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Modulating physico-mechanical, swelling, and adsorption properties of fibrous nanoclay embedded anionically-modified semi-IPNs as new promising materials. Eur Polym J 2022. [DOI: 10.1016/j.eurpolymj.2022.111084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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2
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Wu Y, Xu J, Ding P, Knox WH. Modification of surface morphology of hydrogels due to subsurface femtosecond laser micromachining. APPLIED OPTICS 2021; 60:9799-9808. [PMID: 34807167 DOI: 10.1364/ao.438297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 10/04/2021] [Indexed: 06/13/2023]
Abstract
In this paper, we studied the effects of subsurface femtosecond laser micromachining on surface morphology in hydrogels. Depending on material properties and writing conditions, we found surface bumps when materials were hydrated, and trenches when they were dehydrated, which can be attributed to the localized change in water concentration. Such wavy surfaces by laser-induced refractive index change are not desirable in clinical contact lenses. Therefore, the minimization of surface bumps is necessary to ensure the user eye wearing comfort. In addition, we examined the optical effects of the surface features using interferometry and the surface morphology using profilometry. Finally, we proposed a simplified mechanical model based on localized swelling.
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Johnson EC, Gresham IJ, Prescott SW, Nelson A, Wanless EJ, Webber GB. The direction of influence of specific ion effects on a pH and temperature responsive copolymer brush is dependent on polymer charge. POLYMER 2021. [DOI: 10.1016/j.polymer.2020.123287] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Competitive specific ion effects in mixed salt solutions on a thermoresponsive polymer brush. J Colloid Interface Sci 2020; 586:292-304. [PMID: 33189318 DOI: 10.1016/j.jcis.2020.10.092] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/21/2020] [Accepted: 10/22/2020] [Indexed: 11/22/2022]
Abstract
HYPOTHESIS Grafted poly(ethylene glycol) methyl ether methacrylate (POEGMA) copolymer brushes change conformation in response to temperature ('thermoresponse'). In the presence of different ions the thermoresponse of these coatings is dramatically altered. These effects are complex and poorly understood with no all-inclusive predictive theory of specific ion effects. As natural environments are composed of mixed electrolytes, it is imperative we understand the interplay of different ions for future applications. We hypothesise anion mixtures from the same end of the Hofmeister series (same-type anions) will exhibit non-additive and competitive behaviour. EXPERIMENTS The behaviour of POEGMA brushes, synthesised via surface-initiated ARGET-ATRP, in both single and mixed aqueous electrolyte solutions was characterised with ellipsometry and neutron reflectometry as a function of temperature. FINDINGS In mixed fluoride and chloride aqueous electrolytes (salting-out ions), or mixed thiocyanate and iodide aqueous electrolytes (salting-in ions), a non-monotonic concentration-dependent influence of the two anions on the thermoresponse of the brush was observed. A new term, δ, has been defined to quantitively describe synergistic or antagonistic behaviour. This study determined the specific ion effects imparted by salting-out ions are dependent on available solvent molecules, whereas the influence of salting-in ions is dependent on the interactions of the anions and polymer chains.
