ANTHELMINTIC PREPARATION

Abstract: A pour-on anthelmintic composition, including its method of preparation and use, the composition preferably having been prepared by mixing at a common temperature (i) a premix of an anthelmintic compound or compounds (for example a benzimidazole) with a transdermal vehicle (such as isopropyl myristate) with (ii) a premix of a non-ionic emulsifier with an oil capable of solubilising the emulsifier and, subsequent to the blending of the premixes (preferably after cooling), mixing the blend with a deflocculation agent/diluent or deflocculation agent/diluent mix.

Description: "ANTHELMINTIC PREPARATION" TECHNICAL FIELD This invention relates to a method of preparing an anmelmintic composition and/or an anmelmintic composition (including a preparation so prepared) and/or a method of using such a composition. BACKGROUND ART Benzimidazole anthelmintics are widely used orally in aqueous suspension formulations for the control of parasitic helminths, namely round worms (nematodes), tapeworms (cestodes), or flukes (trematode). This anmelmintic group has been used in a variety of animal species including sheep, cattle, goats, deer, horses, cats, dogs, llama buffalo and poultry. Injectable preparations of benzimidazole anιhehτύntics are also known. Benzimidazole anmelmintic compounds are widely used in veterinary medicine. Common forms include oxfendazole, mebendazole, fenbendazole, albendazole and the probenzimidazoles febantel and netobimin, which are metabolised to benzimidazoles within the animal. In general, these compounds are sparingly soluble in aqueous solutions although the solubility can be improved by heating the aqueous solution. Bayer AG British Patent Specification No.1527584, the full content of which is hereby included by way of reference, refers to the advantages of pour-on application in veterinary practice over oral treatments and additionally discloses a pour-on formulation characterised in that the active compound is dissolved, emulsified or suspended in a suitable solvent or solvent mixture which is tolerable by the skin (optionally with addition of further auxiliaries) and applied with the aid of a suitable device, eg. measuring cup or spray bottle to the skin of the animal to be treated. The active ingredients disclosed are Tetramisole and Levamisole. Reference should also be had to the paper "Seasonal Variation and Anthelmintic Response by Cattle to dermally applied Levamisole", B.A. Forsyth et al. Australian Veterinary Journal, Vol. 60 No.5, May 1983 and "Pharmacokinetics of ivermectin after oral or percutaneous admiriistration to adult milking goats", E.W. Scott et al., Journal Veterinary Pharmacology, Volume 13, pages 432-435, 1990. E.R Squibb & Sons Inc, US Patent Specification No.4145433 discloses the option of topical or parenteral administration to mammalian hosts of benzimidazole dispersed in a non-toxic, non-pyrogenic acceptable carrier. In particular it discloses a solution for cutaneous aoininistration being prepared by dissolving 327 mg of [5-(benzyl)sulfinyl]- 1H- benzimidazole-2-yl] carbamic acid, methyl ester in a solution of about 4cc xylene and lcc dimethyl sulfoxide. Such administrations are stated as being useful in treating infection caused by Haemonchus, Ostertagia, Trichostrongylus, Cooperia, Dictyocaulus, Nematodirus, Bunostomum, Strongyloides, Oesphagostomum, Trichuris and liver flukes at a recommended dosage of from 2.5-25 mg kg body weight. DISCLOSURE OF INVENTION Nevertheless the sparing solubility of anthelmintics restricts their use as pour-ons. The present invention relates to improved methods of formulating compositions of anmelmintics (preferably benzimidazoles) for topical or transdermal administration to provide a substantially stable composition despite any solubility difficulties with the (benzimidazole) active ingredient(s). It is an object of the present invention to provide a method of preparing an alternative anmelmintic composition and/or an anthelmintic composition and/or a method of using an anthelmintic composition which will obviate or minimise the foregoing disadvantages in a simple yet effective manner or which will at least provide the public with a useful choice. More specifically, it is an object of the present invention to provide alternative veterinary preparations, and/or methods of preparation and/or of use of veterinary preparations, whereby preferably benzimidazole anthelmintics may be applied externally to animals so as to pass into and/or through the skin and into the system(s) [eg. blood, lymph and/or tissue] of