Effect of gamma irradiation on the physicochemical and rheological properties of enzyme-catalyzed tragacanth-based injectable hydrogels

2019 ◽  
Vol 39 (5) ◽  
pp. 442-449 ◽  
Author(s):  
Moslem Tavakol ◽  
Ebrahim Vasheghani-Farahani ◽  
Mohammad Amin Mohammadifar ◽  
Maryam Dehghan-Niri
Keyword(s):  
Molecular Weight ◽  
Gamma Irradiation ◽  
Rheological Properties ◽  
Storage Modulus ◽  
Coupling Reaction ◽  
Water Soluble ◽  
Solution Viscosity ◽  
Injectable Hydrogels ◽  
Gum Tragacanth

Abstract In the present study, gamma irradiation was applied to promote the mechanical properties of enzyme- mediated in situ forming hydrogels prepared with tyramine-functionalized gum tragacanth (TA-GT). For this purpose, after gamma irradiation of powder or hydrocolloid solution of gum tragacanth (GT), the physiochemical and rheological properties of GT solution, and resultant hydrogel was investigated. In situ forming hydrogels were prepared via horseradish peroxidase catalyzed coupling reaction of TA-GT in the presence of hydrogen peroxide. Gamma irradiation led to a decrease in GT molecular weight and solution viscosity. Also, the solubility of GT improved and the separation of water soluble/swellable part of gum samples became easier, using gamma irradiation. In addition, by gamma irradiation of GT powder at doses of 5–15 kGy, a polymeric solution with higher concentration could be prepared that resulted in the promotion of hydrogels storage modulus. Further increase of irradiation dose did not improve storage modulus due to the extra decrease of gum molecular weight.

Irradiation-Induced Changes in Hydroxypropyl Cellulose

1995 ◽  
Vol 394 ◽  
Author(s):  
Mark A. Petrich ◽  
Lawrence A. Rosen
Keyword(s):  
Molecular Weight ◽  
Gamma Irradiation ◽  
Pharmaceutical Formulations ◽  
Hydroxypropyl Cellulose ◽  
Water Soluble ◽  
Cross Linking ◽  
Dissolution Behavior ◽  
Subsequent Effect ◽  
Sterilization Process ◽  
Induced Changes

AbstractGamma irradiation is used to sterilize products intended for ophthalmic and parenteral use. Ideally, the sterilization process should not affect the chemical identity or physical properties of the product. We have investigated the effects of gamma irradiation on the structure and molecular weight of hydroxypropyl cellulose (HPC), and the subsequent effect on dissolution behavior of HPC. Hydroxypropyl cellulose is a commonly used excipient in pharmaceutical formulations and tablet coatings, and can be used to manufacture water soluble objects. We find that the moisture content of the HPC influences the extent to which scission and cross-linking reactions occur. At low moisture levels (<5 wt.%), cross-linking is relatively unimportant, while above 12 wt. % moisture cross-linking becomes extensive leading to formation of insoluble, rubber-like gels.

scholarly journals Bone-Mimicking Injectable Gelatine/Hydroxyapatite Hydrogels

2019 ◽  
Vol 33 (3) ◽  
pp. 325-335
Author(s):  
Anamarija Rogina ◽  
Nikolina Šandrk ◽  
Laura Teruel-Biosca ◽  
Maja Antunović ◽  
Marica Ivanković ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Physical Properties ◽  
Storage Modulus ◽  
Hek293 Cells ◽  
Injectable Hydrogels ◽  
Composite Hydrogels ◽  
Natural Bone ◽  
Hydroxyapatite Crystal ◽  
Prepared Composite

Bioactive synthetic hydrogels have emerged as promising materials because they<br /> can provide molecularly tailored biofunctions and adjustable mechanical properties. To<br /> mimic the mineralogical and organic components of the natural bone, hydroxyapatite and<br /> a tyramine conjugate of gelatine were combined in this study. The effect of various amounts of in situ synthesized hydroxyapatite in gelatine-tyramine on the morphology<br /> and physical properties of injectable hydrogels was investigated. Mineralogical identification confirmed successful precipitation of in situ formed hydroxyapatite. Better distribution of hydroxyapatite crystal agglomerates within modified gelatine was found at 5 % of hydroxyapatite, which could be responsible for increased storage modulus with respect to pure gelatine hydrogel. Prepared composite hydrogels are non-toxic and support<br /> the proliferation of Hek293 cells.

