PARASITICIDAL FORMULATIONS AND USE THEREOF

1 . A parasiticidal formulation comprising about 0.1 to about 10% by weight of one or more macrocyclic lactones, about 60 to about 95% by weight of one or more solvents selected from the group consisting of benzyl alcohols and substituted pyrrolidones, and about 5 to about 60% by weight of one or more cosolvents selected from the group consisting of cyclic carbonates and lactones, wherein the one or more macrocyclic lactones are the sole parasiticidal active compound.

2 . The parasiticidal formulation of claim 1 comprising about 0.5 to about 5% by weight of one or more macrocyclic lactones, about 75 to about 95% by weight of one or more solvents selected from the group consisting of benzyl alcohols and substituted pyrrolidones, and about 10 to about 20% by weight of one or more cosolvents selected from the group consisting of cyclic carbonates and lactones.

3 . The parasiticidal formulation of claim 1 further comprising an adjuvant selected from the group consisting of: a preservative, a thickener, a colorant, an antioxidant, a light stabilizer, a tackifier, and combinations thereof.

4 . The parasiticidal formulation of claim 3 , wherein the adjuvant is an antioxidant.

5 . The parasiticidal formulation of claim 3 , wherein the adjuvant is butylated hydroxytoluene (BHT).

6 . The parasiticidal formulation of claim 1 , wherein the macrocyclic lactone is selected from the group consisting of: avermectin B 1a /B 1b , 22,23-dihydroavermectin (B 1a /B 1b ), doramectin, moxidectin, selamectin, and eprinomectin.

7 . The parasiticidal formulation of claim 1 , wherein the macrocyclic lactone is moxidectin.

8 . The parasiticidal formulation of claim 1 , wherein the one or more solvents is benzyl alcohol.

9 . The parasiticidal formulation of claim 1 , wherein the one or more cosolvents is propylene carbonate.

10 . The parasiticidal formulation of claim 1 , wherein the macrocyclic lactone is moxidectin, wherein the solvent is benzyl alcohol, and wherein the cosolvent is propylene carbonate.

11 . The parasiticidal formulation of claim 10 , wherein benzyl alcohol is the sole solvent and wherein propylene carbonate is the sole cosolvent.

12 . The parasiticidal formulation of claim 1 , wherein the formulation is a spot-on formulation.

13 . The parasiticidal formulation of claim 2 comprising about 80% to about 95% by weight of one or more solvents.

14 - 24 . (canceled)

25 . A method of controlling endoparasites in an animal comprising applying to the animal the parasiticidal formulation of claim 1 .

26 . The method of claim 25 , wherein the animal is selected from the group consisting of, a human, a livestock animal, and a pet.

27 . The method of claim 25 , wherein the animal is a dog or a cat.

28 . The method of claim 25 , wherein the formulation is applied to the skin of the animal.

29 . (canceled)

30 . A method of controlling endoparasites in an animal comprising applying to the animal the parasiticidal formulation of claim 2 .

31 . A method of controlling endoparasites in an animal comprising applying to the animal the parasiticidal formulation of claim 13 .