721-50-6 Usage
Description
Prilocaine is an amino acid amide local anesthetic drug, chemically known as N-propyl-DL-alanine and 2-methylaniline, which forms an amide bond. It is a white or almost white, crystalline powder with a melting point of 37-38 ℃ and a boiling point of 159-162 ℃ (0.133kPa). Prilocaine hydrochloride is a water-soluble salt available as a solution for nerve block or infiltration in dental procedures. It is used for intravenous regional anesthesia due to its low risk of CNS toxicity because of quick metabolism. Prilocaine prepared in the crystal form is used in EMLA for topical administration to decrease painful needlesticks in children. The 4% solution should be protected from light, and the manufacturer recommends discarding if the solution turns pinkish or slightly darker than light yellow. Solutions are available in various concentrations up to 4%, with or without epinephrine and with or without preservatives.
Uses
Used in Dentistry:
Prilocaine is used as a local anesthetic for dental procedures due to its better efficacy than procaine, similar local anesthesia intensity and speed as lidocaine, longer duration time, less toxicity, and smaller accumulation effect.
Used in Dermal Anesthesia:
Prilocaine is used as a component in the lidocaine/prilocaine or EMLA preparation for dermal anesthesia, particularly for treatment of conditions like paresthesia.
Used in Regional Anesthesia:
Prilocaine is used as a local anesthetic for intravenous regional anesthesia, as the risk of CNS toxicity is low because of its quick metabolism.
Used in Topical Administration:
Prilocaine prepared in the crystal form is used in EMLA for topical administration to decrease painful needlesticks in children.
Used in Epidural, Conduction, and Infiltration Anesthesia:
Prilocaine is suitable for epidural anesthesia, conduction anesthesia, and infiltration anesthesia due to its longer duration time and less toxicity compared to other local anesthetics.
Local anesthetic drug
Prilocaine belongs to amide local anesthetic drug with its anesthesia intensity and speed being similar as lidocaine but with a longer duration period and weaker effect on vasodilation. It has a lower toxicity than lidocaine. It is clinically for local anesthesia, especially suitable for treating patients who are not allowed to use adrenaline.
[Pharmacological] its 3% solution has a similar local anesthesia efficacy as the anesthesia drug of 2% lidocaine together with adrenaline. It has a slow onset time which lasts about 6~7min and the duration time of about 1.5~2h. It has a strong penetration capability through mucous membranes. Adrenaline has a slightly prolonged duration of action. PPB is 55% and T1/2 of about 1.5h. It is subject to liver metabolism with its metabolites nitroso toluidine being able to oxidize hemoglobin to form methemoglobin. It can be transported to the fetus through the placenta.
[Adverse reactions] once the usage amount exceeds 600mg, methaemoglobinaemia can occur with cyanosis, tachycardia, headache, dizziness and weakness occurring.
[Note] patients of anemia, congenital or acquired methaemoglobinaemia, respiratory failure or heart failure and hypoxic patients should be disabled. It is forbidden for applied to obstetric anesthesia.
[Usage and dosage] infiltration anesthesia: 0.5% to 1% solution with the duration of action of 1 to 1.5 hours.
Nerve blocking anesthesia: use 1% to 2% solution with the duration of action being 2-3 hours.
Epidural anesthesia: use10 to 30 mL of 1.5%~1% solution with the duration of action of 2.5 to 3.5 hours. Use a maximum dose of 600 mg.
Figure 1 the structural formula of prilocaine
The above information is edited by the lookchem of Dai Xiongfeng.
Production method
O-toluidine and α-bromo-propionyl bromide are condensed and further have reaction with propylamine obtain prilocaine.
Pharmacology
Prilocaine is less toxic than lidocaine, with a high clearance, attributable to
metabolism in the lungs, kidneys and liver. It is associated with
methaemoglobinaemia at doses >600mg. It is sometimes used at a
concentration of 0.5% for the provision of intravenous regional anaesthesia, and a combination of prilocaine 3% with felypressin is
available for low-volume local infiltration anaesthesia in dental surgery. A
2% formulation is also available for spinal anaesthesia. Prilocaine is also
formulated in a eutectic mixture with lidocaine (EMLA) for topical
anaesthesia.
Clinical Use
Prilocaine metabolism has beenstudied extensively in animal models, less is known aboutthe human metabolites or the human CYP enzymes involvedin their formation . The metabolism of prilocainein the liver yields o-toluidine, which is a possiblecarcinogen. Many aromatic amines, including o-toluidinehave been shown to be mutagenic, and metabolites of otoluidinehave been shown to form DNA adducts.Metabolites of o-toluidine are also believed to be responsiblefor the methemoglobinemia observed with prilocaineuse. To decrease the potential for methemoglobinemia, strictadherence to the maximum recommended dose should befollowed. Metabolism of prilocaine is extensive with lessthan 5% of a dose excreted unchanged in the urine.
