Rimexolone is a synthetic corticosteroid and glucocorticoid receptor agonist used primarily for ophthalmic anti-inflammatory therapy. It is a steroidal active pharmaceutical ingredient belonging to the glucocorticoid class and has been used in ophthalmic preparations for the management of ocular inflammation.
Rimexolone is chemically identified as C₂₄H₃₄O₃ with a molecular weight of approximately 370.52 g/mol. Its CAS Registry Number is 49697-38-3. FDA's Substance Registration System identifies Rimexolone as a validated chemical substance with absolute stereochemistry.
Rimexolone is a steroidal molecule structurally related to synthetic glucocorticoids. It contains the characteristic steroid nucleus together with hydroxyl, ketone, and propionyl functionalities that contribute to its pharmacological activity.
The API is described as a white to off-white powder. USP-NF provides a specific monograph for Rimexolone and defines the substance as containing NLT 97.0% and NMT 102.0% Rimexolone, calculated on the dried basis. This is an important distinction from vendor-specific purity claims because the USP monograph provides an authoritative compendial acceptance range.
| Property | Rimexolone |
|---|---|
| API Name | Rimexolone |
| CAS Number | 49697-38-3 |
| Molecular Formula | C₂₄H₃₄O₃ |
| Molecular Weight | 370.52 g/mol |
| PubChem CID | 5311412 |
| UNII | O7M2E4264D |
| API Class | Synthetic corticosteroid |
| Pharmacological Class | Glucocorticoid receptor agonist |
| Physical Form | White to off-white powder |
| Stereochemistry | Absolute |
| USP Assay | 97.0–102.0% on dried basis |
The molecular formula, molecular weight, CAS number and substance identity are supported by USP, FDA and PubChem records.
Rimexolone is principally associated with ophthalmic corticosteroid formulations. Its anti-inflammatory activity makes it useful in pharmaceutical preparations designed to manage inflammation affecting ocular tissues.
Historically, Rimexolone ophthalmic preparations have been used for conditions including:
Rimexolone ophthalmic suspension is separately recognized in USP-NF. The USP definition specifies that the finished ophthalmic suspension contains NLT 90.0% and NMT 110.0% of the labeled amount of Rimexolone. This finished-product range should not be confused with the 97.0–102.0% API assay in the Rimexolone drug-substance monograph.
Rimexolone exerts its pharmacological activity through interaction with glucocorticoid receptors. Following receptor interaction, corticosteroid signaling can regulate the expression of inflammatory mediators and suppress multiple components of the inflammatory response.
In ophthalmic applications, this glucocorticoid activity helps reduce inflammatory processes associated with ocular injury, surgery and other steroid-responsive inflammatory conditions. Rimexolone is therefore classified pharmacologically as a glucocorticoid receptor agonist.
Quality control of Rimexolone API requires a combination of identity, assay, purity and physicochemical testing. The USP-NF Rimexolone monograph establishes an authoritative assay range of 97.0–102.0% on the dried basis.
Typical analytical control can include:
Numerical limits should only be stated where supported by the applicable current pharmacopoeial monograph or an approved product/API specification.
Rimexolone API manufacturing involves controlled steroidal chemical synthesis followed by purification and isolation of the active pharmaceutical ingredient. Critical manufacturing controls include reaction control, impurity management, solvent control, crystallization, drying and particle-quality management.
A pharmaceutical-grade Rimexolone manufacturing process should operate under appropriate GMP controls, with validated analytical methods and documented batch-release procedures.
Rimexolone is a steroidal solid with relatively low aqueous solubility. PubChem reports Rimexolone as insoluble based on its referenced experimental property data.
USP reference-standard information describes Rimexolone as a white to off-white powder, with a melting range reported in the USP SDS of approximately 258–268°C. The same source reports it as insoluble in water, freely soluble in chloroform and sparingly soluble in methyl alcohol.
Its relatively low water solubility is relevant to formulation development, particularly for ophthalmic suspension products where particle characteristics and dispersion properties can influence product performance.
Rimexolone API should be packed in suitable pharmaceutical-grade, tightly closed containers that protect the material from contamination, moisture and unsuitable environmental exposure.
Recommended storage conditions should follow the approved API specification and stability data. Packaging should provide adequate protection throughout transportation and storage, with batch identification and traceability maintained.
A pharmaceutical-grade Rimexolone API can be supported by appropriate quality and regulatory documentation, as applicable:
A reliable Rimexolone API manufacturing program requires control over steroidal synthesis, impurity profiles, analytical testing and batch-to-batch consistency. Pharmaceutical manufacturers seeking Rimexolone should evaluate the API against applicable pharmacopoeial requirements and their intended formulation requirements.
A quality-focused Rimexolone API manufacturer in India can support pharmaceutical development and commercial manufacturing through controlled production, analytical characterization, appropriate documentation and consistent quality systems.
| 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 0.1% |
| Individual Impurity | NMT 0.5% |
| Total Impurities | NMT 1.0% |
| Water Content | NMT 0.5% |
| Melting Point | Approximately 258–268°C |