Glass Technology Services (GTS) has welcomed stricter analytical requirements under the revised European Pharmacopoeia.

The requirements aim to improve the accuracy and reproducibility of hydrolytic resistance tests performed on glass primary packaging for pharmaceutical use.

A number of industry studies identified variations in the concentration of extracted elements analysed when performing the hydrolytic resistance glass surface test.

These variations were attributed to differences in autoclaving procedures and have been addressed with the introduction of stricter requirements for autoclaves, including tight control over the thermal cycle, temperature monitoring, and both calibration and validation requirements.

The changes came into effect in January 2019 with the implementation of version 9.6 of the European Pharmacopoeia (Pharmacopée Européenne).

It now specifies that an autoclave must be capable to withstand a specified pressure and allow the connection of an external thermometer or thermocouple for independent measurements to be made for validation and calibration.

Additional instructions allow operators to use the autoclaves own internal thermocouple - provided its calibration is proved to be valid over a defined timespan.

The updated monograph addresses reproduction of the thermal load as a means of ensuring conformity to the thermal cycle on a routine basis.

This also allows for the testing of different size samples alongside one another.

The rates for heating and cooling have been removed, however the thermal cycle itself remains unchanged.

A new section now outlines a suitable autoclave calibration procedure, which requires users to insert a temperature probe into filled vials of an intermediary size (e.g. 10ml), within an autoclave with the tray of the autoclave filled.

This is in order to create a thermal load, which can be re-created on an ongoing basis. Readings from within the filled vial must be used for the calibration and validation of the correct thermal cycle.

For the first time the EP now stipulates that validation of the calibration must be carried out at regular intervals.

The surface test has a revised list of limit values in table 3.2.1-3 with the “up to 1ml” category now split into two further categories, as summarised below.

Matching categories are also introduced in tables 3.2.1.-7 for the flame spectroscopy method.