METHOD OF PRESERVING A REACTIVE ACTIVE COMPOUND, CAPSULE AND FORMULATION

Abstract

A reactive active compound is brought in a liquid. Said liquid, containing said active compound, is encapsulated by a surrounding shell layer and comprises an emulsion of a first liquid in a second liquid. Said active compound is dispersed in said first liquid. Said first liquid, containing said active compound, is dispersed in a second liquid that is substantially immiscible with said first liquid to form said emulsion. Said emulsion is encapsulated by said shell layer to preserve said reactive active compound in one or more a capsules that may be applied in a formulation.

Claims

1. A method of preservation of a reactive active compound, wherein said active compound is brought in a liquid and said liquid, containing said active compound, is encapsulated by a surrounding shell layer, wherein said active compound is brought in a first liquid, wherein said first liquid, containing said active compound, is brought in a second liquid that is substantially immiscible with said first liquid, that an emulsion is formed containing said first liquid and said second liquid, and wherein said emulsion is encapsulated by a solid shell layer, wherein both said first liquid and said shell layer are hydrophilic and said second liquid is hydrophobic.

2. The method according to claim 1, wherein said first liquid comprises water or a water-free hydrophilic solvent, particularly glycerine, glycerol or poly(ethylene glycol).

3. The method according to claim 1, wherein said second liquid comprises at least one of organic (vegetable or animal) oils, waxes and fats.

4. The method according to claim 3, wherein said second liquid comprises a fat or wax in a form of micro-particles, preferably having a size smaller than 1 millimetre.

5. The method according to claim 3, wherein said second liquid comprises a fat or wax that is processed in a liquid condition to solidify below 40° C., particularly between room temperature and human body temperature, in the second liquid.

6. The method according to claim 3, wherein said second liquid comprises a solid wax or fat that was added in the form of solid micro-particles and subjected to a heat treatment to at least partly melt said wax or fat micro-particles while being in the second liquid.

7. The method according to claim 3, wherein said fat or wax has a melting point below 90° C.

8. The method according to claim 7, wherein said fat or wax is selected from a group of montan wax, carnauba wax, glycol montanate, paraffin wax, candililla wax, beeswax, microcrystalline wax and ozocerite wax.

9. The method according to claim 3, wherein said second liquid comprises an oil selected from a group consisting of essential oils, ethereal oils, macerated oils, triglyceride and mixtures or derivatives thereof and particularly comprises sunflower oil.

10. The method according to claim 1, wherein said active compound is dissolved in said first liquid, wherein said first liquid contains said active compound preferably in a supersaturated condition.

11. The method according to claim 1, wherein said first liquid is a hydrophilic solution or suspension of said active compound, particularly an aqueous solution, while said second liquid is hydrophobic.

12. The method according to claim 1, wherein said shell layer comprises a polymer network, particularly an interpenetrating network of two or more cross-linked polymers.

13. The method according to claim 12, wherein said polymer network comprises a hydrophilic polymer network, particularly comprising one or more poly-electrolytes or polysaccharides selected from agar, aliginate, chitosan, dextran, poly(ethylene glycol), collagen, gelatin, hyaluronic acid, carrageenan, fibroin, fibronectin, poly-L-Lysine (PLL), cellulose, graphene, polyethylenimine (PEI), poly(amidoamine) (PAA), dextran sulfate, silk, silk fibroin, Pectin, K-carrageenan, Iota carrageenan, Gellan gum, Guar gum, Tragacanth gum, Xanthan gum, Acacia gum, Karaya gum, Gelatin, and Sodium carboxymethyl cellulose (S-CMC) all of these as naturally derived materials and/or synthetically derived materials including recombinant proteins and/or derivatives of these materials.

14. The method according to claim 13, wherein said polymer network comprises a cross-linked or inter-penetrating aliginate network, particularly a calcium cross-linked aliginate network.

