Molecular Formula | C17H28N4O7S |
Molar Mass | 432.49 |
Melting Point | 202-203°C(lit.) |
Boling Point | 704.6°C at 760 mmHg |
Specific Rotation(α) | 24405 -12.0° (c = 5 in 1N HCl); D25 -4.2° |
Flash Point | 380°C |
Solubility | H2O: soluble |
Vapor Presure | 7.7E-21mmHg at 25°C |
Appearance | powder |
Color | white to off-white |
Merck | 14,9444 |
Storage Condition | 2-8°C |
In vitro study | Timolol Maleate is a beta-adrenergic receptor antagonist, similar in action to propranolol. The levorotatory isomer is more effective. Timolol is proposed as an antihypertensive, antiarrhythmic, antianginal and antiglaucoma agent. Like propranolol and Nadolol, timolol is a non-selective β-adrenergic receptor antagonist. In the human atrium, Timolol showed a higher affinity for β2-adrenaline than for β1-adrenaline. Timolol has no intrinsic sympathomimetic, direct myocardial suppressant, or local anesthetic (membrane stabilizing) activity, but has a high degree of lipid solubility. Timolol, used for external application to the eye, has the effect of reducing elevated and normal intraocular pressure, with or without glaucoma. Elevated intraocular pressure is a major risk factor for the pathogenesis of glaucomatous visual field defects and optic nerve damage. Like propranolol and Nadolol, timolol binds competitively with adrenergic neurotransmitters such as catecholamines to β1 adrenergic receptors in the heart and β2 adrenergic receptors in bronchial and vascular smooth muscle. Β1 receptor blockade leads to a decrease in resting and exercising heart rate and cardiac output, a decrease in systolic and diastolic blood pressure, and, possibly, a decrease in reflex orthostatic hypotension. Β2 blockade leads to increased peripheral vascular resistance. The exact mechanism by which intraocular pressure is reduced by timolol remains unclear. The most likely mechanism is by reducing the secretion of aqueous humor. |
In vivo study | There are reports that indicate lower biological activity of (R)-isomer compared to (S)-isomer. Namely, (R)-timolol is 49 times less potent than (S)-timolol on β-adrenoceptor in animals, 13 times less potent in constricting the airways of normal subjects. |
Risk Codes | R22 - Harmful if swallowed R63 - Possible risk of harm to the unborn child R36/37/38 - Irritating to eyes, respiratory system and skin. |
Safety Description | S36 - Wear suitable protective clothing. S37/39 - Wear suitable gloves and eye/face protection S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. |
WGK Germany | 3 |
RTECS | UA8475000 |
HS Code | 29349990 |
brief introduction | (S)-timolol maleate is a new and powerful β receptor blocker, which has blocking effect on β1 and β2 receptors, with an action intensity 8 times that of propranolol, no membrane stabilization effect, no endogenous sympathomimetic activity, no direct inhibition of heart effect, and obvious intraocular pressure reduction effect. It is clinically used to treat hypertension, angina pectoris, tachycardia and glaucoma. It has a good effect on mild to moderate hypertension, no obvious adverse reactions, and can be combined with diuretics. Long-term medication for patients with myocardial infarction can reduce the incidence of re-infarction and mortality. It has a good effect on glaucoma, especially primary and open-angle glaucoma, which is better than traditional intraocular pressure lowering drugs. |
biological activity | Timolol Maleate (MK-950) is a non-selective β-adrenergic receptor antagonist that acts on β1/β2,Ki is 1.97 nM/2.0 nM. |
Target | Value |
β1-adrenergic receptor | 1.97 nM(Ki) |
β2-adrenergic receptor | 2.0 nM(Ki) |