Ivermectin enteric-coated granules as well as preparation method and application thereof

Abstract

The invention belongs to the field of veterinary drugs, and discloses an ivermectin enteric-coated particle which comprises PEG (polyethylene glycol) 6000, an enteric-coated material HPMCP-hp50 and ivermectin, and the particle size of the ivermectin enteric-coated particle is 20-50 meshes; the dosage of the PEG6000 is equivalent to 54-84% of the total weight of the ivermectin enteric-coated particle, the dosage of the enteric-coated material HPMCP-hp50 is equivalent to 10-15% of the total weight of the ivermectin enteric-coated particle, the particle takes the PEG6000 as a framework, takes the HPMCP-hp50 as the enteric-coated material, and the ivermectin is loaded in the framework, so that the condition that the enteric-coated particle is insoluble in gastric juice can be ensured through the structure; the ivermectin enteric-coated granules can be rapidly released and absorbed in the anterior segment of the intestinal tract, it can be found through an in-vitro release experiment that 67% of the release speed can be kept at the minimum within 1 h, it is found through an in-vivo pharmacokinetic experiment on piglets of the optimal case that the ivermectin enteric-coated granules are drenched by the piglets, compared with ivermectin tablets Cmax, the ivermectin enteric-coated granules are obviously improved, and the relative bioavailability is averagely improved by about 78%; the absolute bioavailability is improved from 37.4% to 66.5%, and meanwhile, the invention further provides a preparation method and application of the ivermectin enteric-coated granules.

Description

Technical Field

[0001] The present invention relates to the field of veterinary medicine, and in particular to ivermectin enteric-coated granules, a preparation method thereof, and uses thereof. Background Art

[0002] Ivermectin for veterinary use is a broad-spectrum antiparasitic drug widely used in the clinical treatment and prevention of internal and external parasitic diseases in animals due to its high efficacy, broad spectrum, and minimal toxicity and side effects. Currently, ivermectin is available in various dosage forms in China, including premixes (compound: albendazole-ivermectin premix), tablets, ointments, injections, and transdermal formulations. It has been widely used to treat and prevent digestive nematodes, lungworms, and external parasites (ticks, lice, and mites) in a variety of livestock and wildlife, including pigs, horses, cattle, sheep, rabbits, camels, foxes, and alpacas. Oral administration is the most common route of drug delivery in large-scale animal husbandry, offering advantages such as minimal irritation to animals, ease of administration, and continuous dosing. To ensure convenient administration and reduce labor costs, centralized drinking water administration and dosing devices are becoming increasingly popular. However, these methods also place higher demands on drug solubility, stability, palatability, and bioavailability. Ivermectin is a macrolide antibiotic. The original drug is a pure white or off-white crystalline powder with a melting point of 154.5-157°C. It is easily soluble in organic solvents such as methanol, ethyl acetate, butyl acetate, acetonitrile, and ethanol. Its solubility in water is extremely low (0.006-0.009 mg / mL). These physical and chemical properties result in low oral bioavailability of ivermectin. Currently, large-scale aquaculture mostly uses albendazole-ivermectin premixes. It has been reported that the oral bioavailability of this premix in pigs is lower than that of subcutaneous administration. Although it is effective in treating gastrointestinal parasites in the body, the drug concentration in the pig's sebum is lower than the effective concentration, resulting in poor treatment of surface parasites in the animal. Furthermore, the acidic environment of the stomach destroys the structure of ivermectin, and the first-pass effect significantly reduces its oral bioavailability.

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

[0004] Therefore, how to achieve rapid release of veterinary ivermectin in the anterior small intestine and achieve higher bioavailability. Summary of the Invention

[0005] The present invention aims to provide an ivermectin enteric-coated granule and a preparation method thereof. The granule uses PEG6000 as a skeleton and HPMCP-hp50 as an enteric-coated material, and ivermectin is loaded in the skeleton. The structure ensures that the enteric-coated granule is insoluble in gastric juice and is rapidly released and absorbed in the anterior intestinal tract. In vitro release experiments show that the release rate can be maintained at a minimum of 67% in 1 hour. In vivo pharmacokinetic tests on piglets, which are the best case, show that Cmax of the ivermectin enteric-coated granules administered orally to piglets is significantly higher than that of the ivermectin tablets administered orally, and the relative bioavailability is increased by an average of about 78%; and the absolute bioavailability is increased from 37.4% to 66.5%.

