Difamilast is a selective phosphodiesterase-4 (PDE4) inhibitor and pharmaceutical active ingredient used in topical treatment of atopic dermatitis. It is a non-steroidal anti-inflammatory agent designed to reduce inflammatory signaling in the skin.
Difamilast is identified by CAS No. 937782-05-3. Its molecular formula is C23H24F2N2O5 and its molecular weight is 446.44 g/mol.
Difamilast is a synthetic small-molecule PDE4 inhibitor. By inhibiting PDE4, it increases intracellular cyclic AMP and reduces the production of various pro-inflammatory cytokines and chemokines involved in inflammatory skin conditions.
Difamilast is also known by the development code OPA-15406.
Difamilast selectively inhibits PDE4, an enzyme responsible for degradation of intracellular cyclic AMP. Increased cyclic AMP signaling can reduce inflammatory mediator production and help suppress inflammatory responses in the skin.
Difamilast inhibits phosphodiesterase-4 (PDE4), resulting in accumulation of intracellular cyclic AMP. This signaling effect reduces the production of inflammatory cytokines and chemokines, thereby helping decrease inflammation associated with atopic dermatitis.
Difamilast is used as a topical treatment for mild to moderate atopic dermatitis. Current regulatory information identifies topical difamilast use in adults and pediatric patients aged 2 years and older.
The U.S. product ADQUEY is formulated as a 1% ointment for topical use.
Difamilast is relevant to pharmaceutical manufacturers and formulation-development organizations working on topical dermatological products and PDE4 inhibitor formulations.
The API may be incorporated into topical formulations according to the approved formulation, target market and applicable regulatory requirements.
Difamilast API quality evaluation may include:
Difamilast is reported to exhibit crystal polymorphism, making appropriate solid-state characterization important for pharmaceutical development.
Difamilast intended for pharmaceutical manufacturing should comply with applicable GMP, quality-control and regulatory requirements. The final specification should correspond to the manufacturer's approved specification and intended market.
A batch-specific Certificate of Analysis (CoA) should provide relevant analytical results and acceptance criteria.
Difamilast API should be stored in appropriately sealed packaging under the manufacturer's specified storage conditions. Protection from excessive moisture, heat and unsuitable environmental exposure should be maintained.
Difamilast is relevant to pharmaceutical companies developing topical dermatological and anti-inflammatory products, particularly formulations targeting atopic dermatitis.
For commercial pharmaceutical applications, customers should verify the API grade, assay, impurity profile, solid-state form, specification, regulatory documentation and batch-specific CoA before use.
Consistent Difamilast API quality is important for reliable topical formulation development. Control of identity, assay, purity, related substances and solid-state characteristics supports reproducible pharmaceutical manufacturing.
| Parameter | Specification |
|---|---|
| Appearance | White to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | NLT 98.0% by HPLC |
| 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 | ≤ 0.5% |
| Total Impurities | ≤ 1.5% |
| Water Content | NMT 1.0% |
| Melting Point | 150°C – 154°C |