the animal, providing a simple and quick administration method which is effective in achieving the necessary dose response. In addition it may provide a simple more prolonged method of administering the anmelmintic, increasing the anthelmintics effectiveness. Accordingly in one aspect the invention consists in a method of preparing an anthelmintic composition capable by means of dermal application of delivery of a effective anmelmintic amount one or more active ingredients into an animal systemically, said method comprising: (i) mixing at least one anthelmintic compound with a vehicle in which said compound(s) dissolves, suspends and/or emulsifies until the vehicle/active ingredient mixture is substantially homogeneous, (ii) before, simultaneously with, or after step (i), mixing a non-ionic emulsifier with an oil capable of solubilising the non-ionic emulsifier, said rnixing being at a temperature where both the non-ionic emulsifier and oil are in a liquid phase, (iii) blending the mixtures of steps (i) and (ii) at a temperature at which all components are in the Hquid phase so as to provide a substantially homogeneous mixture, (iv) lowering the temperature, or allowing the lowering of the temperature, of the mixture of step (iii) while mixing (preferably so that at least said non-ionic emulsifier is no longer in the liquid phase), and (v) mixing with the suspension of step (iv) a deflocculation agent/water (or other diluent) mixture to provide the anthelmintic micro suspension preparation. Preferably said anthelmintic active ingredient is at least one benzimidazole or prodrug therefor. Other options include an avermectin, pyrantel, morantel, closantel, praziquantel etc. Preferably said benzimidazole(s) or prodrug thereof is selected from the group including oxfendazole, thiabendazole, albendazole, cambenazole, fenbendazole, flubendazole, mebendazole, oxibendazole, parbendazole, thiophanate, febantel and netobimin. Preferably said beιιzimidazole(s) is or are oxfendazole and/or albendazole. Preferably said benzimidazole(s) is oxfendazole. Preferably said vehicle is selected from the group including isopropyl myristate, dimethyl sulphoxide, diacetone alcohol, n-methyl-2-pyrrolidone, iso-propyl alcohol, dimethylforamide, and 2 pyrrolidone. Preferably said vehicle is isopropyl myristate. In addition to said vehicle a cosolvent and/or absorption enhancer is selected from the group including polyoxyethylen glyceroltriricinoleate, polyvinylpyrrolidone, polyoxyethylene - glycerol trihydroxystearate, dimethylformarnide (DMF), dimethyl- acetamide, dimethyl isosorbide. Preferably the mixture of step (i) is elevated in temperature prior to the blending step (iii). Preferably the temperature of blending step (iii) is from about 55 °C to about 60°C. Preferably the oil of step (ii) capable of solubilising the non-ionic emulsifier is a mineral oil or a vegetable oil. Preferably said oil is selected from the group consisting of rapeseed or canola oil, polyol fatty acid ester, lauric acid hexyl, oleic acid decyl ester, 2-octyl dodecanol, soybean, sunflower oil, and ground nut refined fixed oils. Preferably said non-ionic emulsifier of step (ii) is selected from the group including sorbitan stearate, polysorbates [including ethoxy (20) sorbitan monopalmitate, ethoxy (20) sorbitan monostearate, ethoxy (4) sorbitan monostearate and ethoxy (20) sorbitan tristearate], polyoxyethylene castor oils and polyoxyethylene glycols. Preferably said non-ionic emulsifier of step (ii) is sorbitan stearate. Preferably the step (ii) is carried out at an elevated temperature. Preferably said elevated temperature at which step (ii) is carried out is from about 55 °C to about 60°C. Preferably the blending step (iii) is carried out only after the substantially homogeneous mixture of step (i) has been raised to a temperature of from about 55 °C to about 60°C. Preferably the temperature lowering step (iv) is to room or ambient temperature(s). Preferably the deflocculation agent/water mixture is of a deflocculation agent selected from the group consisting of sodium hgnosulphonate, silicon dioxides, poly vinyl pyrrolidones and/or said diluent is water. Preferably said deflocculation agent is sodium hgnosulphonate. Preferably said deflocculation agent/water mixture has been mixed with a some mixing procedure. Preferably said deflocculation agent/water mixture is added to the mixture of step (iv) substantially at room or ambient temperatures. Preferably the composition comprises - Oxfendazole 7.5% w/v Iso Propyl Myristate 66.0% w/v Sorbitan Stearate 1.0% w/v