Plenary presentation
10
ANTIARRHYTHMICS BASED ON DITERPENE ALKALOIDS.
CREATING AN INJECTION FORM
M.S. Yunusov, E.M. Tsyrlina, S.P. Ivanov, T.M. Gabbasov, S.G. Yunusova
Ufa Institute of Chemistry, UFRC RAS, Russian Federation,
450054, Ufa, ave. October, 71, e-mail: msyunusov@anrb.ru
The hydrobromic salt of lappaconitine by name "Allapinin"
was introduced into
medical practice as an antiarrhythmic agent in 1987.
The drug allapinin was approved for use, both in tablet and ampoule (injection) form.
However, intravenous use of the drug was not widely used due to the late onset of the
therapeutic effect and adverse cardiac effects.
N-deacetyllappaconitine (DAL), the main
metabolite of the drug allapinin, unlike the latter, realizes its antiarrhythmic effect in a
significantly lower dose, is
less toxic, surpasses allapinin in the speed of development of
the antiarrhythmic effect. The most acceptable
dosage form of DAL is the
monohydrochloride of N-deacetylappaconitine (DAL•НСl).
DAL•HCl, as well as allapinin, inhibits Na+ currents.
Unlike allapinin, DAL•HCl
also exhibits the properties of a K-channel inhibitor and, according to its
electrophysiological characteristics, can be attributed to antiarrhythmics combining the
properties of 1C and III classes according to the Vaugham-Williams classification.
The concentrations of DAL•HCl, which effectively inhibit Na+
channels, are
approximately 20 times less than those for allapinin.
These data seem to be quite
important, since DAL•HCl is not only active in significantly lower concentrations, but
also less toxic than allapinin, which suggests that in the case of its potential use in the
clinic, the spectrum of side effects of DAL•HCl will be significantly less than that of
allapinin.
The study of the basicity of two DAL nitrogen atoms showed, that in the pH range 6-
7, the nitrogen atom of the
piperidine ring is protonated, and in the range pH 2-3 the
nitrogen of the aromatic group is protonated. Given the data obtained, it is obvious that
the stable form, especially in aqueous solutions, can only be a mono-salt of DAL. The
conditions for the analysis of DAL by HPLC have been developed.
Thus, these data suggest that DAL can serve as a basis for obtaining a new effective
antiarrhythmic agent in injectable form.