Isradipine from China
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 — China → United States
19%
Rate breakdown
9903.05.3112.5%Section 301 (forced labor) — additional 12.5% ad valorem on products of China
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