Fiprednil and praziquantel compound drop as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of pharmaceutical preparations, and particularly relates to fipronil and praziquantel compound drops as well as a preparation method and application thereof. The compound drop is prepared from fipronil, praziquantel, a penetration enhancer, a preservative and absolute ethyl alcohol, the fipronil and praziquantel drop comprises the following components in percentage by weight and volume: 8.3% of fipronil, 8.3% of praziquantel, 0-25% of penetration enhancer, 0.2-0.3% of preservative, 0-2% of HPMC-E5 and 60-80% of absolute ethyl alcohol. According to the drops, the accumulative release amount of fipronil and praziquantel is increased, the drug release time is shortened, the release amount of the drops added with 1, 2-propylene glycol is higher than that of the drops without the penetration enhancer, and the release time is obviously shorter than that of the drops without the penetration enhancer. The drops taking crotamiton and the combination of crotamiton and HPMC E5 as the penetration enhancer have the best transdermal effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of pharmaceutical preparations, and in particular relates to a compound drop of fepronil and praziquantel, and a preparation method and application thereof. Background Art

[0002] Fipronil, also known as fipronil and fipronil, and trade name Regent, is a pyrazole insecticide. It primarily targets adult fleas and ticks by inhibiting chloride metabolism controlled by gamma-aminobutyric acid (GABA), disrupting the insect's central nervous system and killing the pests. It primarily acts as a stomach poison, with contact and some systemic effects. Compared to traditional organophosphate insecticides, it boasts high efficacy, a broad insecticide spectrum, minimal side effects, a long half-life, a novel drug structure, high activity, and a unique mechanism of action.

[0003] Praziquantel is a broad-spectrum anti-tapeworm and fluke drug, specifically designed to eliminate tapeworms in pets. It also has a moderate killing effect on parasites such as Taenia solium, schistosomes, and lung flukes. Praziquantel affects the activity of glutathione-S-transferase (GST) within the parasites, causing a buildup of reactive oxygen species (ROS) such as H2O2 and O2. This damages the parasite's antioxidant system, ultimately eliminating the parasite.

[0004] Currently, the most mature praziquantel product on the market is the oral praziquantel tablets produced by Sichuan Jixing Animal Pharmaceutical Co., Ltd., under the trade name "Xuetaoning"; the most mature product on the market for fepronil is the topical fepronil drops produced by Sichuan Decheng Animal Health Co., Ltd.; and the most mature product on the market for the combination of fepronil and praziquantel is the topical compound fepronil praziquantel drops produced by Boehringer Ingelheim Animal Health Co., Ltd. in Toulouse, France, under the trade name "Bolaien." This product consists of four drugs: avermectin, praziquantel, fepronil, and (S)-methoprene. Each 1ml contains 83mg of fepronil, 100mg of methoprene, 4mg of avermectin, and 83mg of praziquantel. However, there are no single combination drops on the market. The combination of four drugs not only increases the number of drug types but also the complexity and cost of the preparation process. The advantage of choosing the combination of two drugs is that the preparation can be applied to the skin to repel fleas, ear mites, ticks and other surface pests; it can also repel worms such as tapeworms and flukes. It not only reduces the types of drugs, but also has better efficacy than a combination of four drugs. Summary of the Invention

[0005] In order to overcome the defects of the prior art, the present invention provides a compound drop of fepronil and praziquantel, which can reduce the types of drugs, while increasing the cumulative release amount of fepronil and praziquantel, shortening the action time, and thus exerting better effects.

[0006] The present invention is achieved through the following technical solutions:

[0007] The invention provides a fepronil and praziquantel compound drops. The compound drops comprise fepronil, praziquantel, a penetration enhancer, a preservative, and anhydrous ethanol. The weight volume percentage of each component in the drops is: 8.3% of fepronil, 8.3% of praziquantel, 0%-25% of the penetration enhancer, 0.2%-0.3% of the preservative, 0-2% of HPMC-E5, and 60-80% of the anhydrous ethanol.

[0008] The penetration enhancer is one of 1,2-propylene glycol, crotamiton, HPMC E5, and laurocapram, or a combination thereof.

[0009] Furthermore, the penetration enhancer is laurocapram, 1,2-propylene glycol, crotamiton, a combination of 1,2-propylene glycol and laurocapram, a combination of 1,2-propylene glycol and HPMC E5, a combination of 1,2-propylene glycol, HPMC E5 and crotamiton, a combination of HPMCE5 and crotamiton, and a combination of 1,2-propylene glycol and crotamiton.

[0010] When the penetration enhancer is laurocapram, the ratio of the penetration enhancer to anhydrous ethanol is 1:11-17.

[0011] When the penetration enhancer is 1,2-propylene glycol, the ratio of the penetration enhancer to anhydrous ethanol is 1:4-15.

[0012] When the penetration enhancer is crotamiton, the ratio of the penetration enhancer to anhydrous ethanol is 1:20-160.

[0013] When the penetration enhancer is a combination of 1,2-propylene glycol and lauryl azone, the ratio of 1,2-propylene glycol to lauryl azone is 1.8-6:1, and the ratio of the penetration enhancer to anhydrous ethanol is 1:3-10.