[0006] At the same time, the present invention also provides a preparation method and application of the ivermectin enteric-coated granules.

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

[0008] The invention discloses an ivermectin enteric-coated granule, comprising PEG6000, an enteric-coated material HPMCP-hp50 and ivermectin. The particle size of the ivermectin enteric-coated granule is 20-50 meshes. The amount of the PEG6000 is equivalent to 54-84% of the total weight of the ivermectin enteric-coated granule, and the amount of the enteric-coated material HPMCP-hp50 is equivalent to 10-15% of the total weight of the ivermectin enteric-coated granule.

[0009] The core innovation of the present invention is:

[0010] 1. The present invention uses PEG6000 as a backbone. After uniformly mixing PEG6000 with the enteric material HPMCP-hp50, the enteric material HPMCP-hp50 is distributed in the formed granules. The enteric pH value of the enteric material HPMCP-hp50 is approximately 5.0, enabling rapid dissolution in the anterior small intestine. Since ivermectin is distributed within the granules, the dissolution of the enteric material HPMCP-hp50 releases ivermectin into the small intestine.

[0011] This release characteristic is not an immediate release of ivermectin, but a sustained release behavior caused by the continuous dissolution of the enteric material HPMCP-hp50. This sustained release behavior effectively overcomes the problem of stable release of fat-soluble ivermectin in the small intestine.

[0012] 2. Ivermectin is a fat-soluble material and cannot be fully dispersed in many systems. As mentioned above, sufficient dispersion is a necessary factor for achieving a sustained release process accompanied by sustained dissolution of Ivermectin and the enteric material HPMCP-hp50.

[0013] Therefore, the present invention adopts PEG6000 as a skeleton and realizes effective and uniform dispersion of ivermectin through melted PEG6000.

[0014] 3. The present invention uses PEG6000 as a carrier, which can be prepared into an additive that can be added to feed. It will not stratify and deposit during the mixing process with the feed, and the drug can be delivered to the animal as the animal eats;

[0015] 4. The present invention has found in research that the absorption of ivermectin in the anterior small intestine is an important factor in achieving its high bioavailability. The present invention achieves a sustained and rapid release of ivermectin in the anterior small intestine by selecting the above-mentioned skeleton and enteric materials. From the perspective of bioavailability, the granules of the present invention have a significantly higher bioavailability Cmax than that of ivermectin tablets.

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

[0017] At the same time, the present invention also discloses a preparation method of the ivermectin enteric-coated granules, which comprises melting PEG6000, mixing the mixture with other raw materials, and granulating the mixture.

[0018] In the above preparation method, the following steps are included:

[0019] (1) Weigh PEG6000 as a solid dispersion according to a certain ratio, heat and melt, and obtain mixture A;

[0020] (2) adding the ivermectin raw material to the mixture A and stirring evenly to allow the ivermectin molecules to bind to the carrier to obtain a mixture B;

[0021] (3) Adding the enteric material HPMCP-hp50 to the mixture B and stirring evenly at a holding temperature to obtain a mixture C;

[0022] (4) The mixture C is freeze-solidified, dried, crushed and sieved.

[0023] In addition, the present invention also discloses the use of the ivermectin enteric-coated granules described above in preparing feed additives.

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

[0025] Finally, a feed and an oral medicament for animals are also disclosed, both of which contain the ivermectin enteric-coated granules as described above.

