Patent ID: 7645271

Claim:
A pressure regulating adaptor for coupling with a closed vial, the adaptor comprising: a housing comprising: a piercing member configured to be inserted into the closed vial; a regulator aperture open to ambient air; and a cap connector comprising a projection for securing the adaptor to the closed vial; a bag having a first position wherein at least a portion of the bag is within the piercing member, the bag configured to move to a second position wherein at least a portion of the bag is configured to be outside the piercing member and inside the vial when the piercing member is inserted into the closed vial, the bag defining a barrier that is substantially impervious to liquid for a medical procedure when the bag is in the second position; a first channel configured to remove fluid from the vial; and a regulator channel in fluid communication with an interior portion of the bag, the regulator channel extending through the housing of the adaptor to the regulator aperture; wherein the bag is configured to move from the first position to the second position in response to pressure changes within the vial when fluid is withdrawn from the vial through the first channel, thereby decreasing the magnitude of pressure changes within the vial.