Structural transformations during swelling of polycomplex matrices based on countercharged (meth)acrylate copolymers (Eudragit® EPO/Eudragit® L 100-55)

With a view to the application in oral controlled drug delivery systems (DDS), the design of new interpolyelectrolyte complexes (IPECs) between countercharged types of Eudragit® EPO (EPO) and Eudragit® L 100-55 (L100-55) was investigated. The formation and composition of four new IPECs between EPO and L100-55 were established by elementary analysis. The structure of the synthesized IPEC was investigated using FTIR spectroscopy and modulated-temperature differential scanning calorimetry. The binding ratio of a unit molecule of EPO with L100-55 was found to range between 1:2.75 (Z = 0.36) and 1:0.55 (Z = 1.81) while increasing the pH value from 5.5 to 7.0. As a result of electrostatic interaction between the copolymer chains, the glass transition temperature of the IPEC increased significantly. A large pH-sensitive swelling behavior was observed for different structures of the IPECs. The outcome of swelling and diclofenac sodium release from the polycomplex matrices confirm that they have great potential to be used as a controlled DDS in specified regions of gastrointestinal tract. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association

Structural and energetic approach in controlling the surface strength of materials during friction

From the standpoint of the structural-energetic theory of friction and wear, general principles of managing the surface strength of materials during friction are proposed. The fundamental principles of tribology and the conditions for the formation of dissipative self-organizing secondary structures are considered. The role of the kinetic phase transition in the energy balance of processes in the zone of frictional contact is determine

МАГНИТНО-РЕЗОНАНСНАЯ ТОМОГРАФИЯ С КОНТРАСТНЫМ УСИЛЕНИЕМ КАК МЕТОД ВИЗУАЛИЗАЦИИ АТЕРОСКЛЕРОТИЧЕСКОГО ПОРАЖЕНИЯ СТЕНКИ АОРТЫ

The article describes patterns of paramagnetic contrast enhanced MR tomographic imaging of atherosclerotic lesions of aorta in patients with extensive atherosclerosis and previous acute myocardial infarction.The purpose. We have analyzed MR tomographic imaging features of atherosclerotic lesions of the aorta, with a paramagnetic contrast enhancement, in patients with extensive atherosclerosis and old acute myocardial infarction (AMI).Materials and methods. The patients population comprised 24 patients with multiple atherosclerosis and old transmural AMI of the left ventricle. As control group eight patients with tumor pathology of the thorax were employed, without evidence of clinically significant atherosclerosis, of the same age range. All patients underwent contrast-enhanced study (paramagnetic in standard dose of 0,1 mmol / kg BW) and index of enhancement (IE) of T1-weighted images was calculated as the ratio of intensities over the aortic wall on contrast and initial MRI studies.Results and discussion. In patients with extensive atherosclerosis and old AMI IE of the atherosclerotic lesions in the aortic wall in all cases was over 1,14 (mean 1,19±0,06), far more than increasing of intensity in the control group. Types of accumulation of contrast paramagnetic was assigned as a local or diffuse accumulation syndrome, depending on the length and circularity of the lesions. In the control group no significant accumulation of contrast paramagnetic material in the aortic wall was observed, IE did not exceed 1.04 (mean 1,01±0,02).Conclusion. Contrast-enhanced MRI allows to visually and quantitatively assess pathology of aortic wall in atherosclerosis.В статье представлена картина МР-томографической визуализации атеросклеротических изменений аорты у пациентов с распространенным атеросклерозом и перенесенным острым инфарктом миокарда при контрастировании парамагнетиком.Цель. Изучить картину МР-томографической визуализации атеросклеротических поражений аорты при парамагнитном контрастировании у пациентов с распространенным атеросклерозом и перенесенным острым инфарктом миокарда (ОИМ).Материалы и методы. В исследование были включены 24 пациента с распространенным атеросклерозом и перенесенным трансмуральным ОИМ левого желудочка. В качестве контрольных обследованных в исследование включены восемь пациентов с опухолевой патологией органов грудной клетки (ОГК) без признаков клинически значимого атеросклероза того же возрастного диапазона. Всем пациентам проведено контрастированое исследование с введением парамагнетика в стандартной дозе 0,1 ммоль/1 кг массы тела и рассчитан индекс усиления Т1-взв. изображения как отношение интенсивности области стенки аорты на контрастированном и исходном МРТ-исследовании.Результаты. У пациентов с распространенным атеросклерозом и перенесенным ОИМ наблюдалось достоверно превосходящее показатели контрольных лиц усиление интенсивности сигнала в атеросклеротически измененной стенке аорты при введении контраста-парамагнетика, значение ИУ во всех случаях было больше 1,14 (среднее значение – 1,19±0,06). Характер накопления контраста-парамагнетика в зависимости от протяженности и циркулярности поражения визуализируется как локально-очаговый либо диффузно-распространенный тип аккумуляции. В контрольной группе было отмечено отсутствие значимого накопления контраста парамагнетика в стенке аорты, ИУ не превышал 1,04 (среднее значение – 1,01±0,02).Заключение. Контрастированная МРТ позволяет визуально и количественно оценить патологическое поражение аортальной стенки при атеросклерозе

