Key words: сверхкритические флюиды, наночастицы, микрочастицы, фармпрепараты, липосомы
The preferences of drugs on the base of nano- and microparticles are reviewed in
comparison with traditional drug forms. The application of supercritical fluids for the
production of nano- and microforms of pharmaceutical substances including drug
delivery systems on the base of polymers and liposomes is discussed. The methods
based upon the use of supercritical fluids, such as RESS, GAS, ASES, SAS, SEDS were
shown to be of the most value for the production of nano- and microforms of drugs.
Key words: сверхкритические флюиды, наночастицы, микрочастицы, хитозан
Micro- and nanoparticles of five chitosan derivatives were obtained for the first time
using Supercritical Assisted Atomization (SAA) method. The investigation of obtained
disperse chitosan forms using optical and scanning electron microscopies (SEM) and
particle size distribution technique demonstrated their uniformity. Depending on the
experimental conditions, particle size varies in the range of 0,3÷5 mm. It was concluded
that SAA method can be efficiently used for micronization of various chitosan
derivatives.
Key words: полимерные микрочастицы, инкапсуляция биоактивных компонентов, сверхкритический диоксид углерода
The results of supercritical fluid synthesis of bioresorbable polymer microparticles
filled with bioactive plantain and calendula extracts are presented and discussed. The
process is based on spraying of the mixture of amorphous aliphatic polyester (D,Llactide)
plasticized by supercritical carbon dioxide with fine-dispersed plant extract
powder into low-pressure receiver through specific nozzle. Kinetics of extract release
from microparticles produced under different CO<sub>2</sub> pressures is analyzed. The rate of
extract release into physiological solution depends on both carbon dioxide pressure
and initial polymer/extract ratio.
Key words: RESS, сверхкритический флюид, моделирование, микрочастицы, антрацен
RESS process can be described in the framework of one-dimensional model, which
allows one to qualitatively analyzed the nucleation. The effects of supercritical solvent
density and of expansion device geometry onto the size of microparticles formed in
RESS process are examined.
Key words: наночастицы, сверхкритический СО<sub>2</sub>, импрегнация, олигоуретанметакрилат, оптическая спектроскопия, УФ облучение
Synthesis of Ag nanoparticles in the matrix of cross-linked olygouretanmetacrilate
(OUM) impregnated with Ag(fod) molecules (fod = 6,6,7,7,8,8,8-heptafluor-2,2-dimethyl-3,5-octadionate) dissolved in supercritical carbon dioxide and ethanol was
studied using absorption spectroscopy and scanning electron microscopy. Size
distribution and concentration of Ag nanoparticles synthesized in polymer matrix is
controlled by polymer structure, solvent type and by processing conditions. Treatment
with hydrogen and UV irradiation of OUM samples impregnated with Ag(fod), causes
both significant rise of Ag nanoparticles concentration and particles size in polymer
matrix. The new approach to fabrication of optical structures (including microstructures)<br>
from nanoparticles in polymers is suggested, based on combination of
polymer samples impregnation and UV irradiation.
Key words: полимеры, Eu(fod)<sub>3</sub>, фотолюминесценция, сверхкритическая импрегнация, молекулы воды, температурное тушение люминесценции
The effects of temperature and humidity on optical properties of transparent polymers
impregnated with Eu(Fod)<sub>3</sub> molecules (fod = 6,6,7,7,8,8,8-heptafluor-2,2-dimethyl-
3,5-octadionate) using supercritical carbon dioxide were studied. Two bands of
Eu(Fod)<sub>3</sub> spectra both in polycrystalline phase and in polymer matrix are revealed,
related to two different forms of these molecules. To explain the observed degradation
of absorption and photoluminescence spectra of polypropylene film impregnated with
Eu(Fod)<sub>3</sub>, the model of atmospheric H<sub>2</sub>O interaction with Eu(Fod)<sub>3</sub> molecules in
polymeric matrix was suggested. The effects of reversible temperature bleaching of
Eu<sup>3+</sup> luminescence was observed and discussed in the context of fabrication of
temperature sensor.<br>
Key words: адиабатический калориметр, вода, водные растворы, кривая сосуществования фаз, критическая точка, изохорная теплоемкость, парциальный мольный объем, сверхкритическая вода, уравнение состояния, этанол
Isochoric heat capacity of binary mixture (0.1446) H<sub>2</sub>O + (0.8554) C<sub>2</sub>H<sub>5</sub>OH have been
measured in the sub- and supercritical conditions with a high-temperature adiabatic
and nearly constant-volume calorimeter. Measurements of <i>C<sub>V</sub></i> were performed as a
function of temperature along various near-critical isochores in the range from 234.8
to 391.1 kg·m<sup>-3</sup> at temperatures between 439.3 and 521.5 K. In total 16 isochores — 4 vapor and 12 liquid, have been studied. The coverage includes the one- and twophase
regions near the liquid.gas coexistence curve at the sub- and the supercritical parameters of state. The uncertainty of isochoric heat capacity, density, and temperature
measurements was estimated to be less than 2÷3 %, 0.05 %, and 15 mK, respectively. The
values of temperature at coexistence curve, <i>T<sub>S</sub></i>(ρ), for each measured densities (isochores)
were determined in calorimetric experiment using a quasi-static thermogram
technique supplemented by the sensor of adiabatic control. Using the measured values
of heat capacity (<i>C<sub>VS</sub></i>), temperature (<i>T<sub>S</sub></i>) and density
(ρ<i><sub>S</sub></i>) on the coexistence curve
near the critical point (CP) the values of the critical parameters (<i>T<sub>C</sub></i>,
ρ<i><sub>C</sub></i>) for the
mixture (0.1446 m.f.) H<sub>2</sub>O + (0.8554 m.f) C<sub>2</sub>H<sub>5</sub>OH were determined. The measured
values of <i>C<sub>V</sub></i> and <i>T<sub>S</sub></i>, ρ<i><sub>S</sub></i> for the saturated liquid and vapor have been analyzed and
interpreted in terms of extended scaling theory to accurately calculate the values of
the asymptotical critical amplitude (<i>A</i><sub>0</sub><sup>±</sup> and <i>B</i><sub>0</sub>) of the power laws and in theory of
isomorphism of the critical phenomena in binary mixtures. The values of the
characteristic parameters (<i>K</i><sub>1</sub>, <i>K</i><sub>2</sub>, τ<sub>1</sub>, τ<sub>2</sub>, &Delta&rho<sub>1</sub>, &Delta&rho<sub>2</sub>)
of the mixture were estimated by using
the critical-curve data for H<sub>2</sub>O + C<sub>2</sub>H<sub>5</sub>OH mixture. It was shown that the heat capacity
of the mixture (o = 0.8554 m.f. C<sub>2</sub>H<sub>5</sub>OH or 96% by volume) near the CP behave just
like of <i>C<sub>V</sub></i> for pure fluid. The same behavior of <i>C<sub>V</sub></i> for this mixture was also predicted
from the analysis of the critical line behavior.
