Implantable, refillable infusion device

An implantable infusion device comprising: a housing (12) including an inner wall and having defined at least in part by the inner wall an inner region (15), defining at least a portion of the inner region one infusate reservoir (16) adapted to store therein a infusate (18) for administration to a patient; a closed chamber (30) of variable volume having an outer wall, the variable volume chamber being disposed within the interior region of the housing, the outer wall of the variable volume chamber spaced from the inner wall of the housing being and being the variable volume chamber located freely within the interior region of the housing; a pressure source (P) contained within the variable volume chamber; a flow path fluid infusate recharging (31) adapted to recharge the infusate reservoir carrying infusate to said infusate reservoir through or along the inner wall of the housing from which the variable volume chamber is supported within the inner region; and a flow path outlet fluid (25) adapted to deliver infusate from infusate reservoir out of the housing.