CN111346046B

CN111346046B - Sustained-release gel preparation containing moxidectin for injection and preparation method thereof

Info

Publication number: CN111346046B
Application number: CN202010151602.2A
Authority: CN
Inventors: 阮祥春; 魏青; 吴育发; 汤春莲; 张莉; 刘华; 许世富; 程帮照
Original assignee: Anhui Agricultural University AHAU
Current assignee: Anhui Agricultural University AHAU
Priority date: 2020-03-06
Filing date: 2020-03-06
Publication date: 2021-07-09
Anticipated expiration: 2040-03-06
Also published as: CN111346046A

Abstract

The invention discloses a moxidectin-containing sustained-release gel preparation for injection and a preparation method thereof. The preparation has high-efficiency killing effect on digestive tract nematodes and parasites on body surfaces in pets such as livestock, dogs and cats, especially on the nematodes with ivermectin resistance generated by sheep, and can effectively prevent and treat in-vivo and in-vitro parasitic diseases of livestock and dogs and cats. The gel preparation has the characteristics of simple preparation method, good biocompatibility, slow release, high efficiency and the like, and can be used for subcutaneous and intramuscular local injection and prevention and treatment of parasitic diseases of pets such as livestock, dogs, cats and the like.

Description

Sustained-release gel preparation containing moxidectin for injection and preparation method thereof

Technical Field

The invention relates to the field of sustained-release gel preparations, in particular to a moxidectin-containing sustained-release gel preparation for injection and a preparation method thereof.

Background

Parasitic diseases are one of the main diseases threatening the breeding industry of cattle and sheep, and the incidence rate accounts for about one third of the diseases of cattle and sheep. The parasitic diseases of cattle and sheep directly affect the production performance of sheep, reduce the quality of meat and reduce economic benefits. The cattle and sheep parasitic diseases are mainly caused by worms, insects, protozoa and the like, and each area has certain distribution characteristics. The ova, larvae and oocysts can be discharged along with the excrement of the sick cattle and sheep, so that forage and drinking water are polluted, and the spreading risk of parasitic diseases is increased. In the pasturing area, the period of summer and fall is more serious, the parasites and the host thereof move frequently, and the number of infectious larvae on pasture and dew is the largest, which is the main infection stage of sheep parasites. In addition, the spread of parasites across territories also presents great difficulties in control.

Moxidectin is a semi-synthetic single-component macrolide antibiotic produced by streptomycin fermentation, and the moxidectin is white or light yellow amorphous powder. Moxidectin belongs to the family of milbemycins, is a derivative of Nemadectin (Nemadectin), and belongs to the third-generation avermectins. Compared with other avermectins, the moxidectin has the advantages of single component, wide insect repelling spectrum, strong insect repelling activity, long acting, safety and the like. The molecular formula of moxidectin is C₃₇H₅₃NO₈The molecular weight is 639.8 g/mol. It is structurally similar to the B1 component of ivermectin, except that C₁₃No disaccharide on C₂₅Having a chain containing olefins in C₂₃Has a methoxy group (FIG. 1). The elemental composition of moxidectin is 69.48% for C, 8.37% for H, 2.15% for N and 20% for O.

As a new generation of macrolide antiparasitic drugs, the compound has high-efficiency killing effect on digestive tract nematodes and body surface parasites of cattle and sheep. For example: moxidectin has a life cycle of at least three weeks for common round nematode of lambs and inhibits the development of eggs, and is particularly effective on ovine larvae at various stages of Haemonchus contortus which are resistant to ivermectin. After the 1% moxidectin injection is subcutaneously administrated, the curative effect on sheep infected by scabies mite is 100%.