Sodium Lignosulphonate 0.9% w/v Canola Oil 0.5% w/v Deionised Water Up to the 100%. Preferably said mixture includes at least one or more of the following compounds, a trace mineral or trace minerals, a synthetic pyrethroid or pyrethroids (eg; cypermethrin), an organic phosphate or organophosphates, closantel, pyrantel, morantel, praziquantel and synthetic pyrethroids. Preferably any such optional trace mineral(s) organophosphate(s) and/or closantel sodium is mixed into (a), in the case of trace mineral(s) the pre-mix of step (iv) or (v), (b), in the case of any organophosphate(s), in a mix of step (iv) or (v), (c) in the case of closantel sodium, a mix of step (i), (d) in the case of pyrantel or morantel, a mix of step (i), (e) in the case of praziquantel, a mix of step (i), (f) in the case of synthetic pyrethroid(s), a mix of step (i). In a further aspect the invention is a benzimidazole anthelmintic composition prepared by a method as previously defined. In still a further aspect the invention consists in an anthelmintic composition capable of being used transdermally such as by a pour-on procedure, said composition comprising at room or ambient temperature at least one benzimidazole or prodrug thereof dissolved in, suspended on and/or emulsified by a transdermal vehicle and a hquid carrier for such benzimidazole/vehicle which includes a non-ionic emulsifier, an oil which solubilises the non-ionic emulsifier, water or other suitable diluent and a deflocculation agent. ■ Preferably said composition comprises - Benzimidazole(s) 1% to 50% w/v, Transdermal vehicle(s) 2% to 80% w/v, Non-ionic emulsifier(s) 0.1% to 10% w/v, Oil(s) 0.1% to 10% w/v, Deflocculation agent(s) 0.1% to 10%, and Water or other suitable diluent 5% to 50% w/v. Preferably said benzimidazole or prodrug thereof is selected from the group consisting of oxfendazole, thiabendazole, albendazole, cambenazole, fenbendazole, flubendazole, mebendazole, oxibendazole, parbendazole, thiophanate, febantel and netobimin, said vehicle is selected from the group including isopropyl myristate, dimethyl sulphoxide, diacetone alcohol, n-methyl-2-pyrrohdone and 2 pyrrolidone, said oil is selected from the group including rapeseed or canola oil, polyol fatty acid ester, lauric acid hexyl, oleic acid decyl ester, 2-octyl dodecanol, soybean, sunflower oil, cold pressed rapeseed and ground nut refined fixed oils. said non-ionic emulsifier is selected from the group including sorbitan stearate, polysorbates, polyoxyethylene castor oils and polyoxyethylene glycols and said deflocculation agent is selected from the group including sodium Hgnosulphonate, siHcon dioxides, poly vinyl pyrroHdones. Preferably said benzimidazole is oxfendazole, said vehicle is isopropyl myristate, said oil is rapeseed or canola oil, said non-ionic emulsifier is sorbitan stearate and said deflocculation agent is sodium Hgnosulphonate. Preferably said composition comprises - Oxfendazole 7.5% w/v Iso Propyl Myristate 66.0% w/v Sorbitan Stearate 1.0% w/v Sodium Lignosulphonate 0.9% w/v Canola Oil 0.5% w/v Deionised Water . up to the 100%. Preferably the composition additionally includes at least one trace mineral and or at least one organo phosphate and/or closantel sodium. In stiU a further aspect the invention consists in a method of controlling hehτrinth(s) (nematode, cestode or trematode) within an animal which comprises applying to the skin of the animal an anmelmintic composition as herein defined and thereafter allowing at least the anthelmintic compound(s) [preferably benzimidazole or prodrug compound(s)] to pass through and/or into the skin of the animal to enter the blood, lymph and/or tissue fluids of the animal in an anmelmintically effective amount. Preferably said composition is applied by a pour-on procedure or other method of skin appHcation. Preferably said composition is about a 75mg/mL suspension of oxfendazole at about a dosage rate oxfendazole/weight of animal at least twice that recommended for oral administration currently being recommended for oxfendazole anthelmintic treatment of any such animal. Preferably said composition is about a 75mg/mL suspension of oxfendazole at a dosage rate of about lOmg oxfendazole/kg body weight of the animal. Preferably the animal is a ruminant but can be other mammals or even non mammals. Preferably said veterinary preparation also includes a surface active dispersant or wetting agent. In a further aspect the invention consists in an anthelmintic composition capable by dermal application to an animal of delivering an anthelminticly effective