The present invention relates to a gel having a three dimensional matrix structure and a drug in the form of a solid contained within the three dimensional matrix. Gels of the invention are preferably for implantation into a patient. Storing the drug as a solid within the gel means that the drug density is high in those areas of the gel which contain solid drug. The high drug density means that a larger amount of drug can be stored in a gel of a given size relative to the amount of drug that can be stored as individual molecules. The large deposit of solid drug means that the gel can sustain release of the drug for an extended period of time. This is advantageous because it minimises the frequency of replacement or replenishment of the implanted gel, thereby minimising discomfort and inconvenience to the patient.