[0014] When the penetration enhancer is a combination of 1,2-propylene glycol and HPMC E5, the ratio of 1,2-propylene glycol to HPMC E5 is 5-105:1, and the ratio of the penetration enhancer to anhydrous ethanol is 1:5-1:7.

[0015] When the penetration enhancer is a combination of 1,2-propylene glycol, HPMC E5 and crotamiton, the ratio of 1,2-propylene glycol, HPMC E5 and crotamiton is 50-55:1:15-20, and the ratio of the penetration enhancer to anhydrous ethanol is 1:6-10.

[0016] When the penetration enhancer is a combination of HPMC E5 and crotamiton, the ratio of HPMC E5 to crotamiton is 1:6-35, and the ratio of the penetration enhancer to anhydrous ethanol is 20-115:1.

[0017] When the penetration enhancer is a combination of 1,2-propylene glycol and crotamiton, the ratio of 1,2-propylene glycol to crotamiton is 20-25:1, and the ratio of the penetration enhancer to anhydrous ethanol is 1:10-15.

[0018] The preservative is ethyl paraben.

[0019] Furthermore, the present invention preferably comprises the following compound drops of fepronil and praziquantel, wherein the weight volume percentage of each component in the drops is: fepronil 8.3%, praziquantel 8.3%, preservative 0.24%-0.25%, crotamiton 1.7%-3.5%, HPMC E5 0-0.1%, and anhydrous ethanol 70%-80%.

[0020] Or the weight volume percentage of each component in the drops is: 8.3% of fepronil, 8.3% of praziquantel, 0.24%-0.25% of preservative, 5.2%-15.6% of 1,2-propylene glycol, and 70%-80% of anhydrous ethanol.

[0021] Furthermore, the present invention preferably comprises the following compound drops of fepronil and praziquantel, wherein the weight volume percentage of each component in the drops is: fepronil is 8.3%, praziquantel is 8.3%, preservative is 0.24%-0.25%, crotamiton is 3.5%, and anhydrous ethanol is 70%-80%;

[0022] Or the weight volume percentage of each component in the drops is: 8.3% of fepronil, 8.3% of praziquantel, 0.24%-0.25% of preservative, 3.5% of crotamiton, 0.1% of HPMC E5, and 70%-80% of anhydrous ethanol;

[0023] Or the weight volume percentage of each component in the drops is: 8.3% of fepronil, 8.3% of praziquantel, 9%-11% of 1,2-propylene glycol, 0.24%-0.25% of preservatives, and 70%-75% of anhydrous ethanol.

[0024] The preparation process of the drops of the present invention is:

[0025] (1) Add anhydrous ethanol to fepronil and praziquantel and sonicate until the drugs are dissolved;

[0026] (2) adding a preservative and a penetration enhancer to the anhydrous ethanol solution of pyrochloridone and praziquantel, stirring evenly, sealing, and allowing to stand to obtain a solution;

[0027] (3) Add HPMC-E5 and anhydrous ethanol to a certain volume, stir evenly, and the mixture is obtained.

[0028] The size of the prepared drops is 70 mL, and each 0.7 mL contains 58 mg of fepronil and 58 mg of praziquantel. This preparation is usually stored sealed at room temperature.

[0029] This experiment used in vitro release experiment and rat transdermal experiment as research methods, and used drug release time and transdermal time as evaluation indicators respectively.

[0030] The present invention provides a compound drop of fepronil and praziquantel. The drops of the present invention not only increase the cumulative release amount of fepronil and praziquantel, but also reduce the release time of the drugs. The drops containing 1,2-propylene glycol not only release a higher amount than the drops without a penetration enhancer, but also have a release time that is significantly shorter than the release time without the penetration enhancer. When crotamiton or a combination of crotamiton and HPMC E5 is added as a penetration enhancer, the drug release amount is further significantly increased and the release time is significantly shortened. Furthermore, transdermal tests show that the drops containing crotamiton or a combination of crotamiton and HPMC E5 as a penetration enhancer have the best transdermal effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 In vitro release profile of fepronil from the fepronil and praziquantel combination drops in Examples 1-15.

[0032] Figure 2 In vitro release profile of praziquantel from the combination drops of fepronil and praziquantel in Examples 1-15.

[0033] Figure 3 Transdermal profile of the fepronil and praziquantel combination drops in Examples 3-5 and 14-15.

[0034] Figure 4 Figure 3-5, 14-15. Transdermal administration of praziquantel in the combination drops of fepronil and praziquantel.

[0035] Figure 5 In vitro release profiles of fepronil from the fepronil and praziquantel combination drops in Examples 4 and 16-22.

[0036] Figure 6 In vitro release profiles of praziquantel from the combination drops of fepronil and praziquantel in Examples 4 and 16-22.

[0037] Figure 7 Figure 4, 16-18 of the transdermal administration of the combination drops of fepronil and praziquantel.

[0038] Figure 8 Figure 4. Praziquantel transdermal effect of the combination drops of fepronil and praziquantel in Examples 4, 16-18.

[0039] Figure 9 In vitro release profiles of fepronil from the fepronil and praziquantel combination drops in Examples 4, 17, and 23-29.

[0040] Figure 10 External release profiles of praziquantel from the combination drops of fepronil and praziquantel in Examples 4, 17, and 23-29.

[0041] Figure 11 Figure 4, 17, 23-26, 28-29 of the transdermal administration of the combination drops of fepronil and praziquantel.

