An ivermectin enteric granule and a preparation method and use thereof

Abstract

The application belongs to the field of veterinary drugs and discloses an ivermectin enteric granule, which comprises PEG6000, enteric material HPMCP-hp50 and ivermectin, the particle size of the ivermectin enteric granule is 20-50 mesh, the amount of the PEG6000 is equivalent to 54-84% of the total weight of the ivermectin enteric granule, and the amount of the enteric material HPMCP-hp50 is equivalent to 10-15% of the total weight of the ivermectin enteric granule, the granule takes PEG6000 as a skeleton, takes HPMCP-hp50 as an enteric material, and loads ivermectin in the skeleton, through the above structure, the enteric granule can be ensured to be insoluble in gastric juice, to be rapidly released and absorbed in the front section of the intestinal tract, through in-vitro release experiments, it can be found that the release speed can be kept at 67% at least in 1h, through in-vivo pharmacokinetic experiments on the best case piglets, it is found that the Cmax of the piglets orally administered with the ivermectin enteric granule is significantly improved compared with the ivermectin tablet, the average relative bioavailability is increased by about 78%, the absolute bioavailability is increased from 37.4% to 66.5%, and the application further provides a preparation method and application of the ivermectin enteric granule.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of veterinary medicine, in particular to an ivermectin enteric granule and a preparation method and use thereof. BACKGROUND

[0002] Veterinary ivermectin is a broad-spectrum antiparasitic drug, which is widely used in the clinical treatment and prevention of animal endo- and ecto-parasitic diseases due to its high efficiency, broad spectrum, and small toxic and side effects. At present, ivermectin has been marketed in the form of premix (compound: albendazole ivermectin premix), tablets, ointments, injections, transdermal preparations, etc., which have been widely used in the treatment and prevention of gastrointestinal nematodes, lung nematodes, and ectoparasites (ticks, lice, mites, etc.) in pigs, horses, cattle, sheep, rabbits, camels, foxes, alpacas, and other domestic and wild animals. Oral administration is the most commonly used method of drug administration in large-scale farms, which has the advantages of less stimulation to animals, convenient administration, and sustained administration. In order to ensure the convenience of drug administration and reduce labor costs, centralized water administration and drug feeder administration are becoming more and more common, but these administration methods also put higher requirements on the solubility, stability, palatability, and bioavailability of the drug. Ivermectin is a macrolide antibiotic, and the original drug is a pure white or off-white crystalline powder with a melting point of 154.5-157℃, which is easily soluble in organic solvents such as methanol, ethyl acetate, butyl acetate, acetonitrile, ethanol, etc. The solubility in water is extremely low (0.006-0.009 mg / mL). These physicochemical properties result in low oral bioavailability of ivermectin, and at present, albendazole ivermectin premix is mostly used in large-scale farming. It is reported that the oral bioavailability of the premix in pigs is lower than that of subcutaneous administration, although it is effective in treating gastrointestinal parasites in animals, the drug concentration on the skin of the animal is lower than the effective concentration, resulting in poor treatment effect on ectoparasites in animals, and the structure of ivermectin is destroyed in the acidic environment of the stomach and the first-pass effect greatly reduces the oral bioavailability of ivermectin.

[0003] Veterinary ivermectin is a fat-soluble material, which has poor solubility in the body, and conventional preparations are difficult to effectively release it.

[0004] Therefore, how to achieve rapid release of veterinary ivermectin in the early small intestine and achieve high bioavailability. SUMMARY

[0005] The purpose of this invention is to provide ivermectin enteric-coated granules and its preparation method. The granules use PEG6000 as the backbone and HPMCP-hp50 as the enteric material, with ivermectin loaded within the backbone. This structure ensures that the enteric-coated granules are insoluble in gastric juice and are rapidly released and absorbed in the early intestinal tract. In vitro release experiments show that the release rate can be maintained at at least 67% within 1 hour. In vivo pharmacokinetic studies on piglets (the optimal case) revealed that oral administration of ivermectin enteric-coated granules significantly increased the Cmax compared to oral administration of ivermectin tablets, with an average increase in relative bioavailability of approximately 78%; the absolute bioavailability increased from 37.4% to 66.5%.

