Slow-release sarafloxacin hydrochloride soluble powder and preparation method thereof

Abstract

The invention provides slow-release sarafloxacin hydrochloride soluble powder and a preparation method thereof, and belongs to the field of sarafloxacin preparations. The preparation method of the slow-release sarafloxacin hydrochloride soluble powder comprises the following steps: preparing composite drug-loaded particles, preparing microcapsules and carrying out post-treatment. According to the slow-release sarafloxacin hydrochloride soluble powder and the preparation method thereof, on the premise of effectively releasing medicine components, residual medicine in livestock and poultry bodies is rapidly metabolized and discharged, and residues of sarafloxacin in body tissues such as muscles and fat after livestock and poultry take the slow-release sarafloxacin hydrochloride soluble powder are reduced; stable and lasting release of the active ingredients in a target area is realized, and the bioavailability is improved; the stability of the soluble powder and sarafloxacin contained in the soluble powder is further improved, and good slow release performance can be kept after long-term storage.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of sarafloxacin preparation, in particular to a sustained-release sarafloxacin hydrochloride soluble powder and a preparation method thereof. BACKGROUND

[0002] Sarafloxacin (SARA) is the first fluoroquinolone special antibiotic for livestock and poultry developed and marketed by Abbott in 1995 and approved by FDA. It is mainly in the form of hydrochloride, i.e. sarafloxacin hydrochloride, which has a wide antibacterial spectrum and strong bactericidal ability, and can kill gram-positive bacteria, gram-negative bacteria, anaerobic bacteria, mycoplasma and chlamydia, and is used for preventing and treating various bacterial diseases such as E. coli, Salmonella, mycoplasma or Staphylococcus infection in pigs and chickens. At the same time, sarafloxacin has no cross-resistance with other antibacterial drugs and has small toxic and side effects, and is widely used in edible livestock and poultry breeding.

[0003] On the one hand, although sarafloxacin has small toxic and side effects and a wide range of safe applications, it has adverse effects on the growth and development of animal bones and is prohibited for use in young animals and pregnant animals. After livestock and poultry take sarafloxacin, the residual amount in their muscle, fat and other body tissues is high, and the metabolic elimination rate is slow, so a long drug holiday is needed for metabolism to reduce the residual amount. Under the premise of effective release of drug components, the residual drug in the livestock and poultry cannot be quickly metabolized and discharged, which reduces the risk of residual.

[0004] On the other hand, sarafloxacin has poor water solubility and unstable physicochemical properties. Although the prior art discloses a technical solution of coating sarafloxacin with β-cyclodextrin to change its solubility. However, after entering the digestive tract of animals, the initial release rate of sarafloxacin is too fast, and the release rate is greatly attenuated in the later period, which cannot achieve the stable and sustained release of sarafloxacin in the predetermined target area, and the bioavailability is poor. At the same time, the sustained release is systemic, which continuously releases sarafloxacin from the entrance of the oral cavity of animals, and sarafloxacin is widely absorbed and distributed to the whole body tissues (muscle, fat, etc.) of animals. This not only cannot accurately control the release of the drug in the animal body, but also leads to a high residual level of sarafloxacin in animal tissues.

[0005] Further, the existing sustained-release sarafloxacin soluble powder has poor stability. In hot and humid areas or during long-term storage in summer, sarafloxacin in the soluble powder is prone to leakage and premature release, and sarafloxacin in the soluble powder is also prone to oxidation and hydrolysis failure. At the same time, the soluble powder also cannot maintain good sustained-release performance after long-term storage, and the effect of late application is significantly reduced.

[0006] Based on this, a slow-release salmefloxacin hydrochloride soluble powder and a preparation method thereof are provided, which can quickly metabolize and discharge the residual drug in livestock and poultry bodies under the premise of effectively releasing the drug ingredients, reduce the residual salmefloxacin in muscle, fat and other body tissues of livestock and poultry after taking, achieve stable and long-lasting release of the active ingredients in the target area, improve the bioavailability, and further improve the stability of the soluble powder and the salmefloxacin contained therein, so that good slow-release performance can be maintained after long-term storage, which has important technical significance and research value. SUMMARY

[0007] To solve the technical problems in the prior art, a slow-release salmefloxacin hydrochloride soluble powder and a preparation method thereof are provided, which can quickly metabolize and discharge the residual drug in livestock and poultry bodies under the premise of effectively releasing the drug ingredients, reduce the residual salmefloxacin in muscle, fat and other body tissues of livestock and poultry after taking, achieve stable and long-lasting release of the active ingredients in the target area, improve the bioavailability, and further improve the stability of the soluble powder and the salmefloxacin contained therein, so that good slow-release performance can be maintained after long-term storage.

[0008] To solve the above technical problems, the technical solutions adopted by the present application are as follows: A preparation method of a slow-release salmefloxacin hydrochloride soluble powder, comprising the following steps: preparing composite drug-loaded particles, preparing microcapsules, and post-treatment. The method for preparing the composite drug-loaded particles is as follows: under stirring, a mixed metal salt solution is added dropwise into a salmefloxacin stock solution, and after the dropwise addition is completed, the mixture is stirred uniformly to obtain a pre-complexing solution; then, under stirring at 900-1000 rpm, a tannic acid solution is added dropwise into the pre-complexing solution, and after the stirring is uniform, the stirring speed is adjusted to 250-300 rpm, and the stirring reaction is carried out to obtain a reaction solution; after the reaction solution is dialyzed through a dialysis bag with a molecular weight cut-off of 3.5KDa, it is concentrated to prepare a composite drug-loaded particle suspension. The mixed metal salt solution is a mixed solution of zinc chloride hexahydrate and zirconium oxychloride octahydrate. The method for preparing the microcapsules is as follows: the composite drug-loaded particles are coated with a chitosan solution and a low-methoxyl pectin solution to prepare microcapsules.

