Isradipine from Canada
Isradipine, a 1,4-dihydropyridine derivative, selectively blocks L-type calcium channels for hypertension therapy. Its nitrogen-heterocyclic aromatic structure fits HTS 2933.99.53.00 as a cardiovascular drug API. Typically imported as micronized powder for tablet coating.
Duty Rate — Canada → United States
100%
Rate breakdown
9903.04.6093.5%Pharmaceuticals: 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
• D50 particle size 5-15μm critical - include laser diffraction report
• Photostability testing required due to yellowing tendency
• Single-source API often - verify supplier DMF status with FDA