Mercaptoethanesulfonic Acid Sodium Salt from Mexico
Sodium 2-mercaptoethanesulfonate (mesna) contains both thiol and sulfonic acid groups but classified under HTS 2930.90.4950 based on principal organo-sulfur characteristics. Direct C-S linkages qualify; used as mucolytic and cytoprotective agent in chemotherapy.
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
• Provide sulfonic vs sulfinic acid differentiation via NMR
• Include ICH stability data for pharma grade material
• Declare bulk API status vs finished dosage to maintain Chapter 29 classification