amount of systemic anthelmintic active ingredient into the animal, systemic anthelmintic compound(s) 1% to 50% w/v, emulsifier 0.1% to 10% w/v, carrier solvent (transdermal vehicle) 2% to 80% w/v, dispersant or wetting agent 0.1% to 10% w/v, oil 0.1% to 10% w/v, and diluent 5% to 50% w/v. Preferably said anthelmintic compound is a benzimidazole. BRD F DESCREPTION OF DRAWINGS The invention also consists in methods of use thereof. The present preferred forms of the invention will now be described. The accompanying drawing (Figure 1) is a plot of hehriinth egg counts against time. BEST MODE(S) FOR CARRYING OUT THE INVENTION According to the invention, a veterinary preparation is provided, along with a method of preparing a veterinary preparation, and a method of using a veterinary preparation. The preparation is so formulated as to be suitable for dermal use, e.g. spread on, spray on, or pour-on (hereinafter "pour-on"). The invention is that the benzimidazole anmelmintic is presented in a carrier or solvent (hereafter "vehicle") which is capable of being absorbed through the skin. By preference, this vehicle is iso propyl myristate, although other compounds may be substituted, for example, dimethyl sulphoxide, diacetone alcohol, N-methyl-2-pyrroHdone, 2 pyrrolidone or other suitable non-toxic compounds which can be absorbed through the skin of the target animals. Thus the formulation when apphed externauy to the animal will pass through the skin and into the systems of the animal where it can take effect. A typical formulation according to the invention consists of 1% to 50% w/v benzimidazole, 2% to 80% w/v vehicle, 5% to 50% w/v diluent, 0.1% to 10% w/v non-ionic emulsifier, 0.1% to 10% w/v deflocculant and 0.1% to 10% oily component. The emulsifier in the preferred form of the invention is sorbitan stearate but this may be substituted by other non-ionic emulsifiers, for example, polysorbates, polyoxyethylene castor oils, polyoxyethylene glycols. The dispersant or wetting agent is in the preferred form of the invention sodium Hgnosulphonate, but this may be substituted by siHcon dioxides, poly vinyl pyrroHdones, or other surface active agents. The preparation also contains an oily component. In the most presently preferred form of the invention, this is rapeseed oil but this may be substituted by polyol fatty acid ester, lauric acid hexyl, oleic acid decyl ester, 2-octyl dodecanol or other vegetable oils such as soybean or sunflower oil. The preparation is made up to volume with a diluent, such as deionised water. This diluent may be substituted by or include or be (any one or more) other miscible diluents such as propylene glycol, sorbitol or glycerol. Example Oxfendazole 7.5% w/v Iso Propyl Myristate 66.0% w/v Sorbitan Stearate 1.0% w/v Sodium Lignosulphonate 0.9% w/v Rapeseed Oil 0.5% w/v Deionised Water Up to the 100%. Other, anmelmintic or therapeutic substances may also be included in the preparation if desired, for example, minerals, trace elements, synthetic pyrethroids and organophosphates. The composition of the present may be prepared as follows: The benzimidazole anthelmintic, for example oxfendazole, is added to the carrier solvent, for example iso propyl myristate, and the two compounds are mixed until the mixture is thoroughly wetted. The non-ionic emulsifier, for example sorbitan stearate is then added to the mixture while mamtaining stirring, foUowed, while continuing to stir, by the dispersant or wetting agent, for example sodium Hgnosulphonate, and the suitable oily component, for example rapeseed or canola oil. The mixture is then made up to volume with the diluent, for example deionised water. The total mixture is then continued to be mixed until it is substantially homogeneous. The more preferred procedure is (i) mixing at least one anmelmintic comporr-d (eg: oxfendazole) with a vehicle (eg: isopropyl myristate) in which said compound(s) dissolves, suspends and/or emulsifies until the vehicle/active ingredient mixture is substantially homogeneous, (ti) before, simultaneously with, or after step (i), mixing a non-ionic emulsifier (eg: sorbitan stearate) with an oil (eg: rapeseed oil) capable of solubiUsing the non-ionic emulsifier, said mixing being at a temperature (preferably elevated to 55 °C to 60 °C) where both the non-ionic emulsifier and oil are in a Hquid phase, (Hi) blending the mixtures of steps (i) and (H) at a temperature (preferably elevated to 55 °C to 60°C) at which aU components are in the liquid phase so as to provide a substantiaUy homogeneous mixture, (iv) lowering the