Timolol maleate is a non-selective beta-adrenergic receptor blocking agent. Its chemical name is (-)-l-(tert-butylamino)-3-[(4-morpholino-l,2,5-thiadiazol-3-yl)oxy]-2-propanolmaleate (1:1) (salt). Timolol maleate possesses an asymmetric carbon atom in its structure and is provided as the levo-isomer. The optical rotation of timolol maleate is:

Its molecular formula is C₁₃H₂₄N₄O₃S•C₄H₄O₄ and its structural formula is:

Timolol maleate has a molecular weight of 432.50. It is a white, odorless, crystalline powder which is soluble in water, methanol, and alcohol. Timolol maleate is stable at room temperature.

Timolol maleate ophthalmic solution is supplied in two formulations: Ophthalmic Solution TIMOPTIC. (timolol maleate ophthalmic solution), which contains the preservative benzalkonium chloride; and Ophthalmic Solution TIMOPTIC (timolol maleate ophthalmic solution), the preservative-free formulation.

Preservative-free Ophthalmic Solution TIMOPTIC is supplied in OCUDOSE, a unit dose container, as a sterile, isotonic, buffered, aqueous solution of timolol maleate in two dosage strengths: Each mL of Preservative-free TIMOPTIC in OCUDOSE 0.25% contains 2.5 mg of timolol (3.4 mg of timolol maleate). The pH of the solution is approximately 7.0, and the osmolarity is 252-328 mOsm. Each mL of Preservative-free TIMOPTIC in OCUDOSE 0.5% contains 5 mg of timolol (6.8 mg of timolol maleate). Inactive ingredients: monobasic and dibasic sodium phosphate, sodium hydroxide to adjust pH, and water for injection.

Last reviewed on RxList: 10/11/2011
This monograph has been modified to include the generic and brand name in many instances.