The injection type in situ gel is prepared by dissolving or dispersing the drug in the gel matrix, injecting the gel locally under the skin or in the muscle, forming semisolid or solid drug storage gel at the administration position, and continuously releasing the drug through slow and continuous degradation to achieve the long-acting and slow-release effect. The long-acting sustained-release preparation is one of the trends of veterinary drug development, and can reduce the administration frequency of animals and reduce the stress response to the animals; and a large amount of manpower and material resources can be saved, and the cultivation cost is saved. Meanwhile, the long-acting slow-release preparation is particularly suitable for preventing and treating animal parasitic diseases in pasturing areas, reduces repeated parasitic infection of cattle and sheep in spring and autumn grazing seasons, and improves breeding benefits.

Disclosure of Invention

Aiming at the problems, the invention aims to provide a moxidectin-containing sustained-release gel preparation for injection and a preparation method thereof, and the moxidectin-containing sustained-release gel preparation for injection has the advantages of simple preparation method, low cost, good biocompatibility, long drug effect maintaining time and the like; can effectively expel the digestive tract nematodes and the parasites on the body surfaces of the livestock, the poultry, the dogs and the cats and prevent and treat the in-vivo and in-vitro parasitic diseases of the livestock, the poultry, the dogs and the cats.

In order to achieve the purpose, the invention provides the following technical scheme: a slow-release gel preparation containing moxidectin for injection comprises moxidectin, a gel matrix, a slow-release agent, an antioxidant, a humectant, a solvent and a preservative, and the moxidectin, the gel matrix, the slow-release agent, the antioxidant, the humectant and the preservative are preferably prepared into the slow-release gel preparation containing moxidectin for injection according to a certain proportion and a certain method.

Preferably, the sustained release agent, the antioxidant, the humectant and the preservative are dissolved in a proper amount of ethanol or sterilized normal saline, water for injection, phosphate buffer and a mixture thereof according to a certain proportion and method. Adding a certain proportion of moxidectin, and carrying out high-speed uniform dispersion or high-pressure homogenization to obtain the nano-scale particle size. After the room temperature is recovered, adding a certain proportion of P188 and P407 which are subjected to sterilization treatment, and standing for 24-72 h at 4 ℃ for natural swelling to obtain the moxidectin sustained-release gel preparation for injection. Compared with the existing gel preparation in which most of the medicine is dissolved in the water solution, the sustained-release preparation has longer sustained-release time.

Preferably, each 100ml of the composition contains 0.25-20 g of moxidectin; more preferably, each 100ml of the composition contains 0.25 to 10g of moxidectin.

Preferably, the gel matrix comprises one or two of poloxamer 188 and poloxamer 407, further preferably, the proportion of poloxamer 188 in the gel matrix is 0.5-4%, the proportion of poloxamer 407 is 17-25%, and further preferably, the proportion of poloxamer 188 in the gel matrix is 1-3%, and the proportion of poloxamer 407 is 18-22%.

Preferably, the sustained release agent comprises one or more of methylcellulose, sodium carboxymethylcellulose, sodium alginate, Arabic gum, polylactic acid-glycolic acid copolymer, polyethylene glycol-polylactic glycolic acid diblock copolymer, polyethylene glycol-polylactic acid-polyethylene glycol triblock copolymer, polylactic acid, polyethylene glycol-polylactic acid diblock copolymer and polyethylene glycol-polylactic acid-polyethylene glycol triblock copolymer; the antioxidant comprises one or more of propyl gallate, butyl hydroxy anisol, 2-tert-butylphenol, sodium thiosulfate, 2, 6-di-tert-butyl-p-cresol, dilauryl thiodipropionate, thioglycerol, potassium metabisulfite, sodium formaldehyde sulfoxylate, thioglycolic acid, thiourea, ascorbyl palmitate, cysteine and salts thereof, isoascorbic acid, Ethylene Diamine Tetraacetic Acid (EDTA) and salts thereof, sodium metabisulfite, 1-thiosorbitol, fumaric acid, malic acid, hydroxybenzyl ester and salts thereof, benzoquinone and salts thereof, n-dihydrohealed acid and alpha-tocopherol.