15. The method according to claim 14, wherein bivalent cations are added to said first liquid, particularly by means of an electrolyte supplying magnesium ions and/or calcium ions, more particularly a calcium or magnesium salt solution providing an ionic calcium concentration of at least 0,001 M in said first liquid, preferably at least 0.01 M, more particularly between 0.1 M and 1.0 M, even more particularly between 0.1 M and 0.5 M.

16. The method according to claim 1, wherein said emulsion is stabilized by solid particles which adsorb onto an interface between said two liquids, particularly solid particles that are micro-particles or nano-particles that act as Pickering stabilizer.

17. The method according to claim 16, wherein said solid particles are charged particles and wherein a electrostatically charged agent having a same polarity as said solid particle is added to the first liquid, particularly said solid particles being charged negatively and said agent comprising a polyanionic polymer or a negatively charged glycosaminoglycan, more particularly hyaluronic acid, carageenan or acacia gum.

18. The method according to claim 16, wherein said solid particles comprise micro-particles and/or nano particles that are selected from a group of particles containing silver, gold, fullerene, silicon, aluminum, calcium carbonate, zinc, mica, titanium, copper, platinum, silicic acid, lithium, magnesium, iron, magnetic nanoparticles, nanotubes, protein, cellulose and clay, particularly laponite clay, including any of the oxidized forms of these materials such as silicon dioxide or silica.

19. The method according to claim 16, wherein said solid particles are hydrophobized, particularly by functionalizing or coating with chlorosilane or silanol, particularly (alkyl)chlorosilane, trimethylsilanol, dimethyldichlorosilane or poly(dimethylsiloxane).

20. The method according to claim 19, wherein said solid particles comprise fumed silica nano-particles, preferably post-treated with dimethyldichlorosilane (Si(CH.sub.3).sub.2Cl.sub.2).

21. The method according to claim 16, wherein said solid particles comprise micro-particles and/or nano particles that are bio-compatible and particularly biodegradable.

22. The method according to claim 21, wherein said solid particles comprises a biodegradable compound or are hydrophobized by functionalizing or coating with a biodegradable compound, particularly with a compound from a group of amino acids, polyhydroxystearic acid, stearoyl glutamic acid, natural olive esters, jojoba ester, magnesium myristate, hydrogenated lecithin, lecithin, silica, isopropyl titanium triisostearate, dimethicone and methicone.

23. The method according to claim 22, wherein said solid particles comprise micro-particles and/or nano particles that are food grade stabilizers such as particles containing aliginate, starch, gelatin, fatty acids and/or derivatives thereof.

24. The method according to claim 1, Wherein an acid, a base and/or a buffer agent is added to said first liquid, maintaining a pH of said first liquid at a predetermined level that further aids in stabilizing said active compound, particularly one or more of ascorbic acid, hyaluronic acid and a zwitterionic sulfonic acid buffering agent, more particularly 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), metaphosphoric acid, citric acid, perchloric acid, acetic acid or orthophosphoric acid.

25. The method according to claim 24, wherein ascorbic acid is added to said first liquid in a form of a micronized ascorbic acid powder, having a maximum particle size below 150 micron, particularly at a concentration of more than 25 wt %.

26. The method according to claim 1, wherein said shell layer encloses a volume of less than one millilitre thereby forming a micro-capsule containing said emulsion comprising said first liquid, said second liquid and said active compound in said first liquid.

27. The method according to claim 1, wherein said active compound comprises at least one active compound that is selected from a group of pharmaceutical agents, flagrances, cosmetic agents, flavours and nutrients.

28. The method according to claim 27, wherein said active compound comprises at least one active compound that is selected from a group of vitamins, anti-oxidants, proteins and/or derivatives thereof.

