Effect of natural polymers on the physicochemical properties and ulcerogenic activity of piroxicam

2000 ◽  
Vol 23 (2) ◽  
pp. 91-98
Author(s):  
T. El-Faham ◽  
M. Mahmoud ◽  
M. Hassan
Keyword(s):  
Physicochemical Properties ◽  
Natural Polymers ◽  
Ulcerogenic Activity

The Influence of Factors of a Biological and Physical Nature on the Biodegradation and Physicochemical Properties of Composites Based on Polyvinyl Chloride and Natural Polymers

2018 ◽  
Vol 45 (6) ◽  
pp. 283-288
Author(s):  
V.F. Smirnov ◽  
A.A. Glagoleva ◽  
A.E. Mochalova ◽  
L.A. Smirnova ◽  
N.A. Anikina
Keyword(s):  
Physicochemical Properties ◽  
Polyvinyl Chloride ◽  
Polymeric Material ◽  
Starch Content ◽  
Physical Nature ◽  
Physical Factors ◽  
Microscopic Fungi ◽  
Natural Polymers ◽  
Properties Of Composites

It has been established that the degree of biodegradation of composites based on polyvinyl chloride and natural polymers by microscopic fungi changes as a function of the chitosan and starch content in the composites. Biodegradation of polymeric material is accompanied with change in its physicochemical properties. A number of physical factors result in an increase in the degree of biodegradation of the materials investigated.

scholarly journals EFFECT OF SELECTED MUCOADHESIVE POLYMERS ON PHARMACEUTICAL PROPERTIES OF CHITOSAN FORMULATIONS

2021 ◽  
Vol 26 ◽  
pp. 61-70
Author(s):  
Bożena Grimling ◽  
Keyword(s):  
Physicochemical Properties ◽  
Xanthan Gum ◽  
Absorption Capacity ◽  
Polymer Complex ◽  
Natural Polymers ◽  
Technical Process ◽  
Polyelectrolyte Complexes ◽  
Mucoadhesive Polymers ◽  
Texture Parameters ◽  
Pharmaceutical Properties

The aim of this study was to develop a technical process and composition of mucoadhesive hydrogels containing benzocaine, based on different concentration ratios of the natural polymers chitosan and xanthan gum. For this purpose, lyophilisates of polymeric complexes with the quantitative ratios of 0.5:1, 1:1 and 1:0.5 chitosan to xanthan gum were prepared and subsequently used to prepare hydrogels of various concentrations. The physicochemical properties and pharmaceutical availability of benzocaine were evaluated and diffractograms and Fourier-transform infrared spectra of individual polymers and their polyelectrolyte complexes were compared. The 1:1 formulation exhibited the highest water absorption capacity and the gels showed the highest viscosity and the shortest blurring times. More chitosan increased carrier texture parameters, including hardness, cohesiveness and consistency, whereas more xanthan gum led to the longest gel blurring times and improved carrier stability. The concentration ratio of chitosan to xanthan gum in lyophilisates determined the viscosity, texture, spreadability and blurring time of the gels. Increases in lyophilisate percentage in the gels also affected the physicochemical properties of the carrier. In addition, the proportions of polymers in the mixture did not influence the availability of the drug from the prepared gel; this factor appears to depend more on the lyophilisate content in the carrier. Variations in the ratio of chitosan to xanthan gum in the polymer complex as well as lyophilisate percentage in the gel may impact the properties of the hydrogel and its efficacy as a carrier for therapeutic substances administered to the oral cavity mucosa.

scholarly journals Mussel-Inspired Catechol Functionalisation as a Strategy to Enhance Biomaterial Adhesion: A Systematic Review

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3317
Author(s):  
Pedro M. Costa ◽  
David A. Learmonth ◽  
David B. Gomes ◽  
Mafalda P. Cautela ◽  
Ana C. N. Oliveira ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Physicochemical Properties ◽  
Selection Criteria ◽  
Biological Tissues ◽  
Clinical Use ◽  
Natural Polymers ◽  
Ample Evidence ◽  
Adhesion Properties ◽  
Poor Adhesion ◽  
Carbodiimide Coupling

