Tazarotene is a synthetic retinoid and prodrug of tazarotenic acid used primarily in topical dermatological formulations. It belongs to the acetylenic retinoid class and is used in the management of plaque psoriasis, acne vulgaris and photodamaged skin. The FDA identifies tazarotene as the active pharmaceutical ingredient in several topical dosage forms, including gels, creams and foams.
Tazarotene has the chemical name ethyl 6-[(4,4-dimethylthiochroman-6-yl)ethynyl]nicotinate. Its molecular formula is C21H21NO2S, and its molecular weight is 351.46 g/mol. The substance is registered in the FDA Global Substance Registration System under UNII 81BDR9Y8PS and has CAS No. 118292-40-3.
Pharmaceutical-grade Tazarotene is supplied as a chemically defined small-molecule active pharmaceutical ingredient for incorporation into topical formulations. It is generally characterized as a crystalline solid and is handled under controlled pharmaceutical manufacturing conditions.
Tazarotene is converted in the skin to its active metabolite, tazarotenic acid, which contributes to its pharmacological activity. PubChem identifies tazarotene as the ethyl ester of tazarotenic acid and classifies it as a retinoid and prodrug.
Tazarotene contains a pyridine carboxylate ester linked through an ethynyl group to a substituted thiochroman ring. The structure contains one sulfur atom, one nitrogen atom and two oxygen atoms. Its molecular formula is C21H21NO2S and its molecular weight is 351.5 g/mol according to PubChem.
The API is not a salt and does not require salt-form differentiation for standard Tazarotene API identification. FDA's substance record confirms the chemical identity and CAS number.
Tazarotene is a topical retinoid prodrug. Following topical administration, it is converted to tazarotenic acid, which acts on retinoic acid receptors and influences gene transcription associated with epidermal differentiation and proliferation.
FDA documentation notes that the precise mechanism of action of tazarotene in acne is not completely defined. Its pharmacological activity is associated with retinoid-mediated regulation of cellular differentiation and proliferation.
Tazarotene API is primarily used in the development and manufacture of topical dermatological products.
Applications include:
FDA-approved topical products have included 0.05% and 0.1% tazarotene gel formulations, while FDA documentation for tazarotene foam describes a 0.1% w/w active concentration.
Tazarotene API quality control generally involves identity testing, assay determination, related-substance analysis, residual-solvent control and physical-property testing.
FDA regulatory documents specifically discuss analytical procedures for tazarotene drug substance, assay and related substances, including HPLC-based testing.
Published analytical research has also developed stability-indicating chromatographic methods for determining tazarotene and its degradation products. One validated UHPLC method reported a 0.03% detection limit and 0.10% quantification limit for its analytical method; these are analytical-method performance characteristics and should not be represented as pharmaceutical API release specifications.
Manufacturing of Tazarotene API requires controlled chemical synthesis followed by purification and crystallization to obtain the required pharmaceutical quality. Important quality attributes include chemical identity, assay, related substances, residual solvents and physical characteristics.
Tazarotene is also susceptible to degradation pathways that have been investigated using stability-indicating HPLC and LC-MS methods. Reported related substances include compounds associated with oxidation and ester-related degradation pathways.
| Property | Value |
|---|---|
| Chemical Name | Ethyl 6-[(4,4-dimethylthiochroman-6-yl)ethynyl]nicotinate |
| CAS No. | 118292-40-3 |
| Molecular Formula | C21H21NO2S |
| Molecular Weight | 351.46 g/mol |
| FDA UNII | 81BDR9Y8PS |
| Physical Form | Crystalline solid / powder |
| API Class | Synthetic retinoid |
| Pharmacological Role | Retinoid prodrug |
| Active Metabolite | Tazarotenic acid |
The chemical identity and molecular properties are supported by FDA GSRS, FDA labeling and PubChem.
Tazarotene API should be packed in suitable pharmaceutical-grade, well-closed containers that protect the material from environmental exposure. Storage conditions should follow the manufacturer's validated stability data and approved API specification.
For commercial API handling, protection from excessive light, heat and moisture is appropriate, with the exact storage conditions established through stability studies.
Pharmaceutical-grade Tazarotene API may be supplied with:
Tazarotene API requires consistent control of assay, related substances, residual solvents and physical characteristics because it is intended for incorporation into pharmaceutical topical formulations. A quality-focused manufacturing program should use validated analytical procedures and appropriate impurity controls.
For pharmaceutical development and commercial manufacturing, Tazarotene should be supplied according to the required customer and regulatory specification, with complete batch documentation and analytical support.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 0.5% |
| Residue on Ignition | NMT 0.2% |
| Heavy Metals | NMT 10 ppm |
| Individual Impurity | NMT 0.5% |
| Total Impurities | ≤ 1.5% |
| Water Content | NMT 0.5% |
| Melting Point | 100–108°C |