scholarly journals Synthesis and Characterization of Chemically Cross-Linked Acrylic Acid/Gelatin Hydrogels: Effect of pH and Composition on Swelling and Drug Release

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Syed Majid Hanif Bukhari ◽  
Samiullah Khan ◽  
Muhammad Rehanullah ◽  
Nazar Mohammad Ranjha
Keyword(s):  
Acrylic Acid ◽  
Phosphate Buffer ◽  
Sol Gel ◽  
Ammonium Persulfate ◽  
Cross Linking ◽  
Release Mechanism ◽  
Ph Values ◽  
Allergy Treatment ◽  
Model Drug ◽  
Release Data

This present work was aimed at synthesizing pH-sensitive cross-linked AA/Gelatin hydrogels by free radical polymerization. Ammonium persulfate and ethylene glycol dimethacrylate (EGDMA) were used as initiator and as cross-linking agent, respectively. Different feed ratios of acrylic acid, gelatin, and EGDMA were used to investigate the effect of monomer, polymer, and degree of cross-linking on swelling and release pattern of the model drug. The swelling behavior of the hydrogel samples was studied in 0.05 M USP phosphate buffer solutions of various pH values pH 1.2, pH 5.5, pH 6.5, and pH 7.5. The prepared samples were evaluated for porosity and sol-gel fraction analysis. Pheniramine maleate used for allergy treatment was loaded as model drug in selected samples. The release study of the drug was investigated in 0.05 M USP phosphate buffer of varying pH values (1.2, 5.5, and 7.5) for 12 hrs. The release data was fitted to various kinetic models to study the release mechanism. Hydrogels were characterized by Fourier transformed infrared (FTIR) spectroscopy which confirmed formation of structure. Surface morphology of unloaded and loaded samples was studied by surface electron microscopy (SEM), which confirmed the distribution of model drug in the gel network.

scholarly journals pH-sensitive polyvinylpyrrolidone-acrylic acid hydrogels: Impact of material parameters on swelling and drug release

2014 ◽  
Vol 50 (1) ◽  
pp. 173-184 ◽  
Author(s):  
Kashif Sohail ◽  
Ikram Ullah Khan ◽  
Yasser Shahzad ◽  
Talib Hussain ◽  
Nazar Muhammad Ranjha
Keyword(s):  
Drug Release ◽  
Acrylic Acid ◽  
Phosphate Buffer ◽  
Ph Sensitive ◽  
Cross Linking ◽  
Release Mechanism ◽  
Effect Analysis ◽  
X Ray Crystallography ◽  
Buffer Solutions ◽  
The One

In this study, we fabricated pH-sensitive polyvinylpyrrolidone/acrylic acid (PVP/AA) hydrogels by a free-radical polymerisation method with variation in the content of monomer, polymer and cross-linking agent. Swelling was performed in USP phosphate buffer solutions of pH 1.2, 5.5, 6.5 and 7.5 with constant ionic strength. Network structure was evaluated by different parameters and FTIR confirmed the formation of cross-linked hydrogels. X-ray crystallography showed molecular dispersion of tramadol HCl. A drug release study was carried out in phosphate buffer solutions of pH 1.2, 5.5 and 7.5 for selected samples. It was observed that swelling and drug release from hydrogels can be modified by changing composition and degree of cross-linking of the hydrogels under investigation. Swelling coefficient was high at higher pH values except for the one containing high PVP content. Drug release increased by increasing the pH of the medium and AA contents in hydrogels while increasing the concentration of cross-linking agent had the opposite effect. Analysis of the drug release mechanism revealed non-Fickian transport of tramadol from the hydrogels.

