Process for preparing submicron particles in the presence of lipid vesicles, and corresponding compositions

A process for preparing submicronic particles in the presence of lipidic vesicles comprising

• (a) preparing a dispersion of lipidic vesicles from (i) at least one nonionic amphiphilic lipid capable of forming vesicles, (ii) an aqueous phase to be encapsulated in said vesicles, and (iii) an aqueous phase forming a dispersion medium in which said vesicles are dispersed,
• (b) dissolving at least one precursor of said submicronic particles in
• (i') said aqueous phase to be encapsulated in said vesicles, or in
• (ii') said aqueous phase forming said dispersion medium for said vesicles, or in
• (iii') both (i') and (ii'),
• said precursor being at least one indolic compound or at least one indolinic compound or a mixture thereof,
• said precursor being dissolved in (i'), or (ii') or (iii'), at a time
• (1) before the preparation of a vesicular phase, or
• (2) during the preparation of a vesicular phase, or
• (3) after the preparation of a vesicular phase, or
• (4) both times (1) and (2) or both times (2) and (3), and
• (c) adding to said precursor at a time (1) or (2) or (3) or (4), defined above, an agent capable of transforming said precursor into said submicronic particles so as to react with said precursor thereby forming said submicronic particles at the exterior of said vesicles or at both the interior and exterior of said vesicles.

A process for preparing submicronic particles of a metallic sulfide pigment in the presence of lipidic vesicles comprising

• (a) preparing a dispersion of lipidic vesicles from (i) at least one lipid capable of forming vesicles, (ii) an aqueous phase to be encapsulated in said vehicles, and (iii) an aqueous phase forming a dispersion medium in which said vesicles are dispersed,
• (b) dissolving at least one metallic sulfide pigment in
• (i') said aqueous phase to be encapsulated in said vesicles, or
• (ii') in said aqueous phase forming said dispersion medium for said vesicles, or
• (iii') both (i') and (ii'), and said at least one metallic sulfide pigment being dissolved in (i'), (ii') or (iii'), at a time
• (1) before the preparation of a vesicular phase, or
• (2) during the preparation of a vesicular phase, or
• (3) after the preparation of a vesicular phase, or
• (4) both times (1) and (2) or both times (2) and (3), and
• (c) adding to said at least one metallic sulfide pigment at a time (1) or (2) or (3) or (4), define above, a precipitation agent capable of transforming said at least one metallic sulfide pigment into said submicronic particles thereby forming said submicronic particles at the exterior of said vesicles or at both the interior and exterior of said vesicles.