Fosamprenavir Calcium API is the calcium salt of fosamprenavir, a phosphate prodrug of amprenavir and an HIV-1 protease inhibitor. It is a single stereoisomer with the (3S)(1S,2R) configuration. Fosamprenavir Calcium has CAS Number 226700-81-8, molecular formula C₂₅H₃₄CaN₃O₉PS, and molecular weight 623.67 g/mol.
The current USP definition requires Fosamprenavir Calcium to contain 98.0%–102.0% of fosamprenavir calcium, calculated on the anhydrous and solvent-free basis.
Fosamprenavir Calcium is described as a white to cream-colored solid/powder. It is soluble in methanol and has limited solubility in water, approximately 0.31 mg/mL at 25°C.
| Property | Value |
|---|---|
| CAS Number | 226700-81-8 |
| Molecular Formula | C₂₅H₃₄CaN₃O₉PS |
| Molecular Weight | 623.67 g/mol |
| Chemical Form | Calcium salt |
| Stereochemistry | Single stereoisomer; (3S)(1S,2R) |
| Appearance | White to cream-colored powder/solid |
These identity details are supported by USP, FDA and DailyMed records.
Fosamprenavir Calcium has an established USP monograph. The USP specification requires an assay of 98.0%–102.0%, calculated on an anhydrous and solvent-free basis. The current USP monograph also specifies water NMT 14.5%.
USP specifies individual organic impurity limits, including fosamprenavir amine NMT 0.3%, fosamprenavir pyrophosphate NMT 0.2%, fosamprenavir n-propyl homolog NMT 0.3%, and fosamprenavir related compound A NMT 0.3%. The overall total impurities limit is NMT 1.3%.
Fosamprenavir is an HIV-1 antiretroviral agent and a phosphate prodrug of amprenavir. Fosamprenavir Calcium is used as the active pharmaceutical ingredient in oral pharmaceutical formulations.
| Parameter | Specification |
|---|---|
| Appearance | White to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | NMT 0.3% |
| Loss on Drying | NMT 1.0% |
| Residue on Ignition | NMT 0.5% |
| Heavy Metals | NMT 10 ppm |
| pH (1% Solution) | 2.0 – 4.0 |
| Individual Impurity | NMT 0.3% |
| Total Impurities | NMT 1.3% |
| Water Content | NMT 14.5% |