AU3506801A - Pour-on formulations containing polymeric material, glycols and glycerides - Google Patents

Description

S&F Ref: 315424D2

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant Actual Inventor(s): Address for Service: Invention Title: Merck Co., Inc.

126 East Lincoln Avenue Rahway New Jersey 07065 United States of America Hoo-Kyun Choi and James B. Williams Spruson Ferguson St Martins Tower,Level 31 Market Street Sydney NSW 2000 Pour-on Formulations Containing Polymeric Material, Glycols and Glycerides The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5845c -1- TITLE OF THE INVENTION POUR-ON FORMULATIONS CONTAINING POLYMERIC MATERIAL, GLYCOLS AND GLYCERIDES BACKGROUND OF THE INVENTION The avermectin series of compounds are potent anthelmintic and antiparasitic agents against internal and external parasites. The natural product avermectins are disclosed in U.S.

4,310,519 to Albers-Schonberg et al., and the 22,23-dihydroavermectin 1" compounds are disclosed in Chabala et al., U.S. 4,199,569.

Administration of the avermectin compounds occur orally, parenterally or topically.

SHowever, the conventional topical formulations do not provide acceptable efficacy against ectoparasites, especially against Chorioptes, fleas and ticks. Often times these formulations fail due to the lack of extended efficacy. The animals are readily reinfested by fleas, ticks and the like after treatment with the above-noted formulations simply by returning to a flea infested environment.

Further, topical formulations of currently available medicinal agents have not demonstrated efficacy against endoparasites, such as 20 heartworms and nematodes.

It is known in the pet care industry that sustained release of an insecticide is obtained by incorporation of the insecticide into a polymeric system. However, conventional polymer based formulations rely on the vaporization of the active compounds, which means this type of system may not be used for non-evaporable drugs. See U.S. Pat.

Nos. 3,852,416 and 4,172,904. Additionally, conventional formulations of current medicinal agents require a withdrawal period of a few weeks after application of the active compound before any milk can be withdrawn from dairy animals for human consumption.

SUMMARY OF THE INVENTION This invention is concerned with avermectin topical pouron formulations which effectively eliminate both ectoparasites, -2especially Chorioptes, fleas and ticks, and endoparasites, especially heartworms and nematodes, of animals such as cattle, swine, etc for an extended period up to a full four weeks, particularly household pets such as cats and dogs.. The instant formulations also unexpectedly provides a zero milk withdrawal time for topically applied antiparasitic agents with regard to dairy animals. The formulations are prepared using solvents such as water, alcohols such as ethanol, methanol, isopropanol and the like, propylene glycol esters, glycerides, or their derivatives as the carrier.

The formulations can contain in addition to the active 10 avermectin ingredient and solvent, a polymer such as polyvinylpyrrolidone. The drug is bound to the skin with the aid of the polymer which remains on the skin surface after the solvents have evaporated following application. Thus it is an object of this invention to describe such ectoparasitic and endoparasitic efficacy. Another 15 object is to describe the avermectin compounds which may be employed in the formulation. A still further object is to describe how the concentration of the active compound in the milk of dairy animals is maintained below a concentration level that provides for a zero 0 withdrawal period for human consumption. A still further object is to 20 describe how extended efficacy against ticks, fleas and heartworms is obtained. Additional objects will become apparent after a reading of the following description.

DESCRIPTION OF THE INVENTION This invention consists of a topical formulation of a glyceride, glycol, or a derivative thereof and an avermectin compound which has been found to effectively eliminate both ectoparasites and endoparasites.The formulation can optionally contain in addition to the glyceride, glycol or derivative thereof and avermectin, an antioxidant such as BHA, BHT and the like, additives such as Crodamol CAP, glycerol formal, Tween 80 and the like, a solvent mixture of water and/or solvents with relative high vapor pressure such as ethanol, methanol, isopropanol and the like, and a polymeric material such as polyvinyl pyrrolidone, polyvinyl alcohol and the like.

Accordingly, a first aspect of the present invention provides a topical pour-on formulation for the treatment of ectoparasites and endoparasites, which provides a zero milk withdrawal time in dairy animals, consisting of from about 40 to about 100% v/v of a glyceride carrier or derivative thereof selected from the group consisting of propylene dicaprylate/dicaprate, caprylic/capric triglycerides, an antioxidant of about 0.005 to 1.0% w/v and from 0.005 to 10% w/v of an avermectin compound having the formula: R1 CH3 22 /CH2R7 4 2 H3C O 7

*OH

0 5* CH3 R3 .where the broken line indicates a single or a double bond at the 22,23-positions;

R

1 is hydrogen or hydroxy provided that R1 is present only when the broken line indicates a single bond;

*R

2 is alkyl of from 1 to 6 carbon atoms or alkenyl of from 3 to 6 carbon atoms is or cycloalkyl of from 3 to 6 carbon atoms;

R

3 is hydroxy, methoxy or =NOR 5 where R 5 is hydrogen or lower alkyl;

R

7 is hydrogen, hydroxy or lower alkyl; and

R

4 is hydrogen, hydroxy, C(1-6) polyalkoxy or

OCH

3

H

3

C

where R 6 is hydroxy, amino, mono- or di-C 1

-C

6 alkylamino or C1-C 6 alkanoylamino.

