Lateral and Rotational Mobility of Some Drug Molecules in a Poly(Ethylene Glycol) Diacrylate Hydrogel and the Effect of Drug-Cyclodextrin Complexation

Tomić, Katarina; Veeman, W. S.; Boerakker, Mark J.; Litvinov, V. M.; Dias, Aylvin A.

doi:10.1002/jps.21251

Cited by 19 publications

(23 citation statements)

References 21 publications

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“…These chains are elastically inactive but can hinder drug diffusion through a viscous drag, favoured by weak van der Walls interactions with drug molecules. Tomic and coworkers [49] found that also very weak van der Waals interactions are sufficient to hinder drug molecule movements in the presence of a polymeric network with mesh size much larger than the drug molecular size. In addition, the rheological analysis suggests that the number of elastically inactive chains is high, as proved by the importance of the viscous contribution to the GGb mechanical behavior (see Figure 5b).…”

Section: Resultsmentioning

confidence: 99%

Guar gum/borax hydrogel: Rheological, low field NMR and release characterizations

Coviello¹,

Matricardi²,

Alhaique³

et al. 2013

Express Polym. Lett.

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Abstract. Guar gum (GG) and Guar gum/borax (GGb) hydrogels are studied by means of rheology, Low Field Nuclear Magnetic Resonance (LF NMR) and model drug release tests. These three approaches are used to estimate the mesh size (!) of the polymeric network. A comparison with similar Scleroglucan systems is carried out. In the case of GGb, the rheological and Low Field NMR estimations of ! lead to comparable results, while the drug release approach seems to underestimate !. Such discrepancy is attributed to the viscous effect of some polymeric chains that, although bound to the network to one end, can freely fluctuate among meshes. The viscous drag exerted by these chains slows down drug diffusion through the polymeric network. A proof for this hypothesis is given by the case of Scleroglucan gel, where the viscous contribution is not so significant and a good agreement between the rheological and release test approaches was found. Vol.7, No.9 (2013) 733-746 Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2013.71 * Corresponding author, e-mail: mariog@dicamp.univ.trieste.it © BME-PT mation in aqueous solution and a single coiled disordered conformation in methylsulphoxide or at high pH values (NaOH$>0.2 M) [10,11]. Due to its peculiar properties, SCLG was extensively used for various commercial applications (secondary oil recovery, ceramic glazes, food, paints, cosmetics, etc.) [12] and it was also investigated for modified/ sustained release formulations and ophthalmic preparations [13]. Actually, it is well known that borax is an efficient crosslinker for polymers bearing hydroxyl groups but the type of formed linkages is still debated and so far two main models have been proposed. The most popular one implies the existence of pure chemical crosslinks between the polymeric chains and borax [14], and it was proposed for the GG/ borax interactions. According to the other model, the borax ions hold together the polymeric chains by means of mixed physical/chemical linkages. This model was firstly proposed for poly-(vinylalcohol) [15] and it was recently suggested also for SCLG [16,17]. The considerable effort devoted to the study of polymer-ion complexes is due to the wide range of application of these systems. In particular, the complex between GG and borate was previously studied by several authors [18,19] that investigated the effect of polymer and borate concentration, temperature, environmental pH conditions, and GG molecular weight on the peculiar rheological properties detected by the frequency dependence of relaxation spectra. Furthermore, a detailed study of the crosslinking reaction of borate ion with polyhydroxy polymers was carried out by means of 11 Keywords: polymer gels, rheology, low field NMR, transport processes, mesh-size eXPRESS Polymer Letters

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Section: Resultsmentioning

confidence: 99%

Guar gum/borax hydrogel: Rheological, low field NMR and release characterizations

Coviello¹,

Matricardi²,

Alhaique³

et al. 2013

Express Polym. Lett.