Biomaterials have long been explored in regenerative medicine strategies for the repair or replacement of damaged organs and tissues, due to their biocompatibility, versatile physicochemical properties and tuneable mechanical cues capable of matching those of native tissues. However, poor adhesion under wet conditions (such as those found in tissues) has thus far limited their wider application. Indeed, despite its favourable physicochemical properties, facile gelation and biocompatibility, gellan gum (GG)-based hydrogels lack the tissue adhesiveness required for effective clinical use. Aiming at assessing whether substitution of GG by dopamine (DA) could be a suitable approach to overcome this problem, database searches were conducted on PubMed® and Embase® up to 2 March 2021, for studies using biomaterials covalently modified with a catechol-containing substituent conferring improved adhesion properties. In this regard, a total of 47 reports (out of 700 manuscripts, ~6.7%) were found to comply with the search/selection criteria, the majority of which (34/47, ~72%) were describing the modification of natural polymers, such as chitosan (11/47, ~23%) and hyaluronic acid (6/47, ~13%); conjugation of dopamine (as catechol “donor”) via carbodiimide coupling chemistry was also predominant. Importantly, modification with DA did not impact the biocompatibility and mechanical properties of the biomaterials and resulting hydrogels. Overall, there is ample evidence in the literature that the bioinspired substitution of polymers of natural and synthetic origin by DA or other catechol moieties greatly improves adhesion to biological tissues (and other inorganic surfaces).

Preparation and characterisation of vanadium pentoxide supported rhodium catalyst

1988 ◽  
Vol 46 ◽  
pp. 946-947
Author(s):  
A. Legrouri
Keyword(s):  
Aqueous Solution ◽  
Thermal Decomposition ◽  
Physicochemical Properties ◽  
Surface Area ◽  
Vanadium Pentoxide ◽  
High Purity ◽  
Gas Adsorption ◽  
Rhodium Catalyst ◽  
Optical Methods ◽  
Reducible Oxides

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.

Studies on the Degradation of Human Fibrinogen by Plasmin and Trypsin

1966 ◽  
Vol 16 (03/04) ◽  
pp. 526-540 ◽  
Author(s):  
E. A Beck ◽  
D. P Jackson
Keyword(s):  
Physicochemical Properties ◽  
Electrophoretic Mobility ◽  
Rapid Loss ◽  
Clotting System ◽  
Human Fibrinogen ◽  
Peptide Bonds ◽  
Physico Chemical ◽  
Starch Gel ◽  
Ph Stat ◽  
Rapid Appearance

SummaryThe effects of trypsin and plasmin on the functional and physicochemical properties of purified human fibrinogen were observed at various stages of proteolysis. Concentrations of plasmin and trypsin that produced fibrinogenolysis at comparable rates as measured in a pH stat produced, at similar rates, loss of precipitability of fibrinogen by heat and ammonium sulphate and alterations in electrophoretic mobility on starch gel. Trypsin produced a more rapid loss of clottability of fibrinogen and a more rapid appearance of inhibitors of the thrombin-fibrinogen clotting system than did plasmin. Consistent differences were noted between the effects of trypsin and plasmin on the immunoelectrophoretic properties of fibrinogen during the early stages of proteolysis.These results are consistent with the hypothesis that trypsin initially reacts with the same peptide bonds of fibrinogen that are split by thrombin, but these same bonds do not appear to be split initially by plasmin. Measurement of the various functional and physico-chemical changes produced by the action of trypsin and plasmin on fibrinogen can be used to recognize various stages of proteolysis.

