AU2008201564A1 - Levamisole, avermectins or similar in pyrrolidone solvent - Google Patents

Description

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AUSTRALIA

FB RICE CO Parent and Trade Mark Attorneys Patents Act 1990 MERIAL LTD COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Levamisole, avermectins or similar in pyrrolidone solvent The following statement is a full description of this invention including the best method of performing it known to us:- 00 la SLEVAMISOLE, AVERMECTINS OR SIMILAR IN PYRROLIDONE

SOLVENT

This application is a divisional application from Australian Patent Application No.

2003281472, the entire contents of which are incorporated herein by reference.

Vt' FIELD OF THE INVENTION This invention relates to the field of veterinary pharmaceuticals and in particular to 0 anthelmintic formulations including a combination of actives.

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SBACKGROUND

Anthelmintics are an important tool for farmers seeking to improve the productivity of grazing cattle. The first class of modem broad-spectrum anthelmintic was the benzimidazoles introduced in the early 1960's, followed by levamisole and morantel in the late 1960's and finally the averrnectins and milbemycins in the early 1980's.

Anthelmintic Year of Main Active's in the Group Introduction Benzimidazoles Early 1960's Thiabendazole, albendazole, fenbendazole, oxfendazole Levamisole/Morantel Late 1960's Levamisole, morantel Avermectins/Milbemycins Early 1980's Abamectin, ivermectin, moxidectin, doramectin, eprinomectin Parasite resistance has developed to each group of anthelmintic since they were introduced. Resistance to benzimidazole-based drenches is widespread throughout the world. Cases have been reported that involve resistance in all three major cattle parasites species: Ostertagia, Trichostrongylus and Cooperia.

Resistance to levamisole/morantel based drenches is well known but is less widespread than benzimidazole resistance.

In 1995, New Zealand researchers reported a strain of the worm parasite Cooperia that was resistant to both ivermectin (a member of the avennectin/milbemycin group) and to oxfendazole (a benzimidazole). In 1996, reports were published of an ivermectin resistant Cooperia strain that was cross-resistant to doramectin and moxidectin (also members of the avermectin/milbemycin group).

206722_1.doc WO 2004/009080 PCT/NZ2003/000157 00 2 To prevent and manage the problem of anthelmintic resistance farmers have relied on various number of strategies including: 0 minimizing anthelmintic use by only treating at strategically important times alternating the type of anthelmintic used 1 10 using combinations of anthelmintics from different groups to reduce the potential of parasites to survive the treatment.

00 SOrally administered combinations of benzimidazole and levamisole anthelmintics are well CI known, and have been used for many years.

However in recent years products based on actives selected solely from the avermectin/milbemycin groups have held the most significant share of the cattle anthelmintic market due to their high efficacy against the major production limiting parasite species, Ostertagia. The availability of easy to apply topical pour-on formulations has further extended their market dominance.

By contrast, levamisole-based products have been used on a much more limited basis.

Despite their having good efficacy against Cooperia, the key dose limiting parasite of the avermectin/milbemycin group.

The table below shows that while each anthelmintic group has particular limitations against certain parasites, a combination of actives selected from the avermectin/milbemycin and levamisole groups would achieve two highly important goals: high efficacy against the key cattle parasites combination potency to help prevent parasites surviving the treatment Anthelmintic Class Cooperia Efficacy Ostertagia Efficacy Levamisole Good Poor Avermectin/Milbemycin .Poor Good Combination of both classes Good Good Despite this rationale for an easy to use product combining levamisole active with an avermectin/milbemycin active combinations have been difficult to formulate.

WO 2004/009080 IICT/NZ2003/000157 00

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Previous attempts included the formulation of a double active formulation including levamisole and niclosamide. This was designed to target tapeworm and roundworm. This formulation however, was unsatisfactory as exposure to water made it too viscous to use.

Further it was found the differing pH requirements of levamisole and other anthelmintics made it difficult to formulate a stable product.