29. The method according to claim 28, wherein said emulsion comprises at least one vitamin, particularly a vitamin that is selected from a group containing thiamine, riboflavin, nicotinic acid, pantothenic acid, pyridoxine, biotin, folic acid, cyanocobalamin, lipoic acid, ascorbic acid, lecithin, glycyrhizin acid, retinol, retinol palmitate, tocopherol, tocopherol acetate, salicylic acid, benzoyl peroxide, and azelaic acid and/or derivatives thereof, more particularly ascorbic acid and/or derivatives thereof.

30. The method according to claim 28, wherein said active compound comprises at least one anti-oxidant, particularly an anti-oxidant that is selected from a group containing poly-phenols, thiol-based components, sulphite and derivatives thereof.

31. A capsule, comprising a core encapsulated in a shell layer, wherein said core comprises a liquid containing an active compound, wherein said liquid comprises an emulsion of a first liquid and a second liquid, said first and second liquid being substantially immiscible with one another and said first liquid comprising said active compound, wherein said core that comprises said emulsion is surrounded by a solid shell layer, wherein said first liquid is hydrophilic, wherein said second liquid is hydrophobic, and wherein said shell layer is hydrophilic.

32. The capsule according to claim 31, wherein said first liquid contains water or a water-free solvent, particularly glycerine, glycerol or poly(ethylene glycol).

33. The capsule according to claim 31, wherein said second liquid comprises at least one of organic (vegetable or animal) oils, waxes and fats.

34. The capsule according to claim 33, wherein said second liquid comprises a wax in a form of micro-particles, preferably having a size smaller than 1 millimetre.

35. The capsule according to claim 33, wherein said second liquid comprises a fat or wax that is processed in a liquid condition to solidify below 40° C., particularly between room temperature and human body temperature.

36. The capsule according to claim 33, wherein said fat or wax has a melting point below 90° C.

37. The capsule according to claim 36, wherein said fat or wax is selected from a group of montan wax, carnauba wax, glycol montanate, paraffin wax, candililla wax, beeswax, microcrystalline wax and ozocerite wax.

38. The capsule according to claim 33, wherein said second liquid is an organic oil that is selected from a group consisting of essential oils, ethereal oils, macerated oils, triglyceride and mixtures or derivatives thereof and particularly comprises sunflower oil.

39. The capsule according to claim 31, wherein said active compound is dissolved in said first liquid.

40. The capsule according to claim 39, wherein said first liquid contains said active compound in a supersaturated condition.

41. The capsule according to claim 31, characterized in said first liquid is a hydrophilic solution or suspension of said active compound, particularly an aqueous solution.

42. The capsule according to, wherein said shell layer comprises a polymer network, particularly an interpenetrating network of two or more cross-linked polymers.

43. The capsule according to claim 42, wherein said polymer network comprises a hydrophilic polymer network, particularly comprising one or more poly-electrolytes or polysaccharides selected from agar, aliginate, chitosan, dextran, poly(ethylene glycol), collagen, gelatin, hyaluronic acid, carrageenan, fibroin, fibronectin, poly-L-Lysine (PLL), cellulose, graphene, polyethylenimine (PEI), poly(amidoamine) (PAA), dextran sulfate, silk, silk fibroin, Pectin, K-carrageenan, Iota carrageenan, Gellan gum, Guar gum, Tragacanth gum, Xanthan gum, Acacia gum, Karaya gum, Gelatin, Agar or Sodium carboxymethyl cellulose (S-CMC) all of these as naturally derived materials and/or synthetically derived materials including recombinant proteins and/or derivatives of these materials, wherein said polymer network particularly comprises a hydrophilic calcium-aliginate network.

44. The capsule according to claim 43, wherein said first liquid comprises bivalent cations, particularly an electrolyte supplying magnesium ions and/or calcium ions, more particularly a calcium or magnesium salt solution providing a ionic calcium concentration of at least 0,001 M in said first liquid, preferably at least 0.01 M, more particularly between 0.1 M and 1.0 M, even more particularly between 0.1 M and 0.5 M.