The effectiveness of granular chalk use for growing winter wheat on grey forest soil

2020 ◽  
pp. 181-191
Author(s):  
M. Tkachenko ◽  
N. Borys ◽  
Ye. Kovalenko
Keyword(s):  
Winter Wheat ◽  
Physicochemical Properties ◽  
Forest Soil ◽  
Active Substance ◽  
Mass Fraction ◽  
Gray Forest Soil ◽  
Mineral Fertilizers ◽  
Acidic Soils ◽  
Grey Forest Soil

The research aims to establish the eff ectiveness of granular chalk use produced by «Slavuta-Calcium» Ltd. under growing Poliska–90 winter wheat variety, changing the physicochemical properties of grey forest soil and the wheat productivity. It also aims to establish optimal dosis of «Slavuta-Calcium» granular chalk as the meliorant and mineral fertilizer for grey forest soil in the system of winter wheat fertilization. In the temporary fi eld studies, various doses of nutrients N60–90–120P30–45–60K60–90–120 combined with «Slavuta–Calcium» granular chalk in a dose of Ca230–460–690 kg/ha of the active substance were studied against the background of secondary plowing of rotation products – soybean biomass that averaged 2.34 t/ha. Granular chalk is a modern complex highly eff ective meliorant with the content of Ca – 37.7 and Mg – 0.2 %, the mass fraction of carbonates (CaCO3 + MgCO3) makes at least 95 %. It is characterized by a high level of solubility when interacting with moisture in soil. It has a form of white granules, the mass fraction of 4.0–6.0 mm in size granules makes not less than 90 % and the one of 1.0 mm in size makes less than 5 %. Reactivity – 97 %. The granular chalk is advisable to apply on acidic soils, as a highly concentrated calcium-magnesium fertilizer, with the former as the dominant fertilizer, to optimize the physicochemical properties of the soil, as well as the plant nutrition system, in particular, increasing the availability of an element for assimilation by plants and as long-term ameliorants. The eff ectiveness of the use of mineral fertilizers, in particular acidic nitrogen on highly and medium acidic soils, after chemical reclamation is increased by 30–50 %, and slightly acidic by 15–20 %. The increase in productivity of crops from the combined eff ects of nutrients and chalk granulated is usually higher than when separately applied. The eff ectiveness of the integrated action of these elements is manifested in the growth of plant productivity and the quality of the resulting products, as well as the optimization of physical chemical properties and soil buff ering in the long term. In order to optimize the physicochemical properties of the arable layer of gray forest soil and the productive nutrition of agricultural crops, winter wheat, in particular, biogenic elements should be used in doses N60-90-120P30-45- 60K60-90-120 with granulated chalk «Slavuta-Calcium» in doses of Ca230-460-690 kg/ha of active substance. Granulated chalk obtained as a result of industrial grinding of solid sedimentary carbonate rocks of natural origin, subsequently under the infl uence of the granulation process of the starting material contains Ca and Mg carbonates of at least 95 %, dense granules which facilitates convenient mechanized application, as well as chalk suitable for accurate metered application on the quest map. Key words: granular chalk, gray forest soil, chemical reclamation, crop productivity.

Characteristics Of The Structure Formation Of Gypsum Binder Modified With Zinc Hydrosilicates

2020 ◽  
pp. 40-46
Keyword(s):  
Synergistic Effect ◽  
Physicochemical Properties ◽  
Structure Formation ◽  
Silicic Acid ◽  
Chemical Properties ◽  
Crystal Formation ◽  
Ability To Act ◽  
Chemical Factors ◽  
Sorption Characteristics

The authors' methodic for assessing the role of chemical and physic-chemical factors during the structure formation of gypsum stone is presented in the article. The methodic is also makes it possible to reveal the synergistic effect and to determine the ranges of variation of controls factors that ensure maximum values of such effect. The effect of a micro-sized modifier based on zinc hydro-silicates on the structure formation of building gypsum is analyzed and corresponding dependencies are found. It is shown that effects of influence of modifier on the properties of gypsum compositions are determined by chemical properties of modifier. Among the mentioned properties are sorption characteristics (which depend on the amount of silicic acid and its state) and physicochemical properties - the ability to act as a substrate during crystal formation. The proposed method can also be extended to other binding substances and materials. This article contributes to the understanding of the processes that occur during the structure formation of composites, which will make it possible to control the structure formation in the future, obtaining materials with a given set of properties.

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