The lethal dose (LD50) of chloroprocaine hydrochloride in mice is 950 mg/kg for subcutaneous injection and 97 mg/kg for intravenous injection[2].

Absorption, Distribution and Excretion
Thanks to its low risk for systemic toxicity, chloroprocaine has a rapid onset of action that usually ranges between 6 to 12 minutes. The duration of chloroprocaine-induced anesthesia may be up to 60 minutes. The absorption rate of local anesthetics depends on the total dose and concentration of chloroprocaine, as well as the route of administration, the vascularity of the administration site, and the presence or absence of epinephrine in the anesthetic injection. The presence of epinephrine reduces the rate of absorption and plasma concentration of local anesthetics. The systemic exposure to chloroprocaine following its topical ocular administration has not been evaluated.
Like most local anesthetics and their metabolites, chloroprocaine is mainly excreted by the kidneys. The urinary excretion of chloroprocaine may be affected by urinary perfusion and factors that have an effect on urinary pH.
PROCAINE IS READILY ABSORBED FOLLOWING PARENTERAL ADMIN ... DOES NOT LONG REMAIN @ SITE OF INJECTION. ... FOLLOWING ABSORPTION, PROCAINE IS RAPIDLY HYDROLYZED ... /PROCAINE/
... Binding of the anesthetic to proteins in the serum and to tissues reduces the concentration of free drug in the systemic circulation and, consequently, reduces toxicity. ... /Ester local anesthetics/ are hydrolyzed and inactivated primarily by a plasma esterase, probably plasma cholinesterase. The liver also participates in hydrolysis of local anesthetics. /Local anesthetics/
THE SYSTEMIC TOXICITY OF CHLOROPROCAINE IS LESS THAN THAT OF ALL OTHER LOCAL ANESTHETICS BECAUSE OF ITS RAPID HYDROLYSIS BY PLASMA CHOLINESTERASE ... WHICH SHORTENS THE PLASMA HALF-LIFE.
... ENZYMATIC HYDROLYSIS OF PROCAINE /GIVES/ ... PARA-AMINOBENZOIC ACID & DIETHYLAMINOETHANOL. FORMER IS EXCRETED IN URINE TO EXTENT OF ABOUT 80%, EITHER UNCHANGED OR IN CONJUGATED FORM. ONLY 30% OF DIETHYLAMINOETHANOL CAN BE RECOVERED IN URINE; REMAINDER UNDERGOES METABOLIC DEGRADATION ... /PROCAINE/
For more Absorption, Distribution and Excretion (Complete) data for CHLOROPROCAINE (9 total), please visit the HSDB record page.

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Metabolism / Metabolites
In plasma, chloroprocaine is quickly metabolized by pseudocholinesterases, a group of enzymes that perform the hydrolysis of the ester linkage. In ocular tissues, chloroprocaine is metabolized by nonspecific esterases. The hydrolysis of chloroprocaine leads to the production of ß-diethylaminoethanol and 2-chloro-4-aminobenzoic acid, which inhibits the action of the sulfonamides.
2-DIETHYLAMINOETHYL 4-AMINO-2-CHLOROBENZOATE YIELDS 4-AMINO-2-CHLOROBENZOIC ACID IN GUINEA PIGS. LIVETT, BH & RM LEE, BIOCHEM PHARMAC 17, 385 (1968). /FROM TABLE/
HYDROLYZED /CHIEFLY/ BY PLASMA PSEUDOCHOLINESTERASES /& ALSO BY ESTERASES IN LIVER/ AS DIETHYLAMINOETHANOL & 2-CHLORO-4-AMINOBENZOIC ACID /HUMAN, PARENTERAL. ANIMAL STUDIES SUGGEST THAT SOME LOCAL ANESTHETICS MAY UNDERGO BILIARY RECYCLING/ /CHLOROPROCAINE HCL/
Chloroprocaine is rapidly metabolized in plasma by hydrolysis of the ester linkage by pseudocholinesterase.
Route of Elimination: Chloroprocaine is rapidly metabolized in plasma by hydrolysis of the ester linkage by pseudocholinesterase. Urinary excretion is affected by urinary perfusion and factors affecting urinary pH.
Half Life: 21 +/- 2 seconds

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Biological Half-Life
In adults, the average _in vitro_ plasma half-life of chloroprocaine is 21 seconds for males and 25 seconds for females. In neonates, the average _in vitro_ plasma half-life is 43 seconds. Following intrapartum epidural anesthesia, the apparent _in vivo_ half-life of chloroprocaine detected in maternal plasma was 3.1 minutes (range from 1.5 to 6.4 minutes).
... Plasma half-life /is/ approximately 25 seconds.

Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
No information is available on the use of chloroprocaine during breastfeeding. Based on the low excretion of other local anesthetics into breastmilk and the extremely short half-life of chloroprocaine, it is unlikely to adversely affect the breastfed infant. However, an alternate drug may be preferred, especially while nursing a newborn or preterm infant.
◉ Effects in Breastfed Infants
Relevant published information was not found as of the revision date.
◉ Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.

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Protein Binding
Compared to the other clinically used local anesthetics, chloroprocaine has one of the lowest protein binding percentages.

[1]. Inhibition of the Na,K-ATPase of Canine Renal Medulla by Several Local Anesthetics. Pharmacol Res. 2001 Apr;43(4):399-403.

[2]. Chloroprocaine HCl Injection.

