Timolol Maleate API is the maleate salt of timolol, a non-selective beta-adrenergic receptor blocker used primarily in ophthalmic medicines for the management of elevated intraocular pressure. It is widely used in pharmaceutical formulations for glaucoma and ocular hypertension. FDA labeling identifies timolol maleate as the active ingredient in ophthalmic preparations and describes it as a beta-adrenergic receptor blocking agent.
Timolol Maleate has the molecular formula C₁₃H₂₄N₄O₃S · C₄H₄O₄, molecular weight 432.49 g/mol, and CAS number 26921-17-5. The British Pharmacopoeia Chemical Reference Substance catalogue also confirms the current BPCRS identity for Timolol Maleate and gives a declared content of 100.0% for its current reference batch.
Timolol Maleate is a synthetic pharmaceutical salt consisting of timolol and maleic acid in a 1:1 stoichiometric ratio. The active timolol component is a beta-adrenergic receptor antagonist, while the maleate salt provides the pharmaceutical form used for API and drug-product manufacturing.
The substance is described as a white or almost white crystalline powder and is soluble in water and alcohol. The International Pharmacopoeia identifies Timolol Maleate as an antiglaucoma drug and specifies protection from light during storage.
| Property | Value |
|---|---|
| Product Name | Timolol Maleate |
| CAS Number | 26921-17-5 |
| Molecular Formula | C₁₃H₂₄N₄O₃S · C₄H₄O₄ |
| Molecular Weight | 432.49 g/mol |
| Active Moiety | Timolol |
| Salt Form | Maleate |
| Pharmacological Class | Non-selective β-adrenergic blocker |
| Therapeutic Category | Ophthalmic / Antiglaucoma API |
| Appearance | White or almost white crystalline powder |
| Pharmacopoeial Standards | USP-NF / Ph. Eur. / BP |
The molecular weight and chemical identity are supported by USP material and FDA product information.
Timolol reduces intraocular pressure primarily by decreasing the formation of aqueous humor in the eye. As a non-selective beta-adrenergic receptor antagonist, it blocks β₁- and β₂-adrenergic receptors in the ciliary body, resulting in reduced aqueous humor production.
Unlike miotic agents, timolol does not primarily reduce intraocular pressure by increasing aqueous outflow. Its pharmacological effect makes timolol maleate an important active ingredient in ophthalmic formulations for pressure control.
Timolol Maleate API is primarily used in pharmaceutical products for:
FDA-approved ophthalmic timolol maleate products include formulations containing 5 mg timolol per mL, equivalent to approximately 6.8 mg timolol maleate per mL. FDA labeling for Istalol reports a finished-product pH of 6.5–7.5, but this is a drug-product specification and should not be confused with the API pH specification.
Timolol Maleate is manufactured through controlled chemical synthesis followed by purification and formation of the maleate salt. Pharmaceutical manufacturing controls should ensure appropriate stereochemical purity, chemical purity, assay, residual solvents and inorganic residue.
Because timolol maleate is a stereochemically defined API, enantiomeric purity is an important quality attribute. The USP specification specifically limits the relevant enantiomeric impurity to NMT 1.0%.
A qualified Timolol Maleate API Manufacturer in India should therefore maintain validated HPLC/chromatographic procedures and appropriate controls for assay, related substances, enantiomeric purity, moisture and inorganic residue.
Timolol Maleate is a white or almost white crystalline powder. The International Pharmacopoeia describes it as soluble in water, methanol and ethanol, sparingly soluble in chloroform and practically insoluble in ether.
The Ph. Eur./BP material reports a melting/decomposition temperature of approximately 199°C.
For your CMS, the pharmacopoeial qualitative solubility description is preferable to inserting an unsupported single mg/mL value.
Timolol Maleate should be protected from light and stored in a well-closed container. The International Pharmacopoeia specifically recommends protection from light.
Bulk API packaging should provide appropriate protection against moisture, light and contamination according to the validated stability program.
A professional Timolol Maleate API supply package may include:
A reliable Timolol Maleate API Manufacturer in India should provide pharmaceutical-grade material supported by validated analytical testing and comprehensive documentation. Timolol Maleate has established compendial standards, allowing quality control to cover assay, enantiomeric purity, organic impurities, pH, loss on drying and residue on ignition.
| 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 1.0% |
| Heavy Metals | NMT 10 ppm |
| pH (1% Solution) | 3.8–4.3 |
| Individual Impurity | NMT 0.10% |
| Total Impurities | NMT 1.0% |
| Water Content | NMT 0.5% |
| Specific Rotation | −11.7° to −12.5° at 405 nm |
| Melting Point | About 199°C with decomposition |