Synthesis and Properties of Thermo- and pH-Sensitive Poly[(Sodium Humate)-(N-Isopropylacrylamide)-(Acrylic Acid)] Intelligent Hydrogel

2013 ◽  
Vol 781-784 ◽  
pp. 536-541
Author(s):  
Xiao Mi Zhou ◽  
Xiao Ran Sun ◽  
Guang Yue Li
Keyword(s):  
Acrylic Acid ◽  
Suspension Polymerization ◽  
Ammonium Persulfate ◽  
Continuous Phase ◽  
Ph Sensitive ◽  
Cross Linking ◽  
Swelling Ratio ◽  
Inverse Suspension Polymerization ◽  
Sensitive Characteristics ◽  
Intelligent Hydrogel

A novel intelligent hydrogel of poly(Humic acid - Nisopropylacrylamide - Acrylic acid) (P(NIPAAm-HA-AA)) was prepared at 70°C by inverse suspension polymerization. The reactions include uses N,N-methylene-bis-acrylamide (MBA) as a cross-linking agent, ammonium persulfate (KPS) as an initiator, cyclohexane as a continuous phase and span-65 as dispersant. The influence such as concentration of monomers and cross-linking agent, mole fraction of span-65 in mixed monomers, and temperature of polymerization on the property of resulting P(NIPAAm-HA-AA) hydrogels was investigated in detail. Fourier transform infrared (FTIR) demonstrated that NIPAAm, HA and AA was synthetized successfully. The results showed that the swelling ratio (SR) of modified hydrogel was improved significantly with the dosage of NIPAAm. It was also observed that the thermosensitive and pH sensitive characteristics was strongly affected by concentrations of NIPAAm. At last, we choose NIPAAm: HA=0.3.

The Preparation of Calcium Carbonate Modified High Water-Absorbing Resin

2014 ◽  
Vol 1035 ◽  
pp. 296-302
Author(s):  
Qi Shi ◽  
Qing Luo Meng ◽  
Nong Wang
Keyword(s):  
Calcium Carbonate ◽  
Acrylic Acid ◽  
Dry Weight ◽  
High Water ◽  
Ammonium Persulfate ◽  
Sodium Acrylate ◽  
Cross Linking ◽  
Optimum Process ◽  
Process Conditions ◽  
Modified Resin

The poly (sodium acrylate/acrylic acid) water-absorbing resin was prepared by aqueous solution polymerization with acrylic acid (AA) as the monomer, calcium carbonate as the modified additives, N, N-methylene double acrylamide (NMBA) as cross-linking agent, ammonium persulfate (APS)/sodium sulfite oxidation reduction type initiator. It was found that the adsorption performance of absorbent resin modified by calcium carbonate strengthened obviously. Orthogonal and single factor experiment were used to establish the optimum parameters related to the product preparation. The best process conditions on water-absorbing properties of the modified resin was obtained. Using 150mL acrylic acid as a benchmark, the result show the optimum process conditions: the reaction temperature is 55°C, the mass fraction of monomer is 20%, the neutralization degree is 45%, modified additive dosage is 10 g, the dosage of cross-linking agent is 0.1%, and the initiator dosage is 2.0%, respectively. After made under the optimum process conditions, the water-absorbing rate of the modified resin was 676.6 times the dry weight.

scholarly journals Highly Porous pH-Responsive Carboxymethyl Chitosan-Grafted-Poly (Acrylic Acid) Based Smart Hydrogels for 5-Fluorouracil Controlled Delivery and Colon Targeting

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Samiullah Khan ◽  
Naveed Anwar
Keyword(s):  
Colon Cancer ◽  
Acrylic Acid ◽  
General Circulation ◽  
Structural Parameters ◽  
Oral Route ◽  
Carboxymethyl Chitosan ◽  
Release Mechanism ◽  
Circulation Current ◽  
Model Drug ◽  
Model Equations

In the present investigation, new formulations of CMCS/AA hydrogels with varying composition of Carboxymethyl chitosan, acrylic acid, and ethylene glycol dimethacrylate (EGDMA) were prepared by free radical polymerization technique using benzoyl peroxide as catalyst. The bioavailability of 5-FU through the oral route is very limited owing to its rapid metabolism and clearance from the general circulation. Current work was aimed at increasing the bioavailability of 5-FU via smart hydrogels and at investigating their potential in delivering 5-FU to target colon cancer. Swelling studies were carried out on dried hydrogel discs in different USP phosphate buffer solutions of various pH values. Porosity and gel fraction of all the samples were measured. 5-FU was used as a model drug and loaded in selected hydrogel samples. The amount of drug loaded and released was determined. Experimental data was fitted to various model equations, and corresponding parameters were calculated to study the release mechanism. Many structural parameters were calculated. The prepared hydrogels were also characterized by FTIR and SEM to study the structure, crystallinity, compatibility, and morphology of the smart hydrogels. The biocompatibility and cytotoxic potential blank and drug-loaded hydrogels were assessed through MTT assay. The prepared hydrogels were found to be an excellent carrier for 5-FU in targeting colon cancer.

