Novel pH-sensitive hydrogels for colon-specific drug delivery

Mahkam, Mehrdad

doi:10.3109/10717541003604908

Cited by 23 publications

(13 citation statements)

References 22 publications

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“…These ‘smart’ polymers [96] sense environmental stimuli [97] including changes in pH [93,97,98,99], temperature [97,100,101,102], light [103,104], pressure [105], etc. Drug release applications often use these pH-sensitive, ‘smart’ SAPs [97,106]. The goal is to release bioactive components at the correct time and/or appropriate site to precisely match physiological needs.…”

Section: Superabsorbent Polymersmentioning

confidence: 99%

“…Acid moieties will be negatively charged above the pK a value, while this is the case for basic moieties below the pK a value. Especially pH-responsive SAPs [30,31,97,106] could be extremely interesting for the envisaged application as admixture in mortar or concrete to mitigate autogenous and plastic shrinkage, to increase the freeze-thaw resistance and for the self-sealing and self-healing of cracks as will be explained in the upcoming sections.…”

Section: Superabsorbent Polymersmentioning

confidence: 99%

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Crack Mitigation in Concrete: Superabsorbent Polymers as Key to Success?

et al. 2017

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Cracking is a major concern in building applications. Cracks may arise from shrinkage, freeze/thawing and/or structural stresses, amongst others. Several solutions can be found but superabsorbent polymers (SAPs) seem to be interesting to counteract these problems. At an early age, the absorbed water by the SAPs may be used to mitigate autogenous and plastic shrinkage. The formed macro pores may increase the freeze/thaw resistance. The swelling upon water ingress may seal a crack from intruding fluids and may regain the overall water-tightness. The latter water may promote autogenous healing. The use of superabsorbent polymers is thus very interesting. This review paper summarizes the current research and gives a critical note towards the use of superabsorbent polymers in cementitious materials.

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Section: Superabsorbent Polymersmentioning

confidence: 99%

Section: Superabsorbent Polymersmentioning

confidence: 99%

Crack Mitigation in Concrete: Superabsorbent Polymers as Key to Success?

et al. 2017

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“…The use of polysaccharides in the formulation of colon-specific drug delivery carriers has gained increasing interest lately (Bajpai and Sonkusley 2002; Mahkam 2010; Mladenovska et al 2007; Prabhu et al 2008; Saboktakin et al 2011; Tavakol et al 2009). Micro- and nanoparticles prepared from some polysaccharides are attractive carriers for colon-specific drug delivery due to their favorite properties such as pH-sensitive swelling behavior, stability in the upper portion of the gastrointestinal tract, and suitable degradability by specific colonic enzymes (Assaad et al 2011; Kim et al 2012; Liu et al 2007a; Sinha and Kumria 2001; Tavakol et al 2009; Vandamme et al 2002).…”

Section: Introductionmentioning

confidence: 99%

The effect of polymer and CaCl2 concentrations on the sulfasalazine release from alginate-N,O-carboxymethyl chitosan beads

2013

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In this study, pH-sensitive blended polymeric beads were prepared by ionic gelation of mixed alginate and N,O-carboxymethyl chitosan (NOCC) solutions in aqueous media containing calcium chloride. To prepare drug-loaded beads, sulfasalazine (SA) as a model drug was added to the initial aqueous polymer solution. These beads were characterized and evaluated in vitro as potential carriers for colon-specific drug delivery. A 32 full factorial experimental design was employed to evaluate the effect of polymer and CaCl2 concentrations on swelling and drug release behavior of the beads in simulated gastrointestinal tract fluid. It was found that the rate of swelling and drug release decreased significantly with increasing polymer and CaCl2 concentrations, but polymer concentration was more effective than CaCl2 concentration. The beads prepared using 4.5% polymer concentration and 4% CaCl2 concentration retained approximately 60% of the loaded drug before approaching the simulated colonic fluid. Based on the results, the alginate-NOCC beads prepared with high polymer concentration could be potentially suitable polymeric carriers for colon-specific delivery of SA.Electronic supplementary materialThe online version of this article (doi:10.1186/2194-0517-2-10) contains supplementary material, which is available to authorized users.

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“…We initially focussed on using 2-acetoxybenzoic acid (more commonly known as Aspirin) as our pendant group. This was done for several reasons: (1) having a substituent on the ortho carbon of the aromatic ring would provide information on the steric restraints of this reaction; (2) drugbound polymers have been reported as slow release formulations, which employ the natural secretases and proteases of the body for cleavage of the drug-polymer bond and thus release of the active agent [49,50] ; and (3) the acetyl group could be selectively cleaved to form its corresponding phenol and thus a new pseudo-polyelectrolyte. [39,40] Briefly, the desired acid NHS and DCC were stirred in CHCl 3 for 3 h (Scheme 1).…”

Section: Resultsmentioning

confidence: 99%

Thermal and Spectral Analysis of Novel Amide-Tethered Polymers from Poly(allylamine)

et al. 2016

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Post-polymerization modification of poly(allylamine hydrochloride) was applied to synthesize a library of amide-linked polyelectrolytes with tethered aliphatic, aromatic, and cubyl moieties. The efficacy of amidation was determined to be between 12 and 98 %, depending on the electronics, sterics, and solubility of the amide linkage. 13 C solid-state NMR was used to further validate their structure. Thermogravimetric analysis and differential scanning calorimetry analysis indicated that none of the new polymers displayed a classic melt/freeze profile, but all displayed onset decomposition temperatures smaller than 2158C. We anticipate that the structure-property relationships observed in the resulting library of graft-modified polymers can facilitate better understanding of how to design polyelectrolytes for the construction of well-defined multilayer systems.

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Novel pH-sensitive hydrogels for colon-specific drug delivery

Abstract: To cite this article: Mehrdad Mahkam (2010) Novel pH-sensitive hydrogels for colon-specific drug delivery, Drug Delivery, 17:3,[158][159][160][161][162][163]

Cited by 23 publications

References 22 publications

Crack Mitigation in Concrete: Superabsorbent Polymers as Key to Success?

Crack Mitigation in Concrete: Superabsorbent Polymers as Key to Success?

The effect of polymer and CaCl2 concentrations on the sulfasalazine release from alginate-N,O-carboxymethyl chitosan beads

Thermal and Spectral Analysis of Novel Amide-Tethered Polymers from Poly(allylamine)

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