Colloidal microgels as transdermal delivery systems

Lopez, Vanessa Castro; Raghavan, Srini; Snowden, Martin J.

doi:10.1016/j.reactfunctpolym.2003.12.004

Cited by 49 publications

(30 citation statements)

References 34 publications

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“…Many of these polymers are stimuli responsive, responding to pH changes, temperature, and ionic strength [1]. These capacities make them excellent options for diverse applications such as sensors, drug delivery, and pharmaceutical uses [2][3][4]. Linear polymers may also be able to respond to stimuli.…”

Section: Introductionmentioning

confidence: 99%

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Rheology of polyacrylate systems depends strongly on architecture

Alves

Lindman

Klotz³

et al. 2015

Colloid Polym Sci

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The relation between polymer architecture of polyacrylic acid (PAA) derivatives and the rheological properties is examined in aqueous systems with and without surfactant. The capability of PAA and its derivates to swell above a critical pH, due to the ionization of the acrylic acid groups, gives completely different properties at low and high pH, both for cross-linked and linear polymers.Four different PAA derivatives of different nature were studied. Two versions are chemically cross-linked and two are linear. In two versions, there exist both long and short hydrophobic groups, while in the other two versions, only short hydrophobic groups are present. The role of chemical cross-linking and of long hydrophobic groups, giving a physical cross-linking, is emphasized. The pH-dependent sol-gel transition observed above a certain polymer concentration, as well as the magnitude of the shear viscosity, is strongly affected by the modification of the polymer architecture. Chemical cross-linking has a very large effect on the sol-gel transition induced by increasing the pH, while physical cross-linking, due to the presence of long hydrophobic groups, plays a more moderate role and is more pronounced in the linear PAA derivatives.It was also found that the onset of polymer swelling occurs at a higher pH for the cross-linked versions of the polymers and for the polymers with long hydrophobic groups. The swelling capacity of the PAA derivatives at low pH, when associated with anionic surfactant, was also explored. The results show a similar rheological behavior of the solutions when pH is increased above 6.5 as when anionic surfactant is added above a certain concentration.

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Section: Introductionmentioning

confidence: 99%

“…Among the main applications are drug delivery [3,5,7], sensing [8,9], and separation and purification technologies [10]. In the case of pH sensitive polymers, a number of recent studies reveal that these systems are particularly useful as potential drug carriers for oral delivery [11][12][13][14] and also as stabilizers of solutions [15].…”

Section: Introductionmentioning

confidence: 99%

Rheology of polyacrylate systems depends strongly on architecture

Alves

Lindman

Klotz³

et al. 2015

Colloid Polym Sci

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“…In an aqueous environment, individual NIPAAm chains show a hydrophilic behaviour with an expanded coil structure below the LCST, but as the temperature increases above 32 ºC, hydrophobic isopropyl groups are exposed undergoing a reversible conformational change to form compact globule shapes. Because of the thermoresponsive properties of NIPAAmbased gels, they have been extensively used and investigated for different applications such as transdermal drug delivery systems, [9] smart surfaces and coatings for cell tissue engineering [10] and also as valves in microfluidic devices, [11] among others.…”

Section: Introductionmentioning

confidence: 99%

Modular microfluidic valve structures based on reversible thermoresponsive ionogel actuators

et al. 2014

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This paper reports for the first time the use of a crosslinked poly(Nisopropylacrylamide) ionogel encapsulating the ionic liquid 1-Ethyl-3-methylimidazolium ethyl sulphate as a thermoresponsive and modular microfluidic valve. The ionogel presents superior actuation behaviour over its equivalent hydrogel.The ionogel swelling and shrinking mechanisms and kinetics are investigated as well as the performance of the ionogel when integrated as a valve in a microfluidic device.The modular microfluidic valve demonstrates fully reversible on-off behaviour without failure for up to eight actuation cycles and a pressure resistance of 1100 mbar.

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“…Moreover, because of their intrinsic biocompatibility and flexibility they are becoming an increasingly common motif in drug delivery, for instance, in transdermal applications, as well as in microfluidic production and processing [1,2]. In each of these settings, vesicles frequently encounter narrow passages: geometric constrictions that force them to change shape dramatically in order to pass.…”

Section: Introductionmentioning

confidence: 99%

Forced transport of deformable containers through narrow constrictions

et al. 2014

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We study, numerically and analytically, the forced transport of deformable containers through a narrow constriction. Our central aim is to quantify the competition between the constriction geometry and the active forcing, regulating whether and at which speed a container may pass through the constriction and under what conditions it gets stuck. We focus, in particular, on the interrelation between the force that propels the container and the radius of the channel, as these are the external variables that may be directly controlled in both artificial and physiological settings. We present Lattice-Boltzmann simulations that elucidate in detail the various phases of translocation, and present simplified analytical models that treat two limiting types of these membrane containers: deformational energy dominated by the bending or stretching contribution. In either case we find excellent agreement with the full simulations, and our results reveal that not only the radius but also the length of the constriction determines whether or not the container will pass.Comment: 9 pages, 4 figure

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Colloidal microgels as transdermal delivery systems

Cited by 49 publications

References 34 publications

Rheology of polyacrylate systems depends strongly on architecture

Rheology of polyacrylate systems depends strongly on architecture

Modular microfluidic valve structures based on reversible thermoresponsive ionogel actuators

Forced transport of deformable containers through narrow constrictions

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