scholarly journals Rutin-Loaded Poloxamer 407-Based Hydrogels for In Situ Administration: Stability Profiles and Rheological Properties

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1069 ◽  
Author(s):  
Elena Giuliano ◽  
Donatella Paolino ◽  
Maria Chiara Cristiano ◽  
Massimo Fresta ◽  
Donato Cosco
Keyword(s):  
Rheological Properties ◽  
Aqueous Media ◽  
Stability Index ◽  
Pharmaceutical Formulations ◽  
Water Soluble ◽  
Poloxamer 407 ◽  
Pharmaceutical Application ◽  
The Stability

Rutin is a flavone glycoside contained in many plants, and exhibits antioxidant, anti-inflammatory, anticancer, and wound-healing properties. The main disadvantage related to the use of this molecule for pharmaceutical application is its poor bioavailability, due to its low solubility in aqueous media. Poloxamer 407-hydrogels show interesting thermo-sensitive properties that make them attractive candidates as pharmaceutical formulations. The hydrophobic domains in the chemical structure of the copolymer, a polymer made up of two or more monomer species, are useful for retaining poorly water-soluble compounds. In this investigation various poloxamer 407-based hydrogels containing rutin were developed and characterized as a function of the drug concentration. In detail, the Turbiscan stability index, the micro- and dynamic rheological profiles and in vitro drug release were investigated and discussed. Rutin (either as a free powder or solubilized in ethanol) did not modify the stability or the rheological properties of these poloxamer 407-based hydrogels. The drug leakage was constant and prolonged for up to 72 h. The formulations described are expected to represent suitable systems for the in situ application of the bioactive as a consequence of their peculiar versatility.

Simultaneous Spectrophotometric Determination of Salbutamol by Coupling with Diazotized 4-Aminobenzoic acid

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Hind Hadi ◽  
Gufran Salim
Keyword(s):  
Pharmaceutical Preparations ◽  
Coupling Reaction ◽  
Dosage Forms ◽  
Water Soluble ◽  
Trace Determination ◽  
Aminobenzoic Acid ◽  
Optimum Conditions ◽  
Colored Product ◽  
Versus Concentration

A simple, rapid and sensitive spectrophotmetric method for trace determination of salbutamol (SAL) in aqueous solution and in pharmaceutical preparations is described. The method is based on the diazotization coupling reaction of the intended compound with 4-amino benzoic acid (ABA) in alkaline medium to form an intense orange, water soluble dye that is stable and shows maximum absorption at 410 nm. A graph of absorbance versus concentration indicates that Beer’s law is obeyed over the concentration range of 0.5-30 ppm, with a molar absorbtivity 3.76×104 L.mol-1 .cm-1 depending on the concentration of SAL. The optimum conditions and stability of the colored product have been investigated and the method was applied successfully to the determination of SAL in dosage forms.

Monitoring Polymer-Assisted Mechanochemical Cocrystallisation Through in Situ X-Ray Powder Diffraction

2020 ◽  
Author(s):  
Luzia S. Germann ◽  
Sebastian T. Emmerling ◽  
Manuel Wilke ◽  
Robert E. Dinnebier ◽  
Mariarosa Moneghini ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Powder Diffraction ◽  
Reaction Rate ◽  
Polymer Additives ◽  
Time Resolved ◽  
X Ray

Time-resolved mechanochemical cocrystallisation studies have so-far focused solely on neat and liquid-assisted grinding. Here, we report the monitoring of polymer-assisted grinding reactions using <i>in situ</i> X-ray powder diffraction, revealing that reaction rate is almost double compared to neat grinding and independent of the molecular weight and amount of used polymer additives.<br>

Functional Poly(p-Xylylene)s via Chemical Reduction of Poly(p-Phenylene Vinylene)s

2019 ◽  
Author(s):  
Ain Uddin ◽  
Weifan Sang ◽  
Yong Gao ◽  
Kyle Plunkett
Keyword(s):  
Film Formation ◽  
Chemical Reduction ◽  
Water Soluble ◽  
Phenylene Vinylene ◽  
Polymer Modification ◽  
Polymer Backbone ◽  
Crosslinking Process ◽  
Conducting Membranes ◽  
In Situ Crosslinking