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“…Such hydrogels can be formed in situ , and under proper conditions they can also entrap small and large molecules, or even cells. Diffusion in reversible hydrogels can be controlled by appropriately tuning external environmental conditions 14, 15. For drug delivery applications, in situ formation and controlled diffusivity of molecules in reversible hydrogels provide a dual benefit.…”

Section: Introductionmentioning

confidence: 99%

Macromolecular Diffusion in Self-Assembling Biodegradable Thermosensitive Hydrogels

et al. 2009

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Hydrogel formation triggered by a change in temperature is an attractive mechanism for in situ gelling biomaterials for pharmaceutical applications such as the delivery of therapeutic proteins. In this study, hydrogels were prepared from ABA triblock polymers having thermosensitive poly(N-(2-hydroxypropyl) methacrylamide lactate) flanking A-blocks and hydrophilic poly(ethylene glycol) B-blocks. Polymers with fixed length A blocks (~22 kDA) but differing PEG-midblock lengths (2, 4 and 10 kDa) were synthesized and dissolved in water with dilute fluorescein isothiocyanate (FITC)-labeled dextrans (70 and 500 kDA). Hydrogels encapsulating the dextrans were formed by raising the temperature. Fluorescence recovery after photobleaching (FRAP) studies showed that diffusion coefficients and mobile fractions of the dextran dyes decreased upon elevating temperatures above 25 °C. Confocal laser scanning microscopy and cryo-SEM demonstrated that hydrogel structure depended on PEG block length. Phase separation into polymer-rich and water-rich domains occurred to a larger extent for polymers with small PEG blocks compared to polymers with a larger PEG block. By changing the PEG block length and thereby the hydrogel structure, mobility of FITC-dextran could be tailored. At physiological pH the hydrogels degraded over time by ester hydrolysis, resulting in increased mobility of the encapsulated dye. Since diffusion can be controlled according to polymer design and concentration, plus temperature, these biocompatible hydrogels are attractive as potential in situ gelling biodegradable materials for macromolecular drug delivery.

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“…In the research of Weiner et al, 23 PEGDA (MW575 and MW700) as a reactive additive in the photocrosslinked polyanhydride (PA) networks improved the system properties for a bone replacement. Additionally, PEGDA-based products have also been successfully used for injectable drug delivery systems [24][25][26] and cell culture mediums. [27][28][29] Although the composite systems of PEGDA and other materials have been extensively developed and used, few studies directly addressed the effects of PEGDA molecular weights on the properties of hygrogels with same polymer concentration.…”

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confidence: 99%

Controllable properties and microstructure of hydrogels based on crosslinked poly(ethylene glycol) diacrylates with different molecular weights

Zhang

Wang

Song

et al. 2011

J of Applied Polymer Sci

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This work describes a comprehensive study of hydrogels based on polyethylene glycol diacrylates (PEGDAs) with the molecular weight (MW) range of 400-2000. The blends of low-and high-molecular weight PEGDA macromers with different ratios were photopolymerized under visible light irradiation, using a blue light sensitive photoinitiator Irgacure819, at the total polymer concentration of 60 wt %. Swelling ratios, wetting property, elastic moduli, transparency, and the microstructure of the resulting hydrogels were investigated. Among them, equilibrium water contents, hydrophilicity, and mesh size of the hydrogels increased while the elastic moduli decreased when increased the PEGDA MW or the content of higher MW PEGDA in the blends. Most of the hydrogels possessed excellent transparency in visible region. The viability of L929 cells on the surface of hydrogel was also estimated. All the selected hydrogels exhibited a relatively high proliferation rate, which demonstrated this hydrogel system with photoinitiator Irgacure819 had good biocompatibility. These results show the properties of PEGDA hydrogel could be easily adjusted by varying PEGDA MW or the ratios of low-and high-MW macromers in the composites. It could be helpful for the design of proper PEGDA hydrogels in the applications as tissue engineering or drug delivery system.

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Lateral and Rotational Mobility of Some Drug Molecules in a Poly(Ethylene Glycol) Diacrylate Hydrogel and the Effect of Drug-Cyclodextrin Complexation

Cited by 19 publications

References 21 publications

Guar gum/borax hydrogel: Rheological, low field NMR and release characterizations

Guar gum/borax hydrogel: Rheological, low field NMR and release characterizations

Macromolecular Diffusion in Self-Assembling Biodegradable Thermosensitive Hydrogels

Controllable properties and microstructure of hydrogels based on crosslinked poly(ethylene glycol) diacrylates with different molecular weights

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