scholarly journals Synthesis and Characterization of Acrylamide/Acrylic Acid Co-Polymers and Glutaraldehyde Crosslinked pH-Sensitive Hydrogels

Gels ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 47
Author(s):  
Munir Ahmad Khan ◽  
Abul Kalam Azad ◽  
Muhammad Safdar ◽  
Asif Nawaz ◽  
Muhammad Akhlaq ◽  
...  
Keyword(s):  
Drug Release ◽  
Acrylic Acid ◽  
Sol Gel ◽  
Ph Sensitive ◽  
Attenuated Total Reflection ◽  
Acidic Media ◽  
Drug Delivery Carrier ◽  
Equilibrium Swelling ◽  
Swelling Characteristics ◽  
Release Data

This project aims to synthesize and characterize the pH-sensitive controlled release of 5-fluorouracil (5-FU) loaded hydrogels (5-FULH) by polymerization of acrylamide (AM) and acrylic acid (AA) in the presence of glutaraldehyde (GA) as a crosslinker with ammonium persulphate as an initiator. The formulation’s code is named according to acrylamide (A1, A2, A3), acrylic acid (B1, B2, B3) and glutaraldehyde (C1, C2, C3). The optimized formulations were exposed to various physicochemical tests, namely swelling, diffusion, porosity, sol gel analysis, and attenuated total reflection-Fourier transform infrared (ATR-FTIR). These 5-FULH were subjected to kinetic models for drug release data. The 5-FU were shown to be soluble in distilled water and phosphate buffer media at pH 7.4, and sparingly soluble in an acidic media at pH 1.2. The ATR-FTIR data confirmed that the 5-FU have no interaction with other ingredients. The lowest dynamic (0.98 ± 0.04% to 1.90 ± 0.03%; 1.65 ± 0.01% to 6.88 ± 0.03%) and equilibrium swelling (1.85 ± 0.01% to 6.68 ± 0.03%; 10.12 ± 0.02% to 27.89 ± 0.03%) of formulations was observed at pH 1.2, whereas the higher dynamic (4.33 ± 0.04% to 10.21 ± 0.01%) and equilibrium swelling (22.25 ± 0.03% to 55.48 ± 0.04%) was recorded at pH 7.4. These findings clearly indicated that the synthesized 5-FULH have potential swelling characteristics in pH 6.8 that will enhance the drug’s release in the same pH medium. The porosity values of formulated 5-FULH range from 34% to 62% with different weight ratios of AM, AA, and GA. The gel fractions data showed variations ranging from 74 ± 0.4% (A1) to 94 ± 0.2% (B3). However, formulation A1 reported the highest 24 ± 0.1% and B3 the lowest 09 ± 0.3% sol fractions rate among the formulations. Around 20% drug release from the 5-FULH was found at 1 h in an acidic media (pH1.2), whereas >65% of drug release (pH7.4) was observed at around 25 h. These findings concluded that GA crosslinked 5-FU loaded AM and AA based hydrogels would be a potential pH-sensitive oral controlled colon drug delivery carrier.

