Dypeptydylpeptidase IV Activity Ingibition after Oral Administration to Rabbits of Strongylocentrotus Droebahiensis Gonads Extract as Possible Biomarker of Pharmakokinetics

Introduction. The pharmacokinetic profiling of active compounds is necessary for drug development and application. Comlex extract of biologically active compounds was isolated from gonads of green sea urchin Strongylocentrotus droebachiensis from Barents Sea. It contains fatty acids, carotenoids and tocopherols and have inhibition activity to ensyme dypeptydylpeptidase IV (DPP-4). Traditional approaches to pharmacokinetic study based on chromatographic methods are not effective for such complex mixtures because they had not enough selectivity and sensitivity. Methods of immunoassay for special enzyme, bioassay, etc. may be used as an alternative way.Aim. The aim: to find approach to pharmacokinetic study of sea urchin gonads extract in rabbits after a three doses oral administration.Materials and methods. Various spectroscopic and chromatographic (HPLC and TLC) methods were used for chemical characteristic of sea urchin gonads extract ant different target analytes quantification in biosamples. The pharmacokinetic of sea urchin gonads extract was studied after single dose oral administration to male rabbits. The correlation between concentration of sea urchin gonads extract in the blood plasma and its biological activity marked by DPP-4 activity was established. The activity of DPP-4 was determined by the chromogenic optical method.Results and discussion. Main groups of sea urchin gonads extract chemical compounds were characterized. Total peptides content was 15-22 %; a-tocopherol content - 0.05-0.15 %, total tocopherols content - 0.23-0.38 %; total carotenoid content - 0.005-0.07 %; total fatty acids content calculated to linolenic acid - 11,03 to 12,74 %. After sea urchin gonads extract chemical composition results it was established that concentrations of identified individual biologically active compound are low, there is no dominant compound or group of compounds responsible for pharmacological activity of sea urchin gonads extract which may be unambiguously chosen as target analyte for its pharmacokinetic study. Approach based on correlation of special marker activity (DPP-4) and extract concentration appears to be the best for pharmacokinetic study of complex extract from green sea urchin gonads. The method for the quantitative determination of sea urchin gonads extract in the blood plasma of rabbits by its effect on DPP-4 activity was developed. The method was validated by parameters: selectivity, lower limit of quantification, linearity range, acc