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

[0027] The ivermectin enteric-coated granules of the present invention use PEG6000 as a skeleton and HPMCP-hp50 as an enteric-coated material, with ivermectin loaded in the skeleton. The structure ensures that the enteric-coated granules are insoluble in gastric juice and are rapidly released and absorbed in the anterior intestinal tract. An in vitro release experiment shows that the release rate can be maintained at a minimum of 67% for 1 hour. An in vivo pharmacokinetic test conducted on piglets, the best case, shows that Cmax is significantly increased when the piglets are gavage-administered with the ivermectin enteric-coated granules compared to when they are gavage-administered with ivermectin tablets, and the relative bioavailability is increased by approximately 78% on average; the absolute bioavailability is increased from 37.4% to 66.5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a curve chart of the in vitro dissolution experiment of the first part of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be described clearly and completely below in conjunction with the examples of the present invention. In the description of the present invention, it should be noted that, where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer were used. Reagents or instruments used where the manufacturer is not specified are conventional products that can be purchased commercially.

[0030] Part I In vitro dissolution test

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

[0032] The preparation of ivermectin enteric-coated granules adopts a melting method, which includes the following steps:

[0033] (1) Weigh PEG6000 as a solid dispersion according to a certain ratio, heat and melt, and obtain mixture A;

[0034] (2) adding the ivermectin raw material to the mixture A and stirring evenly to allow the ivermectin molecules to bind to the carrier to obtain a mixture B;

[0035] (3) Adding the enteric material HPMCP-hp50 to the mixture B and stirring evenly at a holding temperature to obtain a mixture C;

[0036] (4) The mixture C is freeze-solidified, dried, crushed and sieved.

[0037] An orthogonal experimental design was used to screen the optimal formulation of ivermectin enteric-coated solution. The orthogonal design of this experiment used the content ratio of the excipients PEG6000 and HPMCP-hp50 used, as well as the particle size range of the granule product as orthogonal design factors. Each factor was set at three levels. The orthogonal design is shown in Tables 1 and 2.

[0038] Table 1 Orthogonal test factors

[0039]

[0040] Table 2 Orthogonal experimental design table

[0041]

[0042]

[0043] The in vitro release test followed the first method (basket method) of the Chinese Veterinary Pharmacopoeia release test method, at a speed of 100 r / min. 0.1 mol / L hydrochloric acid solution was used as the acidic release buffer medium, and pH 5.1 acetate buffer (containing 0.2% Tween) was used as the simulated intestinal release medium. The in vitro release test method for enteric-coated granules was used. After 2 hours of release in 0.1 mol / L hydrochloric acid solution, 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 minutes, 15 minutes, 30 minutes, 45 minutes, 1 hour, 1.5 hours, 2 hours, 3 hours, and 4 hours, and then the content was determined using HPLC-UV. The cumulative release of ivermectin at different time points was calculated.

[0044] The calculation formula for the cumulative drug release at each time point is:

[0045]

[0046] Where: 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 of the granules.

[0047] According to the above in vitro dissolution test method, different prescriptions and reference preparations were subjected to in vitro dissolution tests, and the cumulative release (%) of ivermectin enteric-coated granules and reference preparations was obtained as follows: Figure 1 As shown in Table 3, the reference preparation was ivermectin tablets (Jiangxi Muhang Pharmaceutical Co., Ltd., veterinary drug number 140616255, 7.5 mg / tablet).

[0048] Table 3 Cumulative release 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, and the optimal particle size was 30-40 mesh. After dissolution in acidic medium for 2 hours, the cumulative release of this formulation in pH 5.1 acetate buffer (containing 0.2% Tween) reached more than 90% in 1 hour and about 95% in 2 hours, while the cumulative release of the reference preparation ivermectin tablets was only about 30% at 2 hours.

[0051] Part II In vivo pharmacokinetic studies

[0052] Experimental Grouping: 18 healthy weaned piglets weighing about 25 kg were selected and randomly numbered using a parallel experimental design method. Six of the piglets were intravenously injected with ivermectin injection, six were orally administered with ivermectin tablets, and six were orally administered with ivermectin enteric-coated granules (prescription 9 above). The dosing regimen is shown in Table 4.