[0006] In addition, the present invention also provides a method for preparing and applying the ivermectin enteric-coated granules.

[0007] To achieve the above objectives, this application discloses:

[0008] An enteric-coated ivermectin granule comprises PEG6000, an enteric-coating material HPMCP-hp50, and ivermectin. The ivermectin enteric-coated granules have a particle size of 20-50 mesh. The amount of PEG6000 is equivalent to 54-84% of the total weight of the ivermectin enteric-coated granules, and the amount of the enteric-coating material HPMCP-hp50 is equivalent to 10-15% of the total weight of the ivermectin enteric-coated granules.

[0009] The core innovation of this invention lies in:

[0010] 1. This invention uses PEG6000 as a framework, which is uniformly mixed with the enteric material HPMCP-hp50 to form particles in which the enteric material HPMCP-hp50 is distributed. The enteric pH value of the enteric material HPMCP-hp50 is about 5.0, which can dissolve rapidly in the front part of the small intestine. Since ivermectin is distributed within the particles, the dissolution process of the enteric material HPMCP-hp50 carries ivermectin into the small intestine.

[0011] This release characteristic is not for the immediate release of ivermectin, but rather a continuous release behavior that occurs with the continuous dissolution of the enteric material HPMCP-hp50; this continuous release behavior effectively overcomes the problem of the difficulty in the stable release of fat-soluble ivermectin in the small intestine.

[0012] 2. Ivermectin is a fat-soluble material, which cannot be sufficiently dispersed in many systems. As mentioned above, sufficient dispersion is a necessary factor for achieving the continuous release process associated with the continuous dissolution of ivermectin and the enteric material HPMCP-hp50.

[0013] Therefore, this invention uses PEG6000 as a framework to achieve effective and uniform dispersion of ivermectin through molten PEG6000.

[0014] 3. This invention uses PEG6000 as a carrier, which can be prepared into an additive that can be added to feed. It will not separate and deposit during the mixing process with feed, and can deliver the drug into the animal's body as the animal eats.

[0015] 4. In its research, this invention discovered that the absorption of ivermectin in the pre-small intestine is an important factor in achieving its high bioavailability. Through the selection of the aforementioned skeleton and enteric-coated materials, this invention achieves continuous and rapid release of ivermectin in the pre-small intestine. From a bioavailability perspective, the granules of this invention have significantly higher Cmax bioavailability than ivermectin tablets.

[0016] In the above-mentioned ivermectin enteric-coated granules, the amounts of PEG6000, enteric material HPMPCP-hp50, and ivermectin are 84wt%, 15wt%, and 1wt%, respectively; the particle size of the ivermectin enteric-coated granules is 30-40 mesh.

[0017] Meanwhile, the present invention also discloses a method for preparing the above-mentioned ivermectin enteric granules, which involves melting PEG6000, mixing it with other raw materials, and then granulating it.

[0018] The above preparation method includes the following steps:

[0019] (1) Weigh out PEG6000 as a solid dispersion according to the proportion, heat and melt it to obtain mixture A;

[0020] (2) Add the ivermectin raw material to mixture A and stir evenly to combine the ivermectin molecules with the carrier to obtain mixture B;

[0021] (3) Add enteric material HPMCP-hp50 to mixture B and stir evenly at the heat preservation temperature to obtain mixture C;

[0022] (4) After freezing and solidifying mixture C, dry it, crush it and sieve it.

[0023] Furthermore, the present invention also discloses the use of ivermectin enteric granules as described above in the preparation of feed additives.

[0024] In the above-mentioned uses, the feed additive is a pig feed additive.

[0025] Finally, a feed and an oral veterinary medicine, both containing ivermectin enteric-coated granules as described above, were also disclosed.