45. The capsule according to claim 31, wherein said emulsion is stabilized by solid particles which adsorb onto an interface between said two liquids, wherein said solid particles are particularly micro-particles or nano-particles that act as Pickering stabilizer.

47. The capsule according to claim 45, wherein said solid particles are charged particles and wherein a electrostatically charged agent having a same polarity as said solid particle is added to the first liquid, particularly said solid particles being charged negatively and said agent comprising a polyanionic polymer or a negatively charged glycosaminoglycan, more particularly hyaluronic acid, carageenan or acacia gum.

47. The capsule according to claim 45, wherein said solid particles comprise micro-particles and/or nano particles that are selected from a group of particles containing silver, gold, fullerene, silicon, aluminum, calcium carbonate, zinc, mica, titanium, titanium, copper, platinum, silicic acid, lithium, magnesium, iron, magnetic nanoparticles, nanotubes, protein, cellulose, clay, particularly laponite clay, including any of the oxidized forms of these materials such as silicon dioxide or silica.

48. The capsule according to one or more of claim 48, wherein said solid particles are hydrophobized, particularly by functionalizing or coating with dimethyldichlorosilane or poly(dimethylsiloxane).

49. The capsule according to claim 48, wherein said solid particles comprise fumed silica nano-particles, preferably post-treated with dimethyldichlorosilane (Si(CH.sub.3).sub.2Cl.sub.2).

50. The capsule according to claim 45, wherein said solid particles comprise micro-particles and/or nano particles that are bio-compatible and particularly biodegradable.

51. The capsule according to claim 50, wherein said solid particles comprises a biodegradable compound or are hydrophobized by functionalizing or coating with a biodegradable compound, particularly a compound from a group of amino acids, polyhydroxystearic acid, stearoyl glutamic acid, natural olive esters, jojoba ester, magnesium myristate, hydrogenated lecithin, lecithin, silica, isopropyl titanium triisostearate, dimethicone and methicone.

52. The capsule according to claim 51, wherein said solid particles comprise micro-particles and/or nano particles that are food grade stabilizers such as particles containing aliginate, starch, gelatin, fatty acids and/or derivatives thereof.

53. The capsule according to claim 31, wherein said first liquid comprises an acid, a base and/or a buffer agent, maintaining a pH of said first liquid at a predetermined level that further aids in stabilizing said active compound, particularly one or more of ascorbic acid, hyaluronic acid and a zwitterionic sulfonic acid buffering agent, more particularly 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), metaphosphoric acid, citric acid, perchloric acid, acetic acid or orthophosphoric acid.

54. The capsule according to claim 31, wherein said active compound comprises at least one active compound that is selected from a group of pharmaceutical agents, cosmetic agents, fragrances, flavours and nutrients.

55. The capsule according to claim 54, wherein said active compound comprises at least one compound that is selected from a group of vitamins, anti-oxidants, proteins and/or derivatives thereof.

56. The capsule according to claim 54, wherein said emulsion comprises at least one vitamin, particularly a vitamin that is selected from a group containing thiamine, riboflavin, nicotinic acid, pantothenic acid, pyridoxine, biotin, folic acid, cyanocobalamin, lipoic acid, ascorbic acid, lecithin, glycyrhizin acid, retinol, retinol palmitate, tocopherol, tocopherol acetate, salicylic acid, benzoyl peroxide, and azelaic acid and/or derivatives thereof, more particularly ascorbic acid and/or derivatives thereof.

57. The capsule according to claim 55, wherein said active compound comprises at least one anti-oxidant, particularly an anti-oxidant that is selected from a group containing poly-phenols, thiol-based components, sulphite and derivatives thereof.

58. The capsule according to claim 31, wherein said shell layer carries a coating, preferably an edible coating, particularly a hydrophobic coating containing nano-particles or a wax like carnauba wax.

59. The capsule according to claim 31, wherein said shell layer is configured to break or rupture under a mechanical load, particularly a manually applied mechanical load, more particularly by squeezing or chewing.

