Aminophylline Base from Mexico
Aminophylline base, theophylline ethylenediamine complex, qualifies as heterocyclic nitrogen compound before salt formation considerations. U.S. note 3 product in 2933.99.79.00. Used in respiratory therapy intermediates.
Duty Rate — Mexico → United States
110%
Rate breakdown
9903.04.6093.5%Except as provided in heading 9903.04.61, patented pharmaceutical articles as provided for in subdivisions (c) and (d) of U.S. note 40 to this subchapter
9903.05.5510%Except for products described in headings 9903.05.85–9903.05.92 and 9903.05.94, articles the product of Mexico, as provided for in U.S. note 52 to this subchapter
Import Tips
• Specify base vs salt form clearly with assay method documentation
• Test for ethylenediamine content to confirm stoichiometric ratio
• Declare moisture content affecting stability during customs valuation