NZ 336139 represents a recent attempt to formulate a combination avermectin/milbemycin 0 and levamisole product.

To achieve co-existance within the formulation Nufarm relies on emulsion technology. The emulsion includes formulation including the levamisole in aqueous acidic phase and including an anthelmintic such as an avermectin or milbemycin in the lipophilic phase. A third active can be suspended in particulate form in the aqueous phase.

The disadvantage of this formulation is the need for the formulation to be shaken or agitated into an emulsion. In addition, the product is chemically complicated including 2 or 3 different phases.

The complicated nature of the formulation in NZ 336139 is due in part to the different formulation requirements of the actives. Avermectins and milbemycins being substantially insoluble in water whereas levamisole is water soluble. In addition, levamisole has previously been found to require a pH of less than about 4 for stability while avermectins and milbemycin require a pH of about 6.6.

As this will be appreciated, in addition to the stability issues topical formulations have a formulation to be acceptable for topical use it must not cause excessive skin irritation.

Accordingly, there is a need for a stable, formulation capable of stably including avermectins or milbemycins together with levamisole.

In addition, it is desirable the formulation be suitable for topical use.

WO 2004/009080 PCI'NZ2003/000157 00 4

OBJECT

It is an object of the present invention to provide a stable anthelmintic formulation or one that will at least provide the public with a useful choice.

STATEMENT OF INVENTION 00 In one aspect the invention relates to a stable formulation suitable for administration to Sanimals including at least 2 actives wherein a first of the actives is selected from the group including the avermectins and the milbemycins and the second of said actives is levamisole, said actives being dissolved in a pyrrolidone solvent.

Preferrably the formulation may additionally include a co-solvent selected from the glycol ether group.

Preferably the avermectin or milbemycin is selected from the group including abamectin, doramectin, eprinomectin, ivermectin and moxidectin.

Preferably the pyrrolidone solvent is N-methyl pyrrolidone or 2-pyrrolidone.

More preferably the avermectin or milbemycin is present in the range of between 0.01 w/v.

Preferably levamisole is present in the range of between I 30% w/v.

Preferably the formulation additionally includes at least one further medicament selected from the group comprising anthelmintics, dietary supplements, vitamins, mineral and other h.enefi.ial anents.

More preferably wherein the formulation additionally includes excipients including preservatives, stabilisers, flavorants, co solvents.

Preferably the formulation is suitable for topical, injectable or oral administration.

More preferably the formulation is suitable for topical administration.

WO 2004/009080 PCT/NZ2003/000157 00 More preferably the formulation does not cause unacceptable levels of skin irritancy when applied topically.

In a further related aspect the invention relates to a method of treating or preventing infection of cattle with Cooperia or Ostertagia by administering a formulation of the present invention.

The formulations of the present invention must be stable to be of commercial use. In this

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I specification, a commercially acceptable anthelmintic formulation is one which is stable at 00 room temperature for a period of at least 6 months. In conditions of accelerated testing, at ,I 40 0 C, this requires the potency of the actives within the formulation to remain within specified and acceptable limits for 3 months.

Avermectins and milbemycins where used in this specification refer to a group of actives having anthelmintic activity. The avermectin group includes by way of example, avermectin, ivermectin, doramection and eprinomectin. The milbemycin group includes moxidectin.

Pyrrolidones solvents useable in this invention include, N-methyl-2-pyrrolidone, 2pyrrolidone, 1-pyrrolidone, N-ethylene-2-pyrrolidone, 3, 3-dimethyl-2-pyrrolidone, N-ethyl- 2-pyrrolidone, 5-dimethyl-2-pyrrolidone, N-ethoxy-2-pyrrolidone, and combinations thereof.

Levamisole is used in this specification includes levamisole base, levamisole phosphate together with other salts and forms.

The invention the subject of the present application is advantageous as it provides stable formulations including an avermectin or milbemycin in combination with levamisole.