[0042] Figure 12 Figure 4 shows the transdermal effect of praziquantel in the combination drops of fepronil and praziquantel in Examples 4, 17, 23-26, and 28-29. DETAILED DESCRIPTION

[0043] The present invention is further illustrated by the following examples, but the present invention is not limited to the following examples. Without departing from the above technical premise of the present invention, corresponding replacements or modifications made according to common technical knowledge and customary means in the field are all included in the scope of the present invention.

[0044] The preparations prepared in the following examples total 70 mL, each preparation having a volume of 0.7 mL, containing 58 mg of fepronil and 58 mg of praziquantel. The percentages in the formula are the weight and volume percentages of each component in the drops.

[0045] Example 1:

[0046] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ Laurocapram 3.19g 4.6％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 52.49g 75.0％

[0047] Preparation method:

[0048] (1) Weigh fepronil and praziquantel, add fepronil and praziquantel to 14 mL of anhydrous ethanol, and sonicate until the drugs are dissolved to prepare a drug solution;

[0049] (2) Accurately weigh the prescribed amount of the penetration enhancer laurocapram and ethylparaben, add them to the above solution, stir evenly, add anhydrous ethanol to 70 mL, stir evenly, and divide into 0.7 mL portions (each 0.7 mL contains 116 mg) to obtain the drops, and seal them for storage.

[0050] The resulting drops are clear, colorless solutions.

[0051] In vitro release experiment:

[0052] This experiment used a vertical diffusion cell. The filter membrane was fixed between the dosing cell and the receiving cell, with the rough surface facing the dosing chamber and the smooth surface facing the receiving chamber. The effective diffusion area was 1.54 cm. 2 . Take Examples 1 to 15 respectively and add them into the dosing pool, pour the drug solution onto the artificial membrane, and add 4 mL of 30% ethanol saline into the receiving pool, remove bubbles, and make the artificial membrane contact with the liquid surface. Stir continuously at 32°C and 500 (r / min), extract 4 mL of the receiving solution at 0.083h, 0.167h, 0.250h, 0.333h, 0.500h, 0.667h, 0.833h, and 1h after administration, and replenish with fresh receiving solution of the same volume and temperature, and calculate the cumulative drug release Q.

[0053]

[0054] ρn is the mass concentration of the nth sampling point (mg·mL －1 ), V is the sampling volume, and A is the penetration area.

[0055] Rat transdermal experiment:

[0056] This experiment used a vertical diffusion cell. The rat skin was fixed between the dosing cell and the receiving cell, with the stratum corneum facing the dosing cell and the dermis facing the receiving cell. The effective diffusion area was 1.54 cm. 2 The test sample was added to the dosing cell and evenly applied to the rat skin. 4 mL of 30% ethanol saline was added to the receiving cell, and bubbles were removed so that the rat skin was in contact with the liquid surface. Stirring was continued at 32°C and 500 (r / min). 4 mL of the receiving solution was extracted at 0.083h, 0.167h, 0.250h, 0.333h, 0.500h, 0.667h, 0.833h, 1h, 1.5h, 2h, 3h, 5h, 8h, 12h, 24h, 30h, and 48h after administration, and the same volume of fresh receiving solution at the same temperature was added. The extracted receiving solution was filtered using a 0.45μm filter membrane to obtain the filtrate, and the cumulative drug permeation amount Q was calculated.

[0057]

[0058] ρn is the mass concentration of the nth sampling point (mg·mL －1 ), V is the sampling volume, and A is the penetration area.

[0059] Example 2:

[0060] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ Laurocapram 4.47g 6.4％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 51.38g 73.4％

[0061] Preparation method:

[0062] Same as Example 1.

[0063] The resulting drops are clear, colorless solutions.

[0064] In vitro release experiment:

[0065] Same as Example 1.

[0066] Example 3:

[0067] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ 1,2-Propanediol 3.63g 5.2％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 52.48g 75.0％

[0068] Preparation method:

[0069] Same as Example 1, except that the penetration enhancer was 1,2-propylene glycol.

[0070] The resulting drops are clear, colorless solutions.

[0071] In vitro release experiment:

[0072] Same as Example 1.

[0073] Rat transdermal experiment:

[0074] Same as Example 1.

[0075] Example 4:

[0076] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ 1,2-Propanediol 7.27g 10.4％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 49.73g 71.0％

[0077] Preparation method:

[0078] Same as Example 1, except that the penetration enhancer was 1,2-propylene glycol.

[0079] The resulting drops are clear, colorless solutions.

[0080] In vitro release experiment:

[0081] Same as Example 1.

[0082] Rat transdermal experiment:

[0083] Same as Example 1.

[0084] Example 5:

[0085] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ 1,2-Propanediol 10.90g 15.6％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 46.96g 67.1％

[0086] Preparation method:

[0087] Same as Example 1, except that the penetration enhancer was 1,2-propylene glycol.

[0088] The resulting drops are a transparent, colorless solution

[0089] In vitro release experiment:

[0090] Same as Example 1.

[0091] Rat transdermal experiment:

[0092] Same as Example 1

[0093] Example 6:

[0094] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ Laurocapram 1.92g 2.7％ 1,2-Propanediol 3.63g 5.2％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 50.83g 72.6％

[0095] Preparation method:

[0096] Same as Example 1, the penetration enhancer is a combination of laurocapram and 1,2-propylene glycol.

