Pharmaceutical compositions are provided comprising an active agent and a dextran polymer derivative. The compositions include from 0.01 to 99 wt % of an active agent and from 1 to 99.99 wt % of a dextran polymer derivative. The dextran polymer derivative is selected from dextran acetate, dextran propionate, dextran succinate, dextran acetate propionate, dextran acetate succinate, dextran propionate succinate, dextran acetate propionate succinate, and mixtures thereof.