A second aspect of the present invention provides a process for the preparation of a formulation of the first aspect of the present invention which comprises a process for the preparation of a formulation of the first aspect of the present invention, which comprises dissolving from about 0.005 to from about w/v of the avermectin compound of claim 1 in about 40% to about 50% v/v of the total volume of the glyceride carrier and adding as a final volume, the remainder of the carrier.

A third aspect of the present invention provides a topical formulation for direct application to the skin of an animal, effective for treatment and prevention of ectoparasites and endoparasitic infestations for four weeks, consisting of from about 0.01 to about 20% w/v of a polymeric material, belonging to the group consisting of polyvinyl pyrrolidone having a molecular weight of about 20,000 to about 65,000, from about 1 to from about 95% v/v of ethanol, 100% v/v obtained with addition of water, and from about 0.05 to from about 10% w/v of an avermectin 15 compound having the formula:

R

CH3 22 CH2R7 R2 C O

OH

CH3 R3 where the broken line indicates a single or a double bond at the 22,23-positions;

R

1 is hydrogen or hydroxy, provided that R 1 is present only when the broken line indicates a single bond;

R

2 is alkyl of from 1 to 6 carbon atoms or alkenyl of from 3 to 6 carbon atoms or cycloalkyl of from 3 to 6 carbon atoms;

R

3 is hydroxy, methoxy, or =NOR 5 where R 5 is hydrogen or lower alkyl;

R

7 is hydrogen, hydroxy or lower alkyl; and

R

4 is hydrogen, hydroxy, poly C( 1 6 alkoxy, or where R 6 is hydroxy, amino, mono- or di-C1-C 6 alkylamino or Cl-C6 alkanoylamino.

A fourth aspect of the present invention provides a process for the preparation of a formulation of the third aspect of the present invention which comprises dissolving from about 0.005 to about 10% w/v of the avermectin compound of claim 1 in from about 1 to about 95% v/v of ethanol to form a clear solution, adding and dissolving from about 0.005 to 1.0% w/v of the anti-oxidant and from about 0.01 to about 20% w/v of the polymeric material in the solution, adding up to 50% v/v of the additive, adjusting the volume to 100% by addition of water and mixing until the 10 solution is homogeneous.

A fifth aspect of the present invention provides the use of the formulations of the first and third aspects of the present invention for the treatment or control of ectoparasites and endoparasites in animals.

The avermectin compounds used in the instant formulations have the 15 following general structure: 1R CH3 22 /CH2R7 R 4 0 2 S R2 H3C

I

1 O H 0

CH

R3 where the broken line indicates a single or a double bond at the 22,23-positions;

R

1 is hydrogen or hydroxy provided that R 1 is present only when the broken line indicates a single bond;

R

2 is alkyl of from 1 to 6 carbon atoms or alkenyl of from 3 to 6 carbon atoms or cycloalkyl of from 3 to 8 carbon atoms;

R

3 is hydroxy, methoxy or =NOR 5 where R 5 is hydrogen or lower alkyl;

R

7 is hydrogen, hydroxy or lower alkyl; and

R

4 is hydrogen, hydroxy, C(16) polyalkoxy or

CH

3 O CH 3

O

0 0

OH

3

OH

3

S.

S

S S

S

S. 55 S S

S

555555

S

S

5555

S

SS

S. S S -4where R 6 is hydroxy, amino, mono-or di-C] to C6 alkylamino or C1 to C6 alkanoylamino.

The term "loweralkyl" when used in the instant application is intended to represent those alkyl groups either straight or branched chain which have from 1-5 carbon atoms. Examples of such alkyl groups are methyl, ethyl, propyl, iso-propyl, butyl, sec-butyl, pentyl, and the like.

ly* The term "loweralkanoyl" is intended to include those alkanoyl groups containing from one to five carbon atoms in either a 10 straight or branched chain. Examples of such alkanoyl groups are formyl, acetyl, propenyl, butyryl, valeryl, and the like.

The term "halogen" is intended to include those halogen atoms fluorine, chlorine, bromine and iodine.

The term "polyalkoxy" is intended to include 15 methoxymethoxy, 2-methoxyethoxy, (2-methoxyethoxy)-methoxy, [2- (2-methoxyethoxy)ethoxy]methoxy; and the like.

A related family of natural products also useful in the present invention is known as the milbemycins. The milbemycins have Sthe same macrocyclic ring structures as the avermectins but have no substitution at position 13 (R4 hydrogen) and have a methyl or ethyl group at position 25 (R 2 methyl or ethyl rather than isopropyl or secbutyl as in the avermectins). The milbemycins and the fermentation conditions used to prepare them are described in U.S. Pat. No.

2 3,950,360. Closely related 13-deoxyavermectin aglycones are prepared by chemical modification of the natural avermectins and have been described in U.S. Pat. No. 4,173,571.

One preferred embodiment (El) of this invention consists of a topical pour-on formulation of a gylceride, glycol, or a derivative thereof as a carrier and an avermectin compound which has been found to effectively eliminate both ectoparasites, especially Chorioptes, and endoparasites, while simultaneously maintaining the concentration of the active compound in the milk of dairy animals below an adequate concentration period for human consumption to provide a zero milk withdrawal time for topically applied endectocides milk concentration of 4"-acetylamino-4"-deoxyavermectin BI (L-653,648) for zero milk withdrawal is 48 ng/ml] The carriers are oleyl alcohol, propylene glycol and its esters such as propylene dicaprylate/dicaprate, propylene glycol laurate, and the like, glycol ethers such as diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol diethyl ether and the like, and glycerides such as PEG-6 caprylic/capric triglyceride, caprylic/capric diglyceryl succinate, polyglycolysed glycerides, and the o like, preferrably propylene caprylate/caprate or caprylate caprate Sglyceride, and is available under such brand names as Miglyol 810, 812, 818, 829 and 840, Softigen and Labrasol®. The in propylene So dicaprylate/dicaprate and PEG-6 caprylic/capric triglycerides indicates a mixture of the two components in a ratio of 65-80/15-30.