[0053] Table 4 Dosage regimen

[0054] Animal number 1-6 7-12 13-18 preparation Ivermectin injection Ivermectin tablets Ivermectin enteric-coated granules Dosage intravenous injection Oral gavage Oral gavage Dosage 0.3mg / kg.bw 0.3mg / kg.bw 0.3mg / kg.bw

[0055] Dosing and Sample Collection: Pigs were restrained in the supine position and administered according to the dosing schedule. Blood was collected from the anterior vena cava. A blank blood sample was collected before dosing. Blood samples were collected at 15 minutes, 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 6 hours, 8 hours, 12 hours, 24 hours, 36 hours, 48 hours, 60 hours, 3 days, 4 days, 5 days, 6 days, 7 days, 8 days, 9 days, and 10 days after dosing for the oral gavage group. An additional sampling point was added at 5 minutes for the intravenous injection group. Approximately 5 mL of blood was collected each time and placed in a sodium heparin anticoagulant tube. After centrifugation at 3500 rpm for 10 minutes, the upper plasma layer was aspirated and stored at -20°C until analysis.

[0056] Sample Preparation and Assay: Plasma samples were thawed and vortexed for 30 seconds. 1 mL of plasma was placed in a 10 mL centrifuge tube, and 1 mL of acetonitrile was added. The mixture was vortexed for 15 minutes, followed by centrifugation at 8000 rpm for 10 minutes. The supernatant was dried with nitrogen at 50°C (traces of water may cause derivatization failure). 100 μL of N-methylimidazole (N-methylimidazole:acetonitrile = 1:1, v / v) was added, and the mixture was vortexed for 2 minutes to dissolve the residue. Trifluoroacetic anhydride (trifluoroacetic anhydride:acetonitrile = 1:2, v / v) was added, and the mixture was vortexed for 1 minute. The mixture was then allowed to stand in the dark for 20 minutes. 750 μL of methanol was added, the mixture was vortexed, and the mixture was allowed to stand for 15 minutes. The supernatant was filtered through a 0.22 μm microporous organic phase filter and analyzed by HPLC.

[0057] Measured blood drug concentration records: The measured blood drug concentration values of healthy piglets collected at different time points after injection of ivermectin injection, oral administration of ivermectin tablets and ivermectin enteric-coated granules by gavage are shown in Tables 5, 6 and 7 respectively.

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

[0059]

[0060]

[0061] Note: ND means no detectable drug concentration

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

[0063]

[0064]

[0065] Note: ND means no detectable drug concentration

[0066] Table 7 Blood concentration of ivermectin enteric-coated granules (ng / mL) in healthy pigs (0.3 mg / kg) after oral gavage (n=6)

[0067]

[0068] Comparison of Pharmacokinetic Parameters: The plasma concentration-time data in the experiment were processed using the Winnonlin non-compartmental model to obtain the main pharmacokinetic parameters shown in Table 8. After intravenous injection, the main pharmacokinetic parameters of ivermectin injection were: elimination half-life (t1 / 2) of 21.975±10.689h, time to peak concentration (Tmax) of 0.08h, peak concentration (Cmax) of 520.567±70.185ng / mL, area under the flexural tract (AUCall) of 1306.480±255.807h·ng / mL and AUCINF-obs of 1319.976±258.239h·ng / mL, respectively. After oral administration of ivermectin tablets, the main pharmacokinetic parameters were: elimination half-life (t1 / 2) of 35.401±16.571h, time to peak concentration (Tmax) of 8.667±1. The main pharmacokinetic parameters of ivermectin enteric-coated granules after oral administration were as follows: elimination half-life (t1 / 2) of 35.401±5.963h, time to peak (Tmax) of 6.333±0.816h, peak concentration (Cmax) of 28.914±4.425ng / mL, area under the qubital interface (AUCall) of 869.294±155.076h·ng / mL and AUCINF-obs of 890.242±158.076h·ng / mL.