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Tanc B, Orakdogen N. A phenomenological approach for structure-property relationship of polybasic cryogels based on n-alkyl methacrylate esters: Anion-specific effect on swelling kinetics and elasticity. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.02.065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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6
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Behere K, Cha B, Yoon S. Protein a resin lifetime study: Evaluation of protein a resin performance with a model-based approach in continuous capture. Prep Biochem Biotechnol 2018; 48:242-256. [DOI: 10.1080/10826068.2018.1425711] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Ketki Behere
- Department of Chemical Engineering, University of Massachusetts Lowell, Lowell, MA, USA
| | - Bumjoon Cha
- Department of Chemical Engineering, University of Massachusetts Lowell, Lowell, MA, USA
| | - Seongkyu Yoon
- Department of Chemical Engineering, University of Massachusetts Lowell, Lowell, MA, USA
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Schneider HJ. Logic-Gate Functions in Chemomechanical Materials. Chemphyschem 2017; 18:2306-2313. [DOI: 10.1002/cphc.201700186] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 06/16/2017] [Indexed: 01/04/2023]
Affiliation(s)
- Hans-Jörg Schneider
- FR Organische Chemie der; Universität des Saarlandes; 66123 Saarbrücken Germany
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Willott JD, Murdoch TJ, Humphreys BA, Edmondson S, Wanless EJ, Webber GB. Anion-specific effects on the behavior of pH-sensitive polybasic brushes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:3707-3717. [PMID: 25768282 DOI: 10.1021/acs.langmuir.5b00116] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The anion-specific solvation and conformational behavior of weakly basic poly(2-dimethylamino)ethyl methacrylate (poly(DMA)), poly(2-diethylamino)ethyl methacrylate (poly(DEA)), and poly(2-diisopropylamino)ethyl methacrylate (poly(DPA)) brushes, with correspondingly increasing inherent hydrophobicity, have been investigated using in situ ellipsometric and quartz crystal microbalance with dissipation (QCM-D) measurements. In the osmotic brush regime, as the initial low concentration of salt is increased, the brushes osmotically swell by the uptake of solvent as they become charged and the attractive hydrophobic inter- and intrachain interactions are overcome. With increased ionic strength, the brushes move into the salted brush regime where they desolvate and collapse as their electrostatic charge is screened. Here, as the brushes collapse, they transition to more uniform and rigid conformations, which dissipate less energy, than similarly solvated brushes at lower ionic strength. Significantly, in these distinct regimes brush behavior is not only ionic strength dependent but is also influenced by the nature of the added salt based on its position in the well-known Hofmeister or lyotropic series, with potassium acetate, nitrate, and thiocyanate investigated. The strongly kosmotropic acetate anions display low affinity for the hydrophobic polymers, and largely unscreened electrosteric repulsions allow the brushes to remain highly solvated at higher acetate concentrations. The mildly chaotropic nitrate and strongly chaotropic thiocyanate anions exhibit a polymer hydrophobicity-dependent affinity for the brushes. Increasing thiocyanate concentration causes the brushes to collapse at lower ionic strength than for the other two anions. This study of weak polybasic brushes demonstrates the importance of all ion, solvent, and polymer interactions.
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Affiliation(s)
- Joshua D Willott
- †Priority Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Timothy J Murdoch
- †Priority Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Ben A Humphreys
- †Priority Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Steve Edmondson
- ‡School of Materials, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Erica J Wanless
- †Priority Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Grant B Webber
- †Priority Research Centre for Advanced Particle Processing and Transport, University of Newcastle, Callaghan, NSW 2308, Australia
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Siegel RA. Stimuli sensitive polymers and self regulated drug delivery systems: a very partial review. J Control Release 2014; 190:337-51. [PMID: 24984012 PMCID: PMC4142101 DOI: 10.1016/j.jconrel.2014.06.035] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Revised: 06/18/2014] [Accepted: 06/21/2014] [Indexed: 10/25/2022]
Abstract
Since the early days of the Journal of Controlled Release, there has been considerable interest in materials that can release drug on an "on-demand" basis. So called "stimuli-responsive" and "intelligent" systems have been designed to deliver drug at various times or at various sites in the body, according to a stimulus that is either endogenous or externally applied. In the past three decades, research along these lines has taken numerous directions, and each new generation of investigators has discovered new physicochemical principles and chemical schemes by which the release properties of materials can be altered. No single review could possibly do justice to all of these approaches. In this article, some general observations are made, and a partial history of the field is presented. Both open loop and closed loop systems are discussed. Special emphasis is placed on stimuli-responsive hydrogels, and on systems that can respond repeatedly. It is argued that the most success at present and in the foreseeable future is with systems in which biosensing and actuation (i.e. drug delivery) are separated, with a human and/or cybernetic operator linking the two.
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Affiliation(s)
- Ronald A Siegel
- Department of Pharmaceutics, University of Minnesota, Minneapolis, MN 55455 USA; Department Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455 USA.