Preferably, the humectant comprises one or more of glycerol, propylene glycol, polyethylene glycol 400(PEG400), polyethylene glycol 200(PEG200) and sorbitol; the preservative comprises one or more of benzyl alcohol, phenethyl alcohol, benzalkonium bromide, benzalkonium chloride and chlorobutanol; the solvent is any one of ethanol, normal saline, water for injection and phosphate buffer solution or a mixture thereof.

Compared with the prior art, the invention has the following beneficial effects:

1. the moxidectin sustained-release gel preparation for injection has the advantages of simple preparation method, low cost, good biocompatibility, long drug effect maintaining time and the like; can effectively expel the digestive tract nematodes and the parasites on the body surfaces of the livestock, the poultry, the dogs and the cats and prevent and treat the in-vivo and in-vitro parasitic diseases of the livestock, the poultry, the dogs and the cats.

Drawings

FIG. 1 is a schematic representation of the molecular formula of moxidectin.

FIG. 2 is a standard curve of moxidectin detected in a UV spectrophotometer.

FIG. 3 is a graph showing the in vitro cumulative release rate of moxidectin according to the present invention.

FIG. 4 is a HPLC chromatogram of 5ng/mL moxidectin according to the present invention.

FIG. 5 is a graph of blood levels of moxidectin provided by the present invention in rabbits.

FIG. 6 is a microscopic image of the worm egg according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a moxidectin-containing sustained-release gel preparation for injection, which comprises moxidectin, a gel matrix, a sustained-release agent, an antioxidant, a humectant, a solvent and a preservative.

Wherein: each 100ml contains 0.25-20 g of moxidectin, and preferably each 100ml contains 0.25-10 g of moxidectin.

Wherein: the gel matrix comprises one or two of poloxamer 188 and poloxamer 407, preferably, the proportion of poloxamer 188 in the gel matrix is 0.5-4%, the proportion of poloxamer 407 is 17-25%, further preferably, the proportion of poloxamer 188 in the gel matrix is 1-3%, and the proportion of poloxamer 407 is 18-22%.

Wherein, the slow release agent comprises one or more of methylcellulose, sodium carboxymethylcellulose, sodium alginate, acacia, polylactic acid-glycolic acid copolymer, polyethylene glycol-polylactic acid-glycolic acid diblock copolymer, polyethylene glycol-polylactic acid-polyethylene glycol triblock copolymer, polylactic acid, polyethylene glycol-polylactic acid diblock copolymer and polyethylene glycol-polylactic acid-polyethylene glycol triblock copolymer; the antioxidant comprises one or more of propyl gallate, butyl hydroxy anisole, 2-tert-butyl phenol, sodium thiosulfate, 2, 6-di-tert-butyl-p-cresol, dilauryl thiodipropionate, thioglycerol, potassium metabisulfite, sodium formaldehyde sulfoxylate, thioglycolic acid, thiourea, ascorbyl palmitate, cysteine and salts thereof, isoascorbic acid, Ethylene Diamine Tetraacetic Acid (EDTA) and salts thereof, sodium metabisulfite, 1-thiosorbitol, fumaric acid, malic acid, hydroxybenzyl ester and salts thereof, benzoquinone and salts thereof, n-dihydrohealed acid and alpha-tocopherol; the humectant comprises one or more of glycerol, propylene glycol, polyethylene glycol 400(PEG400), polyethylene glycol 200(PEG200) and sorbitol; the preservative comprises one or more of benzyl alcohol, phenethyl alcohol, benzalkonium bromide, benzalkonium chloride and chlorobutanol; the solvent is any one or mixture of ethanol, normal saline, water for injection and phosphate buffer solution.

