Methods for phosphorylation of tyrosine and Tyr-Thr-Lys tripeptide with cyclohexylmethyl(deuteromethyl)phosphonochloridates have been developed. These products can be used as reference compounds in ...the analysis of blood plasma of patients presumably exposed to cyclohexylmethylphosphonofluoridate (cyclosarin) action. Conditions for the separation and purification of the synthesized intermediates by means of chromatography have been determined and optimized, allowing high-purity phosphorylated products at the final stage of the synthesis.
A procedure for the phosphorylation of the tripeptide Tyr-Thr-Lys with isopropyl methyl- or (deuteromethyl)phosphonochloridate is developed. The phosphorylated tripeptides are intended for use as ...reference standards in the analysis of blood samples of people suspected to have been exposed to acetylcholinesterase inhibitors. Conditions of hromatographic separation and purification of the synthesized compounds are determined and optimized, which ensures the preparation of high-purity phosphorylated tripeptides.
The results of measurements of trace element contents in brown algae of the families Laminariales and Fucales of different origins are presented, along with supplementary data from the literature. ...Aluminum, cadmium, cobalt, chromium, copper, iron, mercury, manganese, nickel, lead, and zinc concentrations in the biomass of brown algae were found to be affected primarily by the technogenic factor, while strontium concentrations are affected by the geographic latitude of the region in which they grew. In the case of arsenic, no relationship was found between accumulation in algae and the level of pollution or the geographic region in which the algae were collected. Arsenic was found to accumulate better in Laminariales, while aluminum, iron, copper, and manganese in brown algae of the family Fucales. As regards cadmium, mercury, lead, nickel, zinc, chromium, and strontium, differences in accumulation in members of the two families were comparable with differences between species within a single family. We conclude that there is a need to develop additional criteria for standardization of brown algae.
The possibility of the application of diffusion-ordered NMR spectroscopy to the study of the molecular-weight distribution of hydroxyethyl starch is investigated. The use of regression equations ...relating these parameters to the coefficients of the self-diffusion of polymer macromolecules as a whole, namely, the average coefficient of self-diffusion D ₛ and the coefficient of self-diffusion at the peak maximum D ₚ, is proposed for the quantitative assessment of weight-average (M w) and number-averaged (M ₙ) molecular weights and molecular weight at the peak maximum (M ₚ). It is shown that the determination of M w, M ₙ, M ₚ based on the data on D ₛ gives the best results. It was found that the values of polydispersity indexes found using diffusion-ordered NMR spectroscopy are independent of the choice of diffusion parameter D ₛ or D ₚ.
Biperiden hydrochloride, (1
RS
)-1-(1
RS
, 2
SR
, 4
RS
)-bicyclo2.2.1hept-5-en-2-yl-1-phenyl-3-(piperidin-1-yl)prop an-1-ol hydrochloride, is one of the most efficacious cholinolytics. It is used to ...treat Parkinson’s disease and various types of muscular spasms and to ameliorate uncoordinated muscular movements that can accompany the use of several tranquilizers
1
,
2
. Biperiden appears in the vital and essential drug list that was approved by an order of the RF Government
3
.
Amethod for measuring the mean molecular weight of dextrans by diffusion-ordered NMR spectroscopy was developed and validated. This method allows measurements of dextran self-diffusion coefficients ...to determine their mean molecular weight. The linearity, correctness, similarity, intralaboratory precision, and specificity of the method were evaluated. “Added/found” ratios for different dextrans were used to determine the standard deviations, coefficients of variation, significance intervals, systematic errors, Fisher’s
F
test, and Student’s
t
test for measurements of mean molecular weight. These statistical characteristics satisfied the criteria for validation parameters in the Russian and foreign normative documentation.
The acid hydrolysis procedure for glatiramer acetate was modified and the characteristic signals in the
1
H and
13
C spectra were identified, allowing its amino acid composition to be determined. The ...relative molar contents of amino acids in glatiramer acetate measured by HPLC-MS and by
13
C and
1
H NMR had close values.
13
C NMR was found to be a more precise method for assaying the amino acid composition of glatiramer acetate than
1
H NMR.
Diffusion ordered NMR (DOSY) was applied to the determination of the average molecular weights of polymers based on the dependence of the measured self-diffusion coefficient
D
on the corresponding ...weights of a number of polymers of the same type. As a rule, a calibration function is plotted by varying DOSY experimental parameters for each particular test sample; however, this approach is inapplicable to the development of a standard procedure for the quantitative assessment of the molecular weights of dextrans. In this article, an optimization method is considered to ensure high resolution in terms of the values of
D
for dextrans without varying experimental conditions; this method makes it possible to evaluate the average molecular weights of dextrans with a high accuracy over a wide range of their values.