Chloroprocaine is procaine in which one of the hydrogens ortho- to the carboxylic acid group is substituted by chlorine. It is used as its monohydrochloride salt as a local anaesthetic, particularly for oral surgery. It has the advantage over lidocaine of constricting blood vessels, so reducing bleeding. It has a role as a local anaesthetic, a peripheral nervous system drug and a central nervous system depressant. It is a benzoate ester and a member of monochlorobenzenes. It is functionally related to a 2-diethylaminoethanol and a 4-amino-2-chlorobenzoic acid.
Chloroprocaine is an ester local anesthetic commonly available in its salt form, chloroprocaine hydrochloride. Similar to other local anesthetics, it increases the threshold for electrical excitation in nerves by slowing the propagation of the nerve impulse and reducing the rate of rise of the action potential. The pharmacological profile of chloroprocaine is characterized by a short latency and duration, similar to the one observed with [lidocaine]. Chloroprocaine can be given as an injection, and is available in formulations with and without methylparaben as a preservative. Both can be given as intrathecal injections for peripheral and central nerve block, but only the preservative-free formulation can be used for lumbar and caudal epidural blocks. Topical chloroprocaine for ophthalmic use was approved by the FDA in September 2022 for ocular surface anesthesia.
Chloroprocaine is an Ester Local Anesthetic. The physiologic effect of chloroprocaine is by means of Local Anesthesia.
Chloroprocaine hydrochloride is a local anesthetic given by injection during surgical procedures and labor and delivery. Chloroprocaine, like other local anesthetics, blocks the generation and the conduction of nerve impulses, presumably by increasing the threshold for electrical excitation in the nerve, by slowing the propagation of the nerve impulse and by reducing the rate of rise of the action potential.
See also: Chloroprocaine Hydrochloride (has salt form).

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Drug Indication
Chloroprocaine for intrathecal injection is indicated for the production of subarachnoid block (spinal anesthesia) in adults. It is also indicated for the production of local anesthesia by infiltration, peripheral and central nerve block, and a preservative-free form can also be used for lumbar and caudal epidural blocks. Topical chloroprocaine for ophthalmic use is indicated for ocular surface anesthesia.

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Mechanism of Action
Chloroprocaine acts mainly by binding to the alpha subunit on the cytoplasmic region of voltage-gated sodium channels and inhibiting sodium influx in neuronal cell membranes. This lowers the nerve membrane permeability to sodium and decreases the rate of rise of the action potential. Therefore, chloroprocaine inhibits signal conduction and leads to a reversible nerve conduction blockade. The progression of anesthesia depends on the diameter, myelination and conduction velocity of nerve fibers, and the order of loss of nerve function is the following: 1) pain, 2) temperature, 3) touch, 4) proprioception, and 5) skeletal muscle tone.
Local anesthetics prevent the generation and the conduction of the nerve impulse. Their primary site of action is the cell membrane. ... Local anesthetics block conduction by decreasing or preventing the large transient increase in the permeability of excitable membranes to Na+ that normally is produced by a slight depolarization of the membrane. ... As the anesthetic action progressively develops in a nerve, the threshold for electrical excitability gradually increases, the rate of rise of the action potential declines, impulse conduction slows, and the safety factor for conduction decreases; these factors decrease the probability of propagation of the action potential, and nerve conduction fails. ... /Local anesthetics/ can block K+ channels. ... blockade of conduction is not accompanied by any large or consistent change in resting membrane potential due to block of K+ channels. /Local anesthetics/
... SITE AT WHICH LOCAL ANESTHETICS ACT, AT LEAST IN ... CHARGED FORM, IS ACCESSIBLE ONLY FROM THE INNER SURFACE OF THE MEMBRANE. ... LOCAL ANESTHETICS APPLIED EXTERNALLY FIRST MUST CROSS THE MEMBRANE BEFORE THEY CAN EXERT A BLOCKING ACTION. /LOCAL ANESTHETICS/
... /TWO POSSIBILITIES:/ ACHIEVE BLOCK BY INCR SURFACE PRESSURE OF LIPID LAYER THAT CONSTITUTES NERVE MEMBRANE ... CLOSING PORES THROUGH WHICH IONS MOVE. ... /OR:/ AFFECT PERMEABILITY BY INCR DEGREE OF DISORDER OF MEMBRANE. /LOCAL ANESTHETICS/
... ACID SALT MUST BE NEUTRALIZED IN TISSUE & FREE AMINE LIBERATED BEFORE DRUG CAN PENETRATE TISSUES & PRODUCE ANESTHETIC ACTION. ... FORM OF MOLECULE ACTIVE IN NERVE FIBERS IS CATION. ... CATION ... COMBINES WITH SOME RECEPTOR IN MEMBRANE TO PREVENT GENERATION OF ACTION POTENTIAL. /LOCAL ANESTHETICS/
... /SUGGESTED/ THAT PROCAINE ... DIMINISHES RELEASE OF ACETYLCHOLINE BY MOTOR-NERVE ENDINGS. /PROCAINE/

C13H19CLN2O2

270.7549

306.09

133-16-4

Chloroprocaine hydrochloride;3858-89-7

8612

Typically exists as solid at room temperature

1.17g/cm3

402.6ºC at 760mmHg

173-174ºC

197.3ºC

1.08E-06mmHg at 25°C

1.553

3.804

1

4

7

18

259

0

CCN(CC)CCOC(=O)C1=CC=C(C=C1)NCl

VDANGULDQQJODZ-UHFFFAOYSA-N

InChI=1S/C13H19ClN2O2/c1-3-16(4-2)7-8-18-13(17)11-6-5-10(15)9-12(11)14/h5-6,9H,3-4,7-8,15H2,1-2H3

2-(diethylamino)ethyl 4-amino-2-chlorobenzoate

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)