The present disclosure provides formulations for pharmacologically active reagents, including formulations based on particulates formed from a biodegradable polymer (e.g., a polysaccharide such as dextran) linked to a vitamin or related agent (e.g., folic acid). Hydrophobic pharmaceutically active agents (such as anti-cancer drugs, e.g., paclitaxel) are encapsulated into the polysaccharide-vitamin conjugate for the administration of paclitaxel. The active agent is in a core portion of the particulate, instead of on the surface of the particulate. Processes for making and using the particulates and compositions comprising the same are also disclosed. In particular, methods of cancer diagnosis and treatment are provided.
