- Email: [email protected]
Sustained release hydrogels by in situ polymerized polyalkylcyanoacrylate coating
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Abstracts / Journal of Controlled Release 172 (2013) e14–e97
measurement, optical profilometry, scanning electron microscopy, and atomic force microscopy (AFM). The lowest sample roughness (Rq = 9 nm of a 5 × 5 μm2 AFM scan), i.e., the most homogeneous coating was detected for poly(n-butyl-2-cyanoacrylate) [PBCA]. At the same time, a substantially sustained drug release from the PBCA coated hydrogel was detected. Overall, in situ polymerized PACA coatings of hydrogels may be a general strategy to sustain drug release and, since selectively initiated by water at the hydrogel surface, may also be applicable to more complex shaped hydrogel carriers from various matrix polymers.
Scheme 1. The size itself of nanoparticles determined the pathway of entry.
Keywords: Nanoparticles, Size separate, Centrifugation, Uptake Acknowledgments This work was supported by the High-tech Research and Development Plan (863 plan) of China (2012AA092103). References [1] M. Gaumet, R. Gurny, F. Delie, Localization and quantification of biodegradable particles in an intestinal cell model: the influence of particle size, Eur. J. Pharm. Sci. 36 (2009) 465–473. [2] J. Rejman, V. Oberle, I.S. Zuhorn, D. Hoekstra, Size-dependent internalization of particles via the pathways of clathrin and caveolae-mediated endocytosis, Biochem. J. 377 (2004) 159–169. [3] M.A. Jepson, N.L. Simmons, D.T. O'Hagan, B.H. Hirst, Comparison of poly(DLlactide-co-glycolide) and polystyrene microsphere targeting to intestinal M cells, J. Drug Target. 1 (1993) 245–249.
Scheme 1. Scheme of hydrogel coating by PACA serving as a diffusion barrier to sustain drug release.
Keywords: Coated hydrogel, Poly(alkyl-2-cyanoacrylate), In situ polymerization, Diclofenac, Alginate
doi:10.1016/j.jconrel.2013.08.051 References Sustained release hydrogels by in situ polymerized polyalkylcyanoacrylate coating Christian Wischke, Cornelius Schneider, Axel T. Neffe, Andreas Lendlein Center for Biomaterial Development and Berlin-Brandenburg Centre for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Kantstr. 55, Teltow 14513, Germany E-mail address: [email protected] (C. Wischke). Polymeric hydrogels are ideal carriers for sensitive hydrophilic bioactive molecules such as proteins, but have also been extensively explored for the delivery of small molecule drugs. However, due to their high water content and the diffusivity of hydrophilic drugs, a rapid release over a few hours is a common observation for such systems [1]. A prolonged drug release may be possible by establishing physical interactions or covalent bonds between the drug and the hydrogel matrix [2], but this requires a specific design of the matrix polymer possibly limiting its applicability only to a single drug. Therefore, alternative, more widely employable approaches are of interest for sustained release via hydrogels. In this study, alginate was selected as hydrogel matrix (30 mg·ml− 1), filled into a mold, and physically crosslinked with calcium ions to films in the absence or presence of diclofenac sodium (10 mg·ml− 1) as a hydrophilic model drug. In order to reduce the release rates, a polymeric coating of the hydrogel matrix should be established as a rate limiting diffusion barrier. The employed strategy involved an in situ anionic polymerization of poly(alkyl-2-cyanoacrylate) [PACA] exclusively initiated on the hydrogel surface with subsequent PACA deposition. It was further postulated that the diffusion-driven drug release may be controlled by the type of side chain of PACA. A series of PACAs with increasing side chain hydrophobicities was employed and the structure of the coating was characterized by contact angle
[1] K. Moebus, J. Siepmann, R. Bodmeier, Novel preparation techniques for alginate– poloxamer microparticles controlling protein release on mucosal surfaces, Eur. J. Pharm. Sci. 45 (2012) 358–366. [2] N. Bhattarai, J. Gunn, M.Q. Zhang, Chitosan-based hydrogels for controlled, localized drug delivery, Adv. Drug Deliv. Rev. 62 (2010) 83–99.
doi:10.1016/j.jconrel.2013.08.052
pH-responsive mesoporous silica nanocarriers for anticancer drug delivery Xiaojun Zhou, Wei Feng, Kexin Qiu, Weizhong Wang, Chuanglong He⁎ College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, China E-mail address: [email protected] (C. He). Increasing attention has been given to the synthesis and functionalization of mesoporous silica nanoparticles (MSNs) for drug release applications. Synthetic polymers of poly(allylamine hydrochloride) (PAH) and sodium poly(styrene sulfonate) (PSS) have been used as pH-responsive polyelectrolytes in drug delivery systems (DDS) [1]. Here, we prepared a type of pH-responsive DDS based on MSNs coated with PAH/PSS via the layer by layer self-assembly method, and doxorubicin hydrochloride (DOX) was loaded as a model anticancer drug. The morphology and release profiles of DOX from these hybrid composites were investigated. Fig. 1A) a, b shows the TEM morphology of MSNs and PAH/PSS-MSNs coated with eight bilayers of PAH/PSS. The ordered mesoporous nature of the particles can be observed in Fig. 1A) a. After coating with PAH/PSS, these hybrid nanoparticles become larger in particle size, and the thickness of the bilayers on the outer surface of MSNs was around 10 nm (Fig. 1A) b). Moreover, the N2 adsorption– desorption isotherms and pore size distributions also confirm the successful coating of polyelectrolytes on MSNs (Fig. 1B)). The FTIR
Abstracts / Journal of Controlled Release 172 (2013) e14–e97
measurement, optical profilometry, scanning electron microscopy, and atomic force microscopy (AFM). The lowest sample roughness (Rq = 9 nm of a 5 × 5 μm2 AFM scan), i.e., the most homogeneous coating was detected for poly(n-butyl-2-cyanoacrylate) [PBCA]. At the same time, a substantially sustained drug release from the PBCA coated hydrogel was detected. Overall, in situ polymerized PACA coatings of hydrogels may be a general strategy to sustain drug release and, since selectively initiated by water at the hydrogel surface, may also be applicable to more complex shaped hydrogel carriers from various matrix polymers.
