Microcapsules containing an oxidizable active, and a process for preparing the same

Abstract

Disclosed is a microcapsule including a core having an oxidizable active (OA), the outer part of said core being in a solid form, and a water insoluble coating obtained from an encapsulating agent (EA), with the coating surrounding said core. In particular, the EA can be water soluble or organic solvent soluble, in particular in ethanol. The microcapsule can also include an EA in which the water solubility is pH-dependent. Also, the core does not contain a metal oxide, and the coating does not include a disintegrant, such as sodium starch glycolate. Also disclosed is a process for preparing the microcapsules.

1 . A microcapsule consisting of or comprising:
 a core consisting of or comprising an oxidizable active (OA), the outer part of said core being in a solid form, and   a water insoluble coating obtained from an encapsulating agent (EA), said coating surrounding said core,   wherein said EA is water soluble, organic solvent soluble, or an agent having a water solubility that is pH-dependent,   wherein said OA is selected from the group consisting of dihydroxyacetone, omega 3 oil and omega 6 oil,   with the proviso that:   said core does not comprise a metal oxide, and   said coating does not comprise a disintegrant.   
     
     
         2 . The microcapsule according to  claim 1 , wherein said EA is water soluble or organic solvent soluble and said water insoluble coating is induced by one of
 an agent chemically reacting with said EA,   an acid, a base, or a buffer for adjusting pH of said EA, and   drying of said EA.   
     
     
         3 . The microcapsule according to  claim 1 , wherein said coating is such that, when said microcapsule is placed in an alimentary, cosmetically or pharmaceutically acceptable medium:
 said OA is not degraded by element(s) of said medium, and   said element(s) of the medium is (are) not degraded by said OA.   
     
     
         4 . The microcapsule according to  claim 1 , wherein said coating has a mass within the range from 3 to 50% of the total mass of said microcapsule. 
     
     
         5 . The microcapsule according to  claim 1 , wherein said microcapsule has a size in a range from 1 μm to 3 mm. 
     
     
         6 . The microcapsule according to  claim 1 , wherein said OA is:
 in a crystalline state, wherein said core consists of or comprises an OA in a crystalline state and at least one additional element selected from the group consisting of drying agents, antioxidant agents, filmogen agents and emulsifying agents, or   in an amorphous state, wherein said core consists of or comprises an OA in an amorphous state and at least one additional element selected from the group consisting of drying agents, antioxidant agents, filmogen agents and emulsifying agents.   
     
     
         7 . The microcapsule according to  claim 1 , wherein said EA is water soluble and selected from alginates of monovalent cations, and water insolubility is induced by a salt having a divalent metallic cation. 
     
     
         8 . The microcapsule according to  claim 1 , wherein said EA that is water soluble or organic solvent soluble is lac gum, and water insolubility is induced by drying said lac gum, or by adjusting pH of said EA with an acid selected from the group consisting of ascorbic acid, citric acid, acetic acid and hydrochloric acid. 
     
     
         9 . The microcapsule according to  claim 1 , wherein said OA is dihydroxyacetone, omega 3 oil or omega 6 oil or comprises dihydroxyacetone, omega 3 oil or omega 6 oil and wherein said EA is water soluble and selected from alginates of monovalent cations. 
     
     
         10 . The microcapsule according to  claim 9 , wherein said EA is a Na +  alginate or a K +  alginate, and the water insolubility is induced by a salt having a divalent metallic cation. 
     
     
         11 . The microcapsule according to  claim 10 , wherein the water insolubility is induced by a salt has Ca 2+  or Mg 2+  as the divalent metallic cation.