Method and system, using a colorimetric indicator, for detecting a possible loss of integrity of a flexible bag for biopharmaceutical product

A test method for controlling the integrity of a bag containing a biopharmaceutical fluid and having a first wall and a second wall forming two opposite walls on both sides of a longitudinal axis of the bag, the method using a receiving and controlling device comprising at least one pressure sensor, a control unit, two plates having facing surfaces between which is interposed the bag to be controlled, the bag being flexible and already filled with a biopharmaceutical fluid in a single interior volume of the bag, the bag being fluid-tight in a non-altered state, and made of plastic material, the method comprising:

• providing an integrity/non-integrity indicator device that comprises a pair of covering walls extending entirely outside the single interior volume;
• associating the control unit a pressurizing unit or pressure source, so as to actuate and hold, by the receiving and controlling device a restrained configuration of the bag in which the bag is sandwiched between the two plates with a controlled pressurizing effect;
• externally covering the first wall and the second wall at least in the restrained configuration of the bag, by the respective covering walls of the pair of covering walls that are configured to extend between at least one outer surface of the bag -and an inner face of one of the two plates;
• and
• detecting a biopharmaceutical fluid leak through the bag, using a continuous colorimetric detection layer integral with or included in the pair of covering walls, the continuous colorimetric detection layer allowing visual detection of a biopharmaceutical fluid leak through the bag by a color change.