temperature, or aUowing the lowering of the temperature, of the mixture of step (Hi) (eg: to room or ambient temperature) while mixing so that at least said non-ionic emulsifier is no longer in the Hquid phase, and (v) mixing with the suspension of step (iv) a deflocculation agent/diluent mixture (eg: sodium Hgnosulphate/water) to provide the anthelmintic micro suspension preparation, said diluent being selected from the group comprising water, propylene glycol, sorbitol and glycerol. This procedure provides an anthelmintic composition which over time can provide most effective helminth control. The foUowing eleven formulations give examples of different formulations within the present invention. FORMULATION 1 Oxfendazole 7.5% w/v Iso Propyl Myristate 66.0% w/v Canola Oil 0.5% w/v Liposorb S 1.0% w/v Sodium Lignosulphonate 0.9% w/v Benzyl Alcohol 5.0% w/v Deionised Water qs to 100% v/v FORMULATION 2 Albendazole 7.5% w/v Iso Propyl Myristate 66.0% w/v Canola Oil 0.5% w/v Liposorb S 1.0% w/v Sodium Lignosulphonate 0.9% w/v Benzyl Alcohol 5.0% w/v Deionised Water qs to 100% v/v FORMULATION 3 Fenbendazole 2.5% - 10% w/v Iso Propyl Myristate 66.0% w/v Canola Oil 0.5% w/v Liposorb S 1.0% w/v Sodium Lignosulphonate 0.9% w/v Benzyl Alcohol 5.0% w/v Deionised Water qs to 100% v/v FORMULATION 4 Oxfendazole 7.5% w/v Closantel - Sodium 2.5% w/v - 5.0% w/v Iso Propyl Myristate 66.0% w/v Canola Oil 0.5% w/v Liposorb S 1.0% w/v Sodium Lignosulphonate 0.9% w/v Benzyl Alcohol 5.0% w/v Deionised Water qs to 100% v/v FORMULATION 5 Praziquantel 2.5% w/v Oxfendazole 7.5% w/v Iso Propyl Myristate 66.0% w/v Canola Oil 0.5% w/v Sodium Lignosulphonate 0.9% w/v Liposorb S 1.0% w/v Benzyl Alcohol 5.0% w/v Deionised Water qs to 100% v/v FORMULATION 6 Oxfendazole 7.5% w/v Cypermethrin 2.5% w/v Iso Propyl Myristate 66.0% w/v Canola Oil 0.5% w/v Sodium Lignosulphonate 0.9% w/v Benzyl Alcohol 5.0% w/v Liposorb S 1.0% w/v Deionised Water qs to 100% v/v FORMULATION 7 Oxfendazole 7.5% w/v Iso Propyl Myristate 66.0% w/v Canola Oil 0.5% w/v Sodium Lignosulphonate 0.9% w/v Benzyl Alcohol 5.0% w/v Liposorb S 1.0% w/v Copper Disodium Ethylenediamine Tetra 10.7% w/v Acetate Zinc EDTA 5.4% w/v Cobalt EDTA 1.1% w/v Sodium Selenate 0.57% w/v EDDI 0.57% w/v Deionised Water qs to 100% v/v FORMULATION 8 Benzimidazole(s) 1% - 20% w/v Transdermal Vehicle(s) 2% - 80% w/v Non-ionic Emulsifier(s) 0.1% - 10% w/v Oil(s) 0.1% - 10% w/v Deflocculation Agent(s) 0.1% - 10% w/v Preservative(s) 0.5% - 10% w/v Water or suitable diluent 1% - 50% v/v FORMULATION 9 Benzimidazole(s) 1% - 20% w/v Anthelmintic(s) 1% - 5% w/v Transdermal Vehicle(s) 2% - 80% w/v Non-ionic Emulsifier(s) 0.1 - 10% w/v Oil(s) 0.1% - 10% w/v Deflocculation Agent(s) 0.1% - 10% w/v Preservative(s) 0.5% - 10% w/v Water or other suitable diluent 1% - 50% v/v FORMULATION 10 Benzimidazole(s) 1% - 20% w/v Pyrethroid(s) 1% - 5% w/v Transdermal Vehicle(s) 2% - 80% w/v Non-ionic Emulsifier(s) 0.1% - 10% w/v Oil(s) 0.1% - 10% w/v Deflocculation Agent(s) 0.1% - 10% w/v Preservative(s) 0.5% - 10% w/v Water or other suitable dilutent 1% - 50% v/v FORMULATION 11 Anthelmintic(s) (including Benzimidazole(s)) 1% - 20% w/v Transdermal Vehicle(s) 2% - 80% w/v Non-ioniς Emulsifier(s) 0.1% - 10% w/v Oil(s) 0.1% - 10% w/v Deflocculation Agent(s) 0.1% - 10% w/v Trace Mineral(s) 1% - 25% w/v Preservative(s) 0.5% - 10% w/v Water or other suitable dilutent 1% - 50% v/v This formulation may be administered to cattle, for example, in volume dosages of 35-45 mis for cattle of 250-310kg body weight. Of course veterinary advice should also be sought regarding dosages. Dosages in similar ratios are applicable to other animals, eg: sheep, goats, horses, deer, cats, dogs, camel, Uama and buffalo. Thus it can be seen that an improved benzimidazole anthelmintic preparation, a method of preparing a veterinary preparation, and a method of using a veterinary preparation are provided by the invention in its preferred form which have the advantage of increasing the convenience and effectiveness of use of such compounds, through providing for efficacious dermal application. Thus the formulation when apphed externaUy will pass into and or through the skin and be transported by the blood, lymph or tissue fluids to act on the helminth (nematode, cestode or trematode) both within body tissues and body organs including muscle, lung, Hver and kidney and within the lumen of both the gastrointestinal and respiratory tract. The mechanism of action of the benzimidazole anthelmintics on helminths is believed to be due to their disruption of mtraceUular microtubular