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Costa D, Miguel MG, Lindman B. Swelling properties of cross-linked DNA gels. Adv Colloid Interface Sci 2010; 158:21-31. [PMID: 19896108 DOI: 10.1016/j.cis.2009.10.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Revised: 09/26/2009] [Accepted: 10/10/2009] [Indexed: 11/18/2022]
Abstract
This work represents our contribution to the field of physical chemistry of DNA gels, and concerns the synthesis and study of novel chemically cross-linked DNA gels. The use of covalent DNA gels is a very promising way to study DNA-cosolute interactions, as well as the dynamic behaviour of DNA and cationic compacting agents, like lipids, surfactants and polycations. Manipulating DNA in new ways, like DNA networks, allows a better understanding and characterization of DNA-cosolute complexes at the molecular level, and also allows us to follow the assembly structures of these complexes. The use of responsive polymer gels for targeted delivery of toxic and/or labile drugs has, during the past few years, shown to be a promising concept. The features found in the proposed system would find applications in a broader field of gel/drug interaction, for the development of controlled release and targeted delivery devices.
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Affiliation(s)
- Diana Costa
- Physical Chemistry 1, Centre for Chemistry and Chemical Engineering, Lund University, Box 124, S-22100 Lund, Sweden.
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Swann JMG, Bras W, Topham PD, Howse JR, Ryan AJ. Effect of the Hofmeister anions upon the swelling of a self-assembled pH-responsive hydrogel. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:10191-7. [PMID: 20394380 DOI: 10.1021/la100339f] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We report the effect of a range of monovalent sodium salts on the molecular equilibrium swelling of a simple synthetic microphase separated poly(methyl methacrylate)-block-poly(2-(diethylamino)ethyl methacrylate)-block-poly(methyl methacrylate) (PMMA(88)-b-PDEA(223)-b-PMMA(88)) pH-responsive hydrogel. Sodium acetate, sodium chloride, sodium bromide, sodium iodide, sodium nitrate and sodium thiocyanate were selected for study at controlled ionic strength and pH; all salts are taken from the Hofmeister series (HS). The influence of the anions on the expansion of the hydrogel was found to follow the reverse order of the classical HS. The expansion ratio of the gel measured in solutions containing the simple sodium halide salts (NaCl, NaBr, and NaI) was found to be strongly related to parameters which describe the interaction of the ion with water; surface charge density, viscosity coefficient, and entropy of hydration. A global study which also included nonspherical ions (NaAce, NaNO(3) and NaSCN) showed the strongest correlation with the viscosity coefficient. Our results are interpreted in terms of the Collins model, where larger ions have more mobile water in the first hydration cage immediately surrounding the gel, therefore making them more adhesive to the surface of the stationary phase of the gel and ultimately reducing the level of expansion.
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Affiliation(s)
- Joshua M G Swann
- Department of Chemistry, University Of Sheffield, Sheffield, S3 7HF, UK
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Siegel RA, Gu Y, Lei M, Baldi A, Nuxoll EE, Ziaie B. Hard and soft micro- and nanofabrication: An integrated approach to hydrogel-based biosensing and drug delivery. J Control Release 2009; 141:303-13. [PMID: 20036310 DOI: 10.1016/j.jconrel.2009.12.012] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Accepted: 12/09/2009] [Indexed: 11/16/2022]
Abstract
We review efforts to produce microfabricated glucose sensors and closed-loop insulin delivery systems. These devices function due to the swelling and shrinking of glucose-sensitive microgels that are incorporated into silicon-based microdevices. The glucose response of the hydrogel is due to incorporated phenylboronic acid (PBA) side chains. It is shown that in the presence of glucose, these polymers alter their swelling properties, either by ionization or by formation of glucose-mediated reversible crosslinks. Swelling pressures impinge on microdevice structures, leading either to a change in resonant frequency of a microcircuit, or valving action. Potential areas for future development and improvement are described. Finally, an asymmetric nano-microporous membrane, which may be integrated with the glucose-sensitive devices, is described. This membrane, formed using photolithography and block polymer assembly techniques, can be functionalized to enhance its biocompatibility and solute size selectivity. The work described here features the interplay of design considerations at the supramolecular, nano, and micro scales.