The following provides specific embodiments of the present invention

Example 1

0.2g of butylated hydroxyanisole and 0.3g of 2, 6-di-tert-butyl-p-cresol are dissolved in 1mL of ethanol, and a proper amount of sterilized pure water is added and stirred to dissolve. Adding 5g of sorbitol serving as a humectant into the solution, mixing, adding 1g of sodium alginate serving as a slow release agent at room temperature, and stirring for dissolving. 0.05g of benzalkonium bromide preservative was added to the solution, and the mixture was dissolved by stirring. 0.5g of sterile moxidectin is added into the solution sterilized by a filter membrane, and the solution is dispersed for 10 minutes at a high speed of 20000 revolutions per minute in a sterile environment. Then, 18% of sterilized P407 and 1% of sterilized P188 were added, and the mixture was allowed to stand at 4 ℃ for natural swelling for 48 hours. And finally adding sterilized pure water to a constant volume of 100mL, and uniformly mixing to obtain the 0.5% moxidectin sustained-release gel preparation for injection.

Example 2

0.5g of 2-tert-butylphenol was dissolved in 1mL of ethanol, and an appropriate amount of sterilized pure water was added thereto and dissolved by stirring. The humectant PEG400 (10 g) was added to the solution, and after mixing, 0.05g of the preservative benzyl alcohol was added to the solution, and dissolved by stirring. After the solution is sterilized by a filter membrane of 0.45 mu m, the solution is heated to 60 ℃, 0.1g of sustained-release agent polyethylene glycol-polylactic acid-polyethylene glycol triblock copolymer is added under the aseptic condition, after stirring and mixing, 1g of sterile moxidectin is added into the solution, and the high-speed dispersion is carried out for 10 minutes at 20000 revolutions per minute. Then, the temperature is returned to the room temperature, and 18% of sterilized P407 and 1% of sterilized P188 are added to the mixture to naturally swell the mixture for 48 hours at 4 ℃. And finally adding sterilized pure water to a constant volume of 100mL, and uniformly mixing to obtain the 1% moxidectin sustained-release gel preparation for injection.

Example 3

0.5g of 2, 6-di-tert-butyl-p-cresol is dissolved in 1mL of ethanol, and a proper amount of sterilized pure water is added and stirred for dissolution. Adding 5g of sorbitol serving as a humectant into the solution, mixing, adding 2g of methyl cellulose serving as a slow-release agent at room temperature, and stirring for dissolving. 0.05g of benzalkonium bromide preservative was added to the solution, and the mixture was dissolved by stirring. 2g of sterile moxidectin is added into the solution sterilized by the filter membrane, and the solution is dispersed for 10 minutes at a high speed of 20000 revolutions per minute in a sterile environment. Then, adding 22% of sterilized P407 and 1% of sterilized P188, and naturally swelling for 48-72 h at 4 ℃. And finally adding sterilized pure water to a constant volume of 100mL, and uniformly mixing to obtain the 2% moxidectin sustained-release gel preparation for injection.

Example 4

The moxidectin sustained-release gel for injection is prepared by the method of example 1 according to the following table by mixing P407 or P188, and 4mL of the gel is taken out to a test tube with a plug. And (3) placing the test tube into a digital constant-temperature water bath kettle, slowly raising the temperature, and measuring the gelling temperature of different gel matrix components. The measured gelling temperatures of the different gel matrix components are shown in table 1;

TABLE 1 gelling temperature of different gel matrix components

Example 5

The sustained-release moxidectin gel for injection is prepared by adding 10% of the humectants glycerin, propylene glycol, polyethylene glycol 400(PEG400) and sorbitol respectively according to the method of example 1. Take 4mL of gel into sample vial with cap. Placing into a constant temperature box with temperature of 25 + -2 deg.C and humidity of 65 + -3%. The gels were weighed at 7, 14 and 21 days, respectively, and compared with the initial gel mass to calculate the moisture retention rate of the gel. The test result of the moisture retention rate shows that the glycerin, the propylene glycol, the PEG400 and the sorbitol have good moisture retention effect, and the storage time of the gel preparation can be effectively prolonged. The results of different moisturizers on the gel moisturizing rate are shown in table 2.