transport systems by binding selectively to and damage o£ helminth tubulin, preventing tubulin polymerisation and the inhibition of microtubule formation. Benzirnidazoles have also been shown to act at higher levels as inhibitors of metabolic enzymes, including malate dehydrogenase and fumarate reductase, and disrupt metaboHc pathways within the helminth. Orally Benzimadazoles appear to be most effective as anthelmintics (drenches) when given over several days rather than as an oral single dose. The preparation may be applied may be applied according to the invention, dermaUy, eg. as a pour-on on to the mid line of the back or neck of animals such as cattle. The active ingredient (ie. the anthelmintic) is absorbed through the skin and into the blood, tissues and tissue fluids of the animal. Data based on the appHcation of the said pour on, in this case oxfendazole, at 2.2 times the oral dose rate (ie. lOmg/kg) produced blood serum levels up to 0.2μg/mL which is comparable with the blood levels seen in calves orally administered with oxfendazole at a dose rate of 4.5mg/kg. Blood oxfendazole levels in the said pour on calves were generaUy lower and unexpectedly persistent, with low levels of oxfendazole detected in their blood at day 3 and 4 after adrriinistration. Blood levels in calves that received oral oxfendazole were below detection (0.025μg/mL) at day 3. A slower action was also seen in the reduction of faecal egg counts in the pour on group with significant reductions on day 2 and 3 after treatment compared with a significant reduction occurring at day 1 and 2 in the oral group (see Figure 1). Figure 1 shows Faecal Egg Counts (F.E.C's) in Eggs per gram (EPG) in 6 month old Friesan Calves, treated with oral oxfendazole (Synanthic™) at a dose rate of 4.5 mg per kg, the trial oxfendazole pour-on at 10.0 mg/kg and untreated control animals. Treatment was at day 0. The pour-on formulation used for these FEC/Time trials was Oxfendazole 7.5% w/v Iso Propyl Myristate 66.0% w/v Sorbitan Stearate 1.0% w/v Sodium Lignosulphonate 0.9% w/v Canola Oil 0.5% w/v Deionised Water Up to the 100%. It has already been demonstrated that treatment regimes that provide more prolonged levels of benzimidazoles over a number of days such as appear to be demonstrated in this pour on product, increases the effectiveness of the anmehnintic. Table 1 is a comparison of Faecal Egg Counts (F.e.c's) in 6 Month Old Friesan Calves Treated with Oral Oxfendazole (Synanthic™) At 4.5 Mg/Kg and Trial Pour Oxfendazole Product At 13.5 Mg/kg TABLE 1 Oxfendazo le Pour-on Animal No Treatment Group Day l Day O mean: -1,0 Day 7 Day 14 2 Control - 0 0 0 100 5 Control 50 100 75 0 0 10 Control 100 200 150 100 300 12 Control 50 50 50 100 50 25 Control 500 300 400 200 400 33 Control 500 150 325 0 0 51 Control 200 0 100 450 300 58 Control 50 0 25 200 150 59 Control 450 400 425 400 600 70 Control 50 150 100 100 N.D. geometric 217 135 165 150 211 means 1 Oral 50 100 75 0 0 3 Oral 200 200 200 50 0 6 Oral 50 200 125 50 0 8 Oral 50 50 50 0 0 11 Oral 350 50 200 0 0 13 Oral 50 50 50 0 0 16 Oral 350 100 225 0 0 30 Oral 300 250 275 0 50 36 Oral 200 300 250 50 0 38 Oral 100 50 75 0 0 41 Oral 300 200 250 0 0 45 Oral 100 0 50 0 0 47 Oral 500 300 400 0 0 55 Oral 50 150 100 0 0 61 Oral 350 500 425 50 50 62 Oral 300 50 175 0 0 66 Oral 50 50 50 0 0 73 Oral 50 0 25 0 0 74 Oral 400 0 200 0 50 geometric 190 139 168 10 8 mean 4 Pour-on 50 0 25 0 0 7 Pour-on 230 0 125 0 0 9 Pour-on 150 - 75 0 0 14 Pour-on 100 100 100 0 0 18 Pour-on 150 100 125 0 0 20 Pour-on 50 0 25 0 0 21 Pour-on 100 250 175 0 50 22 Pour-on 100 100 100 0 0 23 Pour-on 50 100 75 0 0 26 Pour-on 50 0 25 0 0 28 Pour-on 350 500 425 0 0 31 Pour-on 850 400 625 0 0 37 Pour-on 100 50 75 0 0 40 Pour-on 150 350 250 0 0 42 Pour-on 150 150 150 0 50 44 Pour-on 400 0 200 0 0 50 Pour-on 900 1550 1225 200 750 57 Pour-on 50 0 25 0 0 60 Pour-on 50 50 50 0 0 76 Pour-on 50 0 25 0 0 geometric 205 195 195 10 42 mean SUMMARY Comparison of oral and pour-on formulations. Treatment groups are: Group 0 = untreated controls, Group 1 = oral drench, and Group 3 = pour-on formulation Note: All analyses were carried out on log-transformed FEC's. The analysis of faecal egg counts (FEC's) shows that there were no significant differences between any of the groups either on day -1 or day 0. Subsequently, on days 7, 14 and 21 post-treatment there was a high significant difference between the untreated control group and the groups treated with oxfendazole (p O.0001). There were no significant differences between the orally or topically treated groups.