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Affiliation(s)
- Ronald A Siegel
- Department of Pharmaceutics, University of Minnesota, Minneapolis, MN 55455, USA.
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Abstract
The volumetric response of polymer gels on cosolute addition depends on the interaction of the polymer with the cosolute and can be used as a simple and sensitive way of elucidating these interactions. Here we report on DNA networks, prepared by crosslinking double-stranded DNA with ethylene glycol diglycidyl ether (EGDE); these have been investigated with respect to their swelling in aqueous solution containing different additives, such as metal ions, polyamines, charged proteins, and surfactants. The deswelling on addition of metal ions occurs at lower concentrations with increasing valency of the counterion. The collapse of the gels in the presence of trivalent ions seems to follow the same kind of mechanism as the interaction in solution, but addition of these ions leads to DNA denaturation and formation of single-stranded DNA. Striking features were found in the deswelling of DNA gels by chitosan, spermine, spermidine, lysozyme, poly-l-lysine and poly-l-arginine. Chitosan is the most efficient cosolute of those investigated with respect to DNA gel collapse. The effect of the cationic surfactant tail length on the volume phase transition of DNA gels was studied as a function of surfactant concentration. Cationic surfactants effectively collapsed the gel from the critical aggregation concentration (cac), decreasing with increasing length of the hydrophobic tail. In several cases, the deswelling as a function of cosolute concentration shows a pronounced two-step behavior, which is interpreted in terms of a combination of DNA chain condensation and general osmotic deswelling. The studies included investigations on the state of the DNA chain after deswelling, on the reversibility of the deswelling as well as on the kinetics. With the exception for the trivalent lanthanide ions, it appears that the DNA chain always retains a double-helix conformation; with these metal ions, single-stranded DNA is found. The deswelling appears to be reversible as exemplified by addition of anionic surfactant subsequent to gel collapsed by cationic surfactant and addition of sodium bromide to gels collapsed by a polycation. An investigation of the kinetics shows that an increase in the surfactant tail length gives a pronouncedly slower deswelling kinetics.
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Affiliation(s)
- Diana Costa
- Physical Chemistry 1, Centre for Chemistry and Chemical Engineering, Lund University, Box 124, S-22100 Lund, Sweden.
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Gunasekaran S, Wang T, Chai C. Swelling of pH-sensitive chitosan–poly(vinyl alcohol) hydrogels. J Appl Polym Sci 2006. [DOI: 10.1002/app.24825] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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16
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Lomadze N, Schneider HJ. A chitosan-based chemomechanical polymer triggered by stacking effects with aromatic effectors including aminoacid derivatives. Tetrahedron 2005. [DOI: 10.1016/j.tet.2005.06.092] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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17
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Chiu HC, Hsiue T, Chen WY. FTIR-ATR measurements of the ionization extent of acrylic acid within copolymerized methacrylated dextran/acrylic acid networks and its relation with pH/salt concentration-induced equilibrium swelling. POLYMER 2004. [DOI: 10.1016/j.polymer.2003.12.043] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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18
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Rosa F, Bordado J, Casquilho M. Dynamic and equilibrium swelling of a sulfonic acid superabsorbent copolymer in salt solutions. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/polb.10692] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Effect of divalent cations on the volume of a maleic acid copolymer gel examined by incorporating lysozyme. Eur Polym J 2002. [DOI: 10.1016/s0014-3057(01)00283-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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20
