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
100%
Rate breakdown
9903.04.6093.5%Pharmaceuticals Annex IV: patented pharma articles — 100% floor rate
9903.05.900%Articles already subject to Section 232 (steel/aluminum/copper + derivatives, autos + parts, wood, medium/heavy vehicles + parts, semiconductors, patented pharma) — U.S. note 52(f)
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