Structure and swelling of poly(acrylic acid) hydrogels: effect of pH, ionic strength, and dilution on the crosslinked polymer structure

Elliott, J. P.

doi:10.1016/s0032-3861(03)01191-1

Cited by 108 publications

(135 citation statements)

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“…This implied that the release of GCV was case II or zeroorder transport. For systems exhibiting case II transport, the dominant mechanism for drug transport is due to polymer matrix relaxation as reported previously (9,35). The higher and more constant release observed for the GCVloaded lyomatrix was due to the interconnected highly porous structure compared to the tablet formulation as confirmed by the SEM and AFM results.…”

Section: Analysis Of Drug Release Kineticssupporting

confidence: 77%

“…Polyacrylic acid (PAA) possesses many desirable properties including the ability to exist as a liquid at pH≤5 and as a gel at pH≥7 (9). The permeation of cations into the gelled polymer converts the gel back to a liquid (10).…”

Section: Introductionmentioning

confidence: 99%

“…As sensitivity to pH is required for optimal intestinal drug targeting, many polymers have been investigated (10)(11)(12)(13). Such polymers demonstrated optimal swelling behavior at neutral pH with low swelling ratios at acid pH (9). Furthermore, the water sorption potency of the polymers can be adjusted and enhanced via introducing interconnecting pores (14)(15)(16).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Intestinal Targeting of Ganciclovir Release Employing a Novel HEC-PAA Blended Lyomatrix

et al. 2015

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Abstract. A hydroxyethylcellulose-poly(acrylic acid) (HEC-PAA) lyomatrix was developed for ganciclovir (GCV) intestine targeting to overcome its undesirable degradation in the stomach. GCV was encapsulated within the HEC-PAA lyomatrix prepared by lyophilization. Conventional tablets were also prepared with identical GCV concentrations in order to compare the GCV release behavior from the lyomatrix and tablets. GCV incorporation (75.12%) was confirmed using FTIR, DSC, and TGA. The effect of GCV loading on the microstructure properties of the lyomatrix was evaluated by SEM, AFM, and BET surface area measurements. The in vitro drug release study showed steady and rapid release profiles from the GCV-loaded lyomatrix compared with the tablet formulation at identical pH values. Minimum GCV release was observed at acidic pH (≤40%) and maximum release occurred at intestinal pH values (≥90%) proving the intestinal targeting ability of the lyomatrix. Kinetic modeling revealed that the GCV-loaded lyomatrix exhibited zero-order release kinetics (n=1), while the tablets were best described via the Peppas model. Textural analysis highlighted enhanced matrix resilience and rigidity gradient (12.5%, 20 Pa) for the GCV-loaded lyomatrix compared to the pure (7%, 9.5 Pa) HEC-PAA lyomatrix. Bench-top MRI imaging was used to confirm the mechanism of GCV release behavior by monitoring the swelling and erosion rates. The swelling and erosion rate of the tablets was not sufficient to achieve rapid zero-order GCV release as with the lyomatrix. These combined results suggest that the HEC-PAA lyomatrix may be suitable for GCV intestinal targeting after oral administration.

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Section: Analysis Of Drug Release Kineticssupporting

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Intestinal Targeting of Ganciclovir Release Employing a Novel HEC-PAA Blended Lyomatrix

et al. 2015

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“…This behaviour at acidic solution makes the copolymer system to be highly pH-responsive and consequently it may be a suitable candidate for designing controlled drug delivery systems. Similar results have been reported by other hydrogel systems [25,26].…”

Section: Deswelling Kineticssupporting

confidence: 92%

Deswelling of Hydrogels in Aqueous and Polyethylene Glycol Solutions. A New Approach for Drug Delivery Application

Angar

Aliouche

2017

Period. Polytech. Chem. Eng.

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“…They can be used in pharmacy as drug delivery systems, in hygiene products as absorbents, in biotech as ion-exchange resins, in engineering as self repairing seals, among other applications [1][2][3]. Poly(acrylic acid) (PAA) is commonly used to form hydrogels because acrylic acid is cheap and easy to polymerize into high molecular weight compounds and because of its ability to absorb many times its own weight of water [1,4]. The performance of hydrogels in different applications is dependent on the visco-elastic properties, the absorbance capacity and the swelling kinetics of the gels.…”

Section: Introductionmentioning

confidence: 99%

Effect of calcium neutralization on elastic and swelling properties of crosslinked poly(acrylic acid) - correlation to inhomogeneities and phase behaviour

et al. 2009

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Abstract:Crosslinked hydrogels of poly(acrylic acid) neutralized with calcium hydroxide were synthesized using free radical co-polymerization. The effects of the amount added calcium on the elastic modulus and swelling properties of the gels and the correlation to phase behaviour and structural changes within the gels were studied using texture analysis, gravimetric analysis, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis and atomic force microscopy (AFM). It was found that the elastic modulus decreased nonlinearly with increasing amount of added calcium and that the swelling's dependence on the amount of added calcium was complicated. The maximum swelling increased with increasing amount of added calcium until a critical calcium content was reached, upon which the gels phase separated, with a strong decrease in swelling as a result. The changes in properties are explained by the fact that calcium affects the structure of the polymer network during synthesis and by the phase behaviour of the gels. Changes in the gel structure with the addition of calcium were detected with AFM. Furthermore, AFM revealed different phases on the nanometre scale for the sample with a calcium content around which phase separation is macroscopically observed. Finally, it was shown that the sulphur from the initiator potassium persulfate formed crystal like regions with high sulphur and calcium content upon drying of the hydrogels.

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Structure and swelling of poly(acrylic acid) hydrogels: effect of pH, ionic strength, and dilution on the crosslinked polymer structure

Cited by 108 publications

References 0 publications

Intestinal Targeting of Ganciclovir Release Employing a Novel HEC-PAA Blended Lyomatrix

Intestinal Targeting of Ganciclovir Release Employing a Novel HEC-PAA Blended Lyomatrix

Deswelling of Hydrogels in Aqueous and Polyethylene Glycol Solutions. A New Approach for Drug Delivery Application

Effect of calcium neutralization on elastic and swelling properties of crosslinked poly(acrylic acid) - correlation to inhomogeneities and phase behaviour

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