A coordination complex having a physiologically acceptable pKa includes a metal and a biologically active agent. The pKa of the coordination complex is less than the pKa of the biologically active agent. A pharmaceutical solution for treating a patient includes a coordination complex and water, wherein the coordination complex is at least partially soluble in the water at physiological pH and in a therapeutically efficacious concentration. A method for treating a patient includes administering a pharmaceutical solution including a coordination complex and water to a patient in need of a biologically active agent.
