The invention relates to an injectable composition for rapid and sustained delivery of a biologically active agent and to uses of the injectable composition in the treatment or prevention of a condition in a subject. The injectable composition comprises a water-in-oil emulsion having an aqueous phase dispersed in an oil phase. The aqueous phase comprises a plurality of hydrogel particles and an aqueous liquid and a biologically active agent is contained in the hydrogel particles and in the aqueous liquid.