The present invention provides a flowable composition suitable for use as a controlled release implant. The flowable composition can be administered into the ocular region of a mammal. The composition includes: (a) a biodegradable, biocompatible thermoplastic polymer that is at least substantially insoluble in aqueous medium, water or body fluid; (b) a biological agent, a metabolite thereof, a biological agently acceptable salt thereof, or a prodrug thereof; and (c) a biocompatible organic liquid, at standard temperature and pressure, in which the thermoplastic polymer is soluble. The present invention also provides methods of medical treatment that include administering the flowable composition into the ocular region of a mammal.