TABLE 2 moisturizing ratio of different moisturizers to gels

Example 6

A sustained-release gel for injection containing 1% moxidectin was prepared as in example 3, and 3 stoppered tubes were filled with 4mL of the gel per stoppered tube. The test tube with the gel is placed in a constant-temperature shaking water bath, and 8mL of release medium is added after the gel is gelled. Wherein the release medium contains 6%

O20 polyoxyethylene lauryl ether (Brij 98) and 40% ethanol in water. The gel was subjected to an in vitro release test at 37 ℃ with shaking at a speed of 100 times/min. Samples were taken at 0.5,1,2,4,6,8,12h and 1,2,3,4,5,6,7d times. All release medium was collected each time and a new 8mL of release medium was added until the end of the gel in vitro release.

Diluting the sample with anhydrous ethanol, using anhydrous ethanol as blank control, and performing ultraviolet irradiation at 243.8nm wavelengthAnd detecting by a spectrophotometer. The moxidectin has good linear relation in the concentration range of 0.5-20 mu g/mL, and R²Is 1. The standard curve of moxidectin detected in a UV spectrophotometer is shown in FIG. 2.

The moxidectin gel in-vitro release shows that compared with the condition that no sustained release agent is added, the moxidectin gel in-vitro release is prolonged to 7 days, and the average cumulative release rate of the moxidectin reaches 88.91 percent. The cumulative release profile of moxidectin in the moxidectin gel for injection is shown in fig. 3.

Comparative example 6

0.5g of 2, 6-di-tert-butyl-p-cresol is dissolved in 1mL of ethanol, and a proper amount of sterilized pure water is added and stirred for dissolution. Adding 5g of sorbitol serving as a humectant into the solution, mixing, adding 2g of sodium carboxymethylcellulose serving as a slow release agent at room temperature, and stirring for dissolving. 0.05g of benzalkonium bromide preservative was added to the solution, and the mixture was dissolved by stirring. Adding 2g of sterile moxidectin into the solution subjected to sterilization by a filter membrane, adding sterilized 22% of P407 and sterilized 1% of P188, and naturally swelling for 48-72 h at 4 ℃. And finally adding sterilized pure water to a constant volume of 100mL, and uniformly mixing to obtain the 2% moxidectin sustained-release gel preparation for injection. 3 stoppered tubes were removed and 4mL of the prepared gel was added to each stoppered tube. The test tube with the gel is placed in a constant-temperature shaking water bath, and 8mL of release medium is added after the gel is gelled. Wherein the release medium contains 6%

O20 polyoxyethylene lauryl ether (Brij 98) and 40% ethanol in water. The gel was subjected to an in vitro release test at 37 ℃ with shaking at a speed of 100 times/min. Samples were taken at 0.5,1,2,4,6,8,12h and 1,2,3,4,5d times. All release medium was collected each time and a new 8mL of release medium was added until the end of the gel in vitro release. The in vitro release test showed that this example had a short in vitro release time of 5 days compared to the moxidectin gel preparation prepared in example 3. As the preparation of the method is not carried out with high-speed dispersion or high-pressure homogenization to form nano-scale particle size, the in vitro release concentration of the moxidectin has larger range change.

Example 7

Sustained-release injection gel containing 0.25% moxidectin was prepared according to the method of example 3 and tested for blood concentration in rabbits. 8 healthy New Zealand white rabbits with the body weight of 2.5kg +/-0.5 kg are selected, and fed normally for one week in half of males and females. Before the start of the test, the test was fasted for at least 8 h. Before administration, 2mL of anticoagulated blood was collected from the marginal ear vein of each rabbit, labeled, and used as blank blood. The prepared moxidectin gel preparation is subcutaneously administered to the neck and the back according to the weight of 1.0 mg/kg. After administration, 2mL of anticoagulated samples were collected from the rabbit marginal ear vein at 1,2,4, 8,12, 24, 36, 48h and 3,4,5,6, 8, 10, 15, 20, 30, 40, 50, 60, 70, 80 d. The sample was centrifuged at 3000rpm for 10min, the upper plasma portion was removed and transferred to another 2mL labelled EP tube and stored at-20 ℃ for HPLC detection.