The above carriers impart to the formulation good penetration and spreadability of the active compound even at cold temperatures.

The preferred avermectin compounds of El have the following structural formula:

R

R

1

CH

3 0

CH

3 22 CH 2

R

7

R

6 0 0 0 2 0 0 0 R 2

CH

3 CH 3

CH

3

IOH

O -CH 3

OH

wherein the broken line represents a single bond; R 1 is hydrogen; R 2 is isopropyl of sec-butyl; R 6 is hydroxy, amino, mono-or di-C1 to C6 -6alkyl-amino or Ci to C6 alkanoylamino; and R 7 is hydrogen, hydroxy, or loweralkyl.

Examples of preferred compounds of the instant El formulation are: 4"-keto avermectin BI; 4"-keto avermectin B2; 4"-keto-22,23-dihydro averiectin Bi; 4"-keto-22,23-dihydro averrnectin B2; 4" -deoxy-4 %amino avermectin BI; 4" -deoxy -amino avermr-ectin B2; 4"-deoxy-4"-amino-22,23 -dihydro avermectin B 1; 4"-deoxy-4'"-amino-22,23 -dihydro avermnectin B2; 4" -deoxy-4 -acetyl amino avermectin Bi; 4"-deoxy-4"-acetylamino avermectin B2; *4"-dox-"-acetylamino-22,23 -dihydro avermectin BI; 4" -deoxy-4"-acetylamino-22,23-dihydro avermectin B2; 4"-deoxy-4"-dimethylamino avermectin BI; 4"-deoxy-4"-dimethylamino avermectin B2; 4"-deoxy-4" -dimethylamino-22,23-dihydro avermectin B 1; 4"-deoxy-4"-dimethylamino-22,23-dihydro avermectin B2; 4 "-deoxy-4"-p-chloro benzenesulfonylamino-22,23-dihydro avermectin Bi; 4"-deoxy-4"-p-chloro benzenesulfonylamino-22,23-dihydro avermectin B2; 4" -deoxy-4 "-(2-methylbenzenesulfonylamino)avermectin BI; 4 "-deoxy- 4 "-(2-methylbenzenesulfonylwmino)avermectin B2.

The compounds, those with a 25-iso-propyl, group, are not necessarily separated from the corresponding compound with a group and the compounds are generally isolated as -7mixtures of the two compounds, consisting of at least 80% of the secbutyl compound and no more than 20% of the iso-propyl compound.

Thus references in the instant application to compounds such as Bla, Ala, and the like, are construed to actually contain a certain proportion of the corresponding compound. Alternatively, this representation of a mixture is sometimes done by referring to the BI or B2 compounds or by separating the compound from the compound by a slash such as Bla/Blb, B2a/B2b and the like. Additionally, the products of synthetic procedures such as racemization or epimerization, procedures known to those skilled in the art, can be a mixture of stereoisomers. In 10 particular, the stereoisomers at the 13- and 23-positions may be oriented either ao- or 3- representing such groups being below or above the general plane of the molecule, respectively. In each case, and at other positions in the molecule, both the ca- and P- configurations are intended to be included within the ambit of this invention.

15 In the topical forms of the avermectin formulation it has not been possible to provide a formulation which provides an acceptable efficacy against ectoparasites, especially Chorioptes.

S. Additionally, currently available topical formulations do not provide a zero milk withdrawal time with the application of endectocides which thus precludes the use of such compounds on milk producing animals.

S. El of the instant invention gives the advantages of a pouron topical formulation which provides the animal with effective treatment and protection against endoparasites and ectoparasites, especially Chorioptes and at the same time maintains the concentration of the active compound in the milk of dairy animals below a safe concentration for human consumption. Additional advantages of this invention are that the formulation is non-flammable, it is not readily washable by rain, it has good spreadability and cold temperature usage and has good compatibility with currently available dosing devices.

El can contain the avermectin compound and the glycol or glyceride carrier as the only ingredients. The formulations will generally be prepared to administer a safe and effective amount from 0.005 to 10% by weight of the avermectin component, most preferrably -8from 0.01 to 5% by weight. Most preferably a formulation containing about 0.5% of the avermectin is employed. At a preferred dose volume of about 5 ml to treat 50 kg of animal body weight the formulation contains from about 1.0 to 50 mg of avermectin compound per ml of solution. The glycol or glyceride carrier is added to the formulation from about 40 to 100% The most preferred formulation for El contains in addition to the glycol, glyceride, or derivatives thereof and avermectin compound, an antioxidant such as propyl gallate, BHA (butylated 10 hydroxy anisole), BHT (butylated hydroxy toluene) monothioglycerol and the like, preferrably BHT. The anti-oxidants are generally added to the formulation at rates of from 0.005 to 1.0% Additives such as Crodamol CAP, glycerol formal, Tween 80 propylene glycol and the

S.

like, preferrably Crodamol CAP, may also be used. The additives are generally added to the formulation at volumes of up to 60% of the volume of glycol or glyceride carrier, preferrably up to 40% of the volume of carrier.

