Dietary Supplement "Flexible" Testing Requirements Proposed In GMPs FDA's proposed good manufacturing practices for dietary supplements would require final product testing for adherence to identity, purity, quality, strength and composition specifications

'We would require that you test each finished batch of the dietary ingredient or dietary supplement produced before releasing for distribution to confirm that specifications are met' the proposed regulation states. 
In the absence of a validated method for finished products, the agency would mandate testing of incoming shipment lots of components, dietary ingredients or dietary supplements. The proposal rule is slated for publication in the March 13 Federal Register; comments are due after 90 days on June 11. The proposal notes appropriate validated methods would include those created by FDA or AOAC International, as would those based on research in scientific journals or text books. 

'We are not aware of a situation where an appropriate scientifically valid analytical method is not available,' FDA says, adding the tests could be performed by the manufacturer or by a third party.
The agency's approach is based in part on its conclusion that 'identity testing requirements are needed but that no single approach or test method may be appropriate for every dietary ingredient,' the proposal says. For example, herbs or plant parts lend themselves to microscopic or organoleptic tests 'because you can see, taste or smell them,' but amino acids cannot use the same methodology, since they can neither be seen nor detected using human senses.' FDA says it is also considering developing a guidance on ingredient identity testing.
The proposal would require ingredient testing by manufacturers instead of allowing companies to rely on their supplier's certification of product identity and purity. Use of the supplier's guarantee 'would not necessarily ensure that the identity, purity, quality, strength or composition of a component, dietary ingredient or dietary supplement is met,' FDA says. The testing requirements are part of a long-awaited set of proposed standards for supplement manufacturing. Quality problems that may be prevented by the regs including subpotency; superpotency; contamination with filth, bacteria, microbial organisms, or drug ingredients; tablet size or color variation; under-filled containers; mislabeling; and improper packaging, FDA points out.
The GMPs would apply to all firms that manufacture, package or hold dietary ingredients or dietary supplements, including those involved with the activities of testing, quality control, packaging and labeling, and distributing them' for sale in the U.S., according to the agency. The proposal envisions a three-part implementation schedule based on company size, where small companies would have three years to comply with the rule, medium-size companies would have two, and large firms would have one year to comply.

Release of the proposed rule comes six years after publication of an advance notice of proposed rulemaking on supplement GMPs in February 1997. Since then, the agency has sought advice from its Food Advisory Committee, held several public meetings and received numerous comments on the rule. The proposal was submitted by FDA to the Office of Management and Budget for review three times before it was finally cleared for release in January.