In the years 2016 to 2019, the chapter USP <857> was subjected to a further revision; the resulting USP <857> (42nd edition, update from Dec. 2019) is showing the following major changes:
- Control of Wavelength Accuracy below 240 nm with Cerium liquid filter.
- Control of Absorbance Accuracy in the UV range can alternatively be realized with nicotinic acid (niacin).
- New: Verification of Photometric Response (linearity) in the UV range and in the Vis range required.
- Limit of Stray Light can be checked with two alternative procedures - Procedure B corresponds to the Ph. Eur. method.
The following parameters must be checked according to USP <857>: