Relevance. International non-proprietary name (INN) Ebastin is widely used in medical practice in the treatment of urticaria and allergic rhinitis. It is an antiallergic drug, which belongs to the second generation of H1-histamine receptor blocker, it is necessary to emphasize that Ebastin is effective when taken orally. As part of the registration of trade name Allergostin, a clinical study of its bioequivalence with Kestin was conducted with the participation of 26 healthy volunteers.
 Aim. The aim of this publication is summarize results of the clinical study of the comparative pharmacokinetics and bioequivalence, safety and tolerability of Allergostin, film-coated tablets, 20 mg (NTFF POLYSAN LLC, Russia), and Kestin, film-coated tablets, 20 mg (Almiral S.A., Spain), in healthy volunteers after a single oral dose on an empty stomach.
 Materials and methods. To confirm bioequivalence, an open, randomized, two-period, cross-over study of comparative pharmacokinetics and bioequivalence of drugs with a single oral intake on an empty stomach in adult healthy male and female volunteers was conducted. During the study, blood plasma samples were taken from volunteers. Each sample was tested by using a validated high performance liquid chromatography with tandem mass spectrometry method, the concentrations of ebastine and the active metabolite carabastin were determined. Based on obtained data , pharmacokinetic and statistical analysis was carried out, 90% confidence intervals (CI) were calculated for the ratio of the geometric mean values of the pharmacokinetic parameters Cmax and AUC0-72 for carabastin.
 Results. Based on results of statistical analysis, it was shown that the pharmacokinetic parameters of the test (Allergostin) and reference (Kestin) drug are characterized by high similarity. For the estimated pharmacokinetic parameters of carabastin, 90% CI ranged from 80-125% for AUC0-t and Cmax.
 Conclusion. Thus, according to the applied criteria, the drugs are recognized as bioequivalent.