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Benzonatate Excipients & Degradants
Difficult to Separate due to Secondary Amine
Method Conditions
| Column |
Cogent Bidentate C18™, 4µm, 100A |
| Catalog No. |
40018-75P |
| Dimensions |
4.6 x 75 mm |
| Mobile Phase |
A: 100% DI water + 10mM Sodium Phosphate Monobasic
B: 80:20 Acetonitrile + 10mM Sodium Phosphate Monobasic |
| Gradient |
Time=0 0%B
Time=15 min 100% B (linear gradient) |
| Flow rate |
1.5 mL/minute |
| Peaks |
1. Excipient
2. Degradant
3. Degradant
4. Benzonatate
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| Injection Volume |
10 µL |
| Detection |
UV 280 nm |
| Temperature |
40°C |
Discussion
This Gradient method will produce excellent separation of Benzonatate from excipients and degradants in a USP capsule formulation.
Note the excellent resolution along with the excellent peak shape for this sometimes difficult molecule, which contains a secondary
amine group.
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Note: Benzonatate or 2,5,8,11,14,17,20,23,26-nonaoxaoctacosan-28-yl parabutylaminobenzoate is a non-narcotic oral antitussive
(cough suppressant) drug, taken orally, which works by anesthetizing the tissues of the lungs and pleura responsible for the
cough reflex. It has a numbing action similar to that of benzocaine that calms the stretch sensors in the lungs. It is the
stretching of these sensors with breathing that causes the cough. Benzonatate begins to work within 15 to 20 minutes. Its
effects last for approximately 3 hours. It is sold under the brand name Tessalon Perles (gelcaps) or Tessalon Capsules. The
medication must be swallowed whole. If the capsules are bitten into or sucked on, it may make the mouth numb and in some
cases cause choking.
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