[0009] Further, the method for preparing the microcapsules is as follows: the composite drug-loaded particle suspension is added into the chitosan solution, and after the stirring is uniform, the low-methoxyl pectin solution is continuously added dropwise to obtain a pre-coating solution; after the pre-coating solution is added dropwise into a calcium chloride solution for solidification, the solid is separated and collected, and after the solid is washed, it is dispersed into deionized water to obtain a microcapsule suspension. The method for post-treatment is as follows: mannitol, maltodextrin and the microcapsule suspension are mixed and then spray-dried to prepare the slow-release salmefloxacin hydrochloride soluble powder.

[0010] Preferably, in the preparation of the composite drug-loaded particles, the dropping time of the mixed metal salt solution is controlled to be 2-5 min. The stirring time of the tannic acid solution dropped into the pre-complexing solution is 30-40 min; and the stirring reaction time after adjusting the stirring speed to 250-300 rpm is 2-3 h.

[0011] Preferably, in the preparation of the composite drug-loaded particles, the sarafloxacin stock solution is prepared by dissolving sarafloxacin hydrochloride in dimethyl sulfoxide, and then mixing with Tris-HCl buffer solution with a pH of 8.5. The volume ratio of dimethyl sulfoxide to Tris-HCl buffer solution in the sarafloxacin stock solution is 0.1-0.12:5-5.2. The tannic acid solution is prepared by dissolving tannic acid in Tris-HCl buffer solution with a pH of 8.5. The mixed metal salt solution is prepared by dissolving zinc chloride hexahydrate and zirconium oxychloride octahydrate in Tris-HCl buffer solution with a pH of 8.5.

[0012] Preferably, in the preparation of the composite drug-loaded particles, the content of sarafloxacin hydrochloride in the sarafloxacin stock solution is 5-5.5 mg / mL. The content of tannic acid in the tannic acid solution is 2.1-2.3 mg / mL. The content of zinc chloride hexahydrate in the mixed metal salt solution is 11.5-12 mg / mL, and the content of zirconium oxychloride octahydrate is 0.3-0.35 mg / mL.

[0013] Preferably, in the preparation of the composite drug-loaded particles, the volume ratio of the sarafloxacin stock solution, the mixed metal salt solution, and the tannic acid solution is 4-4.2:1:5.1-5.3.

[0014] Preferably, in the preparation of the microcapsules, the chitosan solution is prepared by stirring chitosan in an aqueous acetic acid solution with a volume concentration of 1-1.2%. The mass concentration of the chitosan solution is 0.4-0.5 wt%. The mass concentration of the low-methoxyl pectin solution is 1-1.1 wt%. The mass concentration of the calcium chloride solution is 1.5-2 wt%.

[0015] Preferably, in the preparation of the microcapsules, the dropping time of the low-methoxyl pectin solution is controlled to be 20-30 min. The volume ratio of the composite drug-loaded particle suspension, the chitosan solution, and the low-methoxyl pectin solution is 1.8-2:1-1.2:2-2.1. The volume ratio of the pre-coating solution to the calcium chloride solution is 1:1.8-2.2.

[0016] Preferably, the weight ratio of mannitol, maltodextrin and microcapsule suspension in the post-processing is 0.3-0.4:1.1-1.3:5-5.3; The inlet temperature of the spray drying is controlled to be 125-130 DEG C, the outlet temperature is controlled to be 70-75 DEG C, and the spray pressure is controlled to be 0.3-0.35 MPa.

[0017] A slow-release salmefloxacin hydrochloride soluble powder is prepared by the preparation method.

[0018] Compared with the prior art, the beneficial effects of the present application are: (1) The slow-release salmefloxacin hydrochloride soluble powder has the cumulative release rate of 1.2-1.4% at 0.5h, 2.0-2.2% at 1h, 3.4-3.6% at 2h and 5.2-5.6% at 3h in a simulated gastric juice environment with pH of 1.2; and after being transferred into a simulated intestinal juice environment with pH of 6.8, the cumulative release rate is 40.2-40.5% at 3.5h, 51.7-51.8% at 4h, 67.2-67.9% at 6h, 83.8-84.2% at 8h, 93.0-93.5% at 10h and 98.8-98.9% at 12h.

[0019] (2) The slow-release salmefloxacin hydrochloride soluble powder does not appear discoloration and caking after being stored in a constant temperature and humidity environment with temperature of 45 DEG C and relative humidity of 85% for 180 days, and the salmefloxacin content of the soluble powder after being stored for 180 days decreases by 2.7% compared with that before storage; the cumulative release rate of the soluble powder after being stored for 180 days in a simulated intestinal juice environment with pH of 6.8 is 46.5% at 0.5h, 57.9% at 1h, 76.4% at 3h, 91.7% at 5h, 96.0% at 7h and 98.6% at 9h.

[0020] (3) The slow-release salmefloxacin hydrochloride soluble powder is used in poultry breeding test, and after being administered at the dose of 10 mg / kg of body weight, the area under the blood concentration-time curve of the drug-time curve is increased by 41.4% compared with that of the blank control group (β-cyclodextrin coated salmefloxacin hydrochloride).

[0021] (4) The slow-release salmefloxacin hydrochloride soluble powder of the present application is used in poultry breeding test, and is administered at a dose of 10 mg / kg of body weight for 5 days, and then the administration is stopped. On the 5th day of the drug holiday, the salmefloxacin residue in the egg is 0.9 μg / kg, the salmefloxacin residue in the breast muscle tissue is 3.0 μg / kg, the salmefloxacin residue in the leg muscle tissue is 2.7 μg / kg, and the salmefloxacin residue in the fat tissue is 5.8 μg / kg.

[0022] (5) The preparation method of the slow-release salmefloxacin hydrochloride soluble powder of the present application is simple in process flow, safe and controllable in preparation process, and beneficial to industrialized production. DETAILED DESCRIPTION

[0023] In order to have a clearer understanding of the technical features, objectives and effects of the present application, the specific embodiments of the present application are described below. It should be pointed out that the following detailed description is exemplary and is intended to provide further description of the present application. Unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as generally understood by those skilled in the art to which the present application belongs.

