プソイドエフェドリン 化学特性,用途語,生産方法
解説
プソイドエフェドリン．漢薬マオウ(麻黄)に含まれるアルカロイドの一つ．エフェドリンの(1S,2S)-ジアステレオマーである．融点118 ℃．[α]D＋51°(エタノール)．水に難溶，エタノール，エーテルに可溶．気管支拡張作用はエフェドリンよりも弱い．LD50 500 mg/kg．(マウス，経口)．
用途
プソイドエフェドリン (pseudoephedrine, PSE) は、内服用の鼻づまり薬として広く用いられてきた医薬品である。塩酸塩または硫酸塩の形で用いられる。
日本ではフェニルプロパノールアミン（PPA）の代替としてOTCの鼻炎薬に配合されている。
プソイドエフェドリンは覚醒剤の原料となる。アメリカ国内での覚醒剤合成にはプソイドエフェドリンを原料とするものがほとんどである。
またプソイドエフェドリン自体に覚醒作用があるため、フェニレフリン内服に転換する動きが広がっている。
効能
血管収縮薬, アドレナリン受容体作動薬
説明
Pseudoephedrine is a stereoisomer of ephedrine, in the drug
class of sympathomimetics. It occurs naturally in plants of the
genus Ephedra. Pseudoephedrine is a mixed-acting decongestant,
which activates α- and β-adrenergic receptors directly by
binding to the receptor itself, and indirectly by causing
norepinephrine release in synaptic nerve terminals.
Pseudoephedrine is also used illicitly in the production of
methamphetamine. In the United States, two recent acts of legislation
– the Combat Methamphetamine Epidemic Act of 2005
and the Methamphetamine Production Prevention Act of 2008–
have created stringent regulation on the sale of pseudoephedrine
without a prescription. Pseudoephedrine-containing products
were moved behind the counter, only to be sold by the
pharmacist using their professional judgment and discretion.
Limitations on the quantity of pseudoephedrine that could be
purchased at one time and over a period of timewere enacted, and
strict record keeping was required.
化学的特性
white crystals
使用
Pseudoephedrine is an orally active sympathomimetic amine
that is used as a nasal decongestant. It exerts its decongestant
action by acting directly on a-adrenergic receptors in the
respiratory tract mucosa producing vasoconstriction resulting
in shrinkage of swollen nasal mucous membranes, reduction of
tissue hyperemia, edema, and nasal congestion, and an increase
in nasal airway patency. Drainage of sinus secretions is
increased and obstructed eustachian ostia may be opened.
Relaxation of bronchial smooth muscle by stimulation of
b-adrenergic receptors may also occur.
定義
ChEBI: A member of the class of the class of phenylethanolamines that is (1S)-2-(methylamino)-1-phenylethan-1-ol in which the pro-S hydrogen at position 2 is replaced by a methyl group.
一般的な説明
(Sudafed, Afrinol, Drixoral) isthe (S,S) diastereoisomer of ephedrine. Whereas ephedrinehas a mixed mechanism of action, L-(+)-pseudoephedrineacts mostly by an indirect mechanism and has virtually nodirect activity. The structural basis for this difference inmechanism is the stereochemistry of the carbon atom possessingthe β-OH group. In pseudoephedrine, this carbon atompossesses the (S) configuration, the wrong stereochemistryat this center for a direct-acting effect at adrenoceptors.Although it crosses the BBB (log P=1.05, pKa=9.38),L-(+)-pseudoephedrine’s lack of direct activity affords fewerCNS effects than does ephedrine. It is a naturally occurringalkaloid from the Ephedra species. This agent is found inmany OTC nasal decongestant and cold medications.Although it is less prone to increase blood pressure thanephedrine, it should be used with caution in hypertensiveindividuals, and it should not be used in combination withMAO inhibitors.
接触アレルゲン
This sympathomimetic a-adrenergic agonist is found
in plants of the genus Ephedra (Ephedraceae) and is
systemically used as a nasal decongestant. It can induce
drug skin reactions such as acute generalized exanthematic
pustulosis or generalized eczema.
環境運命予測
Through use as a decongestant and production, release to
the environment may result from various waste streams. Pseudoephedrine is also found in plants in the genus Ephedra
(Ephedraceae) otherwise known as Ma Huang. It has a vapor
pressure of 8.3×104 mm Hg at 25 °C and if released into air
it will exist both as vapor and in particulate phase in the
atmosphere. Vapor-phase pseudoephedrine will be degraded
by reactions with hydroxyl radicals, which are photochemically
produced. The half-life for this reaction is estimated at 4 h.
Particulate-phase pseudoephedrine will be removed from the
atmosphere by wet and dry deposition. Pseudoephedrine is not
susceptible to direct photolysis by sunlight.
Based upon an estimated Koc of 73, pseudoephedrine is
expected to have a high mobility in soil. The pKa of 10.25
indicates that it will exist primarily in the cation form in the
environment and it will absorb more strongly to soil containing
clay or organic carbon.
純化方法
Crystallise the amine from dry diethyl ether, or from water and dry it in a vacuum desiccator. [Beilstein 13 IV 1878.]
プソイドエフェドリン 上流と下流の製品情報
原材料
準備製品