[0069] Table 8 Comparison of main pharmacokinetic parameters

[0070]

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

[0072] Summarize:

[0073] The advantages of the present invention are as follows:

[0074] 1. The present invention uses PEG6000 as a backbone. After uniformly mixing PEG6000 with the enteric material HPMCP-hp50, the enteric material HPMCP-hp50 is distributed in the formed granules. The enteric pH value of the enteric material HPMCP-hp50 is approximately 5.0, enabling rapid dissolution in the anterior small intestine. Since ivermectin is distributed within the granules, the dissolution of the enteric material HPMCP-hp50 releases ivermectin into the small intestine.

[0075] This release characteristic is not an immediate release of ivermectin, but a sustained release behavior caused by the continuous dissolution of the enteric material HPMCP-hp50. This sustained release behavior effectively overcomes the problem of stable release of fat-soluble ivermectin in the small intestine.

[0076] 2. Ivermectin is a fat-soluble material and cannot be fully dispersed in many systems. As mentioned above, sufficient dispersion is a necessary factor for achieving a sustained release process accompanied by sustained dissolution of Ivermectin and the enteric material HPMCP-hp50.

[0077] Therefore, the present invention adopts PEG6000 as a skeleton and realizes effective and uniform dispersion of ivermectin through melted PEG6000.

[0078] 3. The present invention uses PEG6000 as a carrier, which can be prepared into an additive that can be added to feed. It will not stratify and deposit during the mixing process with the feed, and the drug can be delivered to the animal as the animal eats;

[0079] 4. The present invention has found in research that the absorption of ivermectin in the anterior small intestine is an important factor in achieving its high bioavailability. The present invention achieves a sustained and rapid release of ivermectin in the anterior small intestine by selecting the above-mentioned skeleton and enteric materials. From the perspective of bioavailability, the granules of the present invention have a significantly higher bioavailability Cmax than that of ivermectin tablets.

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

[0081] The applicant declares that while the above-described embodiments illustrate the process of the present invention, the present invention is not limited to the above-described process steps, nor does it imply that the present invention must rely on the above-described process steps for implementation. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the raw materials used, additions of auxiliary ingredients, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. An ivermectin enteric-coated granule, characterized in that: The enteric-coated granules comprise PEG6000, an enteric-coated material HPMCP-hp50, and ivermectin. The particle size of the enteric-coated granules of ivermectin is 20-50 meshes. The dosage of the PEG6000 is equivalent to 54-84% of the total weight of the enteric-coated granules of ivermectin, and the dosage of the enteric-coated material HPMCP-hp50 is equivalent to 10-15% of the total weight of the enteric-coated granules of ivermectin.

2. The ivermectin enteric-coated granules according to claim 1, characterized in that The dosages of PEG6000, enteric material HPMCP-hp50 and ivermectin are 84wt%, 15wt% and 1wt% respectively; the particle size of the ivermectin enteric granules is 30-40 meshes.

3. The method for preparing ivermectin enteric-coated granules according to claim 1, wherein After PEG6000 is melted, it is mixed with other raw materials and granulated.

4. The preparation method according to claim 3, characterized in that The steps include: (1) Weigh PEG6000 as a solid dispersion according to a certain ratio, heat and melt, and obtain mixture A; (2) adding the ivermectin raw material to the mixture A and stirring evenly to allow the ivermectin molecules to bind to the carrier to obtain a mixture B; (3) Adding the enteric material HPMCP-hp50 to the mixture B and stirring evenly at a holding temperature to obtain a mixture C; (4) The mixture C is freeze-solidified, dried, crushed and sieved.

5. Use of the ivermectin enteric-coated granules according to claim 1 or 2 in preparing a feed additive.

6. The use according to claim 5, characterized in that The feed additive is a pig feed additive.

7. A feed, characterized in that Containing the ivermectin enteric-coated granules according to claim 1 or 2.

8. An oral medicament for animals, characterized in that: Containing the ivermectin enteric-coated granules according to claim 1 or 2.

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