Laboratory Research of Degradation of Polyhydroxyalkanoates of Different Chemical Structure in Soil

Исследована деградация трех типов полигидроксиалканоатов (ПГА) в лабораторных условиях в полевой почве при двух температурных режимах в течение 35 суток. Показано существенное влияние состава мономеров и степени кристалличности ПГА на разрушаемость в лабораторных почвенных микроэкосистемах. Пленочные образцы поли-3- гидроксибутирата (П3ГБ), поли-3-гидроксибутирата/4-гидроксибутирата (П3ГБ/4ГБ), поли- 3-гидроксибутирата/3-гидроксивалерата (П3ГБ/3ГВ) по активности разрушения в почве расположены в ряду: П3ГБ/4ГБ > П3ГБ/3ГВ > П3ГБ. Наиболее активно разрушаются образцы сополимеров П3ГБ/4ГБ, имеющие самую низкую степень кристалличности, для которых зарегистрировано значительное падение молекулярной массы по мере разрушения. Влияния исходной величины молекулярной массы образцов на процесс разрушения ПГА не обнаружено. Подтверждено существенное влияние температуры среды на активность разрушения ПГА; при 28 °С образцы ПГА разрушаются в 1,5-2 раза активнее, чем при 21 ºСDegradation of three types of polyhydroxyalkanoates (PHAs) was studied in the laboratory conditions in the field soil at two temperature regimes during 35 days. It was shown that composition of PHA and the degree of crystallinity have a significant effect on degradation of PHA films. The order of biodegradability of film samples was: poly-3-hydroxybutyrate-co-4-hydroxybutyrate (P3HB-co-4HB) > poly-3-hydroxybutyrate-co-3-hydroxyvalerate (P3HB-co-3HV) > poly-3-hydroxybutyrate (P3HB). Samples of P3HB-co-4HB copolymers with the lowest degree of crystallinity were destroyed most actively; a significant decrease of molecular weight of P3HB-co-4HB during destruction was found. The initial molecular weight of the samples did not affect the process of PHA destruction. A significant effect of the medium temperature on the rate of PHA degradation was found; PHA samples were destroyed 1.5-2 times more actively at 28 °С compared to 21 º

Laboratory Research of Degradation of Polyhydroxyalkanoates of Different Chemical Structure in Soil

Исследована деградация трех типов полигидроксиалканоатов (ПГА) в лабораторных условиях в полевой почве при двух температурных режимах в течение 35 суток. Показано существенное влияние состава мономеров и степени кристалличности ПГА на разрушаемость в лабораторных почвенных микроэкосистемах. Пленочные образцы поли-3- гидроксибутирата (П3ГБ), поли-3-гидроксибутирата/4-гидроксибутирата (П3ГБ/4ГБ), поли- 3-гидроксибутирата/3-гидроксивалерата (П3ГБ/3ГВ) по активности разрушения в почве расположены в ряду: П3ГБ/4ГБ > П3ГБ/3ГВ > П3ГБ. Наиболее активно разрушаются образцы сополимеров П3ГБ/4ГБ, имеющие самую низкую степень кристалличности, для которых зарегистрировано значительное падение молекулярной массы по мере разрушения. Влияния исходной величины молекулярной массы образцов на процесс разрушения ПГА не обнаружено. Подтверждено существенное влияние температуры среды на активность разрушения ПГА; при 28 °С образцы ПГА разрушаются в 1,5-2 раза активнее, чем при 21 ºСDegradation of three types of polyhydroxyalkanoates (PHAs) was studied in the laboratory conditions in the field soil at two temperature regimes during 35 days. It was shown that composition of PHA and the degree of crystallinity have a significant effect on degradation of PHA films. The order of biodegradability of film samples was: poly-3-hydroxybutyrate-co-4-hydroxybutyrate (P3HB-co-4HB) > poly-3-hydroxybutyrate-co-3-hydroxyvalerate (P3HB-co-3HV) > poly-3-hydroxybutyrate (P3HB). Samples of P3HB-co-4HB copolymers with the lowest degree of crystallinity were destroyed most actively; a significant decrease of molecular weight of P3HB-co-4HB during destruction was found. The initial molecular weight of the samples did not affect the process of PHA destruction. A significant effect of the medium temperature on the rate of PHA degradation was found; PHA samples were destroyed 1.5-2 times more actively at 28 °С compared to 21 º

Distribution, excretion and metabolic pathways of a single parenteral administration of kappa-opioid receptor agonist RU-1205

Introduction: The purpose was to study the pharmacokinetic properties of RU-1205 with the previously identified kappa-agonistic and analgesic effects after parenteral administration. Materials and methods: Pharmacokinetic parameters of RU-1205 after intravenous and subcutaneous administration at doses of 10 mg/kg and 50 mg/kg, respectively, were investigated, using the method of high-performance liquid chromatography with measurement of the compound according to a pre-established calibration curve. The indices of the area under the pharmacokinetic curve, clearance, half-life, residence time of the drug molecule in the body, total (apparent) volume of distribution, as well as the indicator of absolute bioavailability for subcutaneous administration were calculated. Tissue distribution and excretion of RU-1205 were also studied. Evaluation of metabolism of RU-1205 was conducted in silico, using the PALLAS 3.00 software, with the use of specific tests with CYP 450 substrates and by studying the ability of RU-1205 to form conjugates with endogenous acids. Results and discussion: It was found that after a single intravenous administration, the investigated substance was determined in the blood for 12 h; the half-life was 8.49 hours. The absolute bioavailability after subcutaneous administration is 57.35%. RU-1205 is eliminated within 3–4 days. The main route of excretion is extrarenal. The biotransformation of the substance probably proceeds mainly with the formation of oxidized forms of the initial molecule according to the reactions of the first phase of metabolic transformation, so the chance to observe phase 2 of the metabolism could be very low. Conclusion: The test substance undergoes a long process of elimination, has the highest tropism to the elimination organs and undergoes active biotransformation processes in the body of animals