Thermo- and pH-Responsive CeF3 Nanocrystals/HPC–PAA Complex Nanogel and Its Drug Release Behavior

NANO ◽  
2019 ◽  
Vol 14 (08) ◽  
pp. 1950102 ◽  
Author(s):  
Ben Liu ◽  
Qiusheng Song ◽  
Qiancheng Zhang ◽  
Haihong Ma ◽  
Ziwen Zhang ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Environmental Temperature ◽  
Ph Value ◽  
Water Solution ◽  
Drug Loading ◽  
Ammonium Persulfate ◽  
Crosslinking Reaction ◽  
Sensitive Material ◽  
Redox Initiator ◽  
Model Drug

In this study, a kind of novel rare-earth nanocrystals/hydroxypropylcellulose–poly (acrylic acid) (HPC–PAA) complex fluorescent nanogel, its responsive behavior to environmental temperature and pH value were reported. For preparation, with HPC being used as template, HPC–PAA nanogel was first synthesized by polymerization and crosslinking reaction of acrylic acid (AA) in water solution. In the process, a redox initiator, which composed of ammonium persulfate (APS) and N,N,N′,N′-tetramethylethylenediamine (TEMED), was used to initiate the reaction. Then, the as-prepared nanogel reacted with Ce(NO[Formula: see text] and NH4F solution successively, and a novel CeF3 nanocrystals/HPC–PAA complex nanogel was fabricated. The microstructure of the nanogel was characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), Thermogravimetric (TG) and Transmission electron microscopy (TEM). The environmental sensitivity of the nanogel was investigated by photoluminescence (PL) and UV–Visible spectrophotometer (UV–Vis). The thermo- and pH-sensitive fluorescence were studied by PL at various temperatures and pH values; besides, the behavior of drug loading and release was researched by PL with a famous antibiotic of Ibuprofen as model drug. The results show that the PL intensity of the nanogel was largely affected by environmental temperature, or content of Ibuprofen loaded in the nanogel. The as-prepared nanogel can be used as useful sensitive material to detect temperature and pH value change, and drug loading or release property of Ibuprofen can be detected by PL emission of the nanogels conveniently.

scholarly journals The development and characterization of a novel coagulant for dust suppression in open-cast coal mines

2017 ◽  
Vol 36 (1-2) ◽  
pp. 608-624 ◽  
Author(s):  
Gang Zhou ◽  
Tao Fan ◽  
Mao Xu ◽  
Han Qiu ◽  
Jiayuan Wang ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Ph Value ◽  
High Standard ◽  
Ammonium Persulfate ◽  
Cross Linking ◽  
Swelling Kinetics ◽  
Mass Ratio ◽  
Dust Suppression ◽  
The Cross ◽  
Open Cast

This paper proposes the development of a novel coagulant for dust suppression in open-cast mines. Specifically, pretreated sodium lignin sulfonate and acrylic acid were first cross-linked, then the graft copolymerization of the intermediate product (the cross-linking product) and acrylamide was conducted and finally the resulting gelatinous substances were crushed. During the reaction process, N,N’-methylene-bis-acrylamide and ammonium persulfate were used as the cross-linking agent and initiator, respectively. Subsequently, the functional groups, crystalline structure, and thermal stability of the dust coagulant were examined by means of Fourier transform infrared spectra measurements, X-ray diffraction spectra measurements, and differential scanning calorimeter analysis. Moreover, single-factor experiments were conducted to explore the optimal synthesis condition. According to the experimental results, the coagulant achieved its optimal dust suppression performance under the following conditions: the mass ratio of lignin to acrylic acid was 1:3, the mass ratio of lignin to acrylamide was 2:7, the content of the cross-linking agent was 0.9%, the mass ratio of initiator to acrylamide was 2:100, the reaction temperature was set as 60℃, and the pH value was set as 7. Finally, the coagulant was measured for its swelling kinetics, viscosity, film-forming hardness, peeling strength, and ability to suppress dust. It can be concluded that the coagulant exhibits a very high standard of both dust suppression and wind resistance.

The Role of the Initiator System in the Synthesis of Acidic Multifunctional Nanoparticles Designed for Molecular Imprinting of Proteins

2020 ◽  
Vol 65 (1) ◽  
pp. 28-41
Author(s):  
Marwa Aly Ahmed ◽  
Júlia Erdőssy ◽  
Viola Horváth
Keyword(s):  
Acrylic Acid ◽  
Binding Affinity ◽  
Molecular Imprinting ◽  
Low Temperatures ◽  
Ammonium Persulfate ◽  
Sodium Bisulfite ◽  
Multifunctional Nanoparticles ◽  
High Affinity ◽  
Initiator System

