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

Sohail, Kashif; Khan, Ikram Ullah; Shahzad, Yasser; Hussain, Talib; Ranjha, Nazar Muhammad

doi:10.1590/s1984-82502011000100018

Cited by 80 publications

(31 citation statements)

References 32 publications

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“…Due to molecular dispersion of drug into polymer matrix, the dissolution rate of water‐insoluble drugs increases, thus improving the bioavailability. Similar findings have been reported earlier …”

Section: Resultssupporting

confidence: 93%

Fabrication and in vitro evaluation of novel pH‐sensitive poly (2‐methoxyethyl methacrylate‐co‐itaconic acid) microgels

et al. 2016

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The present work focused on the synthesis and evaluation of cross-linked poly (2-methoxyethyl methacrylate-co-itaconic acid) [p(MEMA-co-IA)] microgels for controlled and extended drug delivery, in an attempt to improve the bioavailability of the drugs and to get maximum therapeutic benefits. A series of p(MEMA-co-IA) microgels were prepared by modified free-radical suspension polymerization using ethylene glycol dimethacrylate as cross-linker. Characterization was performed through FTIR, TGA, DSC, XRD, DLS and SEM. pH responsiveness was evaluated by equilibrium swelling studies in phosphate buffer solutions of different pH values (pH 1.2, 4, 6.5, and 7.4) with constant ionic strength. To demonstrate the potential use of microgels for drug delivery, esomeprazole magnesium trihydrate (EMT) was loaded as model drug and in vitro dissolution studies were performed. FTIR and thermal analysis confirmed the formation of cross-linked p(MEMA-co-IA) microgels. XRD indicated dispersion of drug into the network at molecular level. SEM illustrated smooth, round and uniformly distributed microspheres. A remarkably higher swelling at higher pH values (pH 6.5 and 7.4) compared to pH 1.2 demonstrated the pH-responsive nature of the microgels. All the formulations showed pH-dependent drug release following Higuchi with non-fickian mechanism of drug diffusion. In light of the results obtained from this study, it was concluded that p(MEMA-co-IA) microgels have potential to release drug in controlled manner responsive to pH of the external environment.

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Section: Resultssupporting

confidence: 93%

Fabrication and in vitro evaluation of novel pH‐sensitive poly (2‐methoxyethyl methacrylate‐co‐itaconic acid) microgels

et al. 2016

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“…Secondly, increased AA content may influence the preference of homopolymerization over copolymerization thus swelling ratio decreased at higher AA content. [ 36,37 ]…”

Section: Resultsmentioning

confidence: 99%

The structural, morphological and thermal properties of grafted pH-sensitive interpenetrating highly porous polymeric composites of sodium alginate/acrylic acid copolymers for controlled delivery of diclofenac potassium

Jalil

Khan

Naeem

et al. 2016

Designed Monomers and Polymers

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In present investigation new formulations of Sodium Alginate/Acrylic acid hydrogels with high porous structure were synthesized by free radical polymerization technique for the controlled drug delivery of analgesic agent to colon. Many structural parameters like molecular weight between crosslinks (M c), crosslink density (M r), volume interaction parameter (v 2,s), Flory Huggins water interaction parameter and diffusion coefficient (Q) were calculated. Water uptake studies was conducted in different USP phosphate buffer solutions. All samples showed higher swelling ratio with increasing pH values because of ionization of carboxylic groups at higher pH values. Porosity and gel fraction of all the samples were calculated. New selected samples were loaded with the model drug (diclofenac potassium).The amount of drug loaded and released was determined and it was found that all the samples showed higher release of drug at higher pH values. Release of diclofenac potassium was found to be dependent on the ratio of sodium alginate/acrylic acid, EGDMA and pH of the medium. Experimental data was fitted to various model equations and corresponding parameters were calculated to study the release mechanism. The Structural, Morphological and Thermal Properties of interpenetrating hydrogels were studied by FTIR, XRD, DSC, and SEM.

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“…Another series of techniques enabling the fast characterization of thin metallic films rely on the use of focused beams of ions. Ionic probes display different beam-matter interactions with respect to electrons, resulting in different effects of the impinging beam on the surface [56][57][58][59][60][61]. When a focused ion beam (FIB) hits a surface, it can generate a series of different effects with respect to an electron beam; all these effects are a consequence of elastic or inelastic collisions between the charged particles and the atoms forming the surface.…”

Section: Focused Ion Beam Methodsmentioning

confidence: 99%

Measuring the Thickness of Metal Films: A Selection Guide to the Most Suitable Technique

Giurlani

Berretti

Lavacchi

et al. 2020

2nd Coatings and Interfaces Web Conference (CIWC-2 2020)

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The determination of thickness has a fundamental importance in all fields in which the implementation of films and coatings are required and takes a crucial role in the electroplating sector. The thickness influences many aspects of the coatings such as electrical, mechanical, corrosion protection, and even aesthetic properties. In the multitude of applications of thin layer coatings, the variability of thicknesses and materials is very high, as well as the variability of possible techniques that can be used to determine the characteristics of the layers of interest. The first distinction that can be made between these techniques is that which divides destructive techniques from non-destructive ones, in which, however, the semi- or micro-destructive techniques are immediately difficult to place. Other important parameters to consider are the cost, both for the purchase of the instrumentation and for each single analysis, the difficulties in preparing and measuring the sample, data processing, and obviously the detectable thickness ranges, the possible measurable materials, and precision and accuracy. The purpose of this work is to compare the characteristics of the various investigation methods, with a particular focus on metal film applications, so that it will be easier to choose the most suitable technique for each purpose.

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

Cited by 80 publications

References 32 publications

Fabrication and in vitro evaluation of novel pH‐sensitive poly (2‐methoxyethyl methacrylate‐co‐itaconic acid) microgels

Fabrication and in vitro evaluation of novel pH‐sensitive poly (2‐methoxyethyl methacrylate‐co‐itaconic acid) microgels

The structural, morphological and thermal properties of grafted pH-sensitive interpenetrating highly porous polymeric composites of sodium alginate/acrylic acid copolymers for controlled delivery of diclofenac potassium

Measuring the Thickness of Metal Films: A Selection Guide to the Most Suitable Technique

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