Further, the formulations retain each active in solution.

i e formuiations are monophosic and suitable to manufacture on a t;nululial iuua. u addition, as both actives are in solution the formulations are physically stable. in that it does not separate out into separate phases either aqueous and lipophilic phases or liquid and solid phases. This enables the formulations the subject of this application to ne used without requiring agitation or shaking before use and greatly reduces the risk of differing concentrations of actives through the drum or other storage container.

PCT/INZ2003/000157 WO 2004/009080

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0 6 5 In addition, as the formulation excludes water the issue of incompatible pH requirements is alleviated. Enabling the two actives to stability co-exist in a single phase.

DESCRIPTION

A large number of studies were undertaken over a 4 year period to develop a stable anthelmintic formulation combining levamisole and avermectin/milbemycin. In these studies abamectin was used as the representative avermectin/milbemycin active, whilst levamisole, in its base form, was used as the representative levamisole/morantel active.

Study 1 A number of potential formulations were prepared using a soya bean oil base and common excipients used in the preparation of topical anthelmintics.

Formulation 1 Materials %w/v Abamectin 1 Levamisole 20 Benzyl alcohol 5 Capmul PG-8 20 Isopropyl Palmitate 10 Tween 80 2 Soya bean oil q.v.

Formulation 3 Materials %w/w Abamectin

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Benzyl alcohol 5 Capmul PG-8 20 Isopropyl Palmitate 10 Tween 80 2 Soya bean oil q.v.

Formulation 2 Materials %w/v Abarnectin 1 Levamisole Benzyl alcohol Capmul PG-8 Isopropyl Myristate Tween 80 2 Soya bean oil q.v.

Formulation 4 Materials %w/w Abamectin 1 Levamisole Benzyl alcohol Capmul PG-8 lsopropyl Myristate Soya bean oil q.v.

None of these formulations were stable when tested under conditions of elevated temperature. All formulations exhibited significant degradation of the abamectin component.

Animal studies also demonstrated an unexpected degree of skin irritancy with hair loss at the point of application. These results indicated that an oil-base to the product may be unsuitable both from an irritancy and stability perspective.

WO 2004/009080) PCT/NZ2003/000I 57 Study 2 A number of formulations were prepared using propylene glycol and glycol ethers, both common excipients used in veterinary drug formulation. These were then subjected to conditions of elevated temperature to determine their potential shelf stability. As a positive control for stability testing purposes a commercially available avermectin/milbemycin product, IvomecQ Plus Injection was used.

Formulations R.27 R28 R.29 Ivomec® LeviporO IvoinecO Plus injection Lev.base 20.0 g 20.0 g 20.0 g 20.09g- 20.0 g Abamectin 1.0 g I.0g l.0g L.og Ivermectin 0.5 g -3.0 g Propylene Glycol 50g 41 g I50g 41 g Benzy alcohol 1109g 109g BHT 0.2 g 0.2 g O .2g 0.2 g IPA 4 g 4 g *DGMFEF to IlO0mI J lOlmI j lm j lm j *DGME: Diethylene glycol monoethyl ether (Transcuto'' o more details Stabiliy eslt 0Oday I 5d lOd 115d J20d 0 C 160 0 C /600C /600C /600C R26- Lev.base 100 31 1' 92.0%O 80.4% 84.9% 003.251 R27 Lev.base 100% 88.1% 83.6% 83.8% 83.2% 79.9% R28 -Lev.base "100% 85.7% 182.1% 82.7% 79.5% 75.3% W8 1. o O.7 0/U R29 R R 1 0/. 53AMO Is a. J 70 OJ.Z-18 a I.J 572-F 7777,77177 -,FjL: Ivoinec Levipor Ivermectin Le bse 100% 100% 99.9% 82.0% 1 Ivornec iverinectin 0 Plus~ injection]_____ solvent evaporated 100% 197.9% 1 93.1% 1-91.7% 1 95.9% 190.7% in all test formulations at elevated temperatures the abarnectin component degraded significantly over the period of the study. The ivermectin component of the corrunercially PCTI/N Z2003/000157 WO 2004/009080 00 00 available Ivomec®& Plus formulation did not deteriorate to anywhere near the same extent as the abamectin component of the test formulations.