[0024] It should be noted that the terms used herein are only for the purpose of describing the specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, "first", "second", and the like are used to distinguish similar objects, and are not intended to describe a particular order or sequence, and it should also be understood that when the terms "comprise" and / or "include" are used in the specification, the presence of a feature, step, operation, device, component and / or combination thereof is indicated.

[0025] The present application provides a preparation method of a slow-release salmefloxacin hydrochloride soluble powder, which comprises the following steps: preparing a raw material solution, preparing a composite drug-loaded particle, preparing a microcapsule, and post-treatment.

[0026] The method for preparing the raw material solution is as follows: salmefloxacin hydrochloride is put into dimethyl sulfoxide (DMSO), stirred and dissolved, then Tris-HCI buffer solution with a pH of 8.5 is continuously added, and stirred for 20-30 min to obtain a salmefloxacin stock solution with a concentration of 5-5.5 mg / mL; tannic acid is put into Tris-HCI buffer solution with a pH of 8.5, stirred and dissolved to obtain a tannic acid solution with a concentration of 2.1-2.3 mg / mL; zinc chloride hexahydrate and zirconium oxychloride octahydrate are put into Tris-HCI buffer solution with a pH of 8.5, stirred and dissolved to obtain a mixed metal salt solution with a zinc chloride hexahydrate concentration of 11.5-12 mg / mL and a zirconium oxychloride octahydrate concentration of 0.3-0.35 mg / mL.

[0027] The volume ratio of dimethyl sulfoxide to Tris-HCI buffer in the sarafloxacin stock solution is 0.1-0.12:5-5.2.

[0028] The method for preparing the composite drug-loaded particles is as follows: the sarafloxacin stock solution is placed in a reactor at room temperature, the mixed metal salt solution is added dropwise under stirring at 900-1000 rpm, and the dropwise adding time of the mixed metal salt solution is controlled to be 2-5 min; after the dropwise adding of the mixed metal salt solution is completed, the stirring is continued for 10-20 min to obtain a pre-complexing solution; the tannic acid solution is added to the pre-complexing solution under stirring at 900-1000 rpm, and the stirring is continued for 30-40 min, then the stirring speed is reduced to 250-300 rpm, and the stirring reaction is continued for 2-3 h to obtain a reaction solution; the reaction solution is transferred into a dialysis bag with a molecular weight cut-off of 3.5 KDa, and dialysis is performed using deionized water for 24-28 h, and the water is changed 3-4 times during the dialysis; after the dialysis is completed, the material in the dialysis bag is collected and concentrated to adjust the concentration, and a composite drug-loaded particle (particle size in the range of 150-300 nm) suspension with a concentration of 5-6 mg / mL is obtained, which is placed in a 4℃ constant-temperature light-proof environment for use.

[0029] In the preparation of the composite drug-loaded particles, the volume ratio of the sarafloxacin stock solution, the mixed metal salt solution and the tannic acid solution is 4-4.2:1:5.1-5.3.

[0030] In the preparation of the composite drug-loaded particles in the embodiment of the application, the phenolic hydroxyl groups of the tannic acid form coordinate bonds with the metal ions Zn 2+ and Zr 4+ , and a metal polyphenol network with a three-dimensional structure is constructed; at the same time, Zn 2+ serves as an intermediate crosslinking agent and coordinates with sarafloxacin and tannic acid, so as to fix and wrap the sarafloxacin in the skeleton of the metal polyphenol network, realize the effective combination of the sarafloxacin and the metal polyphenol network, and prepare the composite drug-loaded particles with sustained-release performance. The coordinate bond energy between Zr 4+ and tannic acid is higher than that between Zn 2+ , and a small amount of zirconium metal is doped as a rigid anchor point in the metal polyphenol network, so as to improve the stability of the composite drug-loaded particles and further improve the long-acting controlled release performance of the composite drug-loaded particles on the sarafloxacin, and solve the problems of fast initial release rate and attenuation of the release rate in the later period of the existing soluble powder products.

[0031] The method for preparing the microcapsules comprises the following steps: chitosan is put into an acetic acid aqueous solution with a volume concentration of 1-1.2%, and stirred until completely dissolved to obtain a chitosan solution with a mass concentration of 0.4-0.5 wt%; then, under the condition of stirring at 300-350 rpm, the composite drug-loaded particle suspension is added into the chitosan solution; after stirring for 30-40 min, a low-methoxyl pectin solution with a mass concentration of 1-1.1 wt% is continuously added dropwise, and the dropwise adding time of the low-methoxyl pectin solution is controlled to be 20-30 min; after the dropwise adding of the low-methoxyl pectin solution is completed, the stirring is continuously performed for 50-60 min to obtain a pre-coating liquid; then, under the condition of stirring at 150-200 rpm, the pre-coating liquid is added dropwise into a calcium chloride solution with a mass concentration of 1.5-2 wt% at a dropwise adding rate of 1.3-1.7 mL / min; after the dropwise adding of the pre-coating liquid is completed, the stirring is continuously performed for 20-30 min, and then the solid matter is collected by centrifugal separation at 8000-9000 rpm; after the solid matter is washed by deionized water, the solid matter is dispersed into deionized water again to obtain a microcapsule suspension with a concentration of 17-20 mg / mL.

[0032] In the preparation of the microcapsules, the volume ratio of the composite drug-loaded particle suspension, the chitosan solution and the low-methoxyl pectin solution is 1.8-2:1-1.2:2-2.1. The volume ratio of the pre-coating liquid and the calcium chloride solution is 1:1.8-2.2.

