Penicillamine from Mexico
D-Penicillamine, 3-mercapto-D-valine, is a mercaptocarboxylic amino acid used in Wilson's disease treatment. The free mercapto and carboxylic functions qualify it for HTS 2930.90.4920 classification as organo-sulfur compound. Chapter 29 takes precedence over amino acid headings.
Duty Rate — Mexico → United States
100%
Rate breakdown
9903.04.6095.8%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
• Chiral HPLC certificate required showing D-isomer >99%; CAS 52-67-5
• Oxidation-sensitive; import with antioxidant stabilizer per Chapter 29 note 2(f)
• Distinguish from 2922.50 amino acid salts by free base form