Drug delivery involving hydrogels as used for various medical conditions, and includes hydrogels formed in an eye with extended drug release times. An embodiment of the invention is a method of delivering a therapeutic agent to a tissue comprising forming a hydrogel in situ in an eye with a therapeutic agent dispersed in the hydrogel, the agent having a low solubility in water. The agent may be essentially insoluble in water. The hydrogel may be made so that 50% to 100% w/w of the agent is released when the hydrogel is from 100% to 50% persistent, with the persistence being a measure of the dry weight of the hydrogel relative to an initial dry weight of the hydrogel.