The detection method of moxidectin in blood plasma is determined by HPLC fluorescence detection method. The collected sample was returned to room temperature. Adding 0.5mL of acetonitrile extracting solution into an EP tube, vortexing for 3 minutes, centrifuging at 10000rpm for 10 minutes, sucking the supernatant into another EP tube, repeatedly extracting once, and combining the two extracting solutions. The extract was dried at 50 ℃ with nitrogen. Adding 100 μ L of N-methylimidazolyl acetonitrile solution (1:1), and vortexing for 1 min; a further 150. mu.L of trifluoroacetic anhydride in acetonitrile (1:2) was added and vortexed for 1 min. Adding 750 μ L methanol into the solution, vortexing for 1min, filtering with 0.45 μm filter membrane, and detecting with a computer. HPLC with acetonitrile-water (96:4, v/v) mobile phase; agilent extended-C18 chromatography column (4.6X 250mm, 5 μm); the column temperature is 30 ℃; and detecting the moxidectin under the system condition of an excitation wavelength of 365nm and an emission wavelength of 475 nm. Under the detection condition, the concentration of the moxidectin is in the range of 0.5-200 ng/mL, the linear relation of a standard curve is good, and R is²>0.99; the lowest detection limit is 0.1ng/mL, and the lowest quantification limit is 0.5 ng/mL; the average recovery rate of 0.5,10 and 50ng/mL reaches more than 90 percent; the precision in the day and the daytime is less than 10 percent. The chromatogram of moxidectin detected by HPLC is shown in FIG. 4.

After HPLC detection, the moxidectin slow-release gel preparation is injected subcutaneously, and the blood concentration in rabbits can be maintained for 70 days after administration. The average blood concentration of female rabbits reached the highest peak 4 hours after administration, while the average blood concentration of male rabbits reached the highest peak 12 hours after administration. Indicating that the absorption of moxidectin is faster in female rabbits than in male animals. From the corresponding time plot of blood concentration, it can be seen that the concentration of moxidectin in the plasma of female rabbits was substantially lower than that in the plasma of male rabbits from 8 hours after the administration. It was shown that although female rabbits absorbed moxidectin quickly, they also metabolized more quickly than male rabbits. The corresponding time-averaged plasma concentrations (n-4) of the injectable moxidectin gel formulations in male and female rabbits are shown in fig. 5.

Example 8

Sustained-release injection gel containing 2% moxidectin was prepared according to the method of example 3 and used for the in vivo gut nematode therapy test in Tibetan sheep. In a pasture of Bakat, Hainan, Qinghai province, 30 Tibetan sheep with naturally-occurring digestive tract nematodes are selected by collecting intestinal excrement and checking the excrement. The clinical manifestations of the diseased sheep include mental depression, emaciation and anemia. The test was divided into 2 groups, positive no-drug control group and test group. In the test group, 0.2mg/kg of ivermectin injection and 1mg/kg of moxidectin sustained-release gel preparation prepared by subcutaneous injection are respectively adopted.

The Tibetan sheep feces naturally infected by the gastrointestinal nematodes are detected to have mixed infection of the nematode of thin neck, the nematode of round hair, the nematode of Ostertagia and the nematode of haemonchus contortus. Corresponding results of egg microscopy are shown in table 3 and figure 6. After the moxidectin is treated for one week, the effect is better than that of ivermectin, the number of oocysts in excrement is reduced by more than 90%, and clinical symptoms are obviously improved; after 2 weeks of treatment, the number of oocysts in the feces decreased by 100%. The weight of the treated Tibetan sheep is increased, and the health state is recovered. Although ivermectin has some therapeutic effect, an increase in oocyst number in the feces occurs after 2 weeks. The protection time of moxidectin on Tibetan sheep infected with the gastrointestinal nematodes is longer. The results of the specific oocyst count in feces after treatment of the tibetan sheep gut worm infection are shown in table 4;

TABLE 3 observation of egg morphology under microscope

TABLE 4 treatment effect of nematode infection of digestive tract of Tibetan sheep

