scholarly journals Mathematical Modeling of Crosslinked Polyacrylic Based Hydrogels: Physical Properties and Drug Delivery

2021 ◽  
Author(s):  
Filippo Bisotti ◽  
Fabio Pizzetti ◽  
Giuseppe Storti ◽  
Filippo Rossi
Keyword(s):  
Mathematical Modeling ◽  
Drug Delivery ◽  
Hydrophilic Polymers ◽  
Cross Linking ◽  
Transport Mechanisms ◽  
Equilibrium Conditions ◽  
Swelling Behaviour ◽  
Volume Increase ◽  
Ph Values ◽  
Chemical Cross Linking

Abstract Recently, hydrogels have gained significant importance in different applications, such as tissue engineering and drug delivery. They are 3D-structures of hydrophilic polymers held together through physical or chemical cross-linking. Important is their ability to swell in presence of solvents, forming elastic gels able to mantain their original shape. Furthermore, this scaffolds slowly degrade in the physiological environment, leading the growing tissue to replace the former filled site. In this work, hydrogels have been synthetized using branched polyacrilic acid (Carbomer) cross-linked with an aliphatic polyetherdiamine (elastamine). In particular, we focused on the description of their equilibrium conditions in swollen state and the dynamic simulation of the swelling process. These hydrogels exhibited a peculiar swelling behaviour characterized by an overshoot of the volume increase before reaching the equilibrium. Notably, such behavior was found at different pH values. In this manuscript, the swelling behavior was studied by mathematical modelling. Moreover, the ability of these devices to release drugs was also examined through a literature model to understand the different operating transport mechanisms.

scholarly journals Synthesis and Characterization of Chemically Cross-Linked CMC/Acrylamide Hydrogels

2020 ◽  
Vol 32 (5) ◽  
pp. 1109-1115
Author(s):  
Shivakumara Lachakkal Rudrappa ◽  
Sudhir Ramaswamy Iliger ◽  
Demappa Thippaiah
Keyword(s):  
Room Temperature ◽  
Aluminum Sulfate ◽  
Ammonium Persulfate ◽  
Sem Analysis ◽  
Cross Linking ◽  
Swelling Behaviour ◽  
Buffer Solutions ◽  
Aluminium Sulfate ◽  
Chemical Cross Linking

Carboxymethyl cellulose/poly(acrylamide) (CMC/Amm) hydrogels were synthesized by the chemical cross-linking method. Ammonium persulfate used as an initiator, while aluminium sulfate used as a cross-linking agent. The structure and morphology of the hydrogels were characterized by FTIR and scanning electron microscopy (SEM) analysis. The swelling behaviour of the hydrogels can be studied by using acids (CH3COOH, HCl and HClO4) and also in the pH of the buffer solutions at different temperature (room temperature, 30 and 37 ºC) was studied. Swelling of hydrogels increased with an increase in the concentration of aluminum sulfate up to 20 %, above 20 % it has found to be decreased. The effect of four series of cationic different concentrated salt solutions on the swelling had found to be the following order K+ > Na+ > Ca2+ > Mg2+.

Formulation of Vanillin Cross-Linked Chitosan Nanoparticles and its Characterization

2011 ◽  
Vol 335-336 ◽  
pp. 474-477 ◽  
Author(s):  
Guang Wang ◽  
Pu Wang Li ◽  
Zheng Peng ◽  
Mao Fang Huang ◽  
Ling Xue Kong
Keyword(s):  
Drug Delivery ◽  
Particle Size ◽  
Smooth Surface ◽  
Average Particle Size ◽  
Chitosan Nanoparticles ◽  
Aldehyde Group ◽  
Cross Linking ◽  
Average Particle ◽  
Amino Group ◽  
Chemical Cross Linking

Chitosan nanoparticles were successfully prepared by chemical cross-linking with vanillin. The nanoparticles were spherical in shape with smooth surface, and the average particle size of chitosan nanoparticles was 141 nm. The formulation of chitosan nanoparticles is based on Shiff reaction between aldehyde group of vanillin and amino group of chitosan. Chitosan nanoparticles prepared by crosslinking with vanillin are promising vehicle for the drug delivery of various anticancer drugs in the chemotherapy of cancers.

scholarly journals Evaluation of Low Molecular Weight Cross Linked Chitosan Nanoparticles, to Enhance the Bioavailability of 5-Flourouracil

Dose-Response ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. 155932582110253
Author(s):  
Aisha Sethi ◽  
Mahmood Ahmad ◽  
Tayyaba Huma ◽  
Ikrima Khalid ◽  
Imtiaz Ahmad
Keyword(s):  
Drug Delivery ◽  
Molecular Weight ◽  
Drug Release ◽  
Zeta Potential ◽  
Sustained Release ◽  
Drug Delivery Systems ◽  
Chitosan Nanoparticles ◽  
Cross Linking ◽  
Low Molecular Weight ◽  
Chemical Cross Linking