Whist the levamisole component also deteriorated it did so at a much lower rate.

The study Once again demonstrated the difficulty of combiing the two actives and that the presence of levamisole was very problematic in preparing the combination formulation.

Study 3 A further range of formulations were prepared in which benzyl alcohol was used to solubilise the abamectin component of the formulations.

Formulations Ingredients Concentration 029/0 02 Lev.base 20.0 20 Abamectin 1.0U Propylene 41.0 4 Glycol Benzyl 15 Alcohol Isopropyl 4.0 4.4 myristate BHT BRA Diethylene I O0mI glycol monoetliyl ether to Stability results YO, W V) 9/5/1314 9/1 029/2/13H 9/5/11H i: 1 1 29 A H 02 T T

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.0 1) D.0 LU X .0 41.0 41.0 41.0 41.0 0 15.0 15.0 15.0 15.0 O-ml 4.0 0.2 lO0mi 4.0 I O0nd 4.0 0l lO0mI 0 c /60 0

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9V1. -g 90.% /60 0

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8i 8. 1 1 h I I nt /37 0 C /37 0

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029/0 029/ 029/2/B Lev.base 1000K a Ifl~2OL LOAO.

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I ev base 0% 76.3% ~j7~ i 6P VnL IiOAA flS/ 1N HT Lev.base TUUU,70- (7) 1 I) 00 00 WO 2004/009080 1)CTINZ2003/000157 9 I029/381-T TLev.baise T100% [78.1% 70.2% T96.8% 190.8% 1 D- 029/4/BHA Lev.base 100% 82.8% 73.6%/ 32 96.9% 91.7% ND 0295/31A lev.base 100% 85.0% 77.9% 74.5% 100.4% 94.1% ND gum 11 Ivomec®) Iver 1-00%A 98.0% 101.3% [100.3% 100o.3% ND Levior® Lev-bas 1]102.0% 1 102.9% 1100.9% 104.5% 94.-91/-.N In the stability study the presence of benzyl alcohol did not have any significant effect in minimzingthe rate of degradation of the abarnectin component of the formulations.

BHA

and BHT also did not offer any advantage as stabilizing aids.

Study 4 A study was undertaken to determine whether the use of propylene glycol or glycol ethers would have any advantage in stabilizing the formulations.

Two formulations were prepared these are shown in the table below.

Formulations R 3 R 4 Levamnisole base 20.0 g 20.0 g Abarnectin 1.0 g 1.0 g Propylene glycol 40 ml *DGBEto 100 ni 100 MI *DGBE: Diethylene glycol n-butyl ether (Butylcarbitol"w) Stability results 0 day 5 d/60 0 C 1 d6 0 15 d/60uC 20 d/60 C ev.base 100% 98.2% 104.3% 100.5% R4 Lev.base 100% 10.6% U.i/ 89.3%95% Whifle levamisole base was relatively stable in both formulations the abamnectin degraded in both formulations with the rate of degradation much more significant in the formulation that included propylene glycol. This suggested that propylene glycol was probably not beneficial in enhancing the stability of abamectin when used with DGBE.

rCINZ2003/000157 WO 2004/009080 00 Study A study was undertaken to attempt to improve the stability of formulations that used DGBE as their base.

io Formulations 3-1 3-2 3-3 Aba 1.0Og 1.0Og l.0g Leva.base 20.0 g 20.0 g 20.0 g BHLT 0.2 g [*DGBEto 10 lO1 0 lOml l0mI *DGBE: Diethylene Glycol n-butyl Ether StabijqLt esut 0- days 1 AA/A 94.2% 20days/60"C 96.7% 30days/66uC- 92.8% 1 0 1 1 .J

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~T~i nno/. 96.KU/O V /.Y/0 7 1 IF /U .L .A V 7 E I r! r. /U 3-3

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.J~xv~u77T7 The study demonstrated that both BHT and BHA bad no significant effect on enhancing the stability of the abamectin component of the formulation.

