Tamoxifen Citrate API is the citrate salt of tamoxifen, a non-steroidal selective estrogen receptor modulator (SERM) belonging to the antineoplastic hormonal therapy class. Tamoxifen acts primarily by competitively inhibiting estrogen binding to estrogen receptors.
Tamoxifen Citrate is widely used as an active pharmaceutical ingredient in formulations for hormone-responsive breast cancer. The citrate salt is the pharmaceutically recognized form used in conventional tamoxifen oral products.
Tamoxifen Citrate has the molecular formula C₂₆H₂₉NO·C₆H₈O₇, molecular weight 563.64 g/mol, and CAS number 54965-24-1. The current USP monograph specifies an assay of 99.0–101.0% calculated on the dried basis.
Tamoxifen Citrate is a pharmaceutical-grade active ingredient used in the production of oral solid dosage forms. It belongs to the selective estrogen receptor modulator class and produces its principal pharmacological effects through modulation of estrogen receptor activity.
The International Pharmacopoeia describes Tamoxifen Citrate as a white or almost white crystalline powder. It is slightly soluble in water and acetone and soluble in methanol.
Tamoxifen Citrate should be distinguished from tamoxifen free base, which has CAS 10540-29-1 and molecular weight approximately 371.51 g/mol. The citrate salt has a molecular weight of 563.64 g/mol and CAS 54965-24-1.
| Parameter | Details |
|---|---|
| Generic Name | Tamoxifen Citrate |
| API Form | Citrate Salt |
| CAS Number | 54965-24-1 |
| Molecular Formula | C₂₆H₂₉NO·C₆H₈O₇ |
| Molecular Weight | 563.64 g/mol |
| Chemical Class | Non-steroidal selective estrogen receptor modulator |
| Therapeutic Class | Antineoplastic / Hormonal Therapy |
| Drug Category | Selective Estrogen Receptor Modulator (SERM) |
| Active Moiety | Tamoxifen |
| Appearance | White crystalline powder |
| Storage | Well-closed, light-protected container |
USP identifies Tamoxifen Citrate as the (Z)-configured citrate salt of tamoxifen and gives CAS 54965-24-1 and molecular weight 563.64.
Tamoxifen Citrate is primarily used in pharmaceutical formulations for the treatment and management of estrogen receptor-positive breast cancer.
As a selective estrogen receptor modulator, tamoxifen can act as an estrogen antagonist in breast tissue while exhibiting tissue-selective estrogenic effects in other tissues.
Tamoxifen Citrate is therefore an important oncology API for the manufacture of oral pharmaceutical products intended for hormone-responsive breast cancer therapy.
Tamoxifen, the active moiety of Tamoxifen Citrate, competitively binds to estrogen receptors.
In breast tissue, tamoxifen inhibits estrogen-mediated signaling by interfering with estrogen receptor activation and subsequent transcriptional processes. This reduces estrogen-dependent stimulation of susceptible tumor cells.
Tamoxifen also produces tissue-selective estrogen receptor effects, which contribute to its pharmacological profile as a selective estrogen receptor modulator.
Tamoxifen Citrate quality control should include validated pharmaceutical analytical procedures.
Typical quality-control parameters include:
The USP monograph specifies 99.0–101.0% Tamoxifen Citrate on the dried basis. Historical pharmacopoeial references also describe chromatographic control of the E-isomer and other impurities.
Tamoxifen Citrate API manufacturing involves controlled synthesis of tamoxifen followed by appropriate purification and formation/isolation of the citrate salt.
Key manufacturing controls may include:
Particular attention should be given to control of tamoxifen stereoisomeric composition and related substances because pharmacopoeial analytical procedures specifically address related substances and the E-isomer.
The International Pharmacopoeia confirms slight solubility in water and acetone and solubility in methanol. JP XVII describes Tamoxifen Citrate as freely soluble in acetic acid, sparingly soluble in methanol and slightly soluble in water and ethanol.
Tamoxifen Citrate API should be packed in suitable pharmaceutical-grade containers that protect the material from moisture, contamination and excessive light exposure.
The USP monograph specifies well-closed, light-resistant containers, while the International Pharmacopoeia also specifies storage in a well-closed container protected from light.
Storage conditions should follow the approved API specification and validated stability data.
Documentation for Tamoxifen Citrate API may include:
A reliable Tamoxifen Citrate API Manufacturer in India should provide consistent quality, controlled impurity profiles and validated analytical testing for this established oncology API.
Key considerations include:
Swapnroop can position Tamoxifen Citrate as a pharmaceutical-grade oncology API supported by controlled manufacturing, analytical testing and quality documentation.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 99.0–101.0% |
| Loss on Drying | NMT 0.5% |
| Residue on Ignition | NMT 0.2% |
| Heavy Metals | NMT 10 ppm |
| Individual Impurity | NMT 0.3% |
| Total Impurities | NMT 0.8% |
| Water Content | NMT 0.5% |
| Melting Point | Approximately 142–148°C |