 and add it to toluene and mix well. Under N2 atmosphere, add succinic anhydride and dibutyltin dilaurate and stir. V5. Add the product obtained in step V4 to the MES buffer of EDC and NHS, stir, add lysozyme solution, stir, and obtain lysozyme-copolymer; The preparation method of the betulinic acid-polymer includes the following steps: X1. Dissolve propane-2,2-dimethylbis(sulfadiyl)diethylamine and triglycidyl isocyanurate in DMSO, add triethylamine, react, add ethylenediamine, react, and dialyze. X2. Under nitrogen atmosphere, the product obtained in step X1 is reacted with betulinic acid under DMAP and DCC conditions to obtain betulinic acid-polymer.

2. The biodegradable slimming line according to claim 1, characterized in that, In step L1, the ratio of dodecaneamine to ethanol is 1 g: 20 mL; the volume ratio of ethanol, TEOS and triethyl phosphate is 50:10:1; and the mass ratio of calcium nitrate tetrahydrate to dodecaneamine is 2.5:

1.

3. The biodegradable slimming line according to claim 2, characterized in that, In step V1, the molar ratio of p-dioxanone and 1,4-butanediol is 15:1; the molar ratio of Sn(Oct)2 to 1,4-butanediol is 1:

250.

4. The biodegradable slimming line according to claim 3, characterized in that, In step V2, the molar ratio of HPPDO, L-lactide and Sn(Oct)2 is 1:20:0.

02.

5. The biodegradable slimming line according to claim 4, characterized in that, In step V3, the mass ratio of the copolymer, toluene, Sn(Oct)2 and hexamethylene diisocyanate is 40 mg:1 mL:2 mg:1 mg.

6. The biodegradable slimming line according to claim 5, characterized in that, In step V4, the ratio of the product obtained in step V3, succinic anhydride, and dibutyltin dilaurate is 1 g:0.1 g:0.2 g.

7. The biodegradable slimming line according to claim 6, characterized in that, In step X1, the ratio of propane-2,2-dimethylbis(sulfadiyl)diethylamine, triglycidyl isocyanurate, DMSO, triethylamine, and ethylenediamine is 1.2:1.5:15-20 mL:0.3 mL:1.2 mL.

8. The biodegradable slimming line according to claim 7, characterized in that, In step X2, the mass ratio of betulinic acid to the product obtained in step X1 is 1:5-6.

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