Bread production technology modelling using hop starter in ovens of various types

The article studies the processes of structure formation of baked dough pieces using wheat and hop starters and changes in the properties of finished products and semi-finished products depending on the baking methods. A whole complex of physical, chemical and biochemical processes takes place in the dough piece during baking under the influence of heat and moisture, which causes considerable changes in the bread dough. These processes cause changes in the baked dough piece, that cause turning the dough into bread. Duration and intensity of the processes occurring on the surface and in the inner layers of the dough piece during baking depend on the temperature. Therefore, creation of optimal modes of heating the baked dough piece at various stages allows you to get products of the required quality. To simulate the processes of crumb formation, changes in temperature inside the dough piece of baking, and specific volume over time with different methods of dough and baking, regression models were used, that take into account the influence of qualitative factors. Each qualitative factor having two grades was replaced by one binary variable. The solution of a multicriteria optimization problem showed that the studied indicators reach the optimal values when baking in an air-o-steam and preparing a dough using hop starter

Optimization of apple juice dosage in the recipe of bakery products

Research on the development of bakery products of high nutritional value are conducted in FSBEI HE «Saratov State Agrarian University named after N.I. Vavilov». Improving the nutritional and biological value of bakery products remains an urgent task. One way to solve it is to use natural food fortifiers. Apple juice is one of the most affordable for the residents of Russia due to its low price and popularity of apples. It has a great advantage over others, as it contains a rich set of minerals and vitamins, enzymes, organic acids. The quality, structural, mechanical and rheological properties of bakery products depend on the amount of the additive. In the presented work the effect of the dosage of apple juice of the «Simirenko» apple variety on the quality of wheat semi-finished products and finished products has been studied. To determine the optimal dosage of apple juice, semi-finished products and finished products have been analyzed according to the following indicators: effective dough viscosity, humidity, porosity, hardness, color of finished bakery products. For the integrated assessment of the capabilities of the compared indicators, a mathematical apparatus has been used based on the basis of generalized desirability function of Harrington, which allows to obtain a relatively accurate assessment of the effectiveness in the form of a specific number that can be used in further analysis of technological processes. It’s been found that the optimal dosage for baked goods with the addition of apple juice is 30% apple juice to the weight of the liquid

THE FEATURES OF THE PREDICTIVE DISSOLUTION TESTING (REVIEW)

Dissolution test plays an important role at different levels of the development and manufacturing drugs as one of the major quality control tools and an integral part of In vitro tests in the study of drug release from the developed dosage forms. Article describes the basic parameters that should be considered in predictive dissolution tests, such as the selection criteria and the composition of biorelevant dissolution media, fluid dynamics, volume and transfer of the dissolution media