Multifunctional nanoparticles have been shown earlier to bind certain proteins with high affinity and the binding affinity could be enhanced by molecular imprinting of the target protein. In this work different initiator systems were used and compared during the synthesis of poly (N-isopropylacrylamide-co-acrylic acid-co-N-tert-butylacrylamide) nanoparticles with respect to their future applicability in molecular imprinting of lysozyme. The decomposition of ammonium persulfate initiator was initiated either thermally at 60 °C or by using redox activators, namely tetramethylethylenediamine or sodium bisulfite at low temperatures. Morphology differences in the resulting nanoparticles have been revealed using scanning electron microscopy and dynamic light scattering. During polymerization the conversion of each monomer was followed in time. Striking differences were demonstrated in the incorporation rate of acrylic acid between the tetramethylethylenediamine catalyzed initiation and the other systems. This led to a completely different nanoparticle microstructure the consequence of which was the distinctly lower lysozyme binding affinity. On the contrary, the use of sodium bisulfite activation resulted in similar nanoparticle structural homogeneity and protein binding affinity as the thermal initiation.

Formulation and Evaluation of Microbially- triggered tablets of Valdecoxib

2010 ◽  
Vol 2 (1) ◽  
Author(s):  
Surender Verma ◽  
S. Singh ◽  
D. Mishra ◽  
Atul Gupta ◽  
Rakesh Sharma
Keyword(s):  
Phosphate Buffer ◽  
Guar Gum ◽  
Oral Route ◽  
Matrix Tablets ◽  
In Vitro Dissolution ◽  
Wet Granulation ◽  
Dissolution Study ◽  
Caecal Content ◽  
Model Drug

The objective of present study was to develop colon targeted drug delivery using bacterially triggered approach through oral route. Valdecoxib (COX-2 inhibitor) was chosen as a model drug in order to target it to colon which may prove useful in inflammatory bowel disease and related disorders. Matrix tablets of Valdecoxib were prepared by wet granulation technique utilizing different ratio of Guar gum and Sodium starch glycholate. The prepared matrix tablets were evaluated for uniformity of weight, uniformity of content, hardness and in vitro dissolution study in simulated gastric and intestinal fluid (Phosphate Buffer pH-1.2, pH-6.8 and pH-7.4), followed by Dissolution study in bio-relevant dissolution media Phosphate Buffer (pH-6.8) containing rat caecal content. The results revealed that the formulated batch had released lesser quantity of drug at pH 1.2 and pH 7.4 in 2 hors whereas in biorelevent dissolution media containing rat caecal content it released significantly higher amount of drug which was also significantly higher than the dissolution media of same pH without caecal content (microflora) and it was concluded that guar gum can be used as a potential carrier for targeting drugs to colon.

scholarly journals Double-Cross-Linked Networks Based on Methacryloyl Mucin

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1706
Author(s):  
Elena Olăreț ◽  
Brîndușa Bălănucă ◽  
Andra Mihaela Onaș ◽  
Jana Ghițman ◽  
Horia Iovu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Chemical Modification ◽  
Structural Modification ◽  
Aqueous Media ◽  
Cross Linking ◽  
Ph Values ◽  
Acid Aqueous Solution ◽  
Reaction Media ◽  
Double Cross

Mucin is a glycoprotein with proven potential in the biomaterials field, but its use is still underexploited for such applications. The present work aims to produce a synthesis of methacryloyl mucin single-network (SN) hydrogels and their double-cross-linked-network (DCN) counterparts. Following the synthesis of the mucin methacryloyl derivative, various SN hydrogels are prepared through the photopolymerization of methacrylate bonds, using reaction media with different pH values. The SN hydrogels are converted into DCN systems via supplementary cross-linking in tannic acid aqueous solution. The chemical modification of mucin is described, and the obtained product is characterized; the structural modification of mucin is assessed through FTIR spectroscopy, and the circular dichroism and the isoelectric point of methacryloyl mucin is evaluated. The affinity for aqueous media of both SN and DCN hydrogels is estimated, and the mechanical properties of the systems are assessed, both at macroscale through uniaxial compression and rheology tests and also at microscale through nanoindentation tests.

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