[0097] The resulting drops are clear, colorless solutions.

[0098] In vitro release experiment:

[0099] Same as Example 1.

[0100] Example 7

[0101] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ Laurocapram 1.92g 2.7％ 1,2-Propanediol 7.27g 10.4％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 48.07g 68.7％

[0102] Preparation method:

[0103] Same as Example 1, the penetration enhancer is a combination of laurocapram and 1,2-propylene glycol.

[0104] The resulting drops are clear, colorless solutions.

[0105] In vitro release experiment:

[0106] Same as Example 1.

[0107] Example 8

[0108] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ Laurocapram 1.92g 2.7％ 1,2-Propanediol 10.90g 15.6％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 45.31g 64.7％

[0109] Preparation method:

[0110] Same as Example 1, the penetration enhancer is a combination of laurocapram and 1,2-propylene glycol.

[0111] The resulting drops are clear, colorless solutions.

[0112] In vitro release experiment:

[0113] Same as Example 1.

[0114] Example 9

[0115] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ Laurocapram 3.19g 4.6％ 1,2-Propanediol 3.63g 5.2％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 49.73g 71.0％

[0116] Preparation method:

[0117] Same as Example 1, the penetration enhancer is a combination of laurocapram and 1,2-propylene glycol.

[0118] The resulting drops are clear, colorless solutions.

[0119] In vitro release experiment:

[0120] Same as Example 1.

[0121] Example 10

[0122] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ Laurocapram 3.19g 4.6％ 1,2-Propanediol 7.27g 10.4％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 46.96g 67.1％

[0123] Preparation method:

[0124] Same as Example 1, the penetration enhancer is a combination of laurocapram and 1,2-propylene glycol.

[0125] The resulting drops are clear, colorless solutions.

[0126] In vitro release experiment:

[0127] Same as Example 1.

[0128] Example 11

[0129] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ Laurocapram 3.19g 4.6％ 1,2-Propanediol 10.90g 15.6％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 44.20g 63.1％

[0130] Preparation method:

[0131] Same as Example 1, the penetration enhancer is a combination of laurocapram and 1,2-propylene glycol.

[0132] The resulting drops are clear, colorless solutions.

[0133] In vitro release experiment:

[0134] Same as Example 1.

[0135] Example 12

[0136] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ Laurocapram 4.47g 6.4％ 1,2-Propanediol 3.63g 5.2％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 46.49g 66.4％

[0137] Preparation method:

[0138] Same as Example 1, the penetration enhancer is a combination of laurocapram and 1,2-propylene glycol.

[0139] The resulting drops are clear, colorless solutions.

[0140] In vitro release experiment:

[0141] Same as Example 1.

[0142] Example 13

[0143] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ Laurocapram 4.47g 6.4％ 1,2-Propanediol 7.27g 10.4％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 45.86g 65.5％

[0144] Preparation method:

[0145] Same as Example 1, the penetration enhancer is a combination of laurocapram and 1,2-propylene glycol.

[0146] The resulting drops are clear, colorless solutions.

[0147] In vitro release experiment:

[0148] Same as Example 1.

[0149] Example 14

[0150] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ Laurocapram 4.47g 6.4％ 1,2-Propanediol 10.90g 15.6％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 43.95g 62.8％

[0151] Preparation method:

[0152] Same as Example 1, the penetration enhancer is a combination of laurocapram and 1,2-propylene glycol.

[0153] The resulting drops are clear, colorless solutions.

[0154] In vitro release experiment:

[0155] Same as Example 1.

[0156] Rat transdermal experiment:

[0157] Same as Example 1.

[0158] Example 15

[0159] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 55.25g 78.9％

[0160] Preparation method:

[0161] Same as Example 1, without adding penetration enhancer.

[0162] The resulting drops are clear, colorless solutions.

[0163] In vitro release experiment:

[0164] Same as Example 1.

[0165] Rat transdermal experiment:

[0166] Same as Example 1.

[0167] Example 16

[0168] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ 1,2-Propanediol 7.27g 10.4％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 49.73g 71.0％ HPMC-E5 0.07g 0.1％

[0169] Preparation method:

[0170] (1) Weigh fepronil and praziquantel, add fepronil and praziquantel to 14 mL of anhydrous ethanol, and sonicate until the drugs are dissolved to prepare a drug solution;

[0171] (2) Accurately weigh the prescribed amount of 1,2-propylene glycol and ethyl paraben, add them to the above solution, and stir evenly;

[0172] (3) Add HPMC-E5 to the above solution, sonicate for 30 minutes, add anhydrous ethanol to 70 mL, and stir evenly. Dispense (specify in 0.7 mL, each 0.7 mL contains 116 mg) to obtain the drops, and seal and store.

[0173] The resulting drops are clear, colorless solutions.

[0174] In vitro release experiment:

[0175] Same as Example 1.

[0176] Rat transdermal experiment:

[0177] Same as Example 1.

[0178] Example 17

[0179]

[0180]

[0181] Preparation method:

[0182] Same as Example 16.

[0183] The resulting drops are transparent, colorless solutions. In vitro release experiments:

[0184] Same as Example 1.

[0185] Rat transdermal experiment:

[0186] Same as Example 1.