El is prepared by dissolving the avermectin compound in approximately 50-100% of the intended volume of the above mentioned carriers and then adjusting the volume to 100% by the addition of the final volume of the carrier or additive. The anti-oxidant and additive may be combined with the above mentioned carriers prior to mixing the avermectin or added as the final volume of solvent.

The following example is provided in order that the El 2 emobodiment of the invention might be more fully understood. It is not to be construed as a limitation of the invention.

EXAMPLE OF El OF THE INVENTION The formulations of this invention depend upon the particular avermectin compound and treatment. The avermectin is typically dissolved in approximately 50% of the glycol or glyceride carrier.

When dissolved, the antioxidant and/or additive are optionally added and the volume adjusted to 100% with the final volume of glycol or glyceride carrier. The solution is mixed until it becomes homogeneous.

Generally, mixing at room temperature (15-250C) is adequate however, -9 if necessary, warming up to 500C may be helpful. The following are nonlimiting examples of the composition of the present invention, which are conventionally formulated by mixing all components as stated above.

Composition I 4' -acetylamino-4"-deoxyavermectin B 1

BHT

Crodamol CAP 10 Miglyol 840 Composition 11 4 1 -acetylamino-4"-deoxyavermectin B 1

BHT

15 Miglyol 840 Composition III 4" -acetylamnino-4"-deoxyavermectin B I

BHT

Isopropyl Myristate Miglyol 840 Composition I-V 4 '-acetylamino-4"-deoxyavermectin B 1 Triacetin Miglyol 840 0.5 w/v 0.0 1% w/v 10.0 v/v 100.0 v/v 0.5 w/v 0.0 1% w/v 100.0 v/v 0.5 w/v 0.01 w/v 10.0 v/v 100.0 v/v 0.5 w/v 50.0 v/v 100.0 v/v Composition V 4"-acetylamino-4"-deoxyavermectin B 1 Softigen 767 Miglyol 840 Ethanol Composition VI 4"-acetylamino-4"-deoxyavermectin Softigen 767 Isopropanol Composition VII 4"-acetylamino-4"-deoxyavermectin B 1

BHT

Dowanol DB 0.5 w/v 65.0 v/v 25.0 v/v 100.0 v/v 0.5 65.0 100.0 w/v v/v v/v 0.5 w/v 0.01% w/v 100.00% v/v Crodamol CAP is a tradename mixture of isopropyl myristate, cetyl octanoate and stearyl octanoate and Dowanol DB is a tradename for diethylene glycol butyl ether.

El EXAMPLE II The data below are results indicating the avermectin concentration (ng/ml) in the milk of lactating cows after topical application with some of the above formulations and that the avermectin concentration is maintained below 48 ng/ml which is the milk concentration of avermectin required for a zero milk withdrawal.

11 4"-ACETYLAMINO-4"-DEOXYAVERMECTLN B 1 CONCENTRATIONS (nglmL) IN MILK OF LACTATING COWS DOSED TOPICALLY TREATMENT A: MIGLYOL 840/BHT/500 ug/kg ANIMAL 0 1 5950 0.0 1.5 5931 0.0 6.0 5932 0.0 3.4 5938 0.0 5.6 2 3 5.0 6.4 23.2 4.8 15.5 13.0 3.4 9.6 DAY POST DOSE 4 9.5 7.1 3.1 8.5 5 6 7 8.7 8.1 6.3 4.2 2.0 4.5 1.6 3.7

MEAN

STD.

DEV.

0.0 4.1 12.1 8.1 7.1 4.9 4.0 3.6 8.9 4.1 2.8 2.8 2.9 1.9 TREATMENT B: TRIACETIIN/MIGLYOL 840 (50/50)/500 ug/kg ANIMAL DAY POST DOSE DAY POST

DOSE

5946 5949 5929( 5928( 0 1 2 3 4 5 6 1.2 2.9 4.0 5.0 4.7 4.1 2.7 13.3 11.4 8.6 5.3 3.5 1.3 2.8 4.1 5.8 5.7 4.2 4.9 14.6 9.4 5.4 3.1 2.0 7 2.9 2.8 1.4

MEAN

STD.

DEV.

0.0 2.5 8.4 7.2 6.2 1.7 6.4 3.8 1.6 4.7 3.5 1.1 1.0 0.8 -12- TREATMENT C: SOFTIGEN 767/MIGLYOL 840 (70/30)/500 ug/kg ANIMAL DAY POST DOSE 5948 5930 5927 5934 0 0.0 0.0 0.0 0.0 1 1.1 1.4 2.7 1.9 2 4.5 3.8 6.0 4.7 3 6.4 3.9 7.0 10.6 4 6.6 5.8 7.6 15.0 6 5.4 7.6 4.6 4.9 0 0 0

MEAN

10

STD.

DEV.

0.0 1.8 0.7 4.8 7.0 8.8 7.5 5.6 3.9 0.9 3.9 4.2 1.5 1.4 0.7 TREATMENT D: Miglyol/Crodamol CAP (90/10)-500 gg/Kg ANIMAL DAY POST DOSE 0* 0 0000 6384 6385 6379 6386 6377 6382 0 1 0.0 2.1 0.0 7.3 0.0 10.0 0.0 2.7 0.0 5.2 0.0 7.7 2 4.8 7.1 10.6 6.0 9.7 15.5 3 6.8 6.1 7.8 6.0 8.7 11.8 4 7.6 4.8 5.4 5.8 9.8 8.7 7.0 2.0 6 5.4 2.7 1.9 5.4 2.9 3.3 7 3.8 2.3 1.7 5.2 2.3 5MEAN

STD.

