Photostability calculation

photo means UV light only or both fluorescent light when we expose sample we calculate minium light exposure is 1.2mlux hr.But we calibrate the UV light & fluorescent light seperatly and their calculation hr is different,pls told me what is actual procedure of photostability.

Dear Narendra,

As per ICH photo stability testing guideline (Q1B)

For confirmatory studies, samples should be exposed to light providing an overall illumination of not less than 1.2 million lux hours and an integrated near ultraviolet energy of not less than 200 watt hours/square meter.

The samples should be exposed to these two conditions, if integrated chamber is there it’s well and good. The duration of total exposure (two separate exposures to two different conditions) will depend on the photo stability chamber that you will be having and the duration can be calculate with the help of the light meters.

Hope this clarifies your query