Real-time temperature monitoring in pharmaceutical freeze-drying

In this study, a thermocouple array realized by using thin film strips is employed for real-time temperature measurements during pharmaceutical freeze-drying. The thin film thermocouple array is directly deposited on the vial walls and can be employed to monitor the temperature evolution during the freezing stage. Freezing is a critical stage of the entire cycle, since the nucleation temperature influences the morphology of the dried material and, consequently, the subsequent drying phase. Since conventional thermocouples are too invasive, due to the high thermal conductivity of the metallic wires, which alter the product nucleation, innovative measuring approaches have to be developed and validated to optimize the drying cycles. Moreover, conventional thermocouples allow only one-point measurement to be obtained, while the possibility of realizing thermocouple arrays offered by the thin film technology, can give more reliable results.