DEV.

0.0 5.8 9.0 7.9 3.1 3.9 2.2 4.3 3.6 1.0 1.5 1.3 13 TREATMENT E: Miglyol/Crodamol CAP (90/10)-250 rig/Kg ANIMAL. flAY POST DOSP DAY POST

DOSE.

0 1 6389 0.0 1.2 2 2.7 3 2.8 4 2.6 5 6 7 1.9 1.7 1.4 6381 0.0 1.0 1.6 1.8 2.8 6380 0.0 2.8 5.5 4.4 3.5 6378 0.0 2.4 4.8 4.0 2.9 2.6 1.5 1.1 2.4 2.0 0.0 0.0 1.9 1.9 6376 6388 0.0 0.0 1.8 4.2 4.3 0.0 1.3 1.7 4.3 2.8

MEAN

STD.

DEV.

0.0 1.5 3.4 3.2 3.2 2.2 1.9 1.2 1.0 1.7 1.2 0.6 0.5 0.6 TREATMENT F: TRIACETIN/MIGLYOL 840 (50/50)/500 uglkg ANIMAL DAY POST DOSE 0 1 2 3 '4 5 6 7 5977 0.0 1.4 6.8 6.9 4.3 3.4 3.0 2.2 5976 0.0 2.1 10.8 13.8 5.7 5.6 2.9 1.8 MEAN 0.0 1.8 8.8 10.4 5.0 4.5 3.0 SID. 0.5 2.8 4.9 1.0 1.6 0.0 0.3

DEV.

-14- TREATMENT :G IPA/SOFTIGEN 767 (40/60)/500 ug/kg ANIMAL 5984 5980 5987 5982 0 0.0 0.0 0.0 0.0 1 0.0 0.5 0.0 0.0 DAY POST DOSE 2 3 4 0.0 0.6 0.6 0.8 1.6 1.3 0.5 0.9 3.1 2.0 3.8 3.8 5 6 7 0.7 1.0 1.6 2.9 2.3 2.8 6.3 4.6 3.5 2.2 1.6

MEAN

STD.

DEV.

0.0 0.0 0.8 1.7 2.2 3.4 2.5 2.8 0.0 0.9 1.5 1.5 2.3 1.5 1.6 NOTE: Samples with 4"-acetylamino-4"-deoxyavermectin B1 concentrations equal to or less than 0.4 ng/ml are reported as 0 ng/ml: El EXAMPLE III Efficacy trials with Chorioptes and key endoparasites were conducted to evaluate some of the above formulations. For each trial evaluating Chorioptes, four cattle were infested with Chorioptes bovis on Day -1 and treatment was given on Day 0. Respecting the trials 2 evaluating endoparasites, the animals were challenged with Oesophagostamum, Trichuris and Dictyocaulus 17, 7, and 7 days before treatment with the formulation. The results are below.

15 CHORIOPTES MITE COUNTS An.

Nn Day Day 7 Day 14 Day 21 Day 27 Day

S

-1 Trt. 1 Untreated Control H215 32 3 H208 H229 H233 6 708 511 19 5024 875 15 3 2546 601 a 1430 889a 4 1 147 7 b 1 4 3 2b 0 17 6835 1339 Trt. 2 4"-aa-4" deoxy in Miglyol 840/Crodamol CAP/BHT at 500 mcg/kg H224 H223 H234 H-230 79 0 895 2018 378 1007 265 0 150 Trt. 3 H226 H21 8 H228 H23 1 4"-aa-4" 182 3 1644 233 deoxy in Miglyol 840/BHT at 3 0 1 500 mcg/kg 0 0 0 659 358 0 16 603 0 oa 1 33a a Day b Day 28 4"-aa-4" deoxy 4"-acetylamino-4"-deoxy avermectin B I 16 4"-aa-4" deoxy Nematode Counts Total Counts based on 10% aliquots (Dictyocaulus counts are total counts) Animal Qesophagost Qesophagost Trichuris Dictyocaulus Number spp. Adult spp. L4 spp. Adult spp.

