Therefore, given the following from FDA's Guide to Inspections of Pharmaceutical Quality Control Laboratories: "Methods appearing in the USP are considered validated and they are considered validated if part of an approved ANDA" (8), the use of Method 3 would be valid if the conditions stated are met in testing the material of interest. The same FDA document states "For compendial methods, firms must demonstrate that the method works under the actual conditions of use," which, for the sake of this article, will be considered verification. Chapter ‹1047› provides several other procedures, all also validated, that could be considered given test material that does not satisfy the conditions for Method 3.
Remember the purpose. It is important to bear in mind the purpose of the method to be validated. If the method is intended to serve as an alternative to a pharmacopeial method, then one must establish its equivalence to the pharmacopeial method in terms of the end result. Remember that the purpose of a method in the pharmacopeia is to determine whether the pharmacopeial article (for which a monograph exists in the pharmacopeia) satisfies the requirements in the monograph. If instead the purpose behind the use of a pharmacopeial method is for a purpose other than demonstrating that the article complies with monograph requirements (for example, imagine that total organic carbon is to be determined using Chapter ‹643› "Total Organic Carbon"), it is not necessary to perform the validation relative to the pharmacopeial results. This means that the validation should be conducted relative to the specific purpose for which it is intended. Also implicit in this is the use of a nonpharmacopeial method to determine something for which a pharmacopeial method exists, but again for purposes unrelated to satisfying a monograph requirement. In such a case, it is unnecessary to consider validating the method relative to that in the pharmacopeia.