Nanoemulsions

Abstract

The present invention relates to oil-in-water nanoemulsions, processes for their preparation and their use as delivery vehicles for active components for use in opthalmological, dermatological, food, cosmetic, pharmaceutical, agrichemical, textile, polymer and chemical applications. The oil-in-water nanoemulsion comprises up to 40 volume % of an oil phase comprising at least 50 volume % of a triglyceride having a fatty acid chain length of 12 carbon atoms or greater and a hydrophilic non-ionic surfactant having a hydrophilic-lipophilic balance (HLB) greater than 7; and an aqueous phase, in which the oil droplets have an intensity average size of less than 100 nm and the ratio of surfactant to oil is less than 1:1, more preferably 0.2 to 0.8:1.

1 . An oil-in-water nanoemulsion which comprises
 up to 40 volume % of an oil phase comprising at least 50 volume % of a triglyceride having a fatty acid chain length of 12 carbon atoms or greater;   a hydrophilic non-ionic surfactant having a hydrophilic-lipophilic balance (HLB) greater than 7; and   an aqueous phase,   in which the oil droplets of the nanoemulsion have an intensity average size of less than 100 nm and the ratio of surfactant to oil is less than 1:1.   
     
     
         2 . A nanoemulsion according to  claim 1  in which the oil droplets have a diameter of 80 nm or less, 75 nm or less or 60 nm or less. 
     
     
         3 . A nanoemulsion according to  claim 1  in which the triglyceride is fish oil, cod liver oil, blubber, lard, tallow, schmaltz, and butter fat; vegetable origin such as canola oil, castor oil, cocoa butter, coconut oil, coffee seed oil, corn oil, cotton seed oil, evening primrose oil, grapeseed oil, flax seed oil, menhaden oil, mustard seed oil, olive oil, palm oil, palm kernel oil, peanut oil, poppy seed oil, rapeseed oil, rice bran oil, safflower oil, sesame oil, soybean oil, sunflower oil, palm kernel oil, hazelnut oil, sesame oil, wheat germ oil, vegetable oil, synthetic triglyceride, fractionated triglyceride, modified triglyceride, hydrogenated triglyceride, partially hydrogenated triglyceride or mixtures thereof. 
     
     
         4 . A nanoemulsion according to  claim 3  which further comprises one or more additional oils. 
     
     
         5 . A nanoemulsion according to  claim 4  in which the ratio of triglyceride to additional oil is 1:0 to 1:1. 
     
     
         6 . A nanoemulsion according to  claim 5  in which the total amount of oil in the nanoemulsion comprising triglyceride and additional oil if present is 0.01 to 70 wt %, 0.01 to 50 wt % or 0.01 to 40 wt %. 
     
     
         7 . A nanoemulsion according to  claim 1  in which the hydrophilic non-ionic surfactant is selected from polysorbates, polyethylene glycol alkyl ethers, sugar esters, polyethoxylated fatty acids, polyoxyethylene-polyoxypropylene block co-polymers, polyethylene glycol alkyl phenol surfactants, citric acid esters of monoglycerides, polyglycerol esters, polyethoxylated fatty acid diesters, PEG-fatty acid mono and diesters, polyethylene glycol glycerol fatty acid esters and alcohol oil transesters or mixtures thereof. 
     
     
         8 . A nanoemulsion according to  claim 1  in which the amount of hydrophilic surfactant is 0.1 to 15 wt %, 1 to 10 wt % or 3 to 7 wt %. 
     
     
         9 . A nanoemulsion according to  claim 1  which further comprises a co-solvent. 
     
     
         10 . A nanoemulsion according to  claim 9  in which the amount of co-solvent is 0 to 70 wt %, 0 to 50 or 15 to 45 wt %. 
     
     
         11 . A nanoemulsion according to  claim 1  which further comprises a co-surfactant. 
     
     
         12 . A nanoemulsion according to  claim 11  in which the amount of co-surfactant is 0.1 to 15 wt %. 
     
     
         13 . A nanoemulsion according to  claim 11  in which the co-surfactant is present in a ratio relative to the hydrophilic non-ionic surfactant of 0:1 to 2:1, 0:1 to 1.3:1 or 0.5:1 to 1.3:1. 
     
     
         14 . A nanoemulsion according to  claim 1  in which balance of water is 50 to 100 wt %, 40 to 99.99 wt % or 30 to 99.90 wt %. 
     
     
         15 . A process for the preparation of an oil-in-water nanoemulsion according to  claim 1  which comprises
 subjecting up to 40 volume % of an oil phase comprising at least 50 volume % of a triglyceride having a fatty acid chain length of 12 carbon atoms or greater and a hydrophilic non-ionic surfactant having a hydrophilic-lipophilic balance (HLB) greater than 7 and an aqueous phase to homogenisation, sonication or membrane emulsification to prepare a nanoemulsion in which the oil droplets have an intensity average size of less than 100 nm and the ratio of surfactant to oil is less than 1:1. 
 
     
     
         16 . A delivery vehicle for an active component comprising the nanoemulsion according to  claim 1 . 
     
     
         17 . A formulation comprising the nanoemulsion according to  claim 1  and an active component. 
     
     
         18 . A formulation according to  claim 17  in which the active component is selected from food supplements, food additives, aromas, aromatic oils, colours, flavours, sweeteners, cosmetics, pharmaceuticals, nutraceuticals, phytochemicals, vitamins, essential polyunsaturated fatty acids, plant extracts, agrichemicals, textiles, polymers and chemicals. 
     
     
         19 . A process for the preparation of the formulation according to  claim 17  which comprises mixing the nanoemulsion with the active component. 
     
     
         20 . A process for the preparation of the formulation according to  claim 17  which comprises
 subjecting the active component, up to 40 volume % of an oil phase comprising at least 50 volume % of a triglyceride having a fatty acid chain length of 12 carbon atoms or greater and a hydrophilic non-ionic surfactant having a hydrophilic-lipophilic balance (HLB) greater than 7 and an aqueous phase to homogenisation, sonication or membrane emulsification to prepare a nanoemulsion in which the oil particles have an intensity average size of less than 100 nm and the ratio of surfactant to oil is less than 1:1.