Embolic microspheres

Injectable particles comprising:

• a biostable core;
• and
• a coating comprising at least one pH-altering agent that is configured to be released from the injectable particles in vivo upon embolization of an intratumoral artery of a tumor with the injectable particles,
• wherein the at least one pH-altering agent includes a basic agent having a pH of 7.5 or more and a buffering agent having a pKa value of 7.6 or more, and
• the pH-altering agent includes at least one of a carbonate, a bicarbonate, and a phosphate,
• wherein the pH-altering agent is configured to be released from the injectable particle by a mechanism selected from (a) diffusion from all or a portion of the injectable particles, (b) biodisintegration of a portion of the injectable particles wherein the injectable particles further comprise a biodisintegrable polymer, or (c) or a combination of (a) and (b).