Example 9

An injectable sustained-release gel containing 2% moxidectin was prepared according to the method of example 3 to perform a sheep body surface itch mite treatment test. In a farm in shou county, Anhui, 30 sheep were selected for natural onset of itch mites. The clinical manifestations of the affected sheep are rubbing itching of sheep, disorder of the sheep's hair, and local shedding of wool. Wool falls off to produce redness, swelling, fever, and exudation of blood serum. Some parts have suppuration and yellowish scab. Moxidectin slow release gel preparations prepared by subcutaneous injection of 1mg/kg respectively;

after the moxidectin is used for treating, the skin pruritus is quickly relieved, the skin injury is healed after 6 weeks, all sheep are cured after 8 weeks, the cure rate reaches 100%, and no acarid is collected by a skin scraping sheet.

Example 10

Sustained-release gel for injection containing 1% moxidectin was prepared according to the method of example 3 to conduct a body surface lice treatment test for dogs. In a pet clinic of Anhui province, Feizhiza sativa, 12 dogs infected with lice on body surfaces are treated within 3 months. The moxidectin sustained-release gel preparation prepared by subcutaneous injection of 1mg/kg is fed back by livestock owners 24-48 hours after administration, and the symptom of pruritus of the dogs is obviously relieved. After 1 week, the body surface of the affected dog basically disappears without lice, and the cure rate is close to 100 percent.

Example 11

Sustained release gels for injection containing 1% moxidectin were prepared according to the procedure of example 3 for testing cat flea treatment. In a pet clinic of Tu lake, Anhui, 5 cats with fleas on their body surfaces were treated within about 1 month. The moxidectin sustained-release gel preparation prepared by subcutaneous injection of 1mg/kg has good flea killing effect after the administration for 24 hours by livestock owners, and a large amount of fleas die. The cure rate of the moxidectin sustained-release gel preparation to the flea infected on the body surface of the cat reaches 100 percent. Experiments have shown that moxidectin slow release gel formulations for injection provide protection against flea infestation for cats for approximately 3 months.

Example 11

The sustained-release gel for injection containing 2% moxidectin was prepared according to the method of example 3 and used in clinical trials for treating the skin disease of the pig sarcoptic mite. The mange mites of pigs in a certain pig farm in Fengtai county, Anhui, occur. The clinical manifestations of the disease are severe itching and uneasiness, and the sick pigs rub the back or body side everywhere. Even the affected part is rubbed open to bleed, so that the affected part has hair loss, scabbing, pachynsis, wrinkle formation and chapping. Thereby resulting in emaciation and dysplasia. The test selects 60 pigs with natural disease, and the pigs are divided into 2 groups, wherein the pigs are positive and are not dosed with drug, and the test group comprises 20 sick pigs. The experimental group, respectively according to 0.2mg/kg intramuscular ivermectin injection and 1mg/kg intramuscular prepared moxidectin sustained release gel preparation.

After the treatment of the moxidectin, the skin pruritus of the pigs is quickly relieved, and the feed intake of the pigs is gradually recovered. After 1 week, clinical symptoms such as scabbing, pachynsis, wrinkles and chapping are improved, and weight of the pig is increased. The Moxidectin gel preparation can effectively prevent and treat the pig sarcoptidosis for 3 months. In an ivermectin test group, after administration, most of clinical symptoms of pigs are improved, and after 2 weeks, parts of pigs rub the back or body side and the like, so that the clinical effect and the prevention and treatment time of the ivermectin on the pig scabies are shorter than those of a moxidectin slow-release gel preparation. The specific test results are shown in Table 5.