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Chiu HC, Lin YF, Hung SH. Equilibrium Swelling of Copolymerized Acrylic Acid−Methacrylated Dextran Networks: Effects of pH and Neutral Salt. Macromolecules 2002. [DOI: 10.1021/ma0122021] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hsin-Cheng Chiu
- Department of Chemical Engineering, National Chung Hsing University, Taichung, Taiwan 402, R.O.C
| | - Yi-Fong Lin
- Department of Chemical Engineering, National Chung Hsing University, Taichung, Taiwan 402, R.O.C
| | - Shen-Hsiu Hung
- Department of Chemical Engineering, National Chung Hsing University, Taichung, Taiwan 402, R.O.C
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Gemeinhart RA, Chen J, Park H, Park K. pH-sensitivity of fast responsive superporous hydrogels. JOURNAL OF BIOMATERIALS SCIENCE. POLYMER EDITION 2001; 11:1371-80. [PMID: 11261878 DOI: 10.1163/156856200744390] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Stimuli-sensitive hydrogels (or smart hydrogels) are hydrogels that swell or shrink in response to small changes in environmental conditions in which they are placed. While the extent of swelling or shrinking may be large, the kinetics of such changes is slow, since the diffusion of water into and out of the hydrogel is a slow process. To obtain fast responses, we have prepared superporous hydrogels (SPHs) that can swell or shrink extremely fast regardless of their dimensions. The swelling and shrinking are orders of magnitude faster than expected for a nonporous hydrogel of the same dimensions. Water molecules are taken up into the SPHs by capillary forces, and this makes water uptake much faster than diffusion. The swelling ratio of the poly(acrylamide-co-acrylic acid) (p(AM-co-AA)) SPHs was dependent on the pH and ionic strength of the medium. The effect of pH was most pronounced and the effect of ionic strength was observed at all pH values. SPHs made at pH around 5 showed transient maximum swelling when exposed to pH 1.2 medium due to the transient low hydrogen ion concentration inside the swelling SPHs. The p(AM-co-AA) SPHs showed repeated swelling and shrinking by alternating the medium pH between 1.2 and 7.5, and the changes in swelling ratio was quite fast occurring in a matter of a minute. This fast sensitivity may make the stimuli sensitive hydrogels useful in many applications not previously possible. These materials can be used for applications where a single-piece hydrogel is more advantageous than hydrogel microparticulates.
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Affiliation(s)
- R A Gemeinhart
- Cornell University, School of Chemical Engineering, Ithaca, NY 14853-5201, USA
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Sheppard NF, Lesho MJ, Tucker RC, Salehi-Had S. Electrical conductivity of pH-responsive hydrogels. JOURNAL OF BIOMATERIALS SCIENCE. POLYMER EDITION 2001; 8:349-62. [PMID: 9105975 DOI: 10.1163/156856297x00146] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The electrical conductivity of pH-responsive hydrogels based on cross-linked poly(2-hydroxyethyl methacrylate-co-dimethylaminoethyl methacrylate) copolymers has been studied as a function of pH over the range 5-10, for copolymers containing up to 20 mol% of the amine-containing comonomer. The conductivities of membranes equilibrated in buffered potassium chloride solutions were determined by measuring the electrical resistance of a membrane mounted between the chambers of a modified side-by-side diffusion cell. The conductivity, expressed as a fraction of the conductivity of the buffer in which the gels were equilibrated, ranged from 1% for the gels in the collapsed state to 70% for the most highly swollen gels. The observed results are qualitatively consistent with a proposed model in which the ion concentrations in the fluid phase of the gel are described by Donnan partitioning, and the ion mobilities by the free-volume theory of Yasuda. The results suggest that conductivity measurements may provide an alternative to diffusive transport studies for characterizing moderately swollen hydrogel membranes.