The present study aimed to formulate 5-fluorouracil loaded cross linked chitosan nanoparticles based on chemical cross-linking of low molecular weight chitosan with glutaraldehyde by reverse micelles technique as 5-FU is less hydrophobic, relatively potent, has a shorter half-life, is rapidly metabolized, less tolerated, and has low oral bioavailability; therefore, we aimed to formulate potential nanocarriers of 5-FU for efficient drug delivery to specific targeted areas of action, reduce oral toxicity, improve tolerability and therapeutic outcomes of 5-FU, in a restricted fashion to enhance the bioavailability of 5-FU. Nanoparticles were formulated by the reverse micelle method based on the chemical cross-linking of glutaraldehyde (25% aqueous solution) into a w/o emulsion in different ratios. LMWCH-NPs were characterized for post-formulation parameters by mean particle size, zeta potential, %age yield, loading/entrapment efficiency, Fourier transform infrared spectroscopy (FTIR), DSC/TGA, TEM, PXRD, drug release at pH 1.2, and pH 7.4. 5-FU loaded NPs showed a size range (198 nm-200 nm) and zeta potential (−39mV to −41mV), which ensured mechanical stability and increased retention time in blood vessels by the sustained release properties of biodegradable nanocarrier drug delivery systems. % age yield showed the range 92% to 96% while % LC ranged 2.0% to 3.4% and %EE ranged 40% to 43%. The TEM images showed spherical nanoparticles. FTIR revealed the compatibility between the drug and the cross-linked polymer. DSC/TGA ensured the thermal stability of the drug, while the solid-state stability of the drug-loaded cross-linked chitosan nanoparticles was evaluated by powder X-ray diffraction (PXRD) analysis. Drug release studies were performed using the dialysis bag technique at both pH (1.2 and 7.4) to mimic the gastrointestinal tract. Highly stable NPs displayed targeted release in phosphate buffer pH 7.4 at 37°C. Fickian diffusion was the predominant release with an R2 value of 0.9975-0.9973—and an N value 0.45-0.53. Prepared nanoparticles are inert, biodegradable, and biocompatible drug delivery systems for sustained release of 5-FU with maximum therapeutic efficacy and bioavailability.

Statistical Force-Field for Structural Modeling Using Chemical Cross-Linking/mass Spectrometry Distance Constraints

2018 ◽  
Author(s):  
Allan J. R. Ferrari ◽  
Fabio C. Gozzo ◽  
Leandro Martinez
Keyword(s):  
Mass Spectrometry ◽  
Amino Acid ◽  
Force Field ◽  
Protein Structures ◽  
Protein Structure Determination ◽  
Structural Modeling ◽  
Cross Linking ◽  
Amino Acid Residues ◽  
Distance Constraints ◽  
Chemical Cross Linking

<div><p>Chemical cross-linking/Mass Spectrometry (XLMS) is an experimental method to obtain distance constraints between amino acid residues, which can be applied to structural modeling of tertiary and quaternary biomolecular structures. These constraints provide, in principle, only upper limits to the distance between amino acid residues along the surface of the biomolecule. In practice, attempts to use of XLMS constraints for tertiary protein structure determination have not been widely successful. This indicates the need of specifically designed strategies for the representation of these constraints within modeling algorithms. Here, a force-field designed to represent XLMS-derived constraints is proposed. The potential energy functions are obtained by computing, in the database of known protein structures, the probability of satisfaction of a topological cross-linking distance as a function of the Euclidean distance between amino acid residues. The force-field can be easily incorporated into current modeling methods and software. In this work, the force-field was implemented within the Rosetta ab initio relax protocol. We show a significant improvement in the quality of the models obtained relative to current strategies for constraint representation. This force-field contributes to the long-desired goal of obtaining the tertiary structures of proteins using XLMS data. Force-field parameters and usage instructions are freely available at http://m3g.iqm.unicamp.br/topolink/xlff <br></p></div><p></p><p></p>

Biopolymers with Medical Applications Optimized method for obtaining chitosan-based delivery systems

2018 ◽  
Vol 69 (7) ◽  
pp. 1756-1759 ◽  
Author(s):  
Luminita Confederat ◽  
Iuliana Motrescu ◽  
Sandra Constantin ◽  
Florentina Lupascu ◽  
Lenuta Profire
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Average Diameter ◽  
Delivery Systems ◽  
Cross Linking ◽  
Low Molecular Weight ◽  
Polymeric Systems ◽  
Chitosan Microparticles ◽  
Degree Of Swelling

The aim of this study was to optimize the method used for obtaining microparticles based on chitosan � a biocompatible, biodegradable, and nontoxic polymer, and to characterize the developed systems. Chitosan microparticles, as drug delivery systems were obtained by inotropic gelation method using pentasodiumtripolyphosphate (TPP) as cross-linking agent. Chitosan with low molecular weight (CSLMW) in concentration which ranged between 0.5 and 5 %, was used while the concentration of cross-linking agent ranged between 1 and 5%. The characterization of the microparticles in terms of shape, uniformity and adhesion was performed in solution and dried state. The size of the microparticles and the degree of swelling were also determined. The structure and the morphology of the developed polymeric systems were analyzed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM).The average diameter of the chitosan microparticles was around 522 �m. The most stable microparticles were obtained using CSLMW 1% and TPP 2% or CSLMW 0.75%and TPP 1%. The micropaticles were spherical, uniform and without flattening. Using CSLMW in concentration of 0.5 % poorly cross-linked and crushed microparticles have been obtained at all TPP concentrations. By optimization of the method, stable chitosan-based micropaticles were obtained which will be used to develop controlled release systems for drug delivery.

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