Trt. 1 Untreated Control 2477 0 0 20 3 2374 50 0 0 0 2259 0 0 50 17 41 240 0 80 14 Trt. 2 4"-aa-4" deoxy in Miglyol 840 Crodamol CAPIBHT at 500 mcg/kg 2456 0 0 0 0 152478 0 0 0 0 51500 254 0 0 0 0 Trt. 3 4"-aa-4" deoxy in Miglyol 840 BHT at 500 mcg/kg 2510 0 0 0 0 20 2358 0 0 0 0 40 0 0 0 0 2258 0 0 0 0 Trt. 4 4"-aa-4" deoxy in Miglyol 840/LauroglycollBHT 25(0.5%Iq.s.I10%/0.01%) at 500 mcglkg 252528 0 0 0 0 2443 0 0 0 0 44 0 0 0 0 2298 0 0 0 0 17 Another preferred embodiment (E2) of the instant formulation consists of a topical pour-on formulation of a solvent mixture of water and/or solvents with relative high vapor pressure such as ethanol, methanol, isopropanol, acetone, and the like, most preferrably ethanol, a polymeric material such as polyvinyl pyrrolidone, polyvinyl alcohol, cellulose derivatives such as methyl cellulose, ethyl cellulose, carboxy methyl cellulose, and hydroxyethyl cellulose, and the like, most preferrably polyvinyl pyrrolidone (MW from about 20,000 to 65,000, preferrably about 45,000), skin or hair subtantantive protein derivatives such as hydrolyzed wheat protein, hydrolyzed animal protein, gelatin derivatives, collagen derivatives, and the like, hydroalcoholic soluble copolymers such as acrylates/toctylpropenamide copolymer and the like, and cationic quaternary amine salts and the like, which has been found to extended the efficacy of the formulation for up to a full four weeks. The polymeric material helps to keep the drug at the skin level longer by remaining on the skin surface after the solvents have evaporated following application. The remaining avermectin and polymer does not change the appearance of the animal's hair coat and the avermectin is released by diffusion and/or erosion of the polymer.

The preferred avermectin compounds of E2 have the following structural formula: R1

CH

3 22 .CH 2

R

7

R

4 13 0 2 0 R2

CH

3 I

OH

18 wherein Ri1, R2, and R3 are as described above, and R4 is hydrogen, hydroxy, or polyalkoxy, and the broken line indicates a single or double bond at the 22,23-position, provided that R2 is hydroxy only when the broken line indicates a single bond.

Examples of preferred compounds of the instant invention are: 4"-keto avermectin Bi; 4"-keto avermectin B2; ::*4"-keto-22,23-dihydro avermectin BI; 4"-keto-22,23-dihydro averinectin B2; 10doy4-mnoaemci i 4" -deoxy-4" -a-mino averrnectin B2; -deoxy-4"-amino-22 hdo avermectin B1; 4 "-deoxy-4" -actmin23 dro avermectin B I 4"-deoxy-4"-acetylamino avermectin B2; 154"-deoxy-4"-acetylamino-22,23-dciyr aBr2ctn;i 4" -deoxy-4"-acetylamino-22,23-dihydro avermectin B2; 4"-deoxy-4 "-dietylamin2,3hro avermectin B 2 4"-deoxy-4"-dimnethylamino avermectin B2; 4"-deoxy-4"-dimethylamino-22,23 -dihydro avermectin B 1; 4" -deoxy-4" -dimethylamino-22,23 -dihydro avermectin B2; 4"-deoxy-4"-p-chloro benzenesulfonylamino-22,23 -dihydro avermectin

BI;

4" -deoxy-4"-p-chloro benzenesulfonylamino-22,23dihydro- 13-O-[(2-methoxyethoxy)methyl] avermectin BI aglycone (hereinafter referred to as 1 3-0-MEM AVM); 4" -deoxy-4"-(2-methylbenzenesulfonylamino)avermectmn Bi; 4"-deoxy-4"-(2-methylbenzenesulfonylamino)avermectin B2 13 -epi-O-(methoxymethyl)-22,23-dihydro avermectin BI1 aglycone (hereinafter referred to as 13-0-MOM AVM).

19 The most preferred compound is 22,23-dihydro-13-O-[(2methoxyethoxy)methyl] avermectin B 1 aglycone (hereinafter referred to as 13-O-MEM AVM).

In the topical forms of the avermectin formulation it has not been possible to provide a formulation which provides superior extended efficacy against ectoparasites, especially fleas and ticks.

Additionally, currently available topical formulations do not provide adequate efficacy against endoparasites, especially heartworms and nematodes.

The E2 embodiment of the instant formulation gives the advantages of a pour-on topical formulation which provides the animal with extended effective treatment and protection against endoparasites and ectoparasites, especially fleas, ticks, mange mites, hookworms, 15 ascarids, and heartworms. Additional advantages of this invention are that the formulation is not readily dislodgeable by petting the animals, it has good spreadability and cold temperature usage.

The E2 embodiment of the instant formulation can contain the avermectin compound, alcohol, water and the polymer as the only ingredients. The formulations will benerally be prepared to administered the avermectin from about 0.005 by weight to about *.of the total composition, preferrably from 0.1 to 10% by weight and most preferrably about 5% by weight of the active ingredient. At a preferred dose of about 0.5 to 50 mg/kg the formulation is applied at a 2 dose volume of 0.05 to 4.0 ml/kg body weight. The polymer is present in the compositions of the present invention in amounts ranging from about 0% to 20% w/v and preferrably from about 0.5 to 10% w/v by weight of the total composition and up to 95% by volume of alcohol, q.s. to 100% with water.

The preferred E2 embodiment contains in addition to the polymer, alcohol, water and avermectin compound, additional ingredients such as antioxidants and the glycol, glycerides, glycol ethers, and the derivatives thereof mentioned above. The anti-oxidants are generally added to the formulation at rates of from 0.005 to 1.0% (w/v) a.

a and can be propyl gallate, BHA (butylated hydroxy anisole), BHT (butylated hydroxy toluene), monothioglycerol and the like, preferrably

BHT.

The E2 formulation is prepared by dissolving the avermectin compound in the intended volume of alcohol. The antioxidant and one of the polymeric materials listed above are then dissolved in the alcohol/avermectin mixture. The volume is then adjusted to 100% by the addition of the final volume of water, with the solution being mixed until it becomes homogeneous. Alternatively, Seither the BHT or the polymer, or both can be added prior to the addition of the avermectin compound.