[0033] In the preparation of the microcapsules in the embodiment of the present application, the amine groups of chitosan are protonated to be positively charged, and electrostatic adsorption occurs between the positively charged chitosan and the negatively charged composite drug-loaded particles; after a primary coating layer is formed on the surface of the composite drug-loaded particles, the negatively charged pectin and the positively charged chitosan adsorbed on the surface of the particles further form a composite coating layer through electrostatic interaction; then, in the calcium chloride solution, Ca 2+ The crosslinking and solidification of the pectin and the synergistic effect of chitosan improve the stability of the microcapsule wall, isolate the moisture and oxygen in the external environment, improve the long-term storage performance, and avoid the release or invalidation of sarafloxacin during storage; the microcapsules are stable and insoluble in the oral or gastric environment of the organism, effectively avoiding the release of the effective component in the oral cavity or stomach after the microcapsules enter the organism; after the microcapsules enter the intestinal tract, the microcapsule wall is decomposed under the action of the intestinal tract environment and intestinal tract enzymes, and the composite drug-loaded particles are accurately released in the intestinal tract, avoiding the dramatic fluctuation of the blood drug concentration in the organism; while the composite drug-loaded particles release sarafloxacin in the intestinal tract, due to the pH response characteristics of the metal polyphenol network, the release amount of sarafloxacin can be dynamically adjusted according to the environmental characteristics of the infected site in the intestinal tract, the infected site in the intestinal tract is treated as the focus, the release of sarafloxacin in the intestinal tract of the organism is accurately controlled, the bioavailability is improved, and the residue of sarafloxacin in edible tissues (especially muscle and fat) is reduced.

[0034] The method of the post-treatment is that the mannitol, the maltodextrin and the microcapsule suspension are mixed uniformly in a weight ratio of 0.3-0.4:1.1-1.3:5-5.3, and then are fed into a spray dryer, the inlet temperature of the spray drying is controlled to be 125-130℃, the outlet temperature is controlled to be 70-75℃, the spray pressure is controlled to be 0.3-0.35MPa, and the spray drying treatment is performed, so that the slow-release salmefloxacin hydrochloride soluble powder is prepared.

[0035] In the post-treatment process of the embodiment of the application, the mannitol, the maltodextrin and the microcapsule suspension are used in cooperation, so that the water solubility and the flowability of the soluble powder are improved, the effective component is protected from the spray drying, and the stability of the soluble powder product is further improved.

[0036] The embodiment of the application further provides a slow-release salmefloxacin hydrochloride soluble powder prepared by the method.

[0037] The application will be further described below in combination with some specific embodiments.

[0038] Embodiment 1 The embodiment provides a preparation method of a slow-release salmefloxacin hydrochloride soluble powder, and specifically comprises the following steps: 1) Preparation of raw material solution The salmefloxacin hydrochloride is put into dimethyl sulfoxide (DMSO), and after stirring and dissolving, Tris-HCI buffer solution with a pH of 8.5 is continuously added, and stirring is performed for 20min, so that a salmefloxacin stock solution with a concentration of 5mg / mL is obtained; the tannic acid is put into Tris-HCI buffer solution with a pH of 8.5, and after stirring and dissolving, a tannic acid solution with a concentration of 2.1mg / mL is obtained; the zinc chloride hexahydrate and the zirconyl chloride octahydrate are put into Tris-HCI buffer solution with a pH of 8.5, and after stirring and dissolving, a mixed metal salt solution with a zinc chloride hexahydrate concentration of 11.5mg / mL and a zirconyl chloride octahydrate concentration of 0.3mg / mL is obtained.

[0039] In the salmefloxacin stock solution, the volume ratio of dimethyl sulfoxide to Tris-HCI buffer solution is 0.1:5.

[0040] 2) Preparation of composite drug-loaded particles The sarafloxacin stock solution was placed in a reactor at room temperature, and the mixed metal salt solution was added dropwise under stirring at 900 rpm, and the dropwise time of the mixed metal salt solution was controlled to be 2 min. After the dropwise addition of the mixed metal salt solution was completed, stirring was continued for 10 min to obtain a pre-complexing solution. The tannic acid solution was added to the pre-complexing solution under stirring at 900 rpm, and stirring was continued for 30 min, and then the stirring speed was reduced to 250 rpm, and stirring was continued for 2 h to obtain a reaction solution. The reaction solution was transferred into a dialysis bag with a molecular weight cut-off of 3.5 KDa, and deionized water was used for dialysis for 24 h, and the water was changed 4 times during the dialysis. After the dialysis was completed, the material in the dialysis bag was collected and concentrated to adjust the concentration to obtain a composite drug-loaded particle (particle size in the range of 150-300 nm) suspension with a concentration of 5.5 mg / mL, which was placed in a constant-temperature light-proof environment at 4°C for use.

[0041] The volume ratio of the sarafloxacin stock solution, the mixed metal salt solution, and the tannic acid solution was 4:1:5.1.

[0042] 3) Preparation of microcapsules The chitosan was placed into an acetic acid aqueous solution with a volume concentration of 1%, and stirring was performed until the chitosan was completely dissolved to obtain a chitosan solution with a mass concentration of 0.4 wt%, and then the composite drug-loaded particle suspension was added to the chitosan solution under stirring at 300 rpm, and stirring was continued for 30 min, and then the low-methoxyl pectin solution with a mass concentration of 1 wt% was added dropwise, and the dropwise time of the low-methoxyl pectin solution was controlled to be 20 min. After the dropwise addition of the low-methoxyl pectin solution was completed, stirring was continued for 50 min to obtain a pre-coating solution. Then, the pre-coating solution was added dropwise to the calcium chloride solution with a mass concentration of 1.5 wt% under stirring at 150 rpm at a dropwise rate of 1.3 mL / min, and after the dropwise addition of the pre-coating solution was completed, stirring was continued for 20 min, and then the solid was collected by centrifugation at 9000 rpm, and the solid was washed with deionized water and then dispersed in deionized water to obtain a microcapsule suspension with a concentration of 20 mg / mL.