[0187] Example 18

[0188] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ 1,2-Propanediol 7.27g 10.4％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 49.73g 71.0％ HPMC-E5 0.21g 0.3％

[0189] Preparation method:

[0190] Same as Example 16.

[0191] The resulting drops are a transparent, colorless solution. In vitro release experiment:

[0192] Same as Example 1.

[0193] Rat transdermal experiment:

[0194] Same as Example 1.

[0195] Example 19

[0196] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ 1,2-Propanediol 7.27g 10.4％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 49.73g 71.0％ HPMC-E5 0.28g 0.4％

[0197] Preparation method:

[0198] Same as Example 16.

[0199] The resulting drops are transparent, colorless solutions. In vitro release experiments:

[0200] Same as Example 1.

[0201] Example 20

[0202] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ 1,2-Propanediol 7.27g 10.4％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 49.73g 71.0％ HPMC-E5 0.70g 1.0％

[0203] Preparation method:

[0204] Same as Example 16.

[0205] The resulting drops are a transparent, colorless solution. In vitro release experiment:

[0206] Same as Example 1.

[0207] Example 21

[0208] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ 1,2-Propanediol 7.27g 10.4％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 49.73g 71.0％ HPMC-E5 1.05g 1.5％

[0209] Preparation method:

[0210] Same as Example 16.

[0211] The resulting drops are a transparent, colorless solution. In vitro release experiment:

[0212] Same as Example 1.

[0213] Example 22

[0214] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ 1,2-Propanediol 7.27g 10.4％ Ethylparaben 0.17g 0.24％ Anhydrous ethanol 49.73g 71.0％ HPMC-E5 1.40g 2.0％

[0215] Preparation method:

[0216] Same as Example 16.

[0217] The resulting drops are clear, colorless solutions.

[0218] In vitro release experiment:

[0219] Same as Example 1.

[0220] Example 23

[0221] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ 1,2-Propanediol 7.27g 10.4％ Ethylparaben 0.17g 0.24％ HPMC-E5 0.07g 0.1％ Crotamiton 0.45g 0.6％ Anhydrous ethanol 49.73g 71.0％

[0222] Preparation method:

[0223] (1) Weigh fepronil and praziquantel, add fepronil and praziquantel to 14 mL of anhydrous ethanol, and sonicate until the drugs are dissolved to prepare a drug solution;

[0224] (2) Accurately weigh the prescribed amount of crotamiton, 1,2-propylene glycol, and ethyl paraben, add them to the above solution, and stir evenly;

[0225] (3) Add HPMC-E5 to the above solution, sonicate for 30 minutes, add anhydrous ethanol to 70 mL, and stir evenly. Dispense (specify in 0.7 mL, each 0.7 mL contains 116 mg) to obtain the drops, and seal and store.

[0226] The resulting drops are clear anhydrous solutions.

[0227] In vitro release experiment:

[0228] Same as Example 1.

[0229] Rat transdermal experiment:

[0230] Same as Example 1.

[0231] Example 24

[0232] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ Ethylparaben 0.17g 0.24％ HPMC-E5 0.07g 0.1％ Crotamiton 0.45g 0.6％ Anhydrous ethanol 54.87g 78.4％

[0233] Preparation method:

[0234] Same as Example 23.

[0235] The resulting drops are clear, colorless solutions.

[0236] In vitro release experiment:

[0237] Same as Example 1.

[0238] Rat transdermal experiment:

[0239] Same as Example 1.

[0240] Example 25

[0241] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ Ethylparaben 0.17g 0.24％ HPMC-E5 0.07g 0.1％ Crotamiton 2.432g 3.5％ Anhydrous ethanol 53.28g 76.1％

[0242] Preparation method:

[0243] Same as Example 23.

[0244] The resulting drops are transparent, colorless solutions. In vitro release experiments:

[0245] Same as Example 1.

[0246] Rat transdermal experiment:

[0247] Same as Example 1.

[0248] Example 26

[0249] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ 1,2-Propanediol 3.63g 5.2％ Ethylparaben 0.17g 0.24％ HPMC-E5 0.07g 0.1％ Crotamiton 1.213g 1.7％ Anhydrous ethanol 48.73g 71.0％

[0250] Preparation method:

[0251] Same as Example 23.

[0252] The resulting drops are transparent, colorless solutions. In vitro release experiments:

[0253] Same as Example 1.

[0254] Rat transdermal experiment:

[0255] Same as Example 1.

[0256] Example 27

[0257] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ 1,2-Propanediol 7.27g 10.4％ Ethylparaben 0.17g 0.24％ Crotamiton 0.35g 0.5％ Anhydrous ethanol 48.73g 71.0％

[0258] Preparation method:

[0259] Same as Example 23.

[0260] The resulting drops are clear, colorless solutions.

[0261] In vitro release experiment:

[0262] Same as Example 1.

[0263] Example 28

[0264] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ Ethylparaben 0.17g 0.24％ Crotamiton 0.35g 0.5％ Anhydrous ethanol 54.95 78.5％

[0265] Preparation method:

[0266] Same as Example 23.

[0267] The resulting drops are clear, colorless solutions.

[0268] In vitro release experiment:

[0269] Same as Example 1.

[0270] Rat transdermal experiment:

[0271] Same as Example 1.

