1. Imidazole alkaloids Flashcards
What is an example of imidazole alkaloids?
Imidazole ring (glyoxaline) is the principle nucleus in pilocarpine.
It is monoacidic tertiary base containing a lactone group as well as imidazole nucleus.
What is pilocarpine?
Pilocarpus or jaborandi consists of the leaflets of Pilocarpus jaborandi Holmes (Pernambuco jaborandi), of P. microphyllus Stapf (Maranliam jaborandi), or of P. pinnatifolius Lamaire (Paraguay jaborandi)(Fam. Rutaceae).
Give characteristics of pilocarpine.
Pilocarpine is the lactone of pilocarpic acid, an acid with a glyoxaline nucleus. It is an oily, syrupy liquid, though its salts crystallize easily.
What is the extraction of pilocarpine?
It may be obtained by treating the powdered leaves with sodium carbonate, extracting with benzene, and then shaking the benzene extract with dilute hydrochloric or nitric acid. The aqueous solution is then made alkaline and shaken with chloroform; the chloroform solution is then shaken with acid, and the alkaloidal salt is allowed to crystallize.
What are the storage conditions of pilocarpine?
All of the commercial kinds of piocarpus, when freshly dried, yield from 0.5 to 1% of the alkaloid piocarpine. Isopilocarpine, pilocarpidine, and pilosine are also present in some of the species. Even under ideal storage conditions, the leaves lose at least half of their alkaloidal content in 1 year through deterioration. Leaves that are 2 years old are practically worthless.
What are the actions of pilocarpine?
Pilocarpine directly stimulates the muscarinic receptors in the eye, causing constriction of the pupil and contraction of the ciliary muscle.
In narrow-angle glaucoma, miosis opens the anterior chamber angle to improve the outflow of aqueous humor.
In chronic open-angle glaucoma, the increase in outflow is independent of the miotic effect.
Contraction of the ciliary muscle enhances the outflow of aqueous humor via indirect effects on the trabecular system.
What is pilocarpine HCl?
Pilocarpine hydrochloride is the hydrochloride of an alkaloid obtained from the dried leaflets of Pilocarpus jahornudi or of P. micro phyllus . It is hygroscopic.
Pilocarpine hydrochloride occurs as colorless, translucent, odorless, faintly bitter crystals.
What is pilocarpine nitrate?
Pilocarpine nitrate is the nitrate of the alkaloid. It is stable in air but is affected by light. ; pilocarpine nitrate occurs as shiny, white crystals.
What are constituents of pilocarpine?
Maranham leaves contain about 0.7–0.8% of the alkaloids, pilocarpine, isopilocarpine, pilosine and isopilosine and about 0.5% of volatile oil. An examination of the volatile oil composition of a number of species indicated a total of 22 components occurring throughout the samples. These included monoterpenes (e.g. limonene, sabiene, a-pinene) sesquiterpenes (e.g. caryophyllene).
What dose of pilocarpine is used?
They are applied topically, 0.05 to 0.1 nil of a 0.25 to 10% solution of pilocarpine hydrochloride or of a 0.5 to 6% solution of pilocarpine nitrate to the conjunctiva, I to 6 times a day.
What are the uses of pilocarpine?
- Salts of pilocarpine (e.g. Pilocarpine Hydrochloride BP/EP and Nitrate BP/EP) are used in ophthalmic practice, as they cause contraction of the pupil of the eye, their action being antagonistic to that of atropine.
- In early glaucoma treatment they serve to increase the irrigation of the eye and relieve pressure.
- A study in the USA involving 207 patients suffering from dry mouth resulting from radiation treatment for head or neck cancer indicated that oral pilocarpine can possibly offer relief.