[0043] The volume ratio of the composite drug-loaded particle suspension, the chitosan solution, and the low-methoxyl pectin solution was 1.8:1:2.

[0044] The volume ratio of the pre-coating solution and the calcium chloride solution was 1:1.8.

[0045] 4) Post-treatment The mannitol, the maltodextrin, and the microcapsule suspension were mixed uniformly at a weight ratio of 0.3:1.1:5, and then the mixture was fed into a spray dryer, and the inlet temperature of the spray drying was controlled to be 125°C, the outlet temperature was 70°C, and the spray pressure was 0.3 MPa, and the spray drying treatment was performed to prepare a sustained-release type sarafloxacin hydrochloride soluble powder.

[0046] The embodiment further provides the slow-release solubility powder of sarafloxacin hydrochloride prepared by the method.

[0047] Embodiment 2 The embodiment provides a preparation method of a slow-release solubility powder of sarafloxacin hydrochloride, in particular to the following steps. 1) Preparation of raw material solution The sarafloxacin hydrochloride is put into dimethyl sulfoxide (DMSO), and after stirring and dissolving, Tris-HCI buffer solution with a pH of 8.5 is continuously added, and stirring is performed for 25 min to obtain a sarafloxacin hydrochloride stock solution with a concentration of 5.3 mg / mL; the tannic acid is put into Tris-HCI buffer solution with a pH of 8.5, and stirring is performed to dissolve, to obtain a tannic acid solution with a concentration of 2.2 mg / mL; the zinc chloride hexahydrate and the zirconium oxychloride octahydrate are put into Tris-HCI buffer solution with a pH of 8.5, and stirring is performed to dissolve, to obtain a mixed metal salt solution with a concentration of 11.7 mg / mL of zinc chloride hexahydrate and a concentration of 0.32 mg / mL of zirconium oxychloride octahydrate.

[0048] In the embodiment, the volume ratio of the DMSO to the Tris-HCI buffer solution in the sarafloxacin hydrochloride stock solution is 0.11:5.1.

[0049] 2) Preparation of composite drug-loaded particles The sarafloxacin hydrochloride stock solution is placed in a reactor at room temperature, and the mixed metal salt solution is added dropwise under the condition of stirring at 1000 rpm, and the dropwise adding time of the mixed metal salt solution is controlled to be 3 min; after the dropwise adding of the mixed metal salt solution is completed, stirring is continuously performed for 15 min to obtain a pre-complexing solution; the tannic acid solution is added to the pre-complexing solution under the condition of stirring at 1000 rpm, and after stirring is continuously performed for 35 min, the stirring speed is reduced to 300 rpm, and stirring reaction is continuously performed for 2.75 h to obtain a reaction solution; the reaction solution is transferred into a dialysis bag with a molecular weight cut-off of 3.5 KDa, and dialysis is performed for 24 h by using deionized water, and the water is changed for 4 times during the dialysis; after the dialysis is completed, the material in the dialysis bag is collected and concentrated to adjust the concentration, to obtain a composite drug-loaded particle (particle size in the range of 150-300 nm) suspension with a concentration of 5.5 mg / mL, which is placed in a 4 ℃ constant-temperature light-proof environment for use.

[0050] In the embodiment, the volume ratio of the sarafloxacin hydrochloride stock solution, the mixed metal salt solution and the tannic acid solution is 4.1:1:5.2.

[0051] 3) Preparation of microcapsules The chitosan was put into the 1% acetic acid aqueous solution, stirred until completely dissolved, and a chitosan solution with a mass concentration of 0.45 wt% was obtained. Then, the composite drug-loaded particle suspension was added to the chitosan solution under stirring at 320 rpm, and after stirring for 35 min, a low-methoxyl pectin solution with a mass concentration of 1 wt% was continuously added dropwise, and the dropwise adding time of the low-methoxyl pectin solution was controlled to be 25 min. After the dropwise adding of the low-methoxyl pectin solution was completed, the stirring was continued for 55 min to obtain a pre-coating liquid. Then, the pre-coating liquid was added dropwise to a calcium chloride solution with a mass concentration of 1.5 wt% under stirring at 200 rpm, and the dropwise adding rate of the pre-coating liquid was 1.5 mL / min. After the dropwise adding of the pre-coating liquid was completed, the stirring was continued for 25 min, and then the solid was collected by centrifugal separation at 9000 rpm. The solid was washed with deionized water and then dispersed in deionized water to obtain a microcapsule suspension with a concentration of 20 mg / mL.

[0052] The volume ratio of the composite drug-loaded particle suspension, the chitosan solution, and the low-methoxyl pectin solution is 1.9:1.1:2.1.

[0053] The volume ratio of the pre-coating liquid and the calcium chloride solution is 1:2.

[0054] 4) Post-treatment The mannitol, the maltodextrin, and the microcapsule suspension were mixed uniformly in a weight ratio of 0.35:1.2:5.2, and then were fed into a spray dryer. The inlet temperature of the spray drying was controlled to be 125°C, the outlet temperature was 70°C, and the spray pressure was 0.3 MPa. The spray drying treatment was performed to obtain the sustained-release salmaroxacin hydrochloride soluble powder.

[0055] The present embodiment also provides the sustained-release salmaroxacin hydrochloride soluble powder prepared by the foregoing method.

[0056] Example 3 The present embodiment provides a preparation method of a sustained-release salmaroxacin hydrochloride soluble powder, in particular: 1) Preparation of raw material solution The salmaroxacin hydrochloride was put into dimethyl sulfoxide (DMSO), and after stirring and dissolving, a Tris-HCI buffer solution with a pH of 8.5 was continuously added, and the stirring was continued for 30 min to obtain a salmaroxacin stock solution with a concentration of 5.5 mg / mL. The tannic acid was put into a Tris-HCI buffer solution with a pH of 8.5, and after stirring and dissolving, a tannic acid solution with a concentration of 2.3 mg / mL was obtained. The zinc chloride hexahydrate and the zirconyl chloride octahydrate were put into a Tris-HCI buffer solution with a pH of 8.5, and after stirring and dissolving, a mixed metal salt solution was obtained, in which the concentration of the zinc chloride hexahydrate was 12 mg / mL, and the concentration of the zirconyl chloride octahydrate was 0.35 mg / mL.

