Qualification of a new Cytocontrol^® balance prototype under isolator

Objective
Since 2010, in process gravimetric control is used in our chemotherapy production unit. Over time and its evolutions, this method permitted to reinforce the quality of the preparations by securing fabrication process and to gain productivity while strongly promoting operators autonomy. However, the scales used clutter the isolator worktop, hampering operators. We recently co-developed a prototype suspended scale that frees up workspace while eliminating the need for cables in the isolator and providing equipment protection. The objective of this work is to qualify in an isolator this new prototype of Cytocontrol^® scale used since December 2019.

Method
An Operational Qualification (OQ) and a Performance Qualification (PQ) have been realized to analyze 6 criterias for the 2 balances tested (fidelity, accuracy, linearity, eccentricity, precision and inter-test precision), based on the “OMCL: Qualification of Balances 2013”. Weighings have been repeated by 3 differents operators over 3 distincts days, using a 1g to 2000g weights range. Each weighing have been repeated 15 times and logged by the CHIMIO^® software gravimetric module. For eccentricity, weighings have been realized 6 times for each different location. Furthermore, a survey was carried out among operators in order to obtain their feedback.

Results
A total of 1020 weighings were performed. During OQ and PQ, the Maximum Tolerated Deviation (MTD) and the accuracy deviations were not exceeded for each of the weights studied (<0.1g for weights up to 100g; <0.2g for weights up to 2000g). The standard deviations have remained below 5d (d: minimum scale interval = 0.02g) and the linearity coefficients are equal to 1 (> 0.9999). The Coefficients of Variation of the eccentric weights are less than 0.05%. The survey showed a significant advantage of this model in terms of ergonomics and practicality for manipulators, but also postural problems (arms raised at each weigh-in). In addition, the diameter of the scale plate as we have defined it is finally a little tight in width for the 1L pockets. However, this new model is preferred by 53% of operators (n = 17).

Discussion-Conclusion
The prototype complies with the recommendations of the OMCL over a range from 1 to 2000g for the criteria studied. This scale is more ergonomic and allows a real saving of space compared to the usual Cytocontrol^® scales. It would require adjustments to the height and widening of the deck to suit all operators. The mock-up of the isolator and its contents upstream is therefore an essential step in optimizing the installation of this type of equipment.

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