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Affiliation(s)
- N F Sheppard
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
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Sun YM, Hsu SC, Lai JY. Transport properties of ionic drugs in the ammonio methacrylate copolymer membranes. Pharm Res 2001; 18:304-10. [PMID: 11442269 DOI: 10.1023/a:1011098712693] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE Ammonio methacrylate copolymer is a pharmaceutical excipient widely used as a coating material for encapsulation of pellet and tablet dosage forms. Because of the charged ammonio function groups within the polymer, ionic drugs may interact with the coating film while transporting through it. The kinetic swelling and drug permeation properties of the ammonio methacrylate copolymer membranes were studied to delineate the effect of ionic interaction between the ionic drugs and the membranes. METHODS The pH and ionic strength of the solutions and the charged properties of drugs were varied to study the effects on the transport properties through the membranes. Ambroxol was chosen as a model cationic drug and aspirin as a model anionic drug. RESULTS The degree of membrane swelling in the drug-free solution decreases as the ionic strength increases but it is irrelevant to the pH. With the presence of ionic drugs, the degree of membrane swelling is affected by the drug species as well as the pH of the solutions in addition to the effect of ionic strength. The degree of swelling for a membrane in a solution containing aspirin is higher at a lower pH and ambroxol is lower at a lower pH. Aspirin experiences a three-stage permeation and ambroxol a two-stage one. The ion-exchange reaction between the anionic carboxylic groups in aspirin and the cationic ammonio groups in the membranes results in a slow permeation stage during the transient state. The pseudo steady-state permeability for each drug follows the trend as the degree of membrane swelling in the drug media at various pH and ionic strengths. However, it is much higher for aspirin than ambroxol although the degree of membrane swelling is higher in an ambroxol solution than that in an aspirin solution. The permeability of ambroxol through the membrane is largely reduced because of the Donnan exclusion effect. CONCLUSIONS The interaction between ionic drugs with the cationic groups in the membranes affects the ionic strength of the solutions and results in a pH-dependent degree of swelling. The ionic interaction also determines the drug permeation rates as well as the transient permeation behaviors.
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Affiliation(s)
- Y M Sun
- Department of Chemical Engineering, Yuan Ze University, Chung-Li, Taoyuan, Taiwan, Republic of China.
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Eichenbaum GM, Kiser PF, Dobrynin AV, Simon SA, Needham D. Investigation of the Swelling Response and Loading of Ionic Microgels with Drugs and Proteins: The Dependence on Cross-Link Density. Macromolecules 1999. [DOI: 10.1021/ma981945s] [Citation(s) in RCA: 190] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gary M. Eichenbaum
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708-0300; Access Pharmaceuticals, Dallas, Texas 75207-2107; Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290; and Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Patrick F. Kiser
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708-0300; Access Pharmaceuticals, Dallas, Texas 75207-2107; Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290; and Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Andrey V. Dobrynin
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708-0300; Access Pharmaceuticals, Dallas, Texas 75207-2107; Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290; and Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Sidney A. Simon
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708-0300; Access Pharmaceuticals, Dallas, Texas 75207-2107; Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290; and Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710
| | - David Needham
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708-0300; Access Pharmaceuticals, Dallas, Texas 75207-2107; Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290; and Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710
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Schwarte LM, Peppas NA. Novel poly(ethylene glycol)-grafted, cationic hydrogels: preparation, characterization and diffusive properties. POLYMER 1998. [DOI: 10.1016/s0032-3861(98)00087-1] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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González-Sáiz J, Fernández-Torroba M, Pizarro C. Application of weakly basic copolymer polyacrylamide (acrylamide-CO-N,N′-dimethylaminoethyl methacrylate) gels in the recovery of citric acid. Eur Polym J 1997. [DOI: 10.1016/s0014-3057(96)00191-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Abstract
The swelling kinetics of polybasic gels consisting of copolymers of methyl methacrylate and dimethylaminoethyl methacrylate are studied in solutions at various acidic pH values, with monoacidic derivatives of acetic acid added as buffers. The effects of solution pH, as well as buffer pKa and concentration, on swelling rate are assessed. Gel swelling rate shows a nearly linear dependence on the concentration of nonionized buffer in the solution, as determined by the Henderson-Hasselbach equation. This result is explained in terms of the increased availability of protons that are carried by the nonionized buffer to bare amines on the gel. In fact, the so-called pH sensitivity of these gels, under these conditions, can be attributed mainly to the effect of pH on the nonionized buffer concentration. A practical consequence is that these gels may not reliably mediate pH-sensitive swelling-controlled release in oral applications, since the levels of buffer acids in the stomach (where swelling and release are expected to occur) generally cannot be controlled. However, the gels may be useful as mediators of pH-triggered release when precise rate control is of secondary importance.
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Affiliation(s)
- R A Siegel
- Department of Pharmacy, School of Pharmacy, University of California, San Francisco 94143-0446
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