Stable suspensions useful for controlled release of active agents, e.g. cosmetics or plant protectants, obtained by forming multiple emulsion from water-in-oil inverse emulsion and aqueous phase and cooling

摘要

Aqueous particle suspension (A) is obtained by (a) preparing a water-in-oil inverse emulsion from an internal aqueous phase and an organic phase, (b) preparing a multiple emulsion by dispersing the emulsion from (a) in an external aqueous phase at or above the m. pt. of 35 deg C, and (c) cooling to or below 35 deg C. Aqueous particle suspension (A) is obtained by: (1) preparing a water-in-oil inverse emulsion from an internal aqueous phase containing hydrophilic active agent(s) (I) and an organic phase comprising hydrophobic compound(s) (II) of m. pt. 35 deg C or more and nonionic or cationic surfactant(s) (or amphiphilic polymer(s)), at or above the m. pt. of (II); (2) preparing a multiple emulsion by dispersing the emulsion from (a) in an external aqueous phase containing polyoxyalkylene nonionic surfactant(s) (and/or amphiphilic polymer(s)) and anionic surfactant(s), at or above the m. pt. of (II); and (3) cooling to or below the m. pt. of (II). An Independent claim is also included for granules (B) obtained by drying (A), by contact with desiccant(s).