Study 6 Alternate formulations that used benzoic acid and/or BHT were prepared to evaluate their effects on the stability of DGBE based formulations.

Formulations BWenzoic *DGBE to 10 lO100 lnI *DGBE: Diethylene Glycol n-butyl Ether PCT/NZ2003/0001 57 WO 2004/009080 00

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c1 5 Stability results _R2 Lev.base 100% 99.4% 98.7% 986 79 9.% 00 Lev.base 100% 99.6% 99.1% 98.4% 99.2% 98.9% 99.5% TFhe stability of Abamectin showed no improvement with the use of benzoic acid or BHT.

Study 7 A selection of new formulations that included other excipients with DOBE were prepared.

Formulations R3 R4 R5 R6 Lev.base 20.Og 15.Og 2.g20.Og Lev.HCI -5g- Aba Log 1,Og L.og L.og P-CD 0,5g Benzoic acid 5.Og Citric acid 3 .Og Propylene 40m1 40m1 l- Glycerin 30m1 30m1 l- Formal Capmul to 1lOm n !ito 100m] 12, to l it Om DGBE Dityeegyo -butyl ether WO 200410D9080 PCT/NZ2003/OO1 57 00 00 EDTA .1 0.01 0.0 1 0.01 0.01 _g g g EDTA- 0.01 2Na g BHT 2.Og 2.Og 2.Og 2.Og BHA 2.Og 2.Og Benzoic 5.Og acid__ DGMEE to to to to TO to to to 100 100 100 100 100 100 100 100 ml _ml ml ml ml rid ml ml DGBE to I~ I- 4 i I I DPM 1 to r- 100 LT~hla ine ED A:EtmleeimnetactCai;BTBtyteHyrx TEA: Triey ,ie Ff-Eiyendaieeractcai;BT uyae yrx Tolueue; BHA: Butylated Hydroxyanisole; DGME: Diethylene glycol monoethyl ether; DGBE: Diethylene glycol n-butyl ether; DPM: Dipropylene glycol methyl ether Stabilit R3 R4 R6 R7

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R12 ,y results Lev.base 20days/60~C 0 0daj 1 OdaysI6 0

C

99-5%

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100.9% 30days/60"C 100.9% 6 wwd -77 1 7o11-M 0 997%U7 -7w."u Lev.base 100% 98.9%- 69.5%524 Lev.base 100% 101.1% 100.6% 100.4%/ Lev.base 100% 99.9% 100.1% 110 T .ev.hq.-,e M 101.4% 1100.2% 98.8% Lev.base 100% =94.0% ;9=9.3%117 Lev.base 100% 101.70% 99.2%_ 98.3% SLev.base 100% 106.9% 100.1% 97.8% LMev.base 100% 97.0% 98.8% 101 M S WO 2004/009080 WO 204/09080PCTI/NZ2003/0001.57 00 R13 Lev.base I100% 94.9% 99.8% 99.8% R14 Lev.base 100% 64.5% 89.4% 70.6% Lev.base 100% 79.7% 96.0% 82.9% None of the formulations showed great promise in stabilizing the abarnectin component of the formulations.

Study 8 A selection of new formulations that included other excipients with DGMEE were prepared.

