In Vivo Assessment of Parenteral Formulations of Oligo(3-Hydroxybutyric Acid) Conjugates with the Model Compound Ibuprofen

Polymer-drug conjugates have gained significant attention as pro-drugs releasing an active substance as a result of enzymatic hydrolysis in physiological environment. In this study, a conjugate of 3-hydroxybutyric acid oligomers with a carboxylic acid group-bearing model drug (ibuprofen) was evaluated in vivo as a potential pro-drug for parenteral administration. Two different formulations, an oily solution and an o/w emulsion were prepared and administered intramuscularly (IM) to rabbits in a dose corresponding to 40 mg of ibuprofen/kilogramme. The concentration of ibuprofen in blood plasma was analysed by HPLC, following solid–phase extraction and using indometacin as internal standard (detection limit, 0.05 μg/ml). No significant differences in the pharmacokinetic parameters (Cmax, Tmax, AUC) were observed between the two tested formulations of the 3-hydroxybutyric acid conjugate. In comparison to the non-conjugated drug in oily solution, the relative bioavailability of ibuprofen conjugates from oily solution, and o/w emulsion was reduced to 17% and 10%, respectively. The 3-hydroxybutyric acid formulations released the active substance over a significantly extended period of time with ibuprofen still being detectable 24 h post-injection, whereas the free compound was almost completely eliminated as early as 6 h after administration. The conjugates remained in a muscle tissue for a prolonged time and can hence be considered as sustained release systems for carboxylic acid derivatives

The influence of a mineral-vitamin premix on the metabolism of pregnant horses with microelemetosis

The article presents data on research into the influence of a mineral-vitamin premix on the clinical condition, erythropoiesis and the metabolism (macro- and micro-elemental, vitaminic, proteinaceous, enzymic) of Hucul breed mares in the last trimester of pregnancy. The Marmix premix contains: vitamins – А, D3, Е, В1, В2, В12, pantothenic and ascorbic acids, niacin, biotin; nonorganic compounds of microelements – sulphate of cobalt, copper, zinc, iron, manganese; potassium iodide, sodium selenite; amino acids – lysine, threonine, methionine.The usage of the mineral-vitaminic premix Marmix on pregnant mares during 60 days causes recovery of clinical status, erythropoiesis, raises the level of the cobalt (by 45.9%) and copper (by 2.15 times), normalizes the calcium-phosphorus ratio, raises the phosphorus level in the blood (by 17.7%), raises vitamin А (by 2.5 times) and tocopherol (by 2.02 times), total protein (by 27.7%), decreases the level of urea (by 42.2%), activity of AspAT [aspartate transaminase or aspartate aminotransferase] (by 42.9%) and AlAT [alanine transaminase] (by 44.9%) and alkaline phosphatase (by 43.7%). The research conducted contributes to improvements in the study of the pathogenesis of microelementosis of mares and develops an efficient way of treating and preventing the development of microelementosis among these animals