Amino esters
Encyclopedia
Amino esters are a class of local anesthetic
s.
The chemical linkage between the lipophilic part and the intermediate chain can be of the amide-type or the ester-type, and is the general basis for the current classification of local anesthetics.
Amino esters, in reference to anesthetic agents, are rapidly metabolized in the plasma
by butyrlcholinesterase to para-aminobenzoic acid derivatives, then excreted in the urine
. This suggests their very short half lives. Allergy
is more likely to occur with ester-type agents, as opposed to amide-type.
Local anesthetic
A local anesthetic is a drug that causes reversible local anesthesia, generally for the aim of having local analgesic effect, that is, inducing absence of pain sensation, although other local senses are often affected as well...
s.
Structure
Structurally, local anesthetics consist of three molecular components:- a lipophilicLipophilicLipophilicity, , refers to the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. These non-polar solvents are themselves lipophilic — the axiom that like dissolves like generally holds true...
part - an intermediate aliphatic chain
- a hydrophilic (amine) part
The chemical linkage between the lipophilic part and the intermediate chain can be of the amide-type or the ester-type, and is the general basis for the current classification of local anesthetics.
Amino esters, in reference to anesthetic agents, are rapidly metabolized in the plasma
Blood plasma
Blood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...
by butyrlcholinesterase to para-aminobenzoic acid derivatives, then excreted in the urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...
. This suggests their very short half lives. Allergy
Allergy
An Allergy is a hypersensitivity disorder of the immune system. Allergic reactions occur when a person's immune system reacts to normally harmless substances in the environment. A substance that causes a reaction is called an allergen. These reactions are acquired, predictable, and rapid...
is more likely to occur with ester-type agents, as opposed to amide-type.
Examples
Amino ester-type include:- CocaineCocaineCocaine is a crystalline tropane alkaloid that is obtained from the leaves of the coca plant. The name comes from "coca" in addition to the alkaloid suffix -ine, forming cocaine. It is a stimulant of the central nervous system, an appetite suppressant, and a topical anesthetic...
- ProcaineProcaineProcaine is a local anesthetic drug of the amino ester group. It is used primarily to reduce the pain of intramuscular injection of penicillin, and it was also used in dentistry. Owing to the ubiquity of the trade name Novocain, in some regions procaine is referred to generically as novocaine...
(Novocain) - TetracaineTetracaineTetracaine is a potent local anesthetic of the ester group...
(Pontocaine) - BenzocaineBenzocaineBenzocaine is a local anesthetic commonly used as a topical pain reliever, or in cough drops. It is the active ingredient in many over-the-counter anesthetic ointments...