Atomoxetine hydrochloride

China [CN]

I. Basic Information

Item | Details

English Name | Atomoxetine hydrochloride; Strattera (trade name)

Chinese Name | Atomoxetine Hydrochloride

CAS Number | 82248-59-7 (hydrochloride); 83015-26-3 (free base)

Chemical Name | (R)-N-methyl-3-phenyl-3-(o-tolyloxy)propan-1-amine hydrochloride

Molecular Formula | Free base C₁₇H₂₁NO; Hydrochloride C₁₇H₂₁NO・HCl

Molecular Weight | Free base 255.36; Hydrochloride 291.82

Target | Norepinephrine transporter (NET), selective norepinephrine reuptake inhibitor

Developer | Eli Lilly

Market Launch Date | November 2002 (US FDA); October 2007 (China NMPA)

Dosage Forms and Strengths | Capsules: 10mg, 18mg, 25mg, 40mg, 60mg (calculated as atomoxetine)

II. Physicochemical Properties

Parameter | Data (hydrochloride)

Appearance | White to off-white crystalline powder

Solubility | Easily soluble in water (approximately 27 mg/mL, 25℃), methanol, ethanol, slightly soluble in acetone, insoluble in diethyl ether

Dissociation Constant (pKa) | 10.1 (amino group) (measured value)

Melting Point | 179-181℃ (decomposition)

Stability | Stable for 36 months at 25℃/60% RH, stored in a sealed, cool and dry place (20-25℃), avoid high temperature, light and moisture

Chiral Characteristics | Contains 1 chiral center (phenylpropanamine position), single R-configuration (active configuration), optical purity >99.5%

Partition Coefficient (logP) 3.9 (Free base, predicted value)

III. Mechanism of Action

Atomoxetine hydrochloride works by highly selectively inhibiting the norepinephrine transporter (NET) on the presynaptic membrane, reducing norepinephrine reuptake, and increasing norepinephrine concentration in the synaptic cleft. This improves neurotransmission in the prefrontal cortex of the brain. Key characteristics:

It has significantly higher selectivity for NET than for serotonin (5-HT) and dopamine (DA) transporters, without the dopamine reuptake inhibition effect of central nervous system stimulants, and is not addictive.

The prefrontal cortex is a key region for regulating attention, impulse control, and executive function. Increased norepinephrine concentration can significantly improve inattention, hyperactivity, and impulsivity symptoms in ADHD patients.

It has a slow onset of action, usually requiring 2-4 weeks to achieve optimal efficacy, and requires regular medication for maintenance.