60. The capsule according to claim 31, wherein said shell layer is provided with a colouring, particularly coloured particles, more particularly water-insoluble pigments, even more particularly UV-absorbing or UV-reflecting pigments.

61. The capsule according to claim 31, characterized by a substantially spherical shape.

62. The capsule according to claim 61, characterized by a Feret diameter averaged over all directions of between 1 μm and 10 mm, particularly between 10 μm and 10 mm, particularly between 50 micron and 5 mm.

63. The capsule according to claim 62, wherein a shell layer thickness constitutes less than 25% of the diameter of said capsule.

64. The capsule according to claim 63, wherein a ratio of said first liquid to said second liquid is at least 1:100, particularly at least 1:10, more particularly at least 1:3.

65. The capsule according to claim 63, wherein said active compound constitutes 10-50% by weight of said first liquid.

66. A formulation, comprising a fluid material like a cream, lotion, gel, serum, cleanser, soap, shampoo, oil or clay that comprises a cosmetic, pharmaceutical, nutritious or organoleptic active compound, wherein said fluid material comprises a plurality of capsules comprising a hydrophilic first liquid and a hydrophobic second liquid that are immiscible with one another, containing said active compound in said first liquid, confined within a hydrophilic solid shell layer.

67. The formulation according to claim 66, wherein said shell layer is configured to break or rupture under a mechanical load, particularly a manually applied mechanical load, more particularly by squeezing or chewing.

Description

[0068] Hereinafter the invention will be described in further detail with reference to a number of explanatory embodiments and an accompanying drawing. In the drawing:

[0069] FIG. 1 shows a specific example of a capsule according to the invention; and

[0070] FIG. 2 shows an embodiment of a formulation according to the invention.

[0071] It is noted that the figures are drawn purely schematically and not necessarily to a same scale. In particular, certain dimensions may have been exaggerated to a more or lesser extent to aid the clarity of any features. Similar parts are generally indicated by a same reference numeral throughout the figures.

[0072] The capsules 10 that are shown in FIG. 1 are manufactured using a method according to the invention and resemble the protective nature that is provided by the invention to a vulnerable active compound that would otherwise be prone to oxidation or other degradation when exposed to ambient air, for instance. The active compound comprises for example ascorbic acid, being readily soluble in water. By dissolving micronized powder, for instance having a modal particle size of below around 75-100 micron a large quantity of for instance between 20 and 25 wt % ascorbic acid may be brought in an aqueous hydrophilic phase 11. The hydrophilic phase 1 an emulsion with a hydrophobic continuous phase 12, for instance containing a vegetable oil like sunflower oil. Solid nano-clay particles of laponite clay may be added to the mixture to act as a Pickering stabilizer to stabilize the emulsion, counteracting coalescence of the aqueous phase droplets 11 and phase separation. The emulsion comprised of small dispersed hydrophilic droplets 11 surrounded by a hydrophobic continuous phase 12 is encapsulated within a hydrophilic solid shell layer 13, for instance created by a solidified cross-linked hydrophilic calcium-aliginate network. The capsules 10 typically enclose a volume of less than one millilitre thereby forming a micro-capsule containing said emulsion comprising said first liquid 11 and said second liquid 12, protecting said active compound in said first liquid.

[0073] The formulation of FIG. 2 comprises a plurality of micro-capsules 10 as shown in FIG. 1 that contain an appropriate active compound. The capsules are distributed is a suitable fluid material 20 like a cream, lotion, gel, serum, cleanser, soap, shampoo, oil or clay to provide a cosmetic, pharmaceutical, nutritious or organoleptic product that expresses the desired properties of the active compound.

Example 1: Preservation of Ascorbic Acid (AA) Via Encapsulation in Oil-Filled Calcium-Aliginate Capsules

[0074] AA is encapsulated in oil-filled aliginate capsules. Specifically: [0075] (i) creation of a preserved AA laden sample.

