 | C4X-12254 | 92440-76-1 | Impurity | |
| Trimethoprim EP Impurity D |
 | C4X-12255 | 60729-91-1 | Impurity | |
| Trimethoprim EP Impurity E |
 | C4X-12256 | 16285-82-8 | Impurity | |
| Trimethoprim EP Impurity F |
 | C4X-12257 | 78025-68-0 | Impurity | |
| Trimethoprim EP Impurity G |
 | C4X-12259 | 30078-48-9 | Impurity | |
| Trimethoprim EP Impurity I(Mixture of cis/trans isomers) |
| C4X-12261 | N/A | Impurity | |
| Doxepin Impurity 1 |
 | C4X-122610 | 4504-96-5 | Impurity | |
| Doxepin EP Impurity C HCl |
| C4X-122612 | N/A | Impurity | |
| Doxepin Impurity 12 |
| C4X-122613 | N/A | Impurity | |
| Doxepin Impurity 13 |
| C4X-12262 | 131523-93-8 | Impurity | |
| Doxepin Impurity 2 |
