All you need to know about photostability test chambers

For photostability tests according to ICH Q1B, the light sources and illuminance levels are crucial. The light spectra and illuminance doses are precisely specified. The visible light (VIS similar to ISO 10977 (1993)) must reach a VIS light dosage of at least 1.2 million lux hours and the near ultraviolet (320 nm to 400 nm) dosage must be at least 200 Wh/m². There are illumination cassettes providing flexible placement, so homogeneous light distribution is guaranteed in the interior. In terms of the irradiation by UV light, according to ICH guideline Q1B, a significant proportion of the UV radiation must be in the range of 320 to 360 nm as well as in range of 360 to 400 nm. The BINDER photostability test chambers meet this requirement in full.

A distinction is made between systems that use an illumination cassette for UV and VIS and those that use a separate UV illumination cassette and VIS illumination cassette. Separate illumination cassettes for VIS and UV light are used in the BINDER photostability test chambers. After half the test time, the samples are swapped and exposed to the other light source.

The air movement is a constant climate chamber is crucial for climate homogeneity inside the unit. Only homogeneous climate conditions, both in terms of space and time, provide reliable results. Double-sided horizontal air flow allows for particularly homogeneous conditions. The air is extracted via a perforated rear wall and returned back into the usable space after reconditioning. The air is distributed evenly into the chamber via small perforations in the side walls and therefore flows evenly over the test materials from both sides.

• Type of water supply and disposal: 
  The water can be supplied and disposed of via a connection to the on-site water supply or via large-volume water canisters for fresh water supply and collecting condensed water that are mounted directly on the climate chamber.
• Type of humidification:
  The most common types of humidification are steam and ultrasonic humidification systems. Climate chambers from BINDER feature steam humidification systems, as these ensure quick and accurate humidification and this technology prevents condensation in the interior.
• Water quality:
  Fully desalinated water with a conductivity between 1 µS/cm and max. 20 µS/cm is the prerequisite for reliable continuous operation of the unit. If the water quality is inadequate, the tap water must be treated. The BINDER PURE AQUA SERVICE water treatment system can be used here as an accessory, both when using via the mains water connection and when the units are supplied via canisters.

• As many components as possible in the unit should be made from corrosion-resistant stainless steel.
• A triple door gasket guarantees maximum reliability.
• Long-life steam humidifiers have been proven to have a very low failure rate of less than one percent in the first five years of continuous operation.