timolol - Medications

Betimol ® (timolol ophthalmic solution), 0.25% and 0.5%, is a non-selective beta-adrenergic antagonist for ophthalmic use. The chemical name of the active ingredient is (S)-1-[(1, 1-dimethylethyl)amino]-3-[[4-(4-morpholinyl)-1,2,5-thiadiazol-3-yl]oxy]-2-propanol. Timolol hemihydrate is the levo isomer. Specific rotation is [α] 25 405nm =-16° (C=10% as the hemihydrate form in 1N HCl). The molecular formula of timolol is Formula C 13 H 24 N 4 O 3 S and its structural formula is: Timolol (as the hemihydrate) is a white, odorless, crystalline powder which is slightly soluble in water and freely soluble in ethanol. Timolol hemihydrate is stable at room temperature. Betimol ® is a clear, colorless, isotonic, sterile, microbiologically preserved phosphate buffered aqueous solution. It is supplied in two dosage strengths, 0.25% and 0.5%. Each mL of Betimol ® 0.25% contains 2.56 mg of timolol hemihydrate equivalent to 2.5 mg timolol. Each mL of Betimol ® 0.5% contains 5.12 mg of timolol hemihydrate equivalent to 5.0 mg timolol. Inactive ingredients: monosodium and disodium phosphate dihydrate to adjust pH (6.5 - 7.5) and water for injection, benzalkonium chloride 0.01 % added as preservative. The osmolality of Betimol ® is 260 to 320 mOsmol/kg. Chemical Structure