[0026] This application has at least the following beneficial effects:

[0027] The ivermectin enteric-coated granules of this invention use PEG6000 as the backbone and HPMCP-hp50 as the enteric material, with ivermectin loaded in the backbone. This structure ensures that the enteric-coated granules are insoluble in gastric juice and are rapidly released and absorbed in the early intestinal tract. In vitro release experiments show that the release rate can be maintained at at least 67% within 1 hour. In vivo pharmacokinetic studies on piglets, the optimal case, revealed that oral administration of ivermectin enteric-coated granules significantly increased the Cmax compared to oral administration of ivermectin tablets, with an average increase in relative bioavailability of approximately 78%; the absolute bioavailability increased from 37.4% to 66.5%. Attached Figure Description

[0028] Figure 1 This is a graph of the in vitro dissolution experiment of the first part of this invention. Detailed Implementation

[0029] The present invention will now be clearly and completely described in conjunction with embodiments thereof. It should be noted that, unless specific conditions are specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0030] Part 1: In vitro dissolution experiment

[0031] It is prepared using solid dispersion technology and a melt method.

[0032] Ivermectin enteric-coated granules are prepared using a melt method, including the following steps:

[0033] (1) Weigh out PEG6000 as a solid dispersion according to the proportion, heat and melt it to obtain mixture A;

[0034] (2) Add the ivermectin raw material to mixture A and stir evenly to combine the ivermectin molecules with the carrier to obtain mixture B;

[0035] (3) Add enteric material HPMCP-hp50 to mixture B and stir evenly at the heat preservation temperature to obtain mixture C;

[0036] (4) After freezing and solidifying mixture C, dry it, crush it and sieve it.

[0037] An orthogonal experimental design was used to screen the optimal formulation for ivermectin enteric coating. The orthogonal design of this experiment used the ratio of the excipients PEG6000 and HPMCP-hp50 and the particle size range of the finished granules as orthogonal design factors. Each factor was set with three levels. The orthogonal design is shown in Tables 1 and 2.

[0038] Table 1. Factors considered in orthogonal experiments

[0039]

[0040] Table 2 Orthogonal Experimental Design Table

[0041]

[0042]

[0043] The in vitro release assay was performed according to Method I (basket method) of the Chinese Veterinary Pharmacopoeia for the determination of release rate. The rotation speed was 100 rpm. 0.1 mol / L hydrochloric acid solution was selected as the acidic release buffer medium, and pH 5.1 acetate buffer (containing 0.2% Tween) was selected as the simulated intestinal release medium. The in vitro release assay method for enteric-coated particles was used. After release in 0.1 mol / L hydrochloric acid solution for 2 hours, the buffer medium was replaced with pH 5.1 acetate buffer (containing 0.2% Tween) to simulate the intestinal environment after gastric passage. Samples were taken at 5 min, 15 min, 30 min, 45 min, 1 h, 1.5 h, 2 h, 3 h, and 4 h, and after membrane processing, the content was determined by HPLC-UV method. The cumulative release rate of ivermectin preparation at different time points was calculated.

[0044] Formula for calculating the cumulative drug release at each time point:

[0045]

[0046] In the formula: Cn is the mass concentration of solids in the sample taken at the nth time point, V is the total volume of the release medium, Vi is the sampling volume at the ith time point, Ci is the mass concentration of the sample taken at the ith time point, W is the total mass of the enteric-coated granules, and DL is the mass fraction of the drug loading in the granules.

[0047] Based on the above-mentioned in vitro dissolution test method, in vitro dissolution experiments were conducted on different formulations and reference preparations. The orthogonal test results for ivermectin enteric-coated particles and the cumulative release rate (%) of the reference preparation were obtained as follows: Figure 1 As shown in Table 3, the reference preparation was ivermectin tablets (Jiangxi Muhang Pharmaceutical Co., Ltd., Veterinary Drug Approval No. 140616255, 7.5 mg / tablet).

[0048] Table 3 Cumulative Release Rate of Each Prescription and Reference Drug

[0049]

[0050] Based on the above in vitro dissolution results, the optimal formulation of ivermectin enteric-coated granules was determined to be PEG6000:HPMCP-hp50:ivermectin = 84:15:1, with an optimal particle size of 30-40 mesh. After dissolving in acidic medium for 2 hours, this formulation showed a cumulative release of over 90% in pH 5.1 acetate buffer (containing 0.2% Tween) for 1 hour and approximately 95% for 2 hours. In contrast, the reference formulation, ivermectin tablets, showed a cumulative release of only about 30% after 2 hours.