TABLE 5 therapeutic effect of moxidectin on sarcoptidosis

The moxidectin sustained-release gel preparation prepared by the invention has the characteristics of simple preparation method, good biocompatibility, sustained release, high efficiency and the like. Through repeated and multiple batches of clinical tests, excellent performance of preventing and treating the parasitic diseases of livestock, dogs and cats is obtained, and the moxidectin gel preparation has stable and reliable curative effect and practical application value. In conclusion, the invention has the advantages of rigorous and scientific formula and definite curative effect, can effectively prevent and treat the intestinal tract nematode and body surface parasitic disease in pets such as livestock, dogs, cats and the like, and has good clinical application value. The experiment shows that the sustained-release effect of the embodiment 3 obtained by the preparation process and the proportion is obvious.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims

1. A slow-release gel preparation containing moxidectin for injection is characterized in that: comprises moxidectin, a gel matrix, a slow release agent, an antioxidant, a humectant, a solvent and a preservative; dissolving the sustained release agent, the antioxidant, the humectant and the preservative in a proper amount of ethanol or sterilized normal saline, water for injection, phosphate buffer solution or a mixture thereof according to a certain proportion and method, adding a certain proportion of moxidectin, and carrying out high-speed uniform dispersion or high-pressure homogenization to obtain nano-scale particle size; and after the room temperature is recovered, adding the P188 and the P407 which are subjected to sterilization treatment, and standing for 24-72 h at the temperature of 4 ℃ for natural swelling to obtain the moxidectin sustained-release gel preparation for injection.

2. The moxidectin-containing sustained release gel formulation as claimed in claim 1, wherein: each 100ml of the composition contains 0.25-20 g of moxidectin.

3. The moxidectin-containing sustained release gel formulation as claimed in claim 1, wherein: each 100ml of the composition contains 0.25-10 g of moxidectin.

4. The moxidectin-containing sustained release gel formulation as claimed in claim 1, wherein: the gel matrix contains 0.5-4% of poloxamer 188 and 17-25% of poloxamer 407.

5. The moxidectin-containing sustained release gel formulation as claimed in claim 4, wherein: the gel matrix contains 1-3% of poloxamer 188 and 18-22% of poloxamer 407.

6. The moxidectin-containing sustained release gel formulation for injection according to any one of claims 1 to 5, wherein: the sustained release agent comprises one or more of methylcellulose, sodium carboxymethylcellulose, sodium alginate, acacia, polylactic acid-glycolic acid copolymer, polyethylene glycol-polylactic acid-glycolic acid diblock copolymer, polyethylene glycol-polylactic acid-glycolic acid-polyethylene glycol triblock copolymer, polylactic acid, polyethylene glycol-polylactic acid diblock copolymer and polyethylene glycol-polylactic acid-polyethylene glycol triblock copolymer;

the antioxidant comprises one or more of propyl gallate, butyl hydroxy anisole, sodium thiosulfate, 2, 6-di-tert-butyl-p-cresol, dilauryl thiodipropionate, thioglycerol, potassium metabisulfite, sodium formaldehyde sulfoxylate, thioglycolic acid, thiourea, vitamin c palmitate, cysteine and salts thereof, erythorbic acid, sodium metabisulfite, 1-thiosorbitol, n-dihydrohealed acid and alpha-tocopherol.

7. The moxidectin-containing sustained release gel formulation as claimed in claim 6, wherein: the humectant comprises one or more of glycerol, propylene glycol, polyethylene glycol 400(PEG400), polyethylene glycol 200(PEG200) and sorbitol; the preservative comprises one or more of benzyl alcohol, phenethyl alcohol, benzalkonium bromide, benzalkonium chloride and chlorobutanol; the solvent is any one of ethanol, normal saline, water for injection and phosphate buffer solution or a mixture thereof.

8. A method for preparing a moxidectin-containing sustained release gel formulation for injection as claimed in claim 1, wherein: dissolving a sustained release agent, an antioxidant, a humectant and a preservative in a proper amount of ethanol or sterilized normal saline, water for injection, a phosphate buffer solution or a mixture thereof according to a certain proportion and a certain method, adding a certain proportion of moxidectin, carrying out high-speed uniform dispersion or high-pressure homogenization to form a nano-scale particle size, adding a certain proportion of P188 and P407 which are subjected to sterilization treatment after the room temperature is recovered, and standing for 24-72 h at 4 ℃ for natural swelling to obtain the slow-release agent.