Pharmacokinetic Studies Of Darirestat Potassium In Rats

PurposeAs the incidence of diabetes has risen rapidly around the world,treatments for diabetes complications have come out one after the other.Darirestat potassium is an aldose reductase inhibitor developed by Chinese experts based on traditional medicines,alleviating diabetic complications by inhibiting the polyol pathway in glucose metabolism process.In order to ensure the safety and effectiveness of darisstatal potassium,preclinical studies on darirestat potassium are required.MethodIn this study,SD rats were used as subjects for pre-clinical studies of darirestat potassium.1)In order to determine the concentration of darirestat potassium in rat plasma accurately,a rapid,efficient and sensitive quantitative method based on LC-MS/MS was established:The darirestat potassium in plasma samples was extracted by liquid-liquid extraction;it was effectively separated by gradient elution;The negative ion mode of the ESI source was used in the triple quadrupole mass spectrometry API4000,and under the MRM scanning mode,select m/z 390.0→m/z346.0（daristat potassium）and m/z 478.2→434.2（internal standard）as the monitoring ion pairs to achieve the quantitative analysis of darisita potassium,the quantitative range is 10³000 ng/mL.In order to ensure the reliability of the method,the method has been verified by the NMPA guidelines.2)In order to study the pharmacokinetic behavior of darirestat potassium in rat plasma,rats were administered intravenously,fasting intragastric administration and intragastric administration after eating,and the blood concentration was determined by the above quantitative method for analyzing dietary effects.3)Using the time-of-flight,high resolution mass spectrometry TripleTOF^TM5600 combined with IDA technology to identify the metabolites of darirestat potassium in rat urine and fecal samples for analyzing the biotransformation process of darirestat potassium in rats.4)In order to measure the darirestat potassium parent drug with major metabolites in rat urine or fecal samples accurately and calculate the cumulative excretion rate,we established a quantification method for multi-components by using QTRAP^?5500 ion trap mass spectrometry:The sample was pretreated by precipitation protein method,and the darirestat potassium parent drug and main metabolites were separated by gradient elution from column.In the positive ion mode of the ESI source,we use the MRM scanning method to determine the concentration of darirestat potassium parent drug and its main metabolites.The quantitation range is from 1 to 500 ng/mL.Results1)Methodological verification results show:The established quantification method in rat plasma for darirestat potassium has been characterized by high sensitivity,high recovery rate,strong specificity,no residue,and reliable dilution.So it can be used for pharmacokinetic study of darisitarine potassium.2)By intragastrically administered rats,we found the absorption of darirestat potassium was significantly different in different rats,and the food had a significant effect on the absorption of darirestat potassium.Eating can accelerate the elimination of darirestat potassium in rats.The absolute bioavailability of darirestat potassium by intragastric administration（10 mg/kg）after eating was 6.08%,and the result was low.3)In the urine and feces samples of rats,four kinds of darirestat potassium phase I metabolites were found,respectively by oxidation,decarboxylation,demethylation,and demethylation after decarboxylation.4)According to the cumulative excretion rate,60.467%of darirestat potassium was excreted from the feces,7.821%of darirestat potassium was excreted from the urine and 56.09%of it was excreted in the form of parent drug.The main metabolites detected in all excreta samples were the metabolites of oxidation and demethylation,with a ratio of 5.14%and 6.84%.