Key words: зеленый вьетнамский чай, сверхкритический диоксид углерода, потребительские свойства чайного листа, декофеинизация
The effect of suggested procedures - circulation of supercritical (SC) carbon dioxide
and periodical decompression in the system «initial raw material - SC-CO<sub>2</sub>» - of tea
leaves treatment onto the subsequent extraction of target components by hot water.
Some thermodynamic characteristics of SC fluid de-coffeinization process, as applied
to green Vietnamese tea, are investigated.
Key words: сверхкритическая экстракция, масличные культуры, математическое моделирование
A simplified mathematical model of ground oil-bearing crop seeds extraction is developed. It is reduced to a hyperbolic system of two equations related to the main process characteristics: (a) oil concentration in the fluid in microscopic channels of the granular layer of seed particles and (b) a fraction of initial oil reserve extracted from particles. Corresponding task is solved analytically. The solution is shown to have a structure of a running wave propagating at a constant velocity. The applicability of the model to the simulation of real extraction processes is confirmed by testing based on available experimental data.
Key words: субкритическая вода, кверцетин, экстракция
The method of quercetin extraction from plant raw materials in sub-critical water
medium is developed. It is more efficient than conventional extraction by polar organic
solvents (e.g. methanol) and does not require the use of environmentally non-friendly
solvents.
Key words: субкритическая вода, дигидрокверцетин, экстракция
The method of dihydroquercetin extraction from larch wood by sub-critical water is
developed. It is more efficient than conventional extraction by polar organic solvents
(e.g. acetone) and does not require the use of environmentally non-friendly solvents.
Key words: эвкалипт прутовидный (Eucalyptus viminalis Labill.), сверхкритический флюидный СО<sub>2</sub>-экстракт, эфирное масло, химический состав, монотерпены, сесквитерпены, фенолоальдегиды, эвкалимин, хлорофиллипт
A phytochemical comparison of essential oil and supercritical fluid CO<sub>2</sub>- extract (SCF-NI2-extract), and analysis of residues obtained from the leaves of eucalyptus (Eucalyptus viminalis Labill.) are performed. Compositions of essential oil and SCF-CO<sub>2</sub>-extract are similar qualitatively, but significantly differ in relative amounts of their main components. SCF-CO<sub>2</sub>-extract contains substantial amounts of sesquiterpens in addition to essential oil. The residue remaining after the separation of lypophylic fraction is
found to be a source of phenoloaldehyds, which can serve as constituents of pharmaceuticals (Eucaliminum and Chlorophylli ptum). The properties of residues remaining after the SCF-CO<sub>2</sub>-extraction are more technically advantageous.
Key words: экстракция, сверхкритический СО<sub>2</sub>, нефть, тяжелые нефтяные остатки
The method for purification of oils and their heavy residues from asphaltenes and metals based on different solubilities of the main constituents of oil and its undesirable components in supercritical fluids (CO<sub>2</sub>). Effects of temperature, pressure and oil dilution with carbon dioxide, as well as tar dilution with light hydrocarbons and CO<sub>2</sub> onto asphaltenes and metals removal are studied. The method provides with advanced purity of raw oil used further to produce final products (gasoline, base oils).<br>
Key words: сверхкритический диоксид углерода, координационные соединения металлов, β-дикетонаты
Absorption spectra of silver and europium β-diketonates dissolved in supercritical
carbon dioxide and ethanol were studied. The structure of ligand UV absorption bands
was measured by different solvent types and temperature as well by intense UV irradiation
of solvent. The observed complex structure of ligand bands is treated by the formation
of molecular dimer and, also by the formation of hydrated form of β-diketonates. The
effect of silver nanoclasters synthesis under the action of UV radiation on ethanol
solution of silver β-diketonate was revealed, accompanied by the degradation of
ligand absorption band and formation of plasmon band at 420 nm.
Key words: сверхкритическая вода, наночастицы, оксид индия, диоксид циркония, льюисовская кислотность
X-Ray diffraction, Raman and diffusion-reflectance absorption IR-spectroscopy are used to compare physical-chemical surface properties of In-Zr mixed nanocrystalline oxides, synthesized in supercritical water (SCW) and via conventional co-preci pitation technique. Samples synthesized in SCW have more stable surface properties. The basicity of mixed In-Zr oxides increases along with increasing In content.