In spite of intensifying cost pressure and increasing complexity of product ranges, stringent GxP guidelines demand adherence to high quality standards. With the help of its data loggers testo 175 T1 and testo 175 H1 as well as the services offered by daughter company Testo Industrial Services, Testo supports those responsible for quality in the entire process of ambient data monitoring, from temperature mapping to the documentation of measurement values.

Pharmaceutical products are, almost without exception, sensitive to temperature and humidity. Cold-chain-mandatory preparations must be stored at defined upper and lower temperature limits, while it is equally important to avoid temperature and humidity fluctuations, to which modern pharmaceuticals’ reactions are more extreme, due to their larger molecular structures or biotechnical production methods. Since less-sensitive products have also been shown to suffer as a result of extreme temperature fluctuations, so-called ‘controlled room temperature’, which in the past was almost never checked, has become a focus of ambient climate monitoring.

Too-high temperatures favour germ growth, while freezing reduces the efficacy of medicaments containing proteins – in the worst cases, toxic decomposition products are formed.

Hydration, meanwhile, leads to the formation of clusters of individual particles.

Temperature fluctuations cause damage to the storage containers, which can lead to a loss of sterility.

Moisture makes printed labels illegible, and favours mould growth on and inside packaging.

For pharmaceutical distribution providers, the threats of economic collapse due to spoilt goods and loss of image as a reliable partner to industry are ever present. And the lives of patients, hoping for and placing their trust in a cure for their suffering, are also at risk.

In order to minimise these risks, impeccable conditions must be constantly maintained in warehouses. Every violation of the prescribed limits is a deficit that must be assumed if proof of temperature or humidity curves is missing. Thus, the corresponding parameters must be monitored without interruption according to GxP guidelines along the entire process chain, in production, sales and storage.

Qualification, validation, mapping

Calibrated data loggers, which continuously record and document measurement data, are used for this climate-monitoring task. One of the prerequisites for GxP-compliant monitoring is reliable measurement technology with a high level of data security. Another prerequisite is the positioning of a sufficient quantity of data loggers at suitable measurement sites.

Temperature and relative humidity are not uniformly distributed across the inner volume of a warehouse, as, with its shelves and the passages between them, transport systems, loading ramps, tight spots between pallet stacks and free spaces for transferring goods, it resembles a small town in which each neighbourhood has its own microclimate. The differences often go unnoticed. However, only optimum temperature and humidity distribution qualify rooms for the safe, norm-compliant storage of pharmaceutical products.

Unfavourable areas, in which product quality is endangered due to unacceptable conditions, must be identified by mapping, and permanently monitored using a data logger. In the vicinity of the roof, windows or exterior walls, for example, indoor air is warmed or cooled depending on the outdoor temperature. In high-rack shelving, there is a temperature difference between the cooler air on the ground and the warmer air close to the ceiling. Air circulation in narrow passages and corners, meanwhile, can be insufficient. Outside air enters easily and often through loading bay doors. Fan heaters, lamps or ventilators create collections of cold or warm air.

The identification of these ‘critical control points’ (CCP) forms the basis of subsequent long-term monitoring, and visualisation of temperatures using a testo thermal imager can be helpful in this respect. Depending on structural conditions, additional measurement points can be necessary. The relevant standards do not state exact rules on the number of sensors; they merely demand that every measure be justified and provable, each step documented, and all results reproducible.

But norm-compliant, efficient and reliable mapping is time-consuming. Those responsible for quality should avail themselves of external support, which allows them to concentrate on their core tasks. Testo Industrial Services is a subsidiary of Testo that specialises in metrological services such as calibration, validation and qualification. Its mapping professionals are experienced in the definition of CCPs, and always informed regarding updates to standards and legislation.

Precision and security

The insights gained in the course of mapping work must subsequently be translated into a validated ambient climate-monitoring system. With a measurement accuracy of ±0.5°C and ±2% relative humidity, and memory for up to a million measurement values, the professional data loggers testo 175 T1 and testo 175 H1 are suitable for the long-term monitoring of temperature and humidity in warehouses according to GxP and 21 CFR Part 11.

Testo 175 T1 has an internal air sensor for monitoring temperature, while testo 175 H1 measures temperature and humidity values, and, if required, shows the dewpoint in its display. Its external humidity stump probe is characterised by fast reaction time and long-term stability. Both instruments have a non-volatile memory, which can be read out even with completely empty batteries. Recording in a tamper-proof, proprietary format guarantees high measurement-data security and authenticity.

For reading out, the data loggers are connected to a PC by USB interface with the help of a standard cable. Alternatively, the data can be collected on a commercially available SD card without interrupting the recording. The configuration of the logger and analysis of the data take place via software, a version of which can be validated for compliance with 21 CFR Part 11.

By simplifying the automatic control and documentation of temperature and humidity values in pharmaceutical logistics, testo 175 T1 and testo 175 H1 make a crucial contribution to the provable maintenance of product quality.