Formulations Fl F2 F3 F4 F5 F6 F7 F8 Lev.base 20.Og 20.Og 20.Og 20.Og 20.Og 20.Og 20.Og Abamnectin L.og L.og Log L.og L.og L.og Log Log TEA L-1Oml 1.0mI] 1.0m] Ll~m EDTA O- .01g 0.olg H120 log l Og log log BHT 2.Og 2.Og BHA Benzoic, 5.0g 5.Og 5.Og 5.Og Acid UMEE to 10OmmI lO0mI 100m]IlOI lOm lOmI lO-MI-r lO~i TEA: Triethylarninc; EDTA: Et-yl.idi;--inet -traace-tic acid; BHT: Butd'ated Hydroxy, Toluene; BHA: Butylated Hydroxyanisole; DGMEE: Diethylene glycol monoethyl ether Stability results day 10 days/60 0 C 20 days/60'C 30ds60"iC Fl Lev.base 100% 99.6% 78.3% 63.8% ,Aba. 100% AT1 F2 Lev .base, 100% 100.3% 100.3% 104 Aba 700%t

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F 3 Lev.base 100% 99.7% 99.9% 87.7% F4 Lev.base 100% 34.4% 9.2% Lev.base -100% 100.2% 97.2% 47.7% F6 Le~ae 100% 49%40.1% 34.5% 717i:-00 WO 2004/009080 PCTJ'NZ2003/OO0i 57 14 100% 1100.1% 199.0% 126 00 -F7 F8 I p', Iii 0:9< Jw~zzJ'LriTiI7 Lev .base Once again none of the formulations showed great promise in stabilizing the abamectin component of the formulations.

Study 9 Further alternate formulations were prepared according to table below.

Formulations Le~base 2_0g 2 _0g 20.Og 20.Og 20.Og 20.0 g Abamectin 1.Og 1T.Og L.og L.og L.og Log Benzoic 5.-Og 5.Ogb- 5.Og 1O.Og Acid Aceticai*-- .m 4.Oml BRA 2.Og DGMEEtO F0lO I DGBE to IIOmI lO~mI lio-omi lOT-0Ml lO0mi BHA: Butylated Hydroxyanisole; DGMEE: Diethylene glycol monoethyl ether;, DGBE: Dithylene glycol n-butyl ether Stability results 0 day 10 days/60 C 20 days/60"C 30 d iys

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R2 R4 R6 -Lev7b-ase 100% 105.8% 85.5% 79.4%Y Lev.base 100% 98.9% 73.9% 68.4% Lev.bae 1 .00% 5%73.5% 6.% Ieo base 10%0- 69.0% Lev.base 100% _100.0% 100.4% Lev.base 100% 99.8% 99.6%.3 fnr However none of these demnonstrated great promise in stabilizing the abamectin component of the formulations.

00 WO 2004/009080 Is Study Example formulations were prepared according to the table below.

Formulations PCT/NZ2003/000t57 R2 R3 R4 Lev.base 20.0 g 20.0 g 20.0 g 20.0 g 20.0 g Abamnectin 1.0g 1.0Og 1.0Og l.Og l.0g Acetic acid 2.0Oml 4.0Oml 6.0 nmI0. lO nI *DGBE to 10lO1 mlO10 nlOm lO0MI l00 MI *DGBE: Diethylene glycol n-butyl ether Stability results 0 day 10 days/60'C 20 days/60'C 30 RI Lev.base 100% 99% 97% 96% R2 Lev.base 100% 82%6750 R3 Lev.base- 100% 78%604% R4 Lev.base 100% 52%23

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Lev.base 100% 55% 4o19 Formulations containing accti~c acid did not improve the sta-b.iity, of abamectin. Howe-ver, the stability of Jevamnisole base was adversely affected to a significant extent.

Study 11 A trial was carried out to determine whether the addition of varying levels of N-Methyl-2- Pyrollidone (Pharmasolv) to DGBE would enhance stability. All the formulations were kept at 60'C and were analysed to assess the extent of degradation after 7, 14 and 30 days.

Formulations G2 G3 G4 Lev.base 20.0% w.v. 20.0% w/v 20.0% w/v 20.0% w/v 20.0% w/v Abamectin 1. 15% w/v 1.15% w/v 1. 15% w/v 1. 15% w/v 1. 15% w/v DGBE 25% w/v 40% w/v q/v. q.v.