[0076] 50% (w/v) AAsodium salt (sodium L-ascorbate) is dissolved in water, which is then emulsified in sunflower oil. Stable surfactant-free water-in-oil (w/o) emulsion is generated by shaking and ultrasonically treating degassed water and oil solutions.

[0077] The AA-laden w/o emulsion is kept at 70° C. while it is jetted with a flow rate of 13 ml/min from the centre nozzle of a coaxial nozzle assembly (OD=1.6 mm and ID=0.41 mm) as disclosed in the aforementioned co-pending European patent application by applicant, that published as EP3.436.188 A1, whose subject matter is incorporated by reference.

[0078] Concurrently a 0.5% (w/v) sodium aliginate in water solution (WAKO, 1%.sup.˜80-120 cP) of room temperature is jetted from the outer nozzle of the same coaxial nozzle assembly at a flow rate of 55 ml/min, resulting in a compound jet consisting of AA-laden w/o emulsion encapsulated by a sodium aliginate solution. The coaxial nozzle is modulated, using a vibrating element at a frequency of approximately 150 Hz which causes the controlled breakup of the compound jet into a stream of substantially mono-disperse, i.e. substantially uniformly sized, compound droplets with typically a coefficient of variation in size or diameter of less than 10%.

[0079] Via a so called ‘in-air microfluidics’ method, as described in the aforementioned co-pending application (EP 3.436.188), the droplet stream was combined with an intact, i.e. uninterrupted jet of 0.2 M calcium in water solution, resulting in the formation of compound hydrogel capsules consisting of a calcium-aliginate shell layer filled with a core of AA-laden w/o emulsion. These hydrogel capsules were stored in water and incubated for 6 weeks at 40° C. [0080] ii creation of a non-preserved AA laden reference sample

[0081] For comparison purposes a non-preserved AA control sample was created by dissolving 0.5% (w/v) AA in water, i.e. having a same final concentration as the preserved sample. Also this non-preserved AA in water solution was incubated for 6 weeks at 40° C.

[0082] Comparing a colour change of the preserved sample to that of the similarly incubated (6 weeks at 40° C.) reference solution showed a brown colouring of the reference solution, that is typical for the oxidation product of AA, while the preserved sample showed no significant colouring. This reveals that the encapsulation of AA in oil-filled capsules, according to the invention, reduces colouring, indicating suppression or even prevention of AA degradation.

Example 2: Both Physical Encapsulation and the Presence of Calcium

[0083] To investigate the mechanism of AA preservation via encapsulation in calcium-aliginate shells, three conditions were compared: [0084] (i) AA preserved as described in experiment 1; [0085] (ii) Non-preserved control: same as (i), but using a 0.2M sodium chloride solution instead of a 0.2M calcium chloride solution, which will prevent the formation of gelled calcium-aliginate capsules and thus the encapsulation of the AA-laden w/o emulsion; [0086] (iii) Non-preserved control: same as (i), but the 0.2M calcium chloride jet was not impacted with the compound droplets prior to collection in the collector bath, which prevents the in-flight formation of stable calcium-aliginate capsules and thus the encapsulation of the AA-laden w/o emulsion.

[0087] The concentration of AA in all conditions was at least 5% (w/v) in the w/o emulsions and at least 0.5% (w/v) in the final sample volumes. Comparison of the colour change after incubation at 40° C. for 4 weeks showed no significant colouring of the preserved sample (1), comprising AA-laden hydrogel capsules having a calcium cross-linked aliginate shell layer, while sample (ii) showed significant browning after 4 weeks and sample (iii) showed slight colouring. This revealed that the presence of divalent calcium ions has a preserving effect on AA.