The synthesis of poly(p-xylylene)s (PPXs) with sidechains containing alkyl bromide functionality, and their post-polymer modification, is described. The PPXs were prepared by a diimide hydrogenation of poly(p-phenylene vinylene)s (PPVs) that were originally synthesized by a Gilch polymerization. The polymer backbone reduction was carried out with hydrazine hydrate in toluene at 80 °C to provide polymers with the sidechain-containing bromide functionality intact. To demonstrate post-polymer modification of the sidechains, the resulting PPX polymers were modified with trimethylamine to form tetraalkylammonium ion functionality and were evaluated as anion conducting membranes. While PPX homopolymers containing tetralkylammonium ions were completely water soluble and not able to form valuable films, PPX copolymers containing mixed tetraalkylammonium ions and hydrophobic chains were capable of film formation and alkaline stability. In addition, an in situ crosslinking process that used N,N,N',N'-tetramethyl-1,6-hexanediamine during the tetraalkylammonium formation of brominated PPX polymers was also evaluated and gave reasonable films with conductivities of ~10 mS-cm-1.

Functional Poly(p-Xylylene)s via Chemical Reduction of Poly(p-Phenylene Vinylene)s

2019 ◽  
Author(s):  
Ain Uddin ◽  
Weifan Sang ◽  
Yong Gao ◽  
Kyle Plunkett
Keyword(s):  
Film Formation ◽  
Chemical Reduction ◽  
Water Soluble ◽  
Phenylene Vinylene ◽  
Polymer Modification ◽  
Polymer Backbone ◽  
Crosslinking Process ◽  
Conducting Membranes ◽  
In Situ Crosslinking

The synthesis of poly(p-xylylene)s (PPXs) with sidechains containing alkyl bromide functionality, and their post-polymer modification, is described. The PPXs were prepared by a diimide hydrogenation of poly(p-phenylene vinylene)s (PPVs) that were originally synthesized by a Gilch polymerization. The polymer backbone reduction was carried out with hydrazine hydrate in toluene at 80 °C to provide polymers with the sidechain-containing bromide functionality intact. To demonstrate post-polymer modification of the sidechains, the resulting PPX polymers were modified with trimethylamine to form tetraalkylammonium ion functionality and were evaluated as anion conducting membranes. While PPX homopolymers containing tetralkylammonium ions were completely water soluble and not able to form valuable films, PPX copolymers containing mixed tetraalkylammonium ions and hydrophobic chains were capable of film formation and alkaline stability. In addition, an in situ crosslinking process that used N,N,N',N'-tetramethyl-1,6-hexanediamine during the tetraalkylammonium formation of brominated PPX polymers was also evaluated and gave reasonable films with conductivities of ~10 mS-cm-1.

ANALISA KANDUNGAN BETA-GLUKAN LARUT AIR DAN LARUT ALKALI DARI TUBUH BUAH JAMUR TIRAM (Pleurotus ostreatus) DAN SHIITAKE (Lentinus edodes)

2013 ◽  
Vol 13 (3) ◽  
Author(s):  
Netty Widyastuti ◽  
Teguh Baruji ◽  
Henky Isnawan ◽  
Priyo Wahyudi ◽  
Donowati Donowati
Keyword(s):  
Molecular Structure ◽  
Molecular Weight ◽  
Immune System ◽  
Pleurotus Ostreatus ◽  
Water Soluble ◽  
Low Molecular Weight ◽  
Lentinus Edodes ◽  
Beta Glucan ◽  
Oyster Mushrooms ◽  
The Difference

Beta glucan is a polysaccharide compound, generally not soluble inwater and resistant to acid. Beta glucan is used as an immunomodulator (enhancing the immune system) in mammals is usually a beta-glucan soluble in water, easily absorbed and has a low molecular weight. Several example of beta-glucan such as cellulose (β-1 ,4-glucan), lentinan (β-1 0.6-glucan) and (β-1 ,3-glucan), pleuran (β-1, 6 and β-1 ,3-glucan) are isolated from species of fungi Basidiomycota include mushrooms (Pleurotus ostreatus) and shiitake (Lentinus edodes).The purpose of thisresearch activity is to obtain beta-glucan compound that can be dissolved in water and in alkali derived from fungi Basidiomycota, i.e, Oyster mushrooms (Pleurotus ostreatus) and shiitake (Lentinus edodes). The result of beta-glucan compared to characterize the resulting beta glucan that is molecular structure . The difference of beta glucan extraction is based on the differences in solubility of beta-glucan. Beta glucan could be water soluble and insoluble water.

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