Abstract: The present invention relates to a drug release formulation, in particular a sustained release formulation for ophthalmic applications and a method of preparing same. The method is based on the hydration of a given solid polymeric matrix material under mild conditions, allowing versatility with respect to the drug to be formulated. Both said solid polymeric matrix material as well the API hydrated formulation is an object of the present invention. The thus obtained material is particularly suitable for prolonged and sustained delivery of medication to the eye. Thus in a further aspect, the present invention provides the use of said solid polymeric matrix material as well the API hydrated formulation, in ophthalmic applications.