Example 3: Oil-Filled Capsules Using Pickering Emulsifiers

[0088] Fumed silica nanoparticles post-treated with dimethyl-dichlorosilane (DDS) (Evonik, Aerosil R972) were added to the core of the capsules by dispersing 2% (w/v) of nano-particles in the oil phase. The oil that contains hydrophobized silica particles is then processed following the same method as described in example 1, except that a supersaturated AA-solution containing 100% (w/v) was used. In this example calcium carbonate (CaCO.sub.3) is added to the dispersed AA-lade phase before emulsification to load the capsules with excess CaCO.sub.3 that will aid in maintaining a stable the calcium-aliginate shell over time.

[0089] This creates AA-laden silica-oil filled calcium-aliginate capsules, having a final AA concentration in the w/o emulsion (i.e. the core compound) of at least 10% (w/v), a final CaCO.sub.3 concentration in the w/o emulsion of 2% (w/v) and a final hydrophobized silica concentration in the w/o emulsion of 2% (w/v). The capsules were washed two times with demineralised water and incubated in demineralised water at 40° C. for 23 days.

[0090] After 23 days the samples showed no significant colouring, revealing an effective preservation of both the AA active compound in the dispersed phase as well as of the w/o emulsion itself and the surrounding calcium-aliginate shell layer.

Example 4: Oil-Filled Capsules Using Pickering Emulsifiers in Core and Additives in Shell

[0091] Fumed silica nano-particles are post-treated with dimethyl-dichlorosilane (DDS) (Evonik, Aerosil R972) and added to the core of the capsules by dispersing 4% (w/v) of nano-particles in an oil phase. The oil that contains these hydrophobized silica particles and is processed following the same method as described in example 1 together with a aqueous solution of ascorbic acid to form an emulsion, except that a saturated L-ascorbic acid fine powder containing 40% (w/v) was used for the solution.

[0092] Further 0.5% laponite XL21XR nano-clay is added to the 0.5% aliginate phase in the shell during the encapsulation. This creates AA-laden silica-oil filled calcium-aliginate/laponite capsules, having a final AA concentration in the w/o emulsion (i.e. the core compound) of at least 10% (w/v), and a final hydrophobized silica concentration in the w/o emulsion of 4% (w/v).

[0093] The capsules are washed two times with demineralised water and incubated in demineralised water, 0.2M CaCl2+10 wt % ethanol solution, clear hand gel, shampoo, and body lotion at 40° C. for 4 weeks. After 4 weeks the samples showed no significant colouring compared to a similar sample containing the same emulsion without encapsulation and L-ascorbic acid bulk solution in water. This reveals an effective preservation of both the AA active compound in the dispersed phase as well as of the w/o emulsion itself by the surrounding calcium-aliginate shell layer.

Example 5: Agar Reinforced Encapsulated Capsules

[0094] Similar capsules are prepared same as in example 4, but additionally 0.5 wt % agar solution was used for forming the shell composition. This results in ascorbic acid containing emulsion capsules within a 1% laponite XL21XR/0.5% aliginate/0.5% agar solid shell layer. These capsules were stored for 4 weeks in water, shampoo, body lotion and 0.2M CaCl2+10% ETOH to show hardly no colouring compared to the bare emulsion in the same base.

Example 6: Layer-by-Layer Coating of the Solid Shell

[0095] Capsules are prepared similar to example 4, but with coating by a layer using electrostatically interaction of layer-by-layer method (LBL). The aliginate shell is coated by a positively charged biopolymer, such as chitosan, to enhance the barrier property and stability of L-ascorbic acid. Chitosan is applied as a polycationic polymer to ionically crosslink the aliginate shell. Initially, a stable 5 wt % chitosan stock solution is prepared in aid of 1% (v/v) hydrochloric acid (HCl) while stirring for several hours at 50° C. Afterwards, the 5 wt % chitosan solution is neutralized by adjusting the PH to about 6-7 while adding sodium hydroxide (NaOH) solution. Then the neutralized solution is diluted to make a 0.5 wt % chitosan solution to be used in the coating process.