Scheme 1. The size itself of nanoparticles determined the pathway of entry.
Keywords: Nanoparticles, Size separate, Centrifugation, Uptake Acknowledgments This work was supported by the High-tech Research and Development Plan (863 plan) of China (2012AA092103). References [1] M. Gaumet, R. Gurny, F. Delie, Localization and quantification of biodegradable particles in an intestinal cell model: the influence of particle size, Eur. J. Pharm. Sci. 36 (2009) 465–473. [2] J. Rejman, V. Oberle, I.S. Zuhorn, D. Hoekstra, Size-dependent internalization of particles via the pathways of clathrin and caveolae-mediated endocytosis, Biochem. J. 377 (2004) 159–169. [3] M.A. Jepson, N.L. Simmons, D.T. O'Hagan, B.H. Hirst, Comparison of poly(DLlactide-co-glycolide) and polystyrene microsphere targeting to intestinal M cells, J. Drug Target. 1 (1993) 245–249.
Scheme 1. Scheme of hydrogel coating by PACA serving as a diffusion barrier to sustain drug release.
Keywords: Coated hydrogel, Poly(alkyl-2-cyanoacrylate), In situ polymerization, Diclofenac, Alginate
doi:10.1016/j.jconrel.2013.08.051 References Sustained release hydrogels by in situ polymerized polyalkylcyanoacrylate coating Christian Wischke, Cornelius Schneider, Axel T. Neffe, Andreas Lendlein Center for Biomaterial Development and Berlin-Brandenburg Centre for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Kantstr. 55, Teltow 14513, Germany E-mail address: [email protected] (C. Wischke). Polymeric hydrogels are ideal carriers for sensitive hydrophilic bioactive molecules such as proteins, but have also been extensively explored for the delivery of small molecule drugs. However, due to their high water content and the diffusivity of hydrophilic drugs, a rapid release over a few hours is a common observation for such systems [1]. A prolonged drug release may be possible by establishing physical interactions or covalent bonds between the drug and the hydrogel matrix [2], but this requires a specific design of the matrix polymer possibly limiting its applicability only to a single drug. Therefore, alternative, more widely employable approaches are of interest for sustained release via hydrogels. In this study, alginate was selected as hydrogel matrix (30 mg·ml− 1), filled into a mold, and physically crosslinked with calcium ions to films in the absence or presence of diclofenac sodium (10 mg·ml− 1) as a hydrophilic model drug. In order to reduce the release rates, a polymeric coating of the hydrogel matrix should be established as a rate limiting diffusion barrier. The employed strategy involved an in situ anionic polymerization of poly(alkyl-2-cyanoacrylate) [PACA] exclusively initiated on the hydrogel surface with subsequent PACA deposition. It was further postulated that the diffusion-driven drug release may be controlled by the type of side chain of PACA. A series of PACAs with increasing side chain hydrophobicities was employed and the structure of the coating was characterized by contact angle
[1] K. Moebus, J. Siepmann, R. Bodmeier, Novel preparation techniques for alginate– poloxamer microparticles controlling protein release on mucosal surfaces, Eur. J. Pharm. Sci. 45 (2012) 358–366. [2] N. Bhattarai, J. Gunn, M.Q. Zhang, Chitosan-based hydrogels for controlled, localized drug delivery, Adv. Drug Deliv. Rev. 62 (2010) 83–99.
doi:10.1016/j.jconrel.2013.08.052
pH-responsive mesoporous silica nanocarriers for anticancer drug delivery Xiaojun Zhou, Wei Feng, Kexin Qiu, Weizhong Wang, Chuanglong He⁎ College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, China E-mail address: [email protected] (C. He). Increasing attention has been given to the synthesis and functionalization of mesoporous silica nanoparticles (MSNs) for drug release applications. Synthetic polymers of poly(allylamine hydrochloride) (PAH) and sodium poly(styrene sulfonate) (PSS) have been used as pH-responsive polyelectrolytes in drug delivery systems (DDS) [1]. Here, we prepared a type of pH-responsive DDS based on MSNs coated with PAH/PSS via the layer by layer self-assembly method, and doxorubicin hydrochloride (DOX) was loaded as a model anticancer drug. The morphology and release profiles of DOX from these hybrid composites were investigated. Fig. 1A) a, b shows the TEM morphology of MSNs and PAH/PSS-MSNs coated with eight bilayers of PAH/PSS. The ordered mesoporous nature of the particles can be observed in Fig. 1A) a. After coating with PAH/PSS, these hybrid nanoparticles become larger in particle size, and the thickness of the bilayers on the outer surface of MSNs was around 10 nm (Fig. 1A) b). Moreover, the N2 adsorption– desorption isotherms and pore size distributions also confirm the successful coating of polyelectrolytes on MSNs (Fig. 1B)). The FTIR