(a) A drug or device is not subject to the labeling or packaging requirements of this subtitle if a rule or regulation is adopted under the federal act or as provided under this section to exempt it.
(b) The Secretary shall adopt rules and regulations to exempt from the labeling requirements of this subtitle any drug or device that is to be transported in substantial quantities from one establishment to another, if in accordance with the practice of the trade, the drug or device is to be processed, labeled, or repacked at the second establishment.