Coating alginate microspