Photo stability # Lux hour

ICH Q1(B) is the reference guideline for this.


Selection of batch : at least one production batch.

Period of exposure : Expose the sample to 1.2 million lux hours.

How to understand this lux hour:
Explanation :
Lux is the unit of illumunation( )

[Lux is both singular and plural like the word “water”]

Let us assume that the intensity at particular location in the chamber for test sample is 4430 lux.

For the test sample to get exposed to 1.2 million lux hr, it has to be kept in photostability chamber for the following number of days

Y = 1.2 x 106 lux hr / 4430 lux
= 270.88 hr = 271 hr
Converting hours into number of days
= 271 hr/24 hr = 11.29 days ~ 11.5 days.

Bujji Kanchi [attach]534[/attach]

Q1B Step4.doc (124.0 KB)