プロカイン 化学特性,用途語,生産方法
外観
白色～ほとんど白色粉末～結晶
解説
プロカイン,融点61 ℃．水和物の融点51 ℃．エタノール，エーテル，クロロホルム，ベンゼンに可溶．塩酸塩(ノボカイン，融点156 ℃)は局所麻酔薬として用いられる．刺激性はなく，毒性はコカインの1/6～1/10．LD50 340～800 mg/kg(マウス，皮下)．
森北出版「化学辞典（第2版）
効能
局所麻酔薬
製造
プロカイン,p-アミノ安息香酸エチルと2-ジエチルアミノエタノールとを加熱してエステル交換するか，あるいは，塩化p-ニトロベンゾイルと2-ジエチルアミノエタノールとを反応させ，生成物を還元して製造する．
説明
Procaine is a local anesthetic with a para-amino function. Sensitization mainly concerns medical, dental
and veterinary professions.
化学的特性
The hydrochloride salt
of 2-(diethylamino) ethyl p-aminobenzoate (C13H21ClN2O2
or N2C6H4COOCH2CH2NH(C2H5)2HCl) is generally
referred to as procaine. Although the PABA ester is insoluble in water, the
hydrochloride salt is very soluble in water.
使用
Procaine (Novocain) is mainly used in dental or medical
procedures requiring infiltration anesthesia, peripheral
block, or spinal block.
定義
ChEBI:Procaine is a benzoate ester, formally the result of esterification of 4-aminobenzoic acid with 2-diethylaminoethanol but formed experimentally by reaction of ethyl 4-aminobenzoate with 2-diethylaminoethanol. It has a role as a local anaesthetic, a central nervous system depressant, a peripheral nervous system drug and a drug allergen. It is a benzoate ester, a substituted aniline and a tertiary amino compound. It is functionally related to a 2-diethylaminoethanol and a 4-aminobenzoic acid. It is a conjugate base of a procaine(1+).
生物学の機能
Procaine hydrochloride (Novocain) is readily hydrolyzed
by plasma cholinesterase, although hepatic
metabolism also occurs. It is not effective topically but
is employed for infiltration, nerve block, and spinal
anesthesia. It has a relatively slow onset and short (1
hour) duration of action. All concentrations can be
combined with epinephrine. It is available in dental cartridges
with phenylephrine as the vasoconstrictor.
一般的な説明
Procaine was synthesized in 1904 to address the chemical instabilityof cocaine and the local irritation it produced. The pKa of procaine is 8.9; it has low lipid solubility and the estergroup is unstable in basic solutions. Procaine is available inconcentrations ranging from 0.25% to 10% with pHs adjustedto 5.5 to 6.0 for chemical stability. Procaine is also includedin some formulations of penicillin G to decrease the pain ofintramuscular injection.
接触アレルゲン
Procaine is a local anesthetic with para-amino function.
Sensitization mainly concerns the medical, dental,
and veterinary professions.
作用機序
The fundamental mechanism of analgesia underlying all local anesthetics is the blockade of neurotransmission via inhibition of sodium channels along nerve fibers. Procaine acts mainly by inhibiting sodium influx through voltage gated sodium channels in the neuronal cell membrane of peripheral nerves. When the influx of sodium is interrupted, an action potential cannot arise and signal conduction is thus inhibited.
臨床応用
Procaine is very quickly metabolizedin the plasma by cholinesterases and in the liver via ester hydrolysisby a pseudocholinesterase. The in vitroelimination half-life is approximately 60 seconds. Any conditionthat decreases the cholinesterase concentration may increaseexposure to procaine and potential toxicity. Decreasedenzyme activity can be found with genetic deficiency, liverdisease, malignancy, malnutrition, renal failure, burns, thirdtrimester of pregnancy, and following cardiopulmonary bypasssurgery. Ester hydrolysis produces PABA, the compoundresponsible for the allergic reactions common to theester anesthetics. Procaine is not used topically because of itsinability to pass through lipid membranes and finds use as aninfiltration agent for cutaneous or mucous membranes, forshort procedures. Procaine is also used for peripheral nerveblock and as an epidural agent to diagnose pain syndromes.
純化方法
Procain crystallises as the dihydrate from aqueous EtOH and as the anhydrous material from pet ether or diethyl ether. The latter is hygroscopic. [Beilstein 14 IV 1138.]
プロカイン 上流と下流の製品情報
原材料
準備製品