The invention provides polymers and methods for their use. Specifically, certain embodiments of the present invention provide a polymer that comprises a plurality of salicylic acid-adipic (SA-Adipic) units of the following formula and a plurality of salicylic acid-diethylmalonic (SA-DEM) units of the following formula Certain embodiments of the invention also provide slow degrading microspheres comprising polymers described herein for undelayed and sustained drug delivery. Certain embodiments of the present invention provide methods for treating a chronic eye disease or arthritis in a patient, comprising administering to the patient a therapeutically effective amount of a polymer or microsphere as described herein.