Norepinephrine, also called noradrenaline or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as a hormone, neurotransmitter and neuromodulator. Norepinephrine has the molecular formula C8H11NO3 and a molecular weight of 169.18 g mol-1, contains a catechol ring with two adjacent phenolic hydroxyl groups and a primary amine on a two carbon side chain, and is typically handled and formulated as the bitartrate salt for improved stability and solubility. It is highly polar and water soluble, with an estimated log P around -0.7 and a basic pKa for the amine near 8.5, and is synthesized biologically by dopamine beta-hydroxylase converting dopamine to norepinephrine in synaptic vesicles and adrenal chromaffin cells. Pharmacologically it is a potent alpha1 and alpha2 adrenergic agonist with significant beta1 activity and minimal beta2 activity, producing vasoconstriction and increased cardiac contractility and heart rate; systemic clearance is rapid, with plasma half-life on the order of minutes due to metabolism by monoamine oxidase and catechol-O-methyltransferase, and clinical formulations for intravenous use are prepared and administered as controlled concentration infusions with aseptic technique and compatibility testing.
Parent: Noradrenaline
Parent: Noradrenaline
Parent: Norepinephrine / Noradrenaline
Parent: Noradrenaline
Parent: Noradrenaline
Parent: Noradrenaline
Parent: Noradrenaline
Parent: Noradrenaline/ Noradrenaline Tartrate Monohydrate/ Norepinephrine
Parent: Norepinephrine/ Noradrenaline
Parent: Norepinephrine / Noradrenaline
Parent: Norepinephrine / Noradrenaline
Parent: Noradrenaline
Parent: Noradrenaline
Typical impurity and related compound profiles for noradrenaline active pharmaceutical ingredient and injectable formulations focus on oxidation products, catechol degradation products and structurally related catecholamines, and are monitored by validated chromatographic methods such as HPLC-UV and LC-MS and by GC for residual solvents; common related compounds include epinephrine, dopamine, metanephrine and normetanephrine, 3,4-dihydroxyphenylglycol (DHPG), adrenochrome-type oxidation products and low-level dimers or polymeric oxidation species, plus expected counterion residues such as tartaric acid when the bitartrate salt is used. Typical release specifications adopted by manufacturers and pharmacopoeial monographs set individual related compound limits in the low parts-per-thousand range, for example individual impurities commonly controlled to about 0.2 to 0.5 percent w w and total impurities to about 1.0 to 2.0 percent w w depending on impurity identity and stability data, with specific tighter limits applied to potent related catecholamines such as epinephrine or dopamine (often specified at or below 0.05 to 0.2 percent w w); antioxidants like ascorbic acid or careful exclusion of oxygen and light are used in process and finished product controls to minimize formation of oxidative impurities.
Noradrenaline serves as both a neurotransmitter in the central and peripheral nervous systems and as a hormone released from the adrenal medulla; it mediates arousal, attention and stress responses centrally and increases vascular tone and cardiac output peripherally primarily through alpha1 mediated vasoconstriction and beta1 mediated cardiac effects.
In intensive care practice norepinephrine is used as a first line vasopressor to treat acute hypotension and septic shock because it raises systemic vascular resistance and supports mean arterial pressure while preserving or improving coronary and cerebral perfusion; it is administered as a titratable intravenous infusion prepared under aseptic conditions.
Noradrenaline and adrenaline are both catecholamine hormones and neurotransmitters but differ in receptor selectivity and physiological effect: noradrenaline is a stronger alpha adrenergic agonist with predominant vasoconstrictive action and modest beta1 cardiac stimulation, whereas adrenaline has relatively greater beta activity including beta2 mediated vasodilation and bronchodilation, producing more pronounced increases in heart rate and metabolic effects.
During the fight or flight response noradrenaline is released from sympathetic nerve endings and the adrenal medulla to increase alertness and readiness, cause vasoconstriction to support blood pressure, redirect blood flow to skeletal muscle and heart, and enhance cardiac output, thereby mobilizing cardiovascular resources to respond to acute stress.