[0051] Part Two: In vivo pharmacokinetic studies

[0052] Experimental Groups: Eighteen healthy weaned piglets weighing approximately 25 kg were selected and randomly numbered using a parallel experimental design. Six piglets received intravenous injection of ivermectin, six received oral ivermectin tablets via gavage, and six received oral ivermectin enteric-coated granules via gavage (Prescription Nine above). The dosing regimen is shown in Table 4.

[0053] Table 4 Dosing Regimen

[0054] Animal No. 1-6 7-12 13-18 Formulation Ivermectin injection Ivermectin tablet Ivermectin enteric-coated granule Administration method Intravenous injection Oral gavage Oral gavage Dose 0.3 mg / kg.b.w. 0.3 mg / kg.b.w. 0.3 mg / kg.b.w.

[0055] Administration and Sample Collection: Pigs were restrained in a supine position and administered the drug according to the dosing protocol. Blood was collected from the anterior vena cava. A blank blood sample was collected before administration. For the oral gavage group, blood samples were collected at 15 min, 30 min, 1 h, 2 h, 3 h, 4 h, 6 h, 8 h, 12 h, 24 h, 36 h, 48 h, 60 h, 3 d, 4 d, 5 d, 6 d, 7 d, 8 d, 9 d, and 10 d. For the intravenous injection group, an additional 5 min sampling point was added. Approximately 5 mL of blood was collected each time and placed in a heparin sodium anticoagulant tube. After centrifugation at 3500 rpm for 10 min, the supernatant plasma was collected and stored at -20℃ for analysis.

[0056] Sample preparation and determination: Thaw plasma samples and vortex for 30 s. Take 1 mL of plasma into a 10 mL centrifuge tube, add 1 mL of acetonitrile, vortex to mix for 15 min, then centrifuge at 8000 r / min for 10 min. Take the supernatant and dry it under nitrogen at 50 °C (trace amounts of water may cause derivatization failure). Add 100 μL of N-methylimidazole (N-methylimidazole:acetonitrile = 1:1, v / v), vortex for 2 min to dissolve the residue, add trifluoroacetic anhydride (trifluoroacetic anhydride:acetonitrile = 1:2, v / v), vortex for 1 min, and let stand in the dark for 20 min. Then add 750 μL of methanol, vortex to mix, let stand for 15 min, filter through a 0.22 μm microporous organic phase membrane, and inject into HPLC for analysis.

[0057] Actual blood drug concentration records: The actual blood drug concentrations collected at different time points after healthy piglets were injected with ivermectin injection, administered ivermectin tablets orally by gavage, and ivermectin enteric-coated granules are shown in Tables 5, 6, and 7, respectively.

[0058] Table 5. Blood drug concentrations (ng / mL) of IVM injection in healthy pigs (0.3 mg / kg) after intravenous injection (n = 6)

[0059]

[0060]

[0061] Note: ND indicates that no drug concentration could be detected.

[0062] Table 6. Blood concentrations (ng / mL) of ivermectin tablets administered orally (0.3 mg / kg) to healthy pigs (n=6)

[0063]

[0064]

[0065] Note: ND indicates that no drug concentration could be detected.

[0066] Table 7. Blood concentrations (ng / mL) of ivermectin enteric-coated granules administered orally to healthy pigs (0.3 mg / kg) (n = 6)

[0067]

[0068] Comparison of pharmacokinetic parameters: The plasma concentration-time data in the experiment were processed using the Winnonlin non-compartmental model and are shown in Table 8. For ivermectin injection, the main pharmacokinetic parameters after intravenous injection were: elimination half-life (t1 / 2) 21.975±10.689 h, time to peak concentration (Tmax) 0.08 h, peak concentration (Cmax) 520.567±70.185 ng / mL, and area under the curve (AUCall) and area under the curve (AUCNF-obs) 1306.480±255.807 h·ng / mL and 1319.976±258.239 h·ng / mL, respectively. For ivermectin tablets after oral gavage, the main pharmacokinetic parameters were: elimination half-life (t1 / 2) 35.401±16.571 h, and time to peak concentration (Tmax) 8.667±1 h. After 633 hours, the peak concentration (Cmax) was 15.903±2.872 ng / mL, and the area under the curve (AUCall) and AUCINF-obs were 488.064±102.957 h·ng / mL and 517.215±118.629 h·ng / mL, respectively. The main pharmacokinetic parameters of ivermectin enteric-coated granules after oral gavage were: elimination half-life (t1 / 2) 35.401±5.963 h, time to peak concentration (Tmax) 6.333±0.816 h, peak concentration (Cmax) 28.914±4.425 ng / mL, and the area under the curve (AUCall) and AUCINF-obs were 869.294±155.076 h·ng / mL and 890.242±158.076 h·ng / mL, respectively.