[0272] Example 29

[0273] Fipronil 5.80g 8.3％ Praziquantel 5.80g 8.3％ Ethylparaben 0.17g 0.24％ Crotamiton 2.432g 3.5％ Anhydrous ethanol 53.28g 76.1％

[0274] Preparation method:

[0275] Same as Example 23.

[0276] The resulting drops are clear, colorless solutions.

[0277] In vitro release experiment:

[0278] Same as Example 1.

[0279] Rat transdermal experiment:

[0280] Same as Example 1.

[0281] Table 1 Prescriptions of Examples 1-29

[0282]

[0283]

[0284] Experimental Example 1: In vitro release experiment of the drops of Examples 1-29

[0285] Table 2 In vitro release results of fepronil in the drops of Examples 1-15

[0286]

[0287]

[0288] Table 3 In vitro release results of praziquantel in the drops of Examples 1-15

[0289] Praziquantel Cumulative release amount (%) Release duration fitting estimation (h) Example 1 18.3±3.6 5.9 Example 2 17.8±6.5 5.6 Example 3 25.2±1.4 4.0 Example 4 26.2±5.8 3.8 Example 5 28.2±12.7 3.7 Example 6 13.2±3.2 7.9 Example 7 16.2±3.3 6.4 Example 8 15.9±1.5 6.4 Example 9 11.8±4.1 8.8 Example 10 13.3±3.7 8.0 Example 11 13.2±1.2 7.8 Example 12 12.6±2.2 12.2 Example 13 12.3±2.3 8.7 Example 14 9.3±3.1 11.4 Example 15 20.5±5.9 5.1 Bolain 68.5±17.8 13.1

[0290] Table 4 In vitro release results of fepronil in the drops of Examples 16-29

[0291]

[0292]

[0293] Table 5 In vitro release results of praziquantel in the drops of Examples 16-29

[0294] Praziquantel Cumulative release amount (%) Release duration fitting estimation (h) Example 16 35.9±17.1 2.8 Example 17 33.0±8.3 2.9 Example 18 28.6±3.0 3.4 Example 19 29.9±3.5 3.2 Example 20 24.9±3.8 4.1 Example 21 24.9±4.1 3.9 Example 22 25.2±1.4 3.9 Example 23 39.3±16.5 2.6 Example 24 40.1±9.4 2.4 Example 25 75.8±21.1 1.3 Example 26 50.6±10.4 1.9 Example 27 25.4±2.8 3.8 Example 28 40.7±9.8 2.4 Example 29 82.1±9.2 1.1 Bolain 68.5±17.8 13.1

[0295] In Example 15, only anhydrous ethanol was used to prepare the drops without adding any penetration enhancer. The cumulative release of pyroximate and praziquantel in the drops was lower than the release of the two drugs in the commercially available Bolain, and the action time was shorter. On this basis, different penetration enhancers were added. The results showed that when the components and dosages in the prescription were the same, the release of the drugs was different when different penetration enhancers were changed. Different penetration enhancers and dosages were able to increase the cumulative release of the drugs to varying degrees. However, the addition of certain penetration enhancers not only did not increase the release of the drugs, but instead reduced the release of the drugs, such as in Examples 1, 2, 6-14. As can be seen, when 1,2-propylene glycol was used as a penetration enhancer, the cumulative release of pyroximate and praziquantel could be increased. When crotamiton was used as a penetration enhancer, its improvement in drug release was significantly better than 1,2-propylene glycol, such as in Examples 28 and 29.

[0296] On this basis, crotamiton + HPMC E5, 1,2-propylene glycol + HPMC E5, 1,2-propylene glycol + HPMC E5 + crotamiton, and HPMC E5 + crotamiton were used as penetration enhancers to investigate the effects of different penetration enhancer combinations on the in vitro release and transdermal permeation of the two drugs in the drops.

[0297] When 1,2-propylene glycol is used as a penetration enhancer, the weight volume percentage of 1,2-propylene glycol is 5.2%-15.6% and the weight volume percentage of anhydrous ethanol is 67.1%-75.0%, which can significantly increase the cumulative drug release of the drug. Moreover, the greater the amount of 1,2-propylene glycol used and the less the amount of anhydrous ethanol used, the better the cumulative drug release effect of praziquantel.

[0298] When laurocapram is used as a penetration enhancer, the weight volume percentage of laurocapram is 4.6%-6.4% and the weight volume percentage of anhydrous ethanol is 73.4%-75.0%, the cumulative release of the drug is inhibited. It is possible that when laurocapram is used as a penetration enhancer, the solubility of the drug is reduced under the action of anhydrous ethanol.

[0299] When 1,2-propylene glycol and lauryl azone are used as penetration enhancers, the cumulative release of the drug can be inhibited under the action of anhydrous ethanol. It is possible that when 1,2-propylene glycol and lauryl azone are used as penetration enhancers, the solubility of the drug may be reduced under the action of anhydrous ethanol.

[0300] The above results show that the release amounts of Examples 3-5 are significantly better than that of Example 15. It can be seen that the drops with 1,2-propylene glycol as a penetration enhancer can significantly increase the in vitro release amounts of fepronil and praziquantel and shorten the drug action time.

