We report here the first development and validation of a bioanalytical method for the quantitative determination of a new glycylcycline—eravacycline—and a widely used antibiotic, i.e., tigecycline, in human serum samples using high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS). Trimetazidine-d8 was used as internal Standard. The study compounds were extracted from serum with cold methanol. Calibration curves were linear with 1/x2 normalization (correlation coefficient at least 0.99) and could be used to measure tigecycline and eravacycline levels in human serum in the concentration ranges 5–2500 and 10–5000 ng/ml respectively. The validated method can be used to conduct pharmacokinetic studies.
A method for the estimation of tolperisone in human plasma using liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) is proposed and validated. Sample preparation utilized a simple and rapid method of liquid-liquid extraction with ethyl acetate using dibucaine as internal standard. The lower limit of detection was 0.1 ng/ml, the calibration range was 0.1 – 200 ng/ml (R2 = 0.9967), and the total analysis time was 3.8 min. Within- and between-assay accuracy ranged from 92
Experiments on (CBA ∙ C57Bl/6) F1 mice established that a dry extract of Phlojodicarpus sibiricus (Steph. ex Spreng.) K.-Pol. (Siberian bulrush) has immunomodulatory activity in relation to cellular and humoral immunity and the functional activity of macrophages in experimental cyclophosphamide-induced immunosuppression. The study compound was found to be able to weaken the suppressive effects of the cytostatic agent cyclophosphamide on antibody formation, cell-mediated immune responses, and macrophage phagocytosis, which is apparent as increases in the absolute and relative numbers of antibody-forming cells, the index of the delayed-type hypersensitivity reaction, and the phagocytic index, as compared with the level of suppression. Chemical studies indicated that the dry extract of P. sibiricus is characterized by a high content of coumarins (133.36 mg/g), which probably determines the immunomodulatory activity of this substance.
The Ritter reaction of 1-(3,4-diethoxybenzyl)-cyclohexanol with N-R1-N-R2-cyanoacetamides was used to synthesize the hydrochlorides of (3-spiro-cyclohexyl-6,7-diethoxy-3,4-dihydroisoquinolin-1(2H)-ylidene)-acetamides (N-R1-N-R2 = NHAlk, pyrrolidine, piperidine, hexamethyleneimine, morpholine, making a total of 11 compounds). The resulting compounds were tested for antiarrhythmic activity (calcium chloride model); four of the nine substances tested showed antiarrhythmic activity, with a maximum antiarrhythmic index of 3.96. All 11 substances had greater antinociceptive activity than metamizole sodium; the maximum latent period of the defensive reflex was 30.80 sec (Alk = n-Bu). Seven substances had greater anthelminthic activity than pyrantel. Larvicidal (insecticidal) activity was detected with six compounds, reducing the lifespan of larvae to a greater extent than each of three reference drugs.