The following example is provided in order that the E2 emobodiment of the invention might be more fully understood. It is not to be construed as a limitation of the invention.

EXAMPLE OF E2 OF THE INVENTION The E2 formulations of this invention which are employed depend upon the particular avermectin compound and treatment. To test the effective killing power of the E2 formulations against fleas and ticks, the following compositions were prepared: a a a Composition VIII 13-O-MEM AVM polyvinyl pyrrolidone 2 Cremophor RH-40 Anhyd. (Denatured) Ethanol Softigen 767 Water Composition IX 13-O-MEM AVM polyvinyl pyrrolidone Anhydrous Ethanol Water 0.3 w/v 5.0 w/v 1.0 %o w/v 40.0 v/v 20.0 v/v 100.0 v/v 0.3 w/v 5.0 w/v 75.0 v/v 100.0 v/v -21 BHT 0.01% w/v Composition X 13-0-MOM AVM polyvinyl pyrrolidone Anhydrous Ethanol Water

BHT

Composition

XI

13-O-MEM AVM polyvinyl pyrrolidone Anhydrous Ethanol Water Vitamin E Composition XII 13-O-MEM AVM hydrolyzed wheat protein Anhydrous Ethanol Water Vitamin E Composition XII 13-O-MEM AVM Ethocel Anhydrous Ethanol Water Vitamin E 3 Composition XIV 13-O-MEM AVM polyvinyl pyrrolidine Anhydrous Ethanol 5.0 w/v 5.0 w/v 90.0 v/v 100.0 v/v 0.01% w/v 0.6 w/v 5.0 w/v 75.0 v/v 100.0 v/v 0.02% v/v 0.6 w/v 3.0 w/v 90.0 v/v 100.0 v/v 0.02% v/v 0.6 w/v 2.0 w/v 90.0 v/v 100.0 v/v 0.02% v/v 0.6 w/v 5.0 w/v 80.0 v/v 22- Water Vitamin E Miglyol 100.0 v/v 0.02% v/v 0.5 v/v Composition XV 13-O-MEM AVM acrylates/t-octylpropenamide copoly polyvinyl pyrrolidone Anhydrous Ethanol Water 10 t n Vitamin E 0.6 w/v 1.0 w/v 2.0 w/v 80.0 v/v 100.0 v/v 0.02% v/v Softigen 767 is a tradename for PEG-6 caprylic/caprate glyceride, 1 Cremophor RH-40 is a tradename for a mixture of glycerol polyethylene and glycol oxysteasrate, and Ethocel is a tradename for ethyl cellulose.

Composition X above was topically applied in multiple locations, typically 2 to 6 points spaced equidistant between the back of the neck and the head of the tail of a flea infested dog. Counts were made by combing the hair, removing and counting the live parasites on the dog at a specified time. The observed flea kills varying the amount of 13-O-MEM AVM, is given in Table No. 1 below, where 60 dogs were allocated to four treatment groups. The dogs were infested with 100 unfed, adult fleas at times indicated by the down arrow which is equivalent to three days before a flea count is conducted. Treatment was applied on day zero. Table No. 2 summarizes the results of a similar test evaluating the efficacy of the composition, containing 13-0- MEM AVE (termed 2-MEM) in various vehicles, in the treatment of ticks.

23 The instant formulations can be topically administered to warm blooded animals to provide long acting treatment and protection against endoparasites and ectoparasites either locally at the site of infestation or at multiple points, typically 2 to 6 points (multiple-pointapplication) along the back of domesticated animals and household pets such as cattle, sheep, cats, dogs and the like.

*oooo

Claims (24)

1. A topical pour-on formulation for the treatment of ectoparasites and endoparasites, which provides a zero milk withdrawal time in dairy animals, consisting of from about 40 to about 100% v/v of a glyceride carrier or derivative thereof selected from the group consisting of propylene dicaprylate/dicaprate, caprylic/capric triglycerides, an antioxidant of about 0.005 to w/v and from 0.005 to 10% w/v of an avermectin compound having the formula: R1 CH3 22 H2R7 R4R4 is hydrogen, 0 R2 H3C OH CH3 R3 where the broken line indicates a single or a double bond at the 22,23-positions; R1 is hydrogen or hydroxy provided that R1 is present only when the broken line indicates a single bond; R2 is alkyl of from 1 to 6 carbon atoms or alkenyl of from 3 to 6 carbon atoms or cycloalkyl of from 3 to 6 carbon atoms; 15 R3 is hydroxy, methoxy or =NOR5 where R5 is hydrogen or lower alkyl; R7 is hydrogen, hydroxy or lower alkyl; and R4 is hydrogen, hydroxy, C(1-6) polyalkoxy or C C OCH 3 OCH 3 H 3 C where R6 is hydroxy, amino, mono- or di-C1-C6 alkylamino or C1-C6 alkanoylamino.

2. The formulation of claim 1, wherein the avermectin compound is OCH

3 R 6 1 H 3 C OCH 3 H 3 C CH 3 22 CH3 O 0 O R2 H3C OH B. OH SO wherein R1, R2, and R6 are defined as in claim 1. The formulation of claim 1 or claim 2, which contains from 0.01 to 5 w/v of the avermectin compound.

