Core stabilized microcapsules, method of their preparation and uses thereof
The present invention provides core-stabilized microcapsules, wherein said core comprises at least one active agent encapsulated within an inorganic oxide shell, processes for their preparations, comparisons comprising them and uses thereof.
1. A process for preparing microcapsules having a core encapsulated within an inorganic oxide shell, wherein said core comprises at least one active agent and at least one phase changing material, said process comprising:
(a) preparing an oil-in-water emulsion by emulsification of an oily phase comprising at least one active agent, at least one phase changing material and a sol-gel precursor, in an aqueous phase, wherein said aqueous phase comprises at least one inorganic metal salt;
(b) adjusting the pH of the emulsion to be in the range of 3 to 5; and
(c) subjecting said emulsion to microcapsule forming conditions; thereby obtaining said microcapsules;
wherein said at least one phase changing material is not liquid at room temperature, and wherein said core has a viscosity of from about 300 cP to about 1,000,000 cP.
2. The process according to claim 1 wherein said at least one active agent is selected from the group consisting of a pharmaceutical agent, a cosmetic agent and a dermatological agent.
3. The process according to claim 1 , wherein said at least one active agent is a dermatological agent selected from the group consisting of anti-fungal agents, anti-bacterial agents, anti-inflammatory agents, antipruritic agents, anti-psoriatic agents, anti-acne agents, anti-rosacea agents, and any combinations thereof.
4. The process according to claim 1 , wherein said at least one active agent is an anti-acne agent selected from the group consisting of benzoyl peroxide, retinoid, and mixtures thereof.
5. The process according to claim 1 , further comprising adding at least one inorganic oxide nanoparticle to said aqueous phase prior, during or after preparation of oil-in-water emulsion of step (a).
6. The process according to claim 1 , further comprising adding an inorganic oxide salt to said aqueous phase prior, during or after emulsification of step (a).
7. The process according to claim 1 , wherein said oily phase comprises a sol-gel precursor.
8. Microcapsules obtained by the process according to claim 1 .
9. The process according to claim 1 , wherein said phase changing material is selected from the group consisting of natural or synthetic paraffins, waxes, C 10 -C 100 alkane, C 10 -C 100 alkene, C 10 -C 100 alkyne, aliphatic alcohols, aliphatic fatty acids, and any combination thereof, wherein said aliphatic fatty acid has a molecular formula of CH 3 (CH 2 ) n COOH, and wherein n=10-100.