CAPSULE COMPRISING ACTIVE INGREDIENT

Abstract

The present invention relates to a capsule with a core/shell structure, comprising a core which comprises at least one sparingly water-soluble or water-insoluble organic active ingredient, to a method for producing such capsules having a core/shell structure, to the use of the capsules having the core/shell structure and to preparations comprising the capsules having the core/shell structure.

Claims

1.-14. (canceled)

15. A method for producing capsules with a core/shell structure, comprising in each case a core which comprises at least one sparingly water-soluble or water-insoluble organic active ingredient selected from an organic UV filter, and a shell which directly surrounds the core, where the shell comprises nanoparticles of a metal oxide or semimetal oxide and these nanoparticles are joined together by at least one further metal oxide or semimetal oxide, where the further metal oxide or semimetal oxide joining the nanoparticles has been formed by hydrolysis and subsequent polycondensation of a water-insoluble or sparingly water-soluble sol-gel precursor, comprising the steps i) preparation of an oil-in-water emulsion by emulsifying an oil phase which comprises at least one water-insoluble or sparingly water-soluble sol-gel precursor and at least one sparingly water-soluble or water-insoluble organic active ingredient in a water phase which comprises nanoparticles of a metal oxide or semimetal oxide, using shear forces, ii) establishment of a pH in the aqueous phase of the emulsion at a value at which the hydrolysis and the subsequent polycondensation of the water-insoluble or sparingly water-soluble sol-gel precursor to form the shell surrounding the core takes place, and iii) optionally, purification and/or isolation of the capsules with core/shell structure produced in step ii), where the capsule comprises no organic surfactants.

16. The method according to claim 15, where, in step iii), a pH between 8 and 11 is established.

17. A capsule with a core/shell structure, comprising a core which comprises at least one sparingly water-soluble or water-insoluble organic active ingredient selected from an organic UV filter, and a shell which directly surrounds the core, where the shell comprises nanoparticles of a metal oxide or semimetal oxide and these nanoparticles are joined together by at least one further metal oxide or semimetal oxide, where the further metal oxide or semimetal oxide joining the nanoparticles has been formed by hydrolysis and subsequent polycondensation of a water-insoluble or sparingly water-soluble sol-gel precursor, where the capsule comprises no organic surfactants.

18. The capsule according to claim 17, where the metal oxide or semimetal oxide of the nanoparticles and the metal oxide or semimetal oxide formed by hydrolysis of the water-insoluble or sparingly water-soluble sol-gel precursor are in each case silicon dioxide.

19. The capsule according to claim 17, where the capsule has a particle size of from 0.5 to 20 m.

20. The capsule according to claim 17, where the nanoparticles consist of silica gel and have an average particle size of from 5 to 100 nm.

21. The capsule according to claim 17, where the capsule has a transparent shell.

22. The capsule according to claim 17, wherein the water-insoluble or sparingly water-soluble sol-gel precursor used is tetraethoxysilane.

23. A capsule comprising pulverulent or liquid preparations and having a core/shell structure according to claim 17.

24. A cosmetic, pharmaceutical composition, crop protection preparation, animal feed, food or nutritional supplement comprising the capsules having a core/shell structure according to claim 17.

25. A cosmetic, pharmaceutical composition, crop protection preparation, animal feed, food or nutritional supplement comprising the capsules having a core/shell structure produced by the method according to claim 15.

26. The capsule according to claim 17 wherein a mass fraction of the core relative to a total mass of the capsule is from 60 to 90% by weight.

27. The capsule according to claim 17 wherein the core contains more than 90% by weight of the at least one sparingly water-soluble or water-insoluble organic active ingredient.

Description

EXAMPLES

Example 1) Encapsulation of Diethylamino Hydroxybenzoyl Hexyl Benzoate (Uvinul A Plus)

[0077] 24 g of Diethylamino Hydroxybenzoyl Hexyl Benzoate (Uvinul A Plus) were dissolved at 60 C. in 48 g of tetraethoxysilane. This solution (oil phase) was cooled to room temperature (22 C.). The oil phase was then homogenized with an aqueous solution of colloidal silica gel (LUDOX LS 30) consisting of 7.2 g of silica gel (average particle size 12 nm; 220 m.sup.2 surface area per g of silica gel; pH of the surface: 8), 3.6 g of sodium chloride and 288 g of water using a high-pressure homogenizer (M-110F Microfluidizer, Microfluidics) at 500 bar for 2 minutes. The formed emulsion was admixed with stirring (magnetic stirrer) with 25 g of sodium tetraborate buffer solution (pH 9) and stirred for 24 hours.

[0078] The particle size distribution of the formed capsules was determined by means of light scattering in accordance with ISO 13320-1 (Microtrac S3500 Bluewave from Microtrac):

d50=0.5 m.

Example 2) Encapsulation of Ethylhexyl Triazone (Uvinul T 150)

[0079] 10 g of Ethylhexyl Triazone (Uvinul T 150) were dissolved at room temperature (22 C.) in 50 g of ethyl acetate. 40 g of tetraethoxysilane were added thereto. The oil phase prepared in this way was homogenized at room temperature (22 C.) with an aqueous solution of colloidal silica gel (LUDOX TM 40) consisting of 1.0 g of silica gel (average particle size 22 nm; 140 m.sup.2 surface area per g of silica gel; pH of the surface: 9) and 290 g of water using an ultrasound rod (200 W, 7 mm) for 2 minutes. The formed emulsion was admixed with stirring (magnetic stirrer) with 25 g of sodium tetraborate buffer solution (pH 9) and stirred for 24 hours.

[0080] The particle size distribution of the formed capsules was determined by means of light scattering in accordance with ISO 13320-1 (Microtrac S3500 Bluewave from Microtrac):

d50=1.0 m.

Example 3) Encapsulation of resorcinol bis(diphenylphosphate) (PDP)

[0081] 24 g of resorcinol bis(diphenylphosphate) were dissolved at room temperature (22 C.) in 48 g of tetraethoxysilane. The oil phase prepared in this way was homogenized at room temperature (22 C.) with an aqueous solution of colloidal silica gel (LUDOX SM 30) consisting of 7.2 g of silica gel (average particle size 7 nm; 350 m.sup.2 surface area per g of silica gel; pH of the surface: 10) and 288 g of water using a high-pressure homogenizer (M-110F Microfluidizer, Microfluidics) at 500 bar for 5 minutes. The formed emulsion was admixed with stirring (magnetic stirrer) with 25 g of sodium tetraborate buffer solution (pH 9) and stirred for 24 hours.

[0082] The particle size distribution of the formed capsules was determined by means of light scattering in accordance with ISO 13320-1 (Microtrac S3500 Bluewave from Microtrac):

d50=0.7 m.

Example 4) Encapsulation of linalyl acetate

[0083] 10 g of linalyl acetate (boiling point: 220 C.; CAS number: 115-95-7) were dissolved at room temperature (22 C.) in 20 g of tetraethoxysilane and 10 g of white oil. The oil phase prepared in this way was homogenized at room temperature (22 C.) with an aqueous solution of colloidal silica gel (LUDOX LS 30) consisting of 2.0 g of silica gel (average particle size 12 nm; 220 m.sup.2 surface area per g of silica gel; pH of the surface: 8) and 250 g of water using a high-pressure homogenizer (M-110F Microfluidizer, Micro-fluidics) at 500 bar for 5 minutes. The formed emulsion was admixed with stirring (magnetic stirrer) with 25 g of sodium tetraborate buffer solution (pH 9) and stirred for 24 hours. The prepared sample was called sample A.

[0084] The particle size distribution of the formed capsules of sample A was determined by means of light scattering in accordance with ISO 13320-1 (Microtrac S3500 Bluewave from Microtrac):

d50=0.8 m.

[0085] 10 g of linalyl acetate (boiling point: 220 C.; CAS number: 115-95-7) were dissolved at room temperature (22 C.) in 26 g of tetraethoxysilane and 10 g of white oil. The oil phase prepared in this way was homogenized at room temperature (22 C.) with a solution of 1.0 g of cetyltrimethylammonium chloride (CTAC) in 250 g of water using a high-pressure homogenizer (M-110F Microfluidizer, Microfluidics) at 500 bar for 5 minutes. The formed emulsion was admixed with stirring (magnetic stirrer) with 25 g of sodium tetraborate buffer solution (pH 9) and stirred for 24 hours. The prepared sample was called sample B.

[0086] The particle size distribution of the formed capsules of sample B was determined by means of light scattering in accordance with ISO 13320-1 (Microtrac S3500 Bluewave from Microtrac):

d50=0.8 m.

[0087] To remove the water, the samples A and B were in each case firstly spray-dried using a B-290 mini-spray dryer (Bchi, Switzerland). The spray-drying was carried out under the following conditions: entry temperature of ca. 120 C.; exit temperature of ca. 55 C.; use of a twin-material nozzle; use of nitrogen as spray gas.

[0088] The fine powders were dried further for 30 minutes using a HR73 moisture analyzer from Mettler Toledo at 105 C. The weight loss of the powder from sample A before and after the drying at 105 C. was ca. 4.5% by weight; the weight loss of the powder from sample B before and after drying at 105 C. was ca. 9.0% by weight.

[0089] The fine powders were dried further at 130 C. for 15 minutes. The weight loss of the powder from sample A before and after drying at 130 C. was ca. 7.8% by weight; the weight loss of the powder from sample B before and after drying at 130 C. was ca. 13.2% by weight.

[0090] The powder prepared from sample A exhibits better thermal stability than the powder prepared from sample B.