4. The formulation of any one of the preceding claims wherein the carrier is *Goo. propylene dicaprylate/dicaprate.

The formulation of any one of the preceding claims, wherein the antioxidant is selected from the group consisting of n-propyl gallate, BHA, BHT, or 1o monothioglycerol.

6. The formulation of claim 5, wherein the antioxidant is BHT.

7. The formulation of any one of claims 1 to 6, which optionally contains a solvent belonging to the group consisting of Crodamol Cap at up to 60% v/v.

8. The formulation of any one of claims 1 to 6, consisting of 100% v/v propylene dicaprylate/dicaprate or caprylate/caprate glyceride, from about 0.005 to 0.05% w/v BHT and from about 0.01 to 5% w/v of 4"-acetylamino-4"- deoxyavermectin B1.

9. The formulation of claim 8, consisting 0.5% w/v of 4"-acetylamino-4"- deoxyavermectin B1, and 0.01% w/v BHT.

10. A topical pour-on formulation for the treatment of ectoparasites and endoparasites, which provides a zero milk withdrawal time in dairy animals, substantially as hereinbefore described with reference to any one of the examples. 26

11. A process for the preparation of the formulation of any one of claims 1 to which comprises dissolving from about 0.005 to from about 10% w/v of the avermectin compound of claim 1 in about 40% to about 50% v/v of the total volume of the glyceride carrier and adding as a final volume, the remainder of the carrier.

12. A method for the treatment and prevention of internal and external parasites of animals, which comprises topically applying an effective amount, from about 1.0 to 50 mg of avermectin compound per solution of the formulation of any one of claims 1 to 10, to the skin of an animal.

13. A topical formulation for direct application to the skin of an animal, effective for treatment and prevention of ectoparasites and endoparasitic infestations for four weeks, consisting of from about 0.01 to about 20% w/v of a polymeric material, belonging to the group consisting of polyvinyl pyrrolidone having a molecular weight of about 20,000 to about 65,000, from about 1 to from about 95% v/v of ethanol, 100% v/v obtained with addition of water, and from about 0.05 to from about 10% w/v of an avermectin compound having the formula: CH3 22 CH CH2R7 R3R2 o;•o H3 c o• where the broken line indicates a single or a double bond at the 22,23-positions; R 1 is hydrogen or hydroxy, provided that R 1 is present only when the broken line indicates a single bond; R 2 is alkyl of from 1 to 6 carbon atoms or alkenyl of from 3 to 6 carbon atoms or cycloalkyl of from 3 to 6 carbon atoms; R 3 is hydroxy, methoxy, or =NOR 5 where R 5 is hydrogen or lower alkyl; R 7 is hydrogen, hydroxy or lower alkyl; and R 4 is hydrogen, hydroxy, poly C( 1 alkoxy, or OCH 3 where R 6 is hydroxy, amino, mono- or di-C1-C6 alkylamino or C1-C6 alkanoylamino.

14. The formulation of Claim 13, wherein R4 is hydrogen, hydroxy or polyalkoxy.

The formulation of claim 13, which contains from 0.1 to 5.0% w/v of the avermectin compound and 5.0 to 10% w/v of the polymeric material and wherein R4 of the avermectin compound is CH30CH2CH20CH20.

16. The formulation of any one of claims 13 to 15, wherein the polymeric material is polyvinylpyrrolidone.

17. The formulation of claim 16, wherein the polyvinylpyrrolidone has a molecular weight of 45 000.

18. The formulation of any one of claims 13 to 17 which optionally contains S. an anti-oxidant selected from the group consisting of n-propyl gallate, BHA, BHT and monothioglycerol from about 0.005 to 1.0% w/v and an additive selected from the group consisting of Crodamol/CAP, or Vitamin E, at up to 50% v/v.

19. A topical formulation for direct application to the skin of an animal, effective for treatment and prevention of ectoparasites and endoparasitic infestations for four weeks, substantially as hereinbefore described with reference to any one of the examples.

A topical formulation for direct application to the skin of an animal for effective treatment of parasitic infestations consisting of 5.0% w/v of polyvinylpyrollidone, molecular weight 45 000, 5.0% w/v of 22,23-dihydro-13-0-[(2- methoxyethoxy)methyl] avermectin B1 aglycone, 90% v/v ethanol q.s. to 100% with water and 0.01 w/v BHT.

21. A process for the preparation of the formulation of any one of claims 13 to 19, which comprises dissolving from about 0.005 to about 10% w/v of the avermectin compound of claim 1 in from about 1 to about 95% v/v of ethanol to form a clear solution, adding and dissolving from about 0.005 to 1.0% w/v of the anti-oxidant and from about 0.01 to about 20% w/v of the polymeric material in the 28 solution, adding up to 50% v/v of the additive, adjusting the volume to 100% by addition of water and mixing until the solution is homogeneous.

22. A method for the treatment and control of internal and external parasites of animals, which comprises topically applying the formulation of any one of claims 13 to 20, to the skin of an animal.

23. A formulation according to any one of claims 1 to 10 and 13-20 when used for the treatment or control of ectoparasites and endoparasites in animals in need of such treatment or control.

24. The use of an avermectin compound as defined in any one of claims 1- 2, 8, 15 or 20 for the preparation of a formulation for use in the treatment or control of ectoparasites and endoparasites in animals in need of said treatment or control wherein said avermectin compound is present in said formulation in an amount of from 0.005 to 10% w/v. *go Dated 9 April, 2001 Merck Co., Inc. Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON o