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Introduction. α(1,2)-L-rhamno-α(1,4)-D-galactopyranosyluronane is a water-soluble heteropolysaccharide isolated from the rhizomes of calamus marsh (Acorus calamus L.) and has antitumor, antimetastatic, immunomodulatory and hepatoprotective effects, protective effect on hematopoiesis suppressed during cytostatic treatment.Aim. Validation of the bioanalytical method for the determination of α(1,2)-L-rhamno-α(1,4)-D-galactopyranosyluronane Acorus calamus L. and the study of the pharmacokinetic parameters of a new drug based on it after a single administration of 120 mg/kg to rats and 24, 30, 42 mg/kg to rabbits.Materials and methods. In the study, 8 male rats (average weight – 300 g) were used as the main animals. 6 male rabbits (average body weight – 2.5 kg) were used as an additional animal species. The dose assessment experiment was carried out on 24 rabbits (body weight – 2.3–2.5 kg). The quantitative determination of α(1,2)-L-rhamno-α(1,4)-D-galactopyranosyluronane Acorus calamus L. in the blood plasma of animals was carried out by HPLC-MS/MS, the analytical form was galacturonic acid. The method of sample preparation of biological samples included the stage of enzymatic hydrolysis of α(1,2)-L-rhamno-α(1,4)-D-galactopyranosyluronane Acorus calamus L. with a solution of pectinase for the formation of galacturonic acid.Results and discussions. The pharmacokinetics of the new drug α(1,2)-L-rhamno-α(1,4)-D-galactopyranosyluronane Acorus calamus L. was studied after a single dose of 120 mg/kg to rats and 24, 30, 42 mg/kg to rabbits. The average residence time of the drug in the rabbit's body was 1.0 ± 0.21 hours, the half-life was 0.7 ± 0.15 hours. The average residence time of the drug in the rat body was 1.16 hours, the half-life T1/2 was 0.80 hours. After a single intravenous administration to rabbits of 24, 30 and 42 mg/kg, the maximum concentration in the systemic bloodstream is reached 5 minutes after administration and averages 133.95 ± 27.04, 145.86 ± 40.90 and 226.13 ± 41.27 µg/ml, respectively, the half-life ranged from 0.22 to 0.26 h, the half-life from 3.52 to 3.96 hours.Conclusion. The pharmacokinetic parameters of α(1,2)-L-rhamno-α(1,4)-D-galactopyranosyluronane Acorus calamus L. were evaluated in animals based on the use of the method of quantitative determination of galacturonic acid by HPLC-MS/MS.

Currently the development of technologies for labeling somatostatin with technetium-99m for diagnosing radionuclide neuroendocrine tumors is under way. Somatostatin analogues are binded with technetium99m only by the preliminary addition of a chelating agent. Therefore, it is important to develop a method for preparation of an octreotide derivative by modifying octreotide with precursors: ligands with high chelating ability for its tight binding with technetium-99m. ω-Bis(pyridin-2-ylmethyl)amino)aliphatic acids can be used successfully as such precursors.The purpose of the study was to develop a method for obtaining a new octreotide derivative for diagnosing neuroendocrine tumors.Materials and methods. The somatostatin octreotide analogue was used as the object of the study; succinimid-1-yl 6-(bis(pyridin-2-ylmethyl)amino)hexanoate was used as a chelating agent. Methods of high performance liquid chromatography and mass spectrometry were used to separate and analyze the synthesized compounds.Results. A method to produce an original octreotide derivative using a succinimid-1-yl 6-(bis(pyridin2-ylmethyl)amino)hexanoate as a chelating agent was proposed. The conditions of analytical and semipreparative HPLC for the analysis and purification of the active octreotide derivative (a monosubstituted derivative of the amino acid residue of D-phenylalanine) were suggested.Conclusion. The synthesized derivative of octreotide has a chelating center for strong binding to technetium-99m in its structure, which can be useful for diagnosing neuroendocrine tumors.