[0301] The results of Examples 16-29 show that, while the components and dosages in the formulation remain the same, varying the permeation enhancers, their combinations, and dosages significantly increases the release of fepronil and praziquantel from the drops. Examples 23-29 demonstrate that the release of fepronil and praziquantel is most significantly enhanced when the permeation enhancer contains crotamiton, particularly when crotamiton or a combination of crotamiton and HPMC E5 is used as the permeation enhancer, achieving optimal release of fepronil and praziquantel.

[0302] Experimental Example 2: Rat Transdermal Test of the Drops of Examples 1-29

[0303] The results of the rat transdermal test are shown in Tables 6 and 7.

[0304] Table 6 Transdermal test results of fepronil in the drops of Examples 3-5, 14-15

[0305] Fipronil Cumulative permeability (mg / mL) Penetration time fitting calculation (h) Example 3 0.3±0.04 6052.2 Example 4 0.4±0.1 4779.6 Example 5 0.2±0.02 8126.0 Example 14 0.3±0.1 6017.6 Example 15 0.3±0.1 7513.7

[0306] Table 7 Transdermal test results of praziquantel in the drops of Examples 3-5, 14-15

[0307]

[0308]

[0309] The above results show that the cumulative transdermal permeation of fepronil and praziquantel in Example 4 is greater than that in Example 3, Example 5, Example 14, and Example 15, that is, Example 4 is superior to Example 3, Example 5, Example 14, and Example 15, that is, when the weight volume percentage of 1,2-propylene glycol is 9%-11% and the weight volume percentage of anhydrous ethanol is 69%-71% in combination, the cumulative transdermal permeation of the drug can be significantly improved.

[0310] In summary, the transdermal test results of the compound drops of fepronil and praziquantel prepared according to Example 4 were optimal, indicating that Example 4 is the optimal formulation. Therefore, the weight-volume percentages of the components of the present invention in the drops are: 8.3% fepronil, 8.3% praziquantel, 9%-11% 1,2-propylene glycol, 70%-75% anhydrous ethanol, and 0.24%-0.25% ethylparaben to prepare the compound drops of fepronil and praziquantel. The cumulative drug penetration is large, and this preparation can be used for deworming once a month, making it convenient to use.

[0311] Table 8 Transdermal test results of praziquantel in the drops of Examples 16-29

[0312] Praziquantel Cumulative permeability (mg / mL) Release duration fitting estimation (h) Example 16 16.7±10.2 104.9 Example 17 16.0±6.4 110.2 Example 18 10.9±4.7 154.9 Example 23 9.4±3.7 215.1 Example 24 16.5±11.1 113.2 Example 25 28.1±3.3 63.7 Example 26 10.5±3.4 197.1 Example 28 19.8±6.2 100.1 Example 29 34.6±7.9 49.7 Bolain 0.2±0.06 2605.4

[0313] Table 9 Transdermal test results of fepronil in the drops of Examples 16-29

[0314]

[0315]

[0316] The results of Examples 16-22 demonstrate that, with the same formulation components and dosages, the addition of HPMC E5 can enhance drug release. Varying the weight-volume percentage of HPMC-E5 results in varying drug release, with varying weight-volume percentages of HPMC-E5 increasing the cumulative drug release to varying degrees. The lower the weight-volume percentage of HPMC-E5, the higher the cumulative drug release and drug permeation. The highest cumulative drug release and drug permeation were achieved when the weight-volume percentage of HPMC-E5 was 0.1%-0.15%.

[0317] The results of Examples 23-29 show that, while the formulation components and dosages remain the same, varying the dosages of 1,2-propylene glycol, HPMC E5, and crotamiton in different combinations results in different drug release rates. When crotamiton is used alone, a higher weight-to-volume percentage of crotamiton results in higher cumulative drug release and drug permeation. When crotamiton and HPMC E5 are used in combination, while the weight-to-volume ratio of HPMC E5 remains unchanged, a higher weight-to-volume percentage of crotamiton results in higher cumulative drug release and drug permeation. When 1,2-propylene glycol, HPMC E5, and crotamiton are used in combination, while the weight-to-volume ratio of HPMC E5 remains unchanged, a lower weight-to-volume ratio of 1,2-propylene glycol and a higher weight-to-volume percentage of crotamiton result in higher cumulative drug release and drug permeation. When crotamiton and 1,2-propylene glycol are used in combination, the cumulative drug release is the lowest compared to the other combinations. When crotamiton is used alone, with a higher weight-to-volume ratio of crotamiton, the cumulative drug release is the highest compared to the other combinations. This may be because 1,2-propylene glycol, HPMC E5, and crotamiton interact with each other, reducing the cumulative drug release. Therefore, the present invention uses crotamiton, or a combination of crotamiton and HPMC E5 as a penetration enhancer to prepare drops. In this way, the drops achieve optimal in vitro drug release and transdermal permeation, and the release of praziquantel is significantly better than that of the commercially available formulation, Bolain.

[0318] In summary, preferred embodiments 25 and 29 of the present invention prepare a compound drop of fepronil and praziquantel. Here, the weight and volume percentages of the components of the present invention in the drop are: fepronil 8.3%, praziquantel 8.3%, anhydrous ethanol 75%-80%, crotamiton 3.4%, HPMC E5 0-0.1%, and ethylparaben 0.24%-0.25%. The cumulative drug penetration is high, and this preparation can be used for deworming once a month, making it convenient to use.

