Chapter 12. Analysis of medicinal drugs of the arylalkylamine group

General arylalkylamine formula:

Classification

Based on their pharmacological effect, arylalkylamines can be divided into the following groups:

• adrenomimetics (norepinephrine hydrotartrate, epinephrine hydrotartrate, ephedrine hydrochloride, isadrine, etc.);
• β-blockers (anaprilin, atenolol, timolol);
• antibiotics (chloramphenicol and its derivatives);
• dopaminergics (dopamine);
• antiparkinsonians (levodopa, carbidopa);
• antihypertensives (methyldopa, brand names: dopegyt, aldomet);
• hormones (liothyronine, adrenaline);
• psychomotor stimulants (amphetamine and its derivatives).

Some other drugs, such as radio-opaque iodine-containing substances, are also arylalkylamines.

Based on their chemical structure, drugs of this group can be divided into the following subgroups:

• phenylalkylamine and oxyphenylalkylamine derivatives: dopamine, ephedrine hydrochloride, epinephrine (adrenaline) and norepinephrine (noradrenaline), as well as their salts, isoprenaline (isadrine), fenoterol (berotec, partusisten), salbutamol, verapamil;
• aryloxypropanolamine derivatives: propranolol (anaprilin), atenolol, timolol, fluoxetine (Prozac);
• oxyphenylaliphatic amino acid derivatives: levodopa, methyldopa;
• iodine-containing arylaliphatic amino acids: thyroidin, liothyronine, sodium levothyroxine;
• nitrophenylalkylamine derivatives: chloramphenicol (levomycetin) and its esters (chloramphenicol stearate and chloramphenicol sodium succinate);
• dibromophenylaminoalkylamines: bromhexine hydrochloride, ambroxol hydrochloride.

PHENYLALKYLAMINE AND OXYPHENYLALKYLAMINE DERIVATIVES

Ephedrine hydrochloride Ephedrini hydrochloridum l-erythro-2-methylamino-1-phenylpropanol-1-hydrochloride	Adrenomimetic, vasoconstrictor, bronchodilatory, anti-congestive agent
Pseudoephedrine Pseudoephedrinum Dephedrine D-treo-2-methylamino-1-phenylpropanol-1-hydrochloride	Adrenomimetic agent. In terms of pharmacological properties, it is close to ephedrine, but less active and toxic
Norepinephrine hydrotartrate Norepinephrini hydrotartras (Noradrenaline hydrotartrate) 4-[(1R)-2-amino-1-hydroxyethyl]benzene-1,2-diol(2R, 3R)-2,3-dihydroxybutanedioate (1:1), monohydrate	Adrenomimetic agent
Epinephrine hydrotartrate Epinehrini hydrotartras (Adrenaline hydrotartrate) 4 -[(1R)-1-hydroxy-2-(methylamino)ethyl]benzene-1,2-diol(2R, 3R)-2,3-dihydroxybutanedioate (1:1)	Adrenomimetic agent
Isoprenaline hydrochloride Isoprenalini hydrochloridum (Isadrine) 1-(3,4-dihydroxyphenyl)-2-isopropylaminoethanol hydrochloride	Adrenomimetic agent. It has a pronounced bronchodilatory property

OXYPHENYL ALIPHATIC AMINO ACID DERIVATIVES

Levodopa Levodopum (L-DOPA) l-3-(3’,4’-dioxyphenyl)-2-aminopropionic acid	Antiparkinsonian agent
Methyldopa Methyldopum l-3-(3,4-dihydroxyphenyl)-2-methyl-2-aminopropionic acid	Antihypertensive agent

NITROPHENYLALKYLAMINE DERIVATIVES

Chloramphenicol Chloramphenicolum (Levomycetin. Laevomycetinum) N-[(1R, 2R)-2-hydroxy-1-(hydroxymethyl)-2-(4-nitrophenyl) ethyl]-2,2-dichloroacetamide

Antibiotic

IODINATED DERIVATIVES OF ARYLALIPHATIC AMINO ACIDS

Levothyroxine sodium Levothyroxine sodium. L-thyroxine (O- (4-hydroxy-3,5-diiodophenyl)-3,5 diiodo-L-tyrosine sodium)	Levothyroxine sodium, a levorotatory isomer of thyroxine, is a prohormone to triiodothyronine
Liothyronine Liothyronine Triiodothyronine O-(4-hydroxy-3-iodophenyl)-3,5diiodo-L-tyrosine	Lyothyronine is a levorotatory isomer of triiodotyrosine

General Chemical Properties

Acid-base Properties

Base properties are manifested due to the primary or secondary aliphatic amino group, salts are formed with acids (mineral and organic);

As nitrogenous bases, medicinal substances of this group interact with general alkaloid precipitation reagents.

Weak acidic properties are caused by phenolic hydroxyls; water-soluble phenolates are formed when an excess of alkali is added. Acidic properties are weaker in alcohol hydroxyl: it does not form salts.

Oxidation-reduction Properties

The reducing properties of drugs of the hydroxyphenylalkylamine group (norepinephrine hydrotartrate, epinephrine hydrotartrate, isadrine) increase dramatically due to the presence of phenolic hydroxyls. However, the ability to oxidize depends on concomitant factors such as the location of phenolic hydroxyls, ionization of the molecule, etc.

Drugs with the o-diphenol structure are oxidized to colored products of the quinoid structure (for example, adrenaline is oxidized by iodine solution to adrenochrome).