[0069] Table 8 Comparison of major pharmacokinetic parameters

[0070]

[0071] By comparing pharmacokinetic parameters after oral administration of enteric-coated ivermectin and ivermectin tablets to piglets, it was found that the Cmax of piglets administered enteric-coated ivermectin granules was significantly higher than that administered ivermectin tablets, with an average increase in relative bioavailability of approximately 78%; the absolute bioavailability increased from 37.4% to 66.5%.

[0072] Summarize:

[0073] The advantages of this invention are as follows:

[0074] 1. This invention uses PEG6000 as a framework, which is uniformly mixed with the enteric material HPMCP-hp50 to form particles in which the enteric material HPMCP-hp50 is distributed. The enteric pH value of the enteric material HPMCP-hp50 is about 5.0, which can dissolve rapidly in the front part of the small intestine. Since ivermectin is distributed within the particles, the dissolution process of the enteric material HPMCP-hp50 carries ivermectin into the small intestine.

[0075] This release characteristic is not for the immediate release of ivermectin, but rather a continuous release behavior that occurs with the continuous dissolution of the enteric material HPMCP-hp50; this continuous release behavior effectively overcomes the problem of the difficulty in the stable release of fat-soluble ivermectin in the small intestine.

[0076] 2. Ivermectin is a fat-soluble material, which cannot be sufficiently dispersed in many systems. As mentioned above, sufficient dispersion is a necessary factor for achieving the continuous release process associated with the continuous dissolution of ivermectin and the enteric material HPMCP-hp50.

[0077] Therefore, this invention uses PEG6000 as a framework to achieve effective and uniform dispersion of ivermectin through molten PEG6000.

[0078] 3. This invention uses PEG6000 as a carrier, which can be prepared into an additive that can be added to feed. It will not separate and deposit during the mixing process with feed, and can deliver the drug into the animal's body as the animal eats.

[0079] 4. In its research, this invention discovered that the absorption of ivermectin in the pre-small intestine is an important factor in achieving its high bioavailability. Through the selection of the aforementioned skeleton and enteric-coated materials, this invention achieves continuous and rapid release of ivermectin in the pre-small intestine. From a bioavailability perspective, the granules of this invention have significantly higher Cmax bioavailability than ivermectin tablets.

[0080] In this experiment, ivermectin enteric-coated granules can effectively avoid being destroyed by the acidic environment in the stomach, enabling its release and absorption in the intestines, effectively improving the bioavailability of ivermectin, thereby effectively treating external parasites and strengthening the inhibition of nematode infection in the body.

[0081] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, nor does it mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An enteric-coated granule for ivermectin, characterized in that, The product includes PEG6000, enteric-coated material HPMCP-hp50, and ivermectin, wherein the amounts of PEG6000, enteric-coated material HPMCP-hp50, and ivermectin are 84wt%, 15wt%, and 1wt%, respectively; and the particle size of the enteric-coated ivermectin particles is 30-40 mesh. The preparation method of the ivermectin enteric-coated granules includes the following steps: (1) Weigh out PEG6000 as a solid dispersion according to the proportion, heat and melt it to obtain mixture A; (2) Add ivermectin raw material to mixture A and stir evenly to combine ivermectin molecules with the carrier to obtain mixture B; (3) Add enteric material HPMCP-hp50 to mixture B and stir evenly at the heat preservation temperature to obtain mixture C; (4) After freezing and solidifying mixture C, dry it, crush it and sieve it.

2. Use of ivermectin enteric granules as described in claim 1 to prepare feed additives.

3. The use according to claim 2, characterized in that, The feed additive mentioned is a pig feed additive.

4. A feed, characterized in that, It contains ivermectin enteric-coated granules as described in claim 1.

5. A veterinary oral medication, characterized in that, Contains ivermectin enteric-coated granules as described in claim 1.

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