Sorry for the delayed reply, but yes, with the data you have, you would need to label this as protect from light. Remember, this labeling is not intended only for product remaining in your packaging, but for pharmacies and repackagers to ensure they are not exposing your product to light for a prolonged period, such as in a large glass dispenser. An interesting sentence in Q1B highlights how important the naked studies are, where it says “For some products where it has been demonstrated that the immediate pack is completely impenetrable to light, such as aluminum tubes or cans, testing should normally only be conducted on directly exposed drug product.” That tells me that even if your packaging is clearly impenetrable to light you need to know if it is light sensitive and label it as such. As for you other question, no, I’m not aware of any other measure used to determine “protect from light” labeling. I should note (since you indicated it was at the end of the study that the naked sample was impacted) that if your initial result of one batch was somewhat suspect (equivocal per Q1B), you could (should per Q1B) place two more confirmatory batches under study, if it’s worth it to you.
