Trazodone hydrochloride

≥99% (HPLC), powder

2-[3-[4-(3-Chlorophenyl)-1-piperazinyl]propyl]-1,2,4-triazolo[4,3-a]pyridin-3(2H)-one hydrochloride
Empirical Formula (Hill Notation):
C19H22ClN5O · HCl
CAS Number:
Molecular Weight:
EC Number:
MDL number:
PubChem Substance ID:

Quality Level


≥99% (HPLC)




45% (w/v) aq 2-hydroxypropyl-β-cyclodextrin: soluble 23.3 mg/mL
methanol: soluble 25 mg/mL, clear, colorless
0.1 M HCl: soluble 7.4 mg/mL
DMSO: soluble
H2O: soluble, hazy, colorless


Bristol-Myers Squibb

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1, 5 g in glass bottle

Biochem/physiol Actions

Antidepressant that potentiates the activity of serotonin uptake blockers and has full 5-HT2C serotonin receptor agonist activity. It is metabolized to the 5-HT1 serotonin receptor agonist 1-(3-Chlorophenyl)piperazine.

Features and Benefits

This compound is also offered as part of Sigma′s Library of Pharmacologically Active Compounds (LOPAC®1280), a biologically annotated collection of high-quality, ready-to-screen compounds. Click here to learn more.

Preparation Note

Trazodone hydrochloride dissolves in methanol at 25 mg/ml to yield a clear, colorless solution. It also dissolves in water at 50 mg/ml, with heating to yield a hazy colorless solution. Furthermore, the product is soluble in DMSO or in 0.1 N HCl (7.4 mg/ml). The solubility in a 45% (w/v) aqueous 2-hydroxpropyl-β-cyclodextrin is 23.3 mg/ml. However, it is practically insoluble in other common organic solvents. For HPLC test, the product can be dissolved at 0.25 mg/ml in 50:50 water:methanol (v/v), as this gives better results of dissolution and peak shape than using the product as a 1 mg/ml solution in water.

Legal Information

LOPAC is a registered trademark of Sigma-Aldrich Co. LLC


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Personal Protective Equipment

dust mask type N95 (US),Eyeshields,Gloves


NONH for all modes of transport

WGK Germany


Flash Point F

Not applicable

Flash Point C

Not applicable

Certificate of Analysis

Certificate of Origin

M Marcoli et al.
The Journal of pharmacology and experimental therapeutics, 285(3), 983-986 (1998-06-17)
The effects of trazodone on the cyclic GMP elevation elicited by N-methyl-D-aspartate in rat cerebellar slices were analyzed. Trazodone inhibited in a concentration-dependent manner (EC50 = 0.82 nM) the cyclic GMP response evoked by 0.1 microM N-methyl-D-aspartate. The inhibition was...
M Pazzagli et al.
European journal of pharmacology, 383(3), 249-257 (1999-12-14)
The effects of the antidepressant drug, trazodone, on the extracellular 5-hydroxytryptamine (5-HT) levels in the frontal cortex of freely moving rats was investigated using microdialysis coupled to a high performance liquid chromatography (HPLC) detection method. Systemic administration of 1.25 and...
J P Feighner
The Journal of clinical psychiatry, 60 Suppl 4, 4-11 (1999-03-23)
The psychopharmacology of depression is a field that has evolved rapidly in just under 5 decades. Early antidepressant medications--tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs)--were discovered through astute clinical observations. These first-generation medications were effective because they enhanced serotonergic...
A Georgotas et al.
Pharmacotherapy, 2(5), 255-265 (1982-09-01)
Trazodone is a new antidepressant agent that was recently introduced in the United States. It has a unique pharmacological profile that is not typical of either tricyclic or monoamine oxidase inhibitor antidepressants. As such it represents a new class of...
Arnaud Devresse et al.
Acta gastro-enterologica Belgica, 75(2), 263-265 (2012-08-09)
We present the case of a 26-year-old man with schizoid personality disorder who suffered from a very focal and transparietal necrosis of the sigmoid after an overdose of atypical neuroleptics. This is a singular, rather unknown and potentially lethal side...

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