[0057] The volume ratio of dimethyl sulfoxide to Tris-HCI buffer in the sarafloxacin stock solution is 0.12:5.2.

[0058] 2) Preparation of composite drug-loaded particles The sarafloxacin stock solution was placed in a reactor at room temperature, and the mixed metal salt solution was added dropwise under stirring at 950 rpm, with the dropwise addition time of the mixed metal salt solution being controlled to be 5 min. After the dropwise addition of the mixed metal salt solution was completed, stirring was continued for 20 min to obtain a pre-complexing solution. The tannic acid solution was added to the pre-complexing solution under stirring at 950 rpm, and after stirring for 40 min, the stirring speed was reduced to 280 rpm, and the reaction was continued for 3 h to obtain a reaction solution. The reaction solution was transferred into a dialysis bag with a molecular weight cut-off of 3.5 KDa, and deionized water was used for dialysis for 28 h, with water being changed 4 times during the dialysis. After the dialysis was completed, the material in the dialysis bag was collected and concentrated to adjust the concentration, to obtain a composite drug-loaded particle (particle size in the range of 150-300 nm) suspension with a concentration of 5.5 mg / mL, which was placed in a constant-temperature dark environment at 4°C for use.

[0059] The volume ratio of the sarafloxacin stock solution, the mixed metal salt solution, and the tannic acid solution is 4.2:1:5.3.

[0060] 3) Preparation of microcapsules The chitosan was placed into an acetic acid aqueous solution with a volume concentration of 1%, and stirring was performed until the chitosan was completely dissolved, to obtain a chitosan solution with a mass concentration of 0.5 wt%. Then, the composite drug-loaded particle suspension was added to the chitosan solution under stirring at 320 rpm, and after stirring for 40 min, a low-methoxyl pectin solution with a mass concentration of 1 wt% was added dropwise, with the dropwise addition time of the low-methoxyl pectin solution being controlled to be 30 min. After the dropwise addition of the low-methoxyl pectin solution was completed, stirring was continued for 60 min to obtain a pre-coating solution. Then, the pre-coating solution was added dropwise to a calcium chloride solution with a mass concentration of 1.5 wt% under stirring at 180 rpm, with the dropwise addition rate being 1.7 mL / min. After the dropwise addition of the pre-coating solution was completed, stirring was continued for 30 min, and then the solid material was collected by centrifugal separation at 9000 rpm. The solid material was washed with deionized water and then redispersed in deionized water to obtain a microcapsule suspension with a concentration of 20 mg / mL.

[0061] The volume ratio of the composite drug-loaded particle suspension, the chitosan solution, and the low-methoxyl pectin solution is 2:1.2:2.1.

[0062] The volume ratio of the pre-coating solution to the calcium chloride solution is 1:2.2.

[0063] 4) Post-treatment The mannitol, maltodextrin and microcapsule suspension were mixed in a weight ratio of 0.4:1.3:5.3, and then fed into a spray dryer. The inlet temperature of the spray drying was controlled at 130°C, the outlet temperature was 75°C, and the spray pressure was 0.35 MPa. The sustained-release salmaroxacin hydrochloride soluble powder was prepared by spray drying.

[0064] The present embodiment also provides the sustained-release salmaroxacin hydrochloride soluble powder prepared by the above method.

[0065] Comparative Example 1 Comparative Example 1 used the technical solution of Example 2, with the following changes: 1) In the preparation of the raw material solution and the preparation of the composite drug-loaded particles, the addition of zirconium oxychloride octahydrate was omitted in the mixed metal salt solution, and zinc chloride hexahydrate was used to make up the weight amount of zirconium oxychloride octahydrate; 2) In the preparation of the microcapsules, the preparation and use of the chitosan solution were omitted, and the low-methoxyl pectin solution was directly added to the composite drug-loaded particle suspension under stirring to obtain a pre-coated solution.

[0066] Comparative Example 2 Comparative Example 2 used the technical solution of Example 2, with the following changes: The preparation of the raw material solution and the preparation of the composite drug-loaded particles were omitted, and in the subsequent preparation of the microcapsules, a salmaroxacin water dispersion solution with a concentration of 0.5 mg / mL was used to replace the composite drug-loaded particle suspension for the preparation of the microcapsules.

[0067] 2.5 g of the soluble powder of Examples 1-3 and Comparative Examples 1-2 were taken as samples and placed in the rotating blue of the dissolution instrument, and then the rotating blue was placed in 900 mL of simulated gastric fluid. The rotating blue was continuously rotated at a speed of 50 rpm under the condition of 37°C. The cumulative release rate of salmaroxacin was detected at 0.5 h, 1 h, 2 h and 3 h, respectively. The simulated gastric fluid was a hydrochloric acid solution with pH = 1.2, and also contained 0.2 wt% of sodium chloride and 0.4 wt% of pepsin. The specific results are shown in the following table:

[0068] When the above simulated gastric fluid dissolution test was carried out to 3 h, the dissolution instrument was stopped, the rotating blue containing the sample was taken out from the simulated gastric fluid, and then rinsed with simulated intestinal fluid at a temperature of 37°C for 5 s to remove the residual gastric fluid on the surface of the sample. Then the rotating blue was placed in 900 mL of simulated intestinal fluid, and continuously rotated at a speed of 50 rpm under the condition of 37°C. The cumulative release rate of salmaroxacin was detected at 3.5 h, 4 h, 6 h, 8 h, 10 h and 12 h, respectively. The simulated intestinal fluid was a phosphate buffer solution with pH = 6.8, and also contained 0.2 wt% of sodium chloride and 0.4 wt% of pectinase. The specific results are shown in the following table:

