Ethylene diamine derivatives

Ethylene diamine derivatives

Metabolism of ethylene diamine derivatives: These antihistaminic drugs undergo N-demethylation and subsequent deamination. In addition, some compounds produce quaternary N-glucuronide as urinary metabolites, a process that occurs to some extend in many relatively unhindered tertiary aliphatic amines among the antihistamines and also in other liphophilic tertiary aliphatic amine drugs.

i. Tripelennamine (Pyribenzamine HCl)

Synthesis

Properties and uses: It is a white, crystalline powder, soluble in water, freely soluble in alcohol and ether, but insoluble in chloroform or benzene. Tripelennamine is the first ethylenediamine developed in the American laboratories; it appears to be effective as diphenhydramine and may have the advantage of fewer and less severe side reactions. Drowsiness may occur and may impair the ability to perform tasks requiring alertness. The concurrent use of alcoholic beverage should be avoided. It is used in the treatment of allergic rhinitis, allergic conjunctivitis, angioedema, dermagraphism, and anaphylactic reactions.

Dose: Usual dose is 25–50 mg for adults consumed orally four to six times a day.

ii. Pyrilamine (Mepyramine, Anthisan)

Synthesis

Properties and uses: Mepyramine maleate is a white or slightly yellowish crystalline powder, soluble in water and in ethanol. Pyrilamine differs structurally from tripelennamine having a methoxy group in the para position of the benzyl radical. It differs from its more toxic and less potent precursor phenbenzamine (antergan) having a 2-pyridyl group on the nitrogen atom in the place of a phenyl group. Clinically, pyrilamine and tripelennamine are considered to be among the less potent antihistamines. It is used as an antihistaminic agent with a low incidence of sedative effects; it is also used as an antiemetic.

Assay: Dissolve the sample in anhydrous acetic acid and titrate against 0.1 M perchloric acid. Determine the end point potentiometrically.

Dose: Usual dose is 25–50 mg for adults taken orally three to four times per day.

Dosage forms: Mepyramine tablets B.P.

iii. Thonzylamine (Resistab)

Synthesis

Properties and uses: It is recommended for use with streptomycin in exudative human tuberculosis. It is used in treating the symptoms of diseases, such as hay fever, utricaria, and other mild allergic conditions.

Dose: Usual dose is 50 mg for adults consumed orally up to four times a day.