Claims: CLAIMS 1. A method of preparing an anthelmintic composition capable by means of dermal appHcation of delivery of a systemicly effective anthelmintic amount at least one active ingredient into an animal, said method comprising: (i) mixing at least one anthelmintic compound with a vehicle in which said compound(s) dissolves, suspends and or emulsifies until the vehicle/active ingredient mixture is substantially homogeneous, (ii) before, simultaneously with, or after step (i), mixing a non-ionic emulsifier with an oil capable of solubilising the non-ionic emulsifier, said mixing being at a temperature where both the non-ionic emulsifier and oil are in a liquid phase, (Hi) blending the mixtures of steps (i) and (ii) at a temperature at which all components are in the Hquid phase so as to provide a substantially homogeneous mixture, (iv) lowering the temperature, or allowing the lowering of the temperature, of the mixture of step (Hi) while mixing so that at least said non-ionic emulsifier is no longer in the liquid phase, and (v) mixing with the suspension of step (iv) a deflocculation agent/diluent mixture to provide the anmelmintic micro suspension preparation, said diluent being selected from the group comprising water, propylene glycol, sorbitol and glycerol. 2. A method as claimed in claim 1 wherein said anthelmintic active ingredient is a benzimidazole or a prodrug thereof. 3. A method of claim 2 wherein said benzimidazole(s) is or are selected from the group includrng oxfendazole, thiabendazole, albendazole, cambenazole, fenbendazole, flubendazole, mebendazole, oxibendazole, parbendazole, thiophanate, febantel and netobimin. 4. A method as claimed in claim 3 wherein said benzimidazole(s) is oxfendazole. 5. A method of any one of claims 1 to 4 wherein said vehicle is selected from the group including isopropyl myristate, dimethyl sulphoxide, diacetone alcohol, n-methyl-2- pyrroHdone, dimethyl foramide and 2 pyrroHdone. 6. A method as claimed in claim 5 wherein said vehicle is isopropyl myristate. 7. A method as claimed in any one of the preceding claims wherein the mixture of step (i) is elevated in temperature prior to the blending step (iii). 8. A method as claimed in claim 7 wherein the temperature of blending step (in) is from about 55 °C to about 60°C. 9. A method as claimed in any one of the preceding claims wherein the oil of step (H) capable of solubilising the non-ionic emulsifier is a mineral oil or a vegetable oH. 10. A method as claimed in claim 9 wherein said oil is selected from the group includrng canola oil, rapeseed oH, polyol fatty acid ester, lauric acid hexyl, oleic acid decyl ester, 2-octyl dodecanol, soybean and sunflower oil. 11. A method as claimed in any one of the preceding claims wherein said non-ionic emulsifier of step (ti) is selected from the group ncluding sorbitan stearate, polysorbates, [including ethoxy (20) sorbitan monopahnitate, ethoxy (20) sorbitan monostearate, ethoxy (4) sorbitan monostearate and ethoxy (20) sorbitan tristearate], polyoxyethylene castor oils and polyoxyethylene glycols. 12. A method as claimed in claim 11 wherein said non-ionic emulsifier of step (H) is sorbitan stearate. 13. A method of any one of the preceding claims wherein the step (H) is carried out at an elevated temperature. 14. A method as claimed in claim 13 wherein said elevated temperature at which step (ii) is carried out is from about 55°C to about 60°C. 15. A method as claimed in any one of the preceding claims wherein the blending step (iii) is carried out only after the substantially homogeneous mixture of step (i) has been raised to a temperature of from about 55°C to about 60°C. 16. A method as claimed in any one of the preceding claims wherein the temperature lowering step (iv) is to room or ambient temperature(s). 17. A method as claimed in any one of the preceding claims wherein the deflocculation agent/water mixture is of a deflocculation agent selected from the group including sodium Hgnosulphonate, sihcon dioxides, poly vinyl pyrroHdones and said diluent is water. 18. A method as claimed in claim 17 wherein said deflocculation agent is sodium Hgnosulphonate. 19. A method as claimed in claim 17 or 18 wherein said deflocculation agent/water mixture has been mixed with a sonic mixing procedure. 20. A method as claimed in claim 19 wherein said deflocculation agent/water mixture is added to the mixture of step (iv) substantially at room or ambient temperatures. 21. A method as claimed in any one of the preceding claims wherein the composition comprises - 5 Oxfendazole 7.5% w/v Iso Propyl Myristate 66.0% w/v Sorbitan Stearate 1.0% w/v Sodium Lignosulphonate 0.9% w/v Canola Oil 0.5% w/v 10 Deionised Water Up to the 100%. 22. A method as claimed in any one of the preceding claims wherein said mixture includes at least one or more of the following compounds, a trace mineral or trace minerals, synthetic pyrethroid or pyrethroids, an organic phosphate or organo phosphates and closantel sodium. 