N-Methyl-2- q.v. q.v q.v Pyroll idone WO 2004/009080 WO 204/09080PCT/NZ2003/000157 Stability Results Form. Initial 7 days at 60TC 14 days at6 0 T I month at 600 Abarnecti Levamnisole Abainectin Levamisole Abamnectin Levamnisole Abamnectin Lvmsl n GI 96.12 To.43 93.04 -95.5 89.57 89.75 79.13 69 G2 100.24 103.22 95.65 9.0 95.65 9637919.0 GF3 10.3 12.8 3.91 97.00 87.83 95.20 66.96 92.85 G4 109.05 101.70 101.74 9-§9.95 93.91 99.35 66.57 93.80 89.42 100.32 83.48 97.80 80.00 93.30 57.39 89.55 I0 The stability results of the solution containing both the actives in Pharmasolv demonstrated that surprisingly a pyrollidone based formulation was capable of significantly slowing the rate of degradation of both levarnisole and abamectin.

To further confirm the findings of this study new batches were prepared with the formulation as specified in the following table: Material Formulation Lev .base 20.0% w/v Abamectin 1. 15% w/v DGBE 25% wlv N-Methyl-2-Pyrollidone q.v Stability results over a twelve month period of storage at 25 0 C confirmed the increased stability of an abamectin/levamisole formulation containing N-Methyl-2-Pyrollidone (Pharmasolv) and DGBE.

ACTIVE Initial 6 Month 12 Months Abamectin 104.00 102.55 99.95 Levamisole 99.75 99.00 98.55 WO 2004/009080 PC'F/NZ2003/000157 17 Field Studies The formulation of the table above containing DGBE and 1'fmethyl-2- pyrollidone was used in a slaughter study to evaluate the effectiveness of the formulation relative to formulations containing either levarnisole or an avermectin or milbemycin. The results clearly demonstrated that whilst the levamnisole-based formulation (Levipor®) performed poorly against Ostertagia and the eprinomectin-based formulation (Eprinex®) performed poorly against Cooperia, the abamnectin/levamisole combination showed outstanding efficacy against all parasite species.

A large number of field studies on cattle of all ages have also confirmed that in contrast with a number of the other test formulations there is no skin irritation on treated animals.

Table 1: Geometric mean total worm counts for calves treated with Abarnectin levamisole pour-on, Eprinex®O pour-on or Levipor®D pour-on in cornparision with an untreated control group.

Oslertagia (ad ulIt) 1 1435.5a. 4.40 17.3- 5808. 1' Ostertagia (imnmature) 12742 .3 1317.4" Taxei (immature) 4.7" 0n 0'k J.92 Tichosirongylus spp 74.267b46.48 (mature) 2155.8___5__b Cooperia (adult) 15948.8a 5i7 2155.8b Cooperia (immature) 1598.7a Qesophagosionium (mnature) 2.5" 0n jn 0n Trichuris '-means within the same row with different superscripts are significantly different at p<0.05 A a iv A. ikv a ii ,I A L lka U 0%U VJ I r,%LUJ 6.Ahi1% L L1 AA car ~A V V UVA A A %%AJ ILO.

Ostertagia (adult) >99.9% 99.8%492 Osiertagia (immature) 99.8% >99.9% 0% T axei (adult) >99.9% >99.9% 80.1% Taxei (immature) >99.9% >99.9% >99.9% Trichosirongylzis spp 99%93.7% 99.3% (mature) SCooperia (adult) >99.9% 86.5% >99.9% .1 WO 2004/009080 PCI'[NZ2003/0001.57 18 00 0 Cooperia (immnature) 99.8% 99.6% 99.9% Oesophagostomwn (mature) >99.9% >99.9% >99.9% Trichuris (mature) >99.9% >99.9% >99.9% PREFERRED EMBODIMENTS In the preferred embodiments the formulations of the invention there include avermectin or 10 milbemycin in combination with levamisole and a pyrrolidone solvent. A glycol ether may 00 additionally be included.

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The following examples are provided as examples only and are in no way intended to limit the spirit or scope of the invention.

