Пилокарпин

Описание

Pilocarpine acts by stimulating muscarinic receptors, therefore making it similar in action to acetylcholine when systematically introduced. This compound differs from acetylcholine in that it does not react with any nicotinic receptors, but by stimulating the CNS. Its effects are blocked by atropine. It has found therapeutic use in ophthalmology as a myotic agent.

Химические свойства

Colorless crystalline solid or an oil; melts at34°C (93.2°F); dissolves in water, alcohol,and chloroform; slightly soluble in ether andbenzene.

Физические свойства

Appearance: colorless crystal or white crystalline powder. Solubility: freely soluble in water; slightly soluble in ethanol; insoluble in chloroform or diethyl ether. Melting point: 174–178?°C.

История

It has a history of hundreds of years since pilocarpine was used to treat glaucoma .
In 1933, the chemical synthesis of pilocarpine was firstly reported. However, pilocarpine couldn’t be used for treatments, because its synthetic route is so long and focuses on isopilocarpine, of which the pharmacological activities are 1/20– 1/50 of pilocarpine. In 1972, DeGraw successfully synthesized the cis-homopilopic acid employing catalytic hydrogenation of precious metals and obtained pilocarpine as the main part product. Therefore, the study on the production of pilocarpine by chemical synthesis has made new progress and has been artificially synthesized .

Использование

Pilocarpine occurs in the leaves of variousspecies of pilocarpus. It is used as an antidotefor atropine poisoning and in ophthalmologyto produce contraction of the pupil.

Определение

ChEBI: The (+)-enantiomer of pilocarpine.

Угроза здоровью

Pilocarpine is a tropane alkaloid. Toxicsymptoms are characterized by muscariniceffects. Toxic effects include hypersecretionof saliva, sweat, and tears; contraction of thepupils of the eyes; and gastric pain accom panied with nausea, vomiting, and diarrhea.Other symptoms are excitability, twitching,and lowering of blood pressure. High dosesmay lead to death due to respiratory failure.A lethal dose in humans is estimated withinthe range of 150–200 mg.

Фармаколо?гия

Pilocarpine activates cholinergic M-receptor and has an obvious effect on eyes and salivary glands. Pilocarpine nitrate eye drops take part in the actions of myosis, depressing intraocular pressure and alleviating cyclospasm. It increases glandular secretions at 10–20? mg, i.h., including the sweat gland, salivary gland, lacrimal gland, gastric gland, pancreas, intestinal gland, respiratory mucosa, and so on. Pilocarpine activates intestinal smooth muscle and promotes its tension and peristalsis. It induces asthma by activating bronchial smooth muscle and activates smooth muscles of uterus, bladder, gallbladder, and biliary passage as well

Клиническое использование

Pilocarpine nitrate is mainly used to treat glaucoma clinically. Characterized with the progressive cupping of the optic disk, hypopsia, and elevated intraocular pressure, the severe patients will go blind. Patients with angle-closure glaucoma (congestive glaucoma) generally have the narrow anterior chamber angle, the obstruction of aqueous humor outflow, and the elevation of intraocular pressure, and these can be reversed by a low-concentration pilocarpine. But it is noted that a highconcentration pilocarpine will promote the progress of glaucoma. Pilocarpine is also used to treat open-angle glaucoma. The mechanism of the action is not entirely clear. Using atropine and pilocarpine alternately prevents posterior synechiae. In addition, pilocarpine is orally used to treat Zagari’s disease after neck radiotherapy, increasing salivary secretion and sweat secretion

Профиль безопасности

A human poison by subcutaneous route. Poison experimentally by ingestion, intravenous, intraperitoneal, and subcutaneous routes. A very poisonous alkaloid that is used to remove excess fluid accumulations from the body. Its action on the sweat glands makes it a powerful sudorific. It very rarely causes death, but, when it does, it is by paralysis of the heart or edema of the lungs. Dangerous; on heating to decomposition it emits toxic fumes of NOx.

использованная литература

Hardy., Bull. Soc. Chim. Fr., 24,497 (1875) Gerrard., Pharm. J., 5,865,965 (1875)
Gerrard., ibid, 7,255 (1877)
Hardy, Calmels., Compt. rend., 102,1116,1251,1562 (1886)
Wagenaar., Pharm. Weekbl., 67, 285 (1930)
Preobrashenski et al., Ber., 63,460 (1930)
Preobrashenskietal., ibid, 69, 1835 (1936)
Roche, Lynch., Analyst, 73,311 (1948) Pharmacology: Hollander., Gastroenterology, 2, 20 I (1944)