15 23. A method as claimed in any one of the preceding claims wherein any such optional trace mineral(s) organo phosphate(s) and/or closantel sodium is mixed into (a), in the case of trace mineral(s) the pre-mix of step (iv) or (v), (b), in the case of any organo phosphate(s), in a mix of step (iv) or (v) (c) n the case of closantel sodium, a mix of step (i), 20 (d) in the case of pyrantel or morantel, a mix of step (i), (e) in the case of praziquantel, a mix of step (i), and (f) in the case of synthetic pyrethroid(s), a mix of step (i). 24. An anthelmintic composition prepared by a method as claimed in any one of the preceding claims. 25 25. A anmelmintic composition capable of being apphed dermaUy (such as by a pour-on procedure to an animal to dehver a systemicly effective anthehriintic amount of the active ingredient benzimidazole), said composition comprising at room or ambient temperature at least one benzimidazole or prodrug thereof dissolved in, suspended on and/or emulsified by a transdermal vehicle and a Hquid carrier for such benzimidazole/vehicle 30 which includes a non-ionic emulsifier, an oH which solubiHses the non-ionic emulsifier, water or other diluent, and a deflocculation agent. 26. A composition of claim 25 comprising - Benzimidazole(s) 1% to 50% w/v, Transdermal vehicle(s) 2% to 80% w/v, Non-ionic emulsifier(s) 0.1% to 10% w/v, Oil(s) 0.1% to 10% w/v, Deflocculation agent(s) 0.1% to 10%, and Water or other suitable diluent 5% to 50% w/v. 27. A composition of claim 25 or 26 wherein said benzimidazole or prodrug thereof is selected from the group including oxfendazole, thiabendazole, albendazole, cambenazole, fenbendazole, flubendazole, mebendazole, oxibendazole, parbendazole, thiophanate, febantel, and netobimin, said vehicle is selected from the group including isopropyl myristate, dimethyl sulphoxide, diacetone alcohol, n-methyl-2-pyrrolidone and 2 pyrrolidone, said oil is selected from the group including canola oil, polyol fatty acid ester, lauric acid hexyl, oleic acid decyl ester, 2-octyl dodecanol, soybean and sunflower oil, rapeseed, ground nut refined fixed oils. said non-ionic emulsifier is selected from the group including sorbitan stearate, polysorbates [including ethoxy (20) sorbitan monopalmitate, ethoxy (20) sorbitan monostearate, ethoxy (4) sorbitan monostearate and ethoxy (20) sorbitan tristearate], polyoxyethylene castor oils and polyoxyethylene glycols and said deflocculation agent is selected from the group including sodium Hgnosulphonate, siHcon dioxides, poly vinyl pyrrolidones. 28. A composition as claimed in any one of claims 25 to 27wherein said benzimidazole is oxfendazole, said vehicle is isopropyl myristate, said oH is canola oil, said non-ionic emulsifier is sorbitan stearate and said deflocculation agent is sodium Hgnosulphonate. 29. A composition as claimed in any one of claims 25 to 28 which comprises - Oxfendazole 7.5% w/v Iso Propyl Myristate 66.0% w/v Sorbitan Stearate 1.0% w/v Sodium Lignosulphonate 0.9% w/v Canola Oil 0.5% w/v Deionised Water Up to the 100%. 30. A composition as claimed in any one of claims 24 to 29 which additionaUy includes at least one trace mineral and/or at least one organo phosphate and/or closantel sodium 5 and/or praziquantel and/or pyrantel, and or morantel, and/or synthetic pyrethroids. 31. An anthelmintic composition capable by dermal application to an animal of dehvering an anthelminticly effective amount of systemic anthehriintic active ingredient into the animal, systemic anthelmintic compound(s) 1% to 50% w/v, 10 emulsifier 0.1% to 10% w/v, carrier solvent (transdermal vehicle) 2% to 80% w/v, dispersant or wetting agent 0.1% to 10% w/v, oH 0.1% to 10% w/v, and cHluent 5% to 50% w/v. 15 32. A composition of claim 31 wherein said anmelmintic compound is a benzimidazole or a prodrug thereof. 33. A method of controUing helminth(s) (nematode, cestode or trematode) within an animal which comprises applying to the skin of the animal composition as claimed in any one of claims 24 to 30, 31 and 32 and thereafter allowing at least the active anthelmintic 20 compound(s) to pass through and or into the skin of the animal to enter the blood, lymph and or tissue fluids of the animal in an anthelmintically effective amount. 34. A method as claimed in claim 33 wherein said composition is applied by a pour-on procedure. 35. A method of claim 34 wherein said composition is about a 75mg/mL suspension of 25 oxfendazole at about a dosage rate oxfendazole/weight of animal at least twice that recommended for oral administration currently being recommended for oxfendazole anthelmintic treatment of any such animal. 36. A method of claim 34 wherein said composition is about a 75mg/mL suspension of oxfendazole at a dosage rate of about lOmg oxfendazole/kg body weight of the aiiimal. 30 37. A method of any one of claims 33 to 36 wherein the animal is a raminant.

Inventors: LEECH WAYNE FREDERICK, MCLAREN DONALD GEORGE, LEECH, WAYNE, FREDERICK, MCLAREN, DONALD, GEORGE
Applicants: BOMAC LAB LTD, LEECH WAYNE FREDERICK, MCLAREN DONALD GEORGE, BOMAC LABORATORIES LIMITED, LEECH, WAYNE, FREDERICK, MCLAREN, DONALD, GEORGE
Application year: 1995
Main classification: A61K9
IPC codes: A61K9