A fluid transfer device (50) for use with a medicinal vial (20) that has a longitudinal axis of vial (20A) and that includes a vial body (21) that has a vial interior (28) for storing a medicament, a vial flange (22) defining a vial opening (24), a narrow neck (23) intermediate between the devial body and the vial flange, a vial cap (26) that seals the vial opening and having a thickness of the cap T near the vial axis, the vial cap having an upper cap surface (26A), the fluid transfer device comprising: a) a vial adapter (31) having a longitudinal axis of the adapter ( 31A) and including a top wall (32) transverse to said adapter shaft, a skirt suspended downwards (33) with flexible members (34) to fit by pressure on the vial flange for concentric mounting of said adapter for vials on the vial, a tubular cannula (36) having a tip pointed (37) to initially contact the vial cap (26) at a drilling site and drill through it to establish flow communication with the inside of the vial in said pressure-fitting assembly, and a flow communication channel ( 38) in flow communication with said cannula (36)； and b) an elastic sealing element similar to an O-ring (51) that surrounds it so that it can seal it to said cannula, said sealing element being initially arranged next to said cannula and separated from said upper wall (32) and said cannula tip (37 ) to leave a length of the exposed cannula L between said sealing element and said tip of the cannula, said sealing element arranged with respect to said cannula so that, in use, during mounting of the vial adapter on the vial, the sealing element is Initially contacts the vial cap after said tip of the cannula comes into contact with the vial cap at said perforation site and then is pushed so that it can slide towards said upper wall to continuously seal said perforation site during the pressure-fitting assembly of said paravial adapter on the vial.Un dispositivo de transferencia de fluido (50) para su uso con un vial medicina