Synthesis
Prilocaine, 2-(propylamino)-o-propiontoluidine (2.2.14), is structurally
related to the exact same group as ethidocaine, yet it differs structurally in that during synthesis, o-toluidine is used instead of 2,6-dimethylaniline, and instead of a butyric acid, a
fragment of propionic acid, and a terminal propylethylamine group is replaced with a
propylamine group. In order to synthesize prilocaine, o-toluidine is reacted with bromopropionyl bromide, and the resulting bromopropionyltoluidide (2.2.13) is then reacted
with propylamine, which gives prilocaine [22,23].
Check Digit Verification of cas no
The CAS Registry Mumber 721-50-6 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 7,2 and 1 respectively; the second part has 2 digits, 5 and 0 respectively.
Calculate Digit Verification of CAS Registry Number 721-50:
(5*7)+(4*2)+(3*1)+(2*5)+(1*0)=56
56 % 10 = 6
So 721-50-6 is a valid CAS Registry Number.
InChI:InChI=1/C13H20N2O/c1-4-9-14-11(3)13(16)15-12-8-6-5-7-10(12)2/h5-8,11,14H,4,9H2,1-3H3,(H,15,16)
721-50-6Relevant articles and documents
A method for preparing prilocaine hydrochloride
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Paragraph 0051; 0052, (2017/03/14)
The invention relates to a synthetic process of anesthetic, in particular to a method for preparing propitocaine hydrochloride. The method includes the following steps that a, ortho-toluidine is added into dichloromethane, alpha-propionyl chloride is dropwise added at the room temperature, and the reaction lasts for 2-3 h at the temperature of 15 DEG C-25 DEG C, acid solution washing is performed on the obtained reaction liquid, then, aqueous alkali washing is performed on the obtained reaction liquid, water is added to an organic layer to separate solids out, and then propitocaine hydrochloride midbody is obtained through filtration; b, the propitocaine hydrochloride midbody obtained in the step a is added into n-propylamine, reflux is heated for 5-7 h, after the reaction is ended, concentrated hydrochloric acid is added to adjust the PH to be 1-2, white solids are separated out and are refined through ethyl alcohol of 95%, and therefore the propitocaine hydrochloride is obtained. An acetone solvent which is unfriendly to the environment and has hypotoxicity in a traditional method is replaced by the commonly used solvent dichloromethane which is basically free of toxic, and therefore environment-friendly industrial mass production becomes possible on the premise of not affecting the yield.
Kinetics of degradation of 4-imidazolidinone prodrug types obtained from reacting prilocaine with formaldehyde and acetaldehyde
Larsen, Susan Weng,Sidenius, Martin,Ankersen, Michael,Larsen, Claus
, p. 233 - 240 (2007/10/03)
The kinetics of decomposition of 4-imidazolidinone prodrug types obtained by reacting prilocaine (I) with formaldehyde and acetaldehyde has been studied in aqueous solution in the pH range 1-7.4 at 60 and 37°C, respectively. At pHA plot of the logarithm of the apparent first-order rate constants for hydrolysis of II against pH resulted in a sigmoidal-shaped pH-rate profile characteristic for the hydrolysis of many N-Mannich bases. A half-life at pH 7.4 (60°C) of 6.9h for compound II was calculated. Compared to II the 4-imidazolidinone derived from acetaldehyde (III) exhibited enhanced instability in aqueous buffer solutions. The decomposition was followed at 37°C monitoring the decrease in concentration of intact (III). At acidic pH the reactions displayed strict first-order kinetics and the disappearance of III was accompanied by a concomitant formation of I. At pH 7.4, the rate data also applied reasonably well to first-order kinetics despite the observation that small amounts of III was formed at pH 7.4 from a solution containing equimolar concentrations of acetaldehyde and prilocaine (10 -4M). In case of III, a bell-shaped pH-rate profile was obtained by plotting the logarithm of the pseudo-first-order rate constants against pH indicating the involvement of a kinetically significant intermediate in the reaction pathway and a change of the rate-limiting step in the overall reaction with pH. For the stability studies performed at pH 6.9 and 7.4 product analysis revealed that parallel to formation of (I) an unknown compound (X) emerged. Compared to III, compound X is hydrolysed to give I at a slower rate (t 50%=30h at 37°C). Based on LC-MS data it is suggested that (X) is an isomeric form of III, which may exist in four diastereomeric forms. Thus, at physiological pH an initial relatively fast regeneration of I from III is to be expected followed by a slower drug activation resulting from hydrolysis of the isomeric form of III.