[0319] The use of a combination of fepronil and praziquantel drops in the preparation of a parasiticidal and antiparasitic drug can be used both internally and externally. Fepronil inhibits and kills fleas, ear mites, ticks, and other surface pests, while praziquantel inhibits and kills flukes and tapeworms. This first-time combined use of these two drugs not only inhibits external pests by blocking chloride metabolism controlled by the insect's gamma-aminobutyric acid (GABA), disrupting the insect's central nervous system and inhibiting external pests, but also affects the activity of glutathione-S-transferase (GST) in the insect's body, causing a large accumulation of reactive oxygen species such as H2O2 and O2, thereby eliminating internal parasites by damaging the insect's antioxidant system.

[0320] Experimental Example 3: Skin irritation test

[0321] Select male rabbits weighing 2.0-2.5 kg and secure them to a rabbit stand. Use an electric shaver to shave the hair on the rabbit's back where the test is to be performed, exposing the skin. Use a marker to mark an area of ​​3 cm x 3 cm on the rabbit's back. Randomly select three areas and apply 0.3 mL of the optimal formulation (Example 29); randomly select three areas and apply an equal amount of the optimal formulation without the drug; randomly select three areas and apply an equal amount of Boline; and randomly select three areas and apply an equal amount of normal saline. Observe the skin condition 1 hour and 24 hours after administration and score according to the evaluation form.

[0322] Skin irritation rating standard

[0323]

[0324] Skin irritation intensity evaluation form

[0325] strength Score Non-irritating 0-0.4 Mild irritant 0.5-2.9 Moderate irritation 3.0-5.9 Intensity of stimulation 6.0-8.0

[0326]

[0327] According to the evaluation criteria, the preparation is non-irritating when the skin is intact and is suitable for use on pet skin.

Claims

1. A compound drop of fepronil and praziquantel, characterized in that The compound drops comprise fepronil, praziquantel, a penetration enhancer, a preservative, and anhydrous ethanol; the weight volume percentage of each component in the drops is: fepronil 8.3%, praziquantel 8.3%, a penetration enhancer 0%-25%, a preservative 0.2%-0.3%, HPMC-E5 0-2%, and anhydrous ethanol 60-80%; the penetration enhancer is one of 1,2-propylene glycol, crotamiton, HPMC E5, and laurocapram, or a combination thereof.

2. The compound drops of fepronil and praziquantel according to claim 1, characterized in that: The penetration enhancers are laurocapram, 1,2-propylene glycol, crotamiton, a combination of 1,2-propylene glycol and laurocapram, a combination of 1,2-propylene glycol and HPMC E5, a combination of 1,2-propylene glycol, HPMC E5 and crotamiton, a combination of HPMC E5 and crotamiton, and a combination of 1,2-propylene glycol and crotamiton.

3. A compound drop of fepronil and praziquantel according to claim 1 or 2, characterized in that: The penetration enhancer is a combination of 1,2-propylene glycol, crotamiton, HPMC E5 and crotamiton.

4. The compound drops of fepronil and praziquantel according to claim 3, characterized in that: When the penetration enhancer is 1,2-propylene glycol, the ratio of the penetration enhancer to anhydrous ethanol is 1:4-15; when the penetration enhancer is crotamiton, the ratio of the penetration enhancer to anhydrous ethanol is 1:20-160; when the penetration enhancer is a combination of HPMC E5 and crotamiton, the ratio of HPMC E5 to crotamiton is 1:6-35, and the ratio of the penetration enhancer to anhydrous ethanol is 1:20-160.

5. A compound drop of fepronil and praziquantel according to any one of claims 1 to 4, characterized in that: The weight volume percentage of each component in the drops is: 8.3% of fepronil, 8.3% of praziquantel, 0.24%-0.25% of preservative, 1.7%-3.5% of crotamiton, 0-0.1% of HPMC E5, and 70%-80% of anhydrous ethanol.

6. A compound drop of fepronil and praziquantel according to any one of claims 1 to 4, characterized in that: The weight volume percentage of each component in the drops is: 8.3% of fepronil, 8.3% of praziquantel, 0.24%-0.25% of preservative, 5.2%-15.6% of 1,2-propylene glycol, and 70%-80% of anhydrous ethanol.

7. A compound drop of fepronil and praziquantel according to any one of claims 1 to 4, characterized in that: The weight volume percentage of each component in the drops is: 8.3% of fepronil, 8.3% of praziquantel, 0.24%-0.25% of preservative, 3.5% of crotamiton, and 70%-80% of anhydrous ethanol.

8. A compound drop of fepronil and praziquantel according to any one of claims 1 to 4, characterized in that: The weight volume percentage of each component in the drops is: 8.3% of fepronil, 8.3% of praziquantel, 0.24%-0.25% of preservative, 3.5% of crotamiton, 0.1% of HPMC E5, and 70%-80% of anhydrous ethanol.

9. A compound drop of fepronil and praziquantel according to any one of claims 1 to 4, characterized in that: The weight volume percentage of each component in the drops is: 8.3% of fepronil, 8.3% of praziquantel, 9%-11% of 1,2-propylene glycol, 0.24%-0.25% of preservatives, and 70%-75% of anhydrous ethanol.

10. Use of the compound drops of fepronil and praziquantel according to any one of claims 1 to 9 in the preparation of anthelmintic drugs.

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