[0096] Vitamin C encapsulated beads (capsules) in an aliginate shell are coated by a chitosan/aliginate bilayer. First the capsules are rinsed with water and then incubated in 0.5 wt % neutralized chitosan solution while stirring slowly for 15 min. The incubated beads are filtered and rinsed with water, then incubated and stirred slowly in 0.5 wt % of aliginate solution for another 15 min. To avoid the aggregation of capsules, slow movement (stirring) is applied while incubating the beads. To achieve a denser coating, a salt solution (NaCl solution) is applied to coat the same capsules by ionic crosslinking of chitosan/aliginate. The purpose of using salts is to ensure attaining a stable thickness by alternating deposition. 0.8M NaCl solution is applied in all incubation and rinsing steps.

Example 7: Improved Stabilization Using Solidified Solid Wax Particles

[0097] Similar capsules are prepared same as in example 4, but instead of fumed silica nano-particles, 2 wt % micronized carnauba wax (Microcare 350, Micro Powder Inc.) is added to the oil phase (i.e., the second liquid). Alternatively, a sample is prepared containing an oil phase with 4 wt % hydrophobized fumed silica as well as 2 wt % micronized carnauba wax. The capsules are then incubated for 0.5, 1, 2, 5, 10, and 20 minutes at 40, 60, 75, or 90 degrees Celcius. 5 minutes incubation at 90 degrees appears optimal for melting the micronized wax particles in the capsules in order to render the emulsion more stable after the wax has again solidified in the oily phase.

[0098] The capsules were tested for ascorbic acid stability by incubating them in water, shampoo, body lotion and 0.2M CaCl.sub.2+10% ETOH, at 40 degrees Celsius. After this treatment the capsules show hardly no yellow colouring as compared to the same particles that were mechanically disrupted at the start of the stability test, indicating an improved chemical stability (i.e., preservation) of the encapsulated ascorbic acid within capsules containing a Pickering and wax stabilized emulsion of the dispersed ascorbic acid aqueous phase.

Example 8: Electrostatically Loading the First Liquid

[0099] An aqeuous phase from the below list was added to 6% wt Aerosil R972 to act as Pickering stabilizer in sunflower oil. Three homogenization cycles using T25 Ultra-Turrax with 525N-25F dispering element were applied to form a Pickering emulsion: 1 cycle of 2 min at 10.000 rpm and 2 cycles of 1 min at 10.000 rpm. In between the cycles the emulsion was mixed manually to ensure a total incorporation of the phases. [0100] 1. Water [0101] 2. Water+1 wt % NaCl [0102] 3. Water+HCl (pH 2) [0103] 4. Water+20 wt % hyaluronic acid [0104] 5. Water+20 wt % hyaluronic acid+1 wt % NaCl [0105] 6. Water+2 wt % carrageenan [0106] 7. Water+2 wt % acacia gum [0107] 8. Water+2 wt % acacia gum+1 wt % NaCl [0108] 9. Water+1 wt % chitosan

[0109] The resulting emulsion of samples 4-7 appeared to be significantly more stable as the other samples. This supports that the water-in-oil Pickering emulsion based on negatively charged Aerosil R972 as Pickering agent is further stabilized by the addition of polyanionic polymers or (negatively charged) glycosaminoglycans, notably by hyaluronic acid, carrageenan or acacia gum, to the aqueous phase.

[0110] Although the invention has been described herein before with reference to merely a limited number of explanatory embodiments, it should be understood that the invention is by no means limited to those examples. On the contrary many more variations and embodiments are feasible to a skilled person within the framework of the present invention without requiring him or her to exercise any inventive skill. Particularly, further components other than the first fluid may also contain one or more active compounds, notably also the hydrophobic second fluid. The first fluid may be emulsified directly with the second fluid or may find itself in an emulsion with one or more further fluids to be jointly emulsified or mixed with the second fluid. Also the second fluid may itself consist of an emulsion with a further fluid. Each fluid may be used as a carrier for one or more specific active compounds or ingredients.