417
Volume 5, Issue 10: Special Issue
(EJAR)
ISSN: 2181-2020
MPHAPP
THE 6TH INTERNATIONAL SCIENTIFIC AND PRACTICAL
CONFERENCE
“
MODERN PHARMACEUTICS: ACTUAL
PROBLEMS AND PROSPECTS
”
TASHKENT, OCTOBER 17, 2025
in-academy.uz
DETERMINATION OF ALLAPININ CONTENT BY NON-AQUEOUS ACID-BASE
TITRATION AND METHOD VALIDATION
Mirzabdullayeva N.Sh.
Ubaydullayev Q.A.
Tashkent Pharmaceutical Institute, Tashkent, Republic of Uzbekistan
e-mail: nodiramirzabdullayeva@gmail.com, tel: (99)395-56-12
https://doi.org/10.5281/zenodo.17341154
Relevance:
Allapinin is an antiarrhythmic drug that blocks sodium channels in the heart due to
the presence of lappaconitine. As an antiarrhythmic drug belonging to the diterpene alkaloid group,
assessing the quality parameters of Allapinin, studying its properties, and comparatively evaluating
quality control methods are essential. Another important task is to assess the validation parameters of
the quantitative determination method of Allapinin.
Purpose of the Study:
To evaluate the method for determining the quantitative content of
Allapinin using validation parameters.
Methods:
The content of Allapinin was determined by non-aqueous acid-base titration, and the
obtained results were validated.
Results:
Several modern analytical methods were used to determine the content of Allapinin.
One of them is acid-base titration with 0.1% perchloric acid. Salts that are poorly or practically
insoluble in water, or that possess weak acidic or basic properties, are analyzed by acid-base titration
using non-aqueous solvents. Weak electrolytes (acids or bases) are substances with a dissociation
constant Kd < 10⁻⁸, i.e., with pKa > 8. The method was based on non-aqueous titration using
perchloric acid (HClO₄) solution in glacial acetic acid, with crystal violet as an indicator. This method
is used for the quantitative analysis of organic bases that are soluble in acetic acid and react with
perchloric acid. The substance under study is dissolved in acetic acid and titrated with perchloric acid
solution. The change in the color of the solution from violet to blue indicates the endpoint of titration.
Knowing the volume of perchloric acid solution consumed for titration, the content of the analyzed
base can be calculated. During the development of this method, it was determined that the most
suitable solvent for dissolving a 200 mg sample of Allapinin is glacial acetic acid.
Validation of the analytical method is the process of experimentally confirming the suitability
of the method for its intended purpose. This ensures the reliability and reproducibility of the results,
which is of critical importance in the quality control of pharmaceutical substances and finished
products. According to the requirements of the European Pharmacopoeia, the working range for
validation of quantitative determination methods for substances and medicinal products should cover
80–120% of the nominal content. Within this range, the linearity, accuracy, and precision of the
method must be demonstrated.
Conclusion:
According to the validation results, the method for determining Allapinin content
demonstrated specificity, as the use of glacial acetic acid did not introduce interfering substances into
the titration results. The linearity data showed a correlation coefficient of 0.9993, which exceeds the
minimum acceptance criterion (≥ 0.990). Accuracy was within 99.0% – 101.0%. These results
confirm full compliance with validation requirements. Precision testing yielded a coefficient of
variation of 0.47%, and intra-laboratory precision was 0.56%, both not exceeding the ≤ 2%
acceptance limit. Based on these results, non-aqueous acid-base titration using 0.05 M perchloric acid
solution was successfully applied for the quantitative determination of Allapinin. Validation
outcomes confirm that this analytical method is suitable for determining the content of Allapinin.
