Method of preparing nanoparticles by hot-melt extrusion

1. A nanoparticle dispersion for topical delivery to skin of a mammal, the nanoparticle dispersion comprising;

one or more hydrophobic drugs selected from the group consisting of aspirin, benzocaine, hydrocortisone, and lidocaine;

one or more ether type polyethoxylated high hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of laureth-23, laureth-30, steareth-100, steareth-20, steareth-40, ceteareth-20, and ceteareth-30;

one or more low hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of stearic acid, sorbitan oleate, and sorbitan stearate;

one or more water immiscible oils selected from the group consisting of cocoyl caprate/caprylate, benzyl alcohol, diisopropyl adipate, capric/caprylic triglyceride oil, isopropyl rnyristate, limonene, medium chain triglyceride oil, mineral oil, oleyl alcohol, sesame oil, and a combination of isohexadecane, isododecane, and a C 13-15 alkane;

water, and

wherein the one or more hydrophobic drugs each independently having a log P>1 do not form crystals from the nanoparticle dispersion for greater than about 8 months at a temperature from about 18° C. to about 22° C.;

wherein the dispersion is without lamellar structure; and

wherein the dispersion has a latent lamellar structure.

2. The nanoparticle dispersion of claim 1 , further comprising one or more ester type polyethoxylated high hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of PEG100 stearate; PEG20 stearate; PEG30 glyceryl cocoate; PEG32 stearate; polysorbate 20, and polysorbate 80.

3. The nanoparticle dispersion of claim 1 , further comprising one or more phospholipid low hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of phosphatidylcholine and lecithin.

4. The nanoparticle dispersion of claim 1 , further comprising one or more ester type polyethoxylated high hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of PEG100 stearate; PEG20 stearate; PEG30 glyceryl cocoate; PEG32 stearate; polysorbate 20, and polysorbate 80 and one or more phospholipid low hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of phosphatidylcholine and lecithin.

5. The nanoparticle dispersion of claim 1 , further comprising one or more non-polyethoxylated high hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of cocoglucoside, decyl glucoside, and xylityl caprate/caprylate.

6. The nanoparticle dispersion of claim 1 , wherein the nanoparticle dispersion has a weight square mean deviation value of hydrophile-lipophile-balance (HLB) (WMSD HLB ) between about 1.5 and about 4.5.

7. The nanoparticle dispersion of claim 1 , wherein the nanoparticle dispersion has a volume average particle size less than about 150 nm.

8. A nanoparticle dispersion for topical delivery to skin of a mammal, the nanoparticle dispersion comprising;

one or more hydrophobic drugs selected from the group consisting of aspirin, benzocaine, hydrocortisone, and lidocaine;

one or more ether type polyethoxylated high hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of laureth-23, laureth-30, steareth-100, steareth-20, steareth-40, ceteareth-20, and ceteareth-30;

one or more ester type polyethoxylated high hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of PEG100 stearate; PEG20 stearate; PEG30 glyceryl cocoate; PEG32 stearate; polysorbate 20, and polysorbate 80;

one or more low hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of stearic acid, sorbitan oleate, and sorbitan stearate;

one or more water immiscible oils selected from the group consisting of cocoyl caprate/caprylate, benzyl alcohol, diisopropyl adipate, capric/caprylic triglyceride oil, isopropyl myristate, limonene, medium chain triglyceride oil, mineral oil, omega 3 fatty acid, oleyl alcohol, sesame oil, and a combination of isohexadecane, isododecane, and a C 13-15 alkane;

water, and

wherein the one or more hydrophobic drugs each independently having a log P>1 do not form crystals from the nanoparticle dispersion for greater than about 8 months at a temperature from about 18° C. to about 22° C.; and

wherein the dispersion exhibits a positive peak between about 45° C. and 80° C. in the first derivative plot of normalized conductivity versus temperature, the positive peak having a peak amplitude greater than about 0.1° C. −1 .

9. The nanoparticle dispersion of claim 8 , further comprising one or more phospholipid low hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of phosphatidylcholine and lecithin.

10. The nanoparticle dispersion of claim 8 , further comprising one or more ester type polyethoxylated high hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of PEG100 stearate; PEG20 stearate; PEG30 glyceryl cocoate; PEG32 stearate; polysorbate 20, and polysorbate 80 and one or more phospholipid low hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of phosphatidylcholine and lecithin.

11. The nanoparticle dispersion of claim 8 , further comprising one or more non-polyethoxylated high hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of cocoglucoside, decyl glucoside, and xylityl caprate/caprylate.

12. The nanoparticle dispersion of claim 8 , wherein the nanoparticle dispersion has a weight square mean deviation value of hydrophile-lipophile-balance (HLB) (WMSD HLB ) between about 1.5 and about 4.5.

13. The nanoparticle dispersion of claim 8 , wherein the nanoparticle dispersion has a volume average particle size less than about 150 nm.

14. The nanoparticle dispersion of claim 8 , wherein the nanoparticle dispersion has a latent lamellar structure.

15. A nanoparticle dispersion for topical delivery to skin of a mammal, the nanoparticle dispersion comprising;

one or more hydrophobic drugs selected from the group consisting of aspirin, benzocaine, hydrocortisone, and lidocaine;

one or more ether type polyethoxylated high hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of laureth-23, laureth-30, steareth-100, steareth-20, steareth-40, ceteareth-20, and ceteareth-30;

one or more ester type polyethoxylated high hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of PEG100 stearate; PEG20 stearate; PEG30 glyceryl cocoate; PEG32 stearate; polysorbate 20, and polysorbate 80;

one or more phospholipid low hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of phosphatidylcholine and lecithin;

one or more low hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of stearic acid, sorbitan oleate, and sorbitan stearate;

one or more water immiscible oils selected from the group consisting of cocoyl caprate/caprylate, benzyl alcohol, diisopropyl adipate, capric/caprylic triglyceride oil, isopropyl myristate, limonene, medium chain triglyceride oil, mineral oil, omega 3 fatty acid, oleyl alcohol, sesame oil, and a combination of isohexadecane, isododecane, and a C 13-15 alkane;

water,

wherein the nanoparticle dispersion has a latent lamellar structure below 40° C., and wherein the one or more hydrophobic drugs each independently having a log P>1 do not form crystals from the nanoparticle dispersion for greater than about 8 months at a temperature from about 18° C. to about 22° C.

16. The nanoparticle dispersion of claim 15 , further comprising one or more non-polyethoxylated high hydrophile-lipophile-balance (HLB) surfactants selected from the group consisting of cocoglucoside, decyl glucoside, and xylityl caprate/caprylate.

17. The nanoparticle dispersion of claim 15 , wherein the nanoparticle dispersion has a weight square mean deviation value of hydrophile-lipophile-balance (HLB) (WMSD HLB ) between about 1.5 and about 4.5.