Description
Scopolamine is a tropane alkaloid that can be found in many plants of the
Solanaceae (nightshade) family. It is a muscarinic receptor antagonist that can be used to induce memory impairment in animals. Scopolamine prevents motion sickness, nausea, and vomiting in animals.
Chemical Properties
Off-White Solid
Uses
An acetylcholine antagonist. Used in treatment of motion sickness; antiemetic; antispasmodic; mydriatic; preanesthetic medicant
Definition
ChEBI: A hydrobromide that is obtained by reaction of scopolamine with hydrogen bromide.
brand name
Isopto Hyoscine (Alcon); Transderm-Scop (Ciba-Geigy).
General Description
Scopolamine hydrobromide(hyoscine hydrobromide) occurs as white orcolorless crystals or as a white, granular powder. It is odorlessand tends to effloresce in dry air. It is freely soluble inwater (1:1.5), soluble in alcohol (1:20), only slightly solublein chloroform, and insoluble in ether.
Scopolamine is a competitive blocking agent of theparasympathetic nervous system as is atropine, but it differsmarkedly from atropine in its action on the higher nervecenters. Both drugs readily cross the blood-brain barrierand, even at therapeutic doses, cause confusion, particularlyin the elderly.
General Description
Colorless crystals or white powder or solid. Has no odor. pH (of 5% solution): 4-5.5. Slightly efflorescent in dry air. Bitter, acrid taste.
Air & Water Reactions
Sensitive to air, light and moisture. Water soluble.
Reactivity Profile
Scopolamine hydrobromide is incompatible with acids, bases and oxidizing agents. .
Fire Hazard
Flash point data for Scopolamine hydrobromide are not available; however, Scopolamine hydrobromide is probably combustible.
Biological Activity
Non-selective muscarinic antagonist. Widely used clinically to treat motion sickness.
Clinical Use
A sufficiently large dose of scopolamine will cause an individualto sink into a restful, dreamless sleep for about8 hours, followed by a period of approximately the samelength in which the patient is in a semiconscious state.During this time, the patient does not remember events thattake place. When scopolamine is administered with morphine,this temporary amnesia is termed twilight sleep.
Metabolism
Hyoscine hydrobromide is almost entirely metabolised,
probably in the liver; only a small proportion of an oral
dose is excreted unchanged in the urine. In one study in
man, 3.4% of a single dose, administered by subcutaneous
injection was excreted unchanged in urine within 72
hours.
Purification Methods
The hydrobromide is recrystallised from Me2CO, H2O or EtOH/Et2O and dried. It is soluble in H2O (60%) and EtOH (5%) but insoluble in Et2O and slightly in CHCl3. The hydrochloride has m 300o (from Me2CO). The free base is a viscous liquid which forms a crystalline hydrate with m 59o and [] D 20 -28o (c 2.7, H2O). It hydrolyses in dilute acid or base. [Meinwald J Chem Soc 712 1953, Fodor Tetrahedron 1 86 1957, Beilstein 6 III 4185.]
