OTC Actives Testing for Sunscreen
I am working with a CM to manufacture a sunscreen product. We have already completed the FDA required UVB testing, resulting in an SPF 37, so we can claim SPF 35. The CM is validating a method for us to measure the active levels and is asking for a spec range for each active. Is there an industry standard used in this instance? I looked through the FDA's website and could only find very vague answers. I know industry standard for batching is within 1% but does it need to be tighter for OTC actives since they are called out on pack?
Any advice would be much appreciated!