A process for preparing water-dispersible single-chain polymeric nanoparticles

A process for preparing a water-dispersible single-chain polymeric nanoparticle, which comprises cross-linking a polymer having a solubility equal to or higher than 100 mg per litre of water, and an amount of complementary reactive groups comprised from 5 to 60 molar % of the total amount of monomer units present in the polymer chain;

• with a homobifunctional crosslinking agent having crosslinkable groups;
• by
• (a) Adding an aqueous solution of the polymer to an aqueous solution of the homobifunctional crosslinking agent at an addition rate that allows having during the addition of the polymer a concentration of the crosslinkable groups of the polymer in the solution of the homobifunctional crosslinking agent comprised from 10−3 to 10−7 molar;
• or alternatively,
• (a′) Adding an aqueous solution of the homobifunctional crosslinking agent to an aqueous solution of the polymer at an addition rate that allows having during the addition of the homobifunctional crosslinking agent a concentration of the homobifunctional crosslinking agent in the solution of the polymer comprised from 10−3 to 10−7 molar;
• at a temperature comprised from 20 to 25° C. in the absence of a catalyst;
• wherein the water-dispersible single-chain polymeric nanoparticle has a particle size comprised from 3 to 30 nm and a polydispersion of the particle equal to the polydispersion of polymer ±20%;
• optionally the process further comprises an additional step of purifying the water-dispersible single-chain polymeric nanoparticle, and
• optionally the process further comprises an additional step of drying the water-dispersible single-chain polymeric nanoparticle.