[0069] It can be seen that the soluble powder of embodiments 1-3 has good stability in gastric acid environment, the cumulative release rate of sarafloxacin in simulated gastric acid is ≤5.6%, the drug loss is less, and the effective component is effectively avoided from being released in the oral cavity and stomach after entering the body; the soluble powder is transferred to the intestinal fluid environment, and under the action of the characteristics of the intestinal fluid environment and related enzymes, the microcapsule coating is decomposed, triggering the sustained-release mechanism of the composite drug-loaded particles, which can long-acting and stable release sarafloxacin therein, helping to maintain stable blood drug concentration and improve bioavailability. After omitting the zirconium element doping in the preparation of the composite drug-loaded particles in Comparative Example 1, the stability of the prepared composite drug-loaded particles is reduced, and at the same time, the transition coating of chitosan is omitted in the preparation of the microcapsule, the binding performance of the pectin and the composite drug-loaded particles with the same negative charge is reduced, and the controlled release effect of sarafloxacin therein is further reduced. After omitting the preparation of the zinc-zirconium composite metal polyphenol network in Comparative Example 2, the original drug of sarafloxacin is directly coated, and almost no sustained-release function, which is released suddenly after the decomposition of the microcapsule coating in the intestinal fluid environment, which is not conducive to maintaining the blood concentration in the body stable and reducing the bioavailability.

[0070] The soluble powders of embodiments 2 and Comparative Examples 1-2 were respectively placed in a constant temperature and humidity environment with a temperature of 45°C and a relative humidity of 85% for accelerated storage test, and after 180 days of storage, whether discoloration and caking occurred in each sample was observed, and the decrease rate of the sarafloxacin content in each soluble powder after 180 days of storage compared with before storage was detected. The specific results are shown in the following table:

[0071] Further, the soluble powders of embodiments 2 and Comparative Examples 1-2 after 180 days of storage were respectively subjected to simulated intestinal fluid sustained-release test. Specifically, each sample was placed in a rotating blue of a dissolution tester, and then the rotating blue was placed in 900 mL of simulated intestinal fluid, and the rotating blue was continuously rotated at a rotating speed of 50 rpm under the condition of a temperature of 37°C. The cumulative release rate of sarafloxacin was detected at 0.5h, 1h, 3h, 5h, 7h, and 9h, respectively. The specification of the simulated intestinal fluid used was the same as before. The specific results are shown in the following table:

[0072] It can be seen that the soluble powder of Example 2 is isolated from the moisture and oxygen in the external environment by the combination of the zinc-zirconium composite metal polyphenol network with the salmefloxacin in Example 2, and the mutual cooperation of the chitosan transition layer and the pectin protection layer, thereby improving the long-term storage performance and avoiding the release or failure of salmefloxacin in the storage process. The soluble powder of Example 2 was stored in a constant temperature and humidity environment at a temperature of 45°C and a relative humidity of 85% for 180 days, and no discoloration or caking occurred. The long-term storage stability of the soluble powder was good, and the salmefloxacin content in the soluble powder did not decrease significantly compared with that before storage. Moreover, the sustained release performance of the soluble powder in the intestinal fluid environment did not change significantly before and after storage, and the soluble powder still maintained good long-acting and controllable sustained release, and the sustained release curve was stable. The long-term storage performance of Comparative Example 1, which omitted the zirconium element doping in the preparation of the composite drug-loaded particles and the chitosan transition in the preparation of the microcapsules, was greatly reduced. After high-temperature and high-humidity storage, discoloration and caking occurred, and the salmefloxacin content and sustained release performance after storage deteriorated significantly.

[0073] The soluble powders of Example 2 and Comparative Examples 1-2 were used as samples for poultry breeding experiments, and a blank control sample (β-cyclodextrin coated with hydrochloric acid salmefloxacin) was set. Specifically, 70 healthy laying hens with an age of 200-250 days, a body weight of 1.5-1.8 kg, and an egg production rate of greater than 90% were selected as test animals and randomly divided into 7 groups, with 10 in each group. The samples of Example 2, Comparative Example 1, Comparative Example 2, and the blank control were dissolved in water, and the corresponding 1-4 groups of laying hens were administered at a dose of 10 mg / kg of body weight. Blood samples were collected from the jugular vein or wing vein at 0.25 h, 0.5 h, 1 h, 2 h, 4 h, 6 h, 8 h, 12 h, 24 h, 36 h, and 48 h before and after administration, and the salmefloxacin concentration was detected. The blood drug concentration-time curve was drawn, the area under the drug-time curve was calculated, and the improvement rate of the area under the drug-time curve of Example 2, Comparative Example 1, and Comparative Example 2 compared with that of the blank control sample was calculated to evaluate the improvement of the bioavailability compared with the blank control group.

[0074] Meanwhile, the soluble powders of Example 2, Comparative Example 1, and Comparative Example 2 were dissolved in water, and the corresponding 5-7 groups of laying hens were administered at a dose of 10 mg / kg of body weight per day. After 5 days of continuous administration, the administration was stopped, and on the 5th day of drug withdrawal, the eggs of the laying hens in each group were collected, and the breast muscle tissue, leg muscle tissue, and fat tissue were collected from 2 randomly selected laying hens in each group after slaughter. The salmefloxacin residue in the eggs (whole eggs after mixing egg white and yolk), breast muscle tissue, leg muscle tissue, and fat tissue was detected, and the average value was taken.