A COMPARATIVE STUDY OF DRUG RELEASE FROM POLYCOMPLEX MATRICES IN STANDARD AND BIORELEVANT MEDIA USING USP III AND USP IV APPARATUS

The results of Indomethacin release from the oral drug delivery systems based on interpolymer complexes with Eudragit® copolymers are presented. The release assessment was performed by two methods - flow-through cell (USP IV Apparatus) and the reciprocating cylinder (USP III Apparatus) in standard buffer solutions and biorelevant media. The release of indomethacin can be described as "intestinal" type. According to the results Indomethacin was released faster using USP III Apparatus due to stress-effect on the erosion type matrices

Interpolyelectrolyte Complexes Based on Eudragit^® Copolymers as Carriers for Bioadhesive Gastroretentive Metronidazole Delivery System

Introduction. There are a number of drugs, the absorption zone of which is the upper region of the gastrointestinal tract (GIT) – the stomach and duodenum. To increase bioavailability, gastroretentive (intragastric) systems for the controlled drug delivery are being developed. To date, there are various approaches to ensure intragastric drug delivery. One of the most promising approaches is the use of excipients with bioadhesive properties, both individually and in combination with other types of gastroretentive systems.Aim. Development and research of new carriers for gastroretentive bioadhesive drug delivery systems based on interpolyelectrolyte complexes (IPEC) with the participation of chemically complementary poly(meth)acrylates of the Eudragit®.Materials and methods. The study of swelling ability was carried out in a medium of 0.1 M hydrochloric acid solution (pH 1.2) at a temperature of 37 ± 0.5 °C for 6 hours. The study of the release of metronidazole (MZ) from matrices based on the corresponding IPEC was performed on a DFZ II instrument (ERWEKA, Germany) according to the Flow Trough Cell method in 0.1 M HCl medium, pH 1.2, flow rate 4 ml/min in a closed cycle within 6 hours. The amount of released MZ was estimated by UV spectrophotometry on a Lambda 25 instrument (PerkinElmer, USA) at a wavelength of 274 nm. IPEC adhesion was studied using a TA.XTplus texture analyzer (Stable Micro Systems, UK).Results and discussion. Matrices based on IPEC 1 were disintegrated after being in a medium with a pH of 1.2 for 4 hours, matrices based on IPEC 4 were dissolved in an acidic medium for 3 hours. At the same time, matrices based on IPEC 2 and IPEC 3 retain their shape throughout the experiment and are characterized by rather high values of the degree of swelling. IPEC samples are characterized by higher adhesion performance compared to individual copolymers. The release of metronidazole from matrices based on IPEC 1 occurs in accordance with Fick's law of diffusion; from the matrix based on IPEC 4, MZ is released according to the anomalous transport mechanism.Conclusion. IPEC 3 is promising for use as carrier for gastroretentive bioadhesive systems of controlled delivery of metronidazole

Structural transformations during swelling of polycomplex matrices based on countercharged (meth)acrylate copolymers (Eudragit® EPO/Eudragit® L 100-55)

With a view to the application in oral controlled drug delivery systems (DDS), the design of new interpolyelectrolyte complexes (IPECs) between countercharged types of Eudragit® EPO (EPO) and Eudragit® L 100-55 (L100-55) was investigated. The formation and composition of four new IPECs between EPO and L100-55 were established by elementary analysis. The structure of the synthesized IPEC was investigated using FTIR spectroscopy and modulated-temperature differential scanning calorimetry. The binding ratio of a unit molecule of EPO with L100-55 was found to range between 1:2.75 (Z = 0.36) and 1:0.55 (Z = 1.81) while increasing the pH value from 5.5 to 7.0. As a result of electrostatic interaction between the copolymer chains, the glass transition temperature of the IPEC increased significantly. A large pH-sensitive swelling behavior was observed for different structures of the IPECs. The outcome of swelling and diclofenac sodium release from the polycomplex matrices confirm that they have great potential to be used as a controlled DDS in specified regions of gastrointestinal tract. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association