Example Formulations The formulations of the present invention are prepared as follows: 1. Add levamisole base, avermectin/milbemycin and pyrollidone to a mixing vessel.

2. Stir at room temperature until the actives have completely dissolved.

3. Add the glycol ether, if desired, and mix well.

4. Add the pyrolidone to volume and continue mixing until a clear solution is obtained.

Topical Formulations 1. Examples of topically applied formulations of the invention include: Formulation 1.1 I: 1.I Abamectin 1% Levamisole Base n-methyl pyrrolidone q.v.

Formulation 1.2 Ingredient w/v -Ivermectin Levamisole Base WO 2004/009080 WO 2004/0908INZ2003/000157 00 In-methyl pyrrolidone qv Formulation 1.3 Levamnisole Base n-ehy yrrolidone -q.v.

Formulation 1.4 Ingredient w/v Eprinornectin Levamnisole Base DGMBE n-methyl pyrrolidone q.v.

2. Examples of Injectable formulations include: Formulation 2.1 Ingredient W/v Ivermectin Levamisole Phosphate 2- pyrrolidone q.v.

Formulation 2.2 Ingredient w/v Moxidectin Levamisole Phosphiate 2 pyrrolidone q.v.

3. Examples of Orally administered formulations include: Formulation 3.1 IAbamnectin 0.1% Levamisole Base n-methyl pyrrolidone ~q.v.

Formulation 3.2 WO 2004/009080 WO 204/09080PCT/NZ2003/000157 00 00 n-mthl yrrolidoiie Tq.v.

Formulation 3.3 Ingredient %/0Wv Abamnecti n 1% Levainisole Base n-methyl pyrrolidone q.v.

Formulation 3.4 Ingredient w/v Abamnectin 1% Levamisole Base n-methyl pyrrolidone q.v.

Formulation Ingredient W/v Abamectin 1% Levamisole Base n-methyl pyrrolidorie q.v.

The rates for these formulations are generally in the order of Im to 5kg to ImI per 20kg for oral administration, I ml per 25 Ikg or I ml per 50kg for administration by injection, and I mi per 10Okg or 1 ml per 20kg for topical administration.

The methods of administration of the formulations are well known within the art.

Claims (8)

1. A stable formulation suitable for administration to animals including at least one active selected from the group comprising avermectins and milbemycins and levamisole and both of said actives being dissolved in a pyrrolidone solvent.

2. A stable formulation suitable for administration to animals as claimed in claim 1, additionally including a solvent selected from the glycol ethers. 00 S3. A stable formulation suitable for administration to animals as claimed in any previous CN claim, wherein the pyrrolidone solvent is 2-pyrrolidone or N-methyl pyrrolidone.

4. A stable formulation suitable for administration to animals as claimed in any previous claim, wherein the avermectin or milbemycin is present in the range of between 0.01 w/v. A stable formulation suitable for administration to animals as claimed in .claim 4, wherein the avermection or milbemycin is selected from the group comprising abamectin, doramectin, eprinomectin, ivermectin and moxidectin.

6. A stable formulation suitable for administration to animals as claimed in any previous claim, wherein the levamisole is present in the range of between 1 30% w/v.

7. A stable formulation suitable administration to animals as claimed in any previous claim, wherein the formulation additionally includes at least one further medicament selected from the group comprising anthelmintics, dietary supplements, vitamins, mineral and other beneficial agents.

8. A stable formulation suitable for administration to animals as claimed in any previous claim, wherein the formulation is suitable for topical administration.

9. A stable formulation suitable for administration to animals as claimed in any of claims I to 8, wherein the formulation is suitable for parenteral administration.

10. A stable formulation suitable for administration to animals as claimed in any of claims 1 to 8, wherein the formulation is suitable for oral administration. WO 2004/009080 PCTJNZ2003/O0157 22 00 S11. A method of treating or preventing infection of cattle with Cooperia or Oslertagia by administering a formulation as claimed in any of claims 1 00