[0075] The specific results are shown in the following table:

[0076] It can be seen that the soluble powder of embodiment 2 can effectively improve the bioavailability of sarafloxacin by the combination of zinc-zirconium composite metal and polyphenol network with sarafloxacin, and the mutual cooperation of chitosan transition layer and pectin protection layer, and can reduce the residue of sarafloxacin in edible tissues (muscle, fat) and eggs. On the fifth day of the drug holiday, the residue in the edible tissues of the eggs can be reduced to the food safety limit requirement, and the drug holiday can be greatly shortened. Further, although sarafloxacin is currently prohibited for use in the egg laying period of laying hens, the above-mentioned test of the present application also provides a new solution for reducing antibiotic residues in eggs for the prior art.

[0077] Unless otherwise specified, the percentages used in the present application are all mass percentages.

[0078] Finally, it should be noted that: the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or make equivalent replacements to some technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a sustained-release sarafloxacin hydrochloride soluble powder, characterized in that, The process includes the following steps: preparing composite drug-loaded particles, preparing microcapsules, and post-processing; The method for preparing composite drug-loaded particles is as follows: under stirring conditions, a mixed metal salt solution is added dropwise to a sarafloxacin stock solution. After the addition is complete, the solution is stirred until homogeneous to obtain a pre-complexed solution. Then, under stirring conditions of 900-1000 rpm, a tannic acid solution is added dropwise to the pre-complexed solution. After stirring until homogeneous, the stirring speed is adjusted to 250-300 rpm, and the reaction is carried out to obtain a reaction solution. The reaction solution is then dialyzed through a dialysis bag with a molecular weight cutoff of 3.5 kDa and concentrated to obtain a suspension of composite drug-loaded particles. The mixed metal salt solution is a mixed solution of zinc chloride hexahydrate and zirconium oxychloride octahydrate; The method for preparing microcapsules involves encapsulating composite drug-loaded particles with chitosan solution and low-methoxyl pectin solution to form microcapsules.

2. The method for preparing sustained-release sarafloxacin hydrochloride soluble powder according to claim 1, characterized in that, The method for preparing microcapsules is as follows: a composite drug-loaded particle suspension is added to a chitosan solution, stirred evenly, and then a low-methoxyl pectin solution is added dropwise to obtain a pre-coated solution. After the pre-coated liquid was added dropwise to the calcium chloride solution and solidified, the solids were separated and collected. The solids were then washed and dispersed in deionized water to obtain a microcapsule suspension. The post-processing method involves mixing mannitol, maltodextrin, and a microcapsule suspension, followed by spray drying to obtain a sustained-release sarafloxacin hydrochloride soluble powder.

3. The method for preparing sustained-release sarafloxacin hydrochloride soluble powder according to claim 1, characterized in that, In the preparation of the composite drug-loaded particles, the dropping time of the mixed metal salt solution is controlled to be 2-5 min; The tannic acid solution is added dropwise to the pre-complexed solution and stirred for 30-40 minutes; the stirring reaction time after adjusting the stirring speed to 250-300 rpm is 2-3 hours.

4. The method for preparing sustained-release sarafloxacin hydrochloride soluble powder according to claim 1, characterized in that, In the preparation of the composite drug-loaded particles, the sarafloxacin stock solution is prepared by dissolving sarafloxacin hydrochloride in dimethyl sulfoxide and then mixing it evenly with Tris-HCl buffer at pH 8.

5. The volume ratio of dimethyl sulfoxide to Tris-HCl buffer in the sarafloxacin stock solution is 0.1-0.12:5-5.2; The tannic acid solution is prepared by dissolving tannic acid in a Tris-HCl buffer solution with a pH of 8.

5. The mixed metal salt solution was prepared by dissolving zinc chloride hexahydrate and zirconium oxychloride octahydrate in a Tris-HCl buffer solution with a pH of 8.

5.

5. The method for preparing sustained-release sarafloxacin hydrochloride soluble powder according to claim 1, characterized in that, In the preparation of the composite drug-loaded particles, the content of sarafloxacin hydrochloride in the sarafloxacin stock solution is 5-5.5 mg / mL; The tannic acid content in the tannic acid solution is 2.1-2.3 mg / mL; The content of zinc chloride hexahydrate in the mixed metal salt solution is 11.5-12 mg / mL, and the content of zirconium oxychloride octahydrate is 0.3-0.35 mg / mL.

6. The method for preparing sustained-release sarafloxacin hydrochloride soluble powder according to claim 5, characterized in that, In the preparation of the composite drug-loaded particles, the volume ratio of sarafloxacin stock solution, mixed metal salt solution, and tannic acid solution is 4-4.2:1:5.1-5.

3.

7. The method for preparing sustained-release sarafloxacin hydrochloride soluble powder according to claim 2, characterized in that, In the preparation of the microcapsules, the chitosan solution is prepared by adding chitosan to an aqueous acetic acid solution with a volume concentration of 1-1.2% and stirring until homogeneous. The chitosan solution has a mass concentration of 0.4-0.5 wt%. The mass concentration of the low-methoxyl pectin solution is 1-1.1 wt%. The mass concentration of the calcium chloride solution is 1.5-2 wt%.

8. The method for preparing sustained-release sarafloxacin hydrochloride soluble powder according to claim 2, characterized in that, In the preparation of the microcapsules, the dropping time of the low-methoxyl pectin solution is controlled to be 20-30 min; The volume ratio of the composite drug-loaded particle suspension, chitosan solution, and low-methoxyl pectin solution is 1.8-2:1-1.2:2-2.1; The volume ratio of the pre-coating solution to the calcium chloride solution is 1:1.8-2.

2.

9. The method for preparing sustained-release sarafloxacin hydrochloride soluble powder according to claim 2, characterized in that, In the post-processing, the weight ratio of mannitol, maltodextrin, and microcapsule suspension is 0.3-0.4:1.1-1.3:5-5.3; The inlet temperature of the spray dryer is controlled at 125-130℃, the outlet temperature at 70-75℃, and the spray pressure at 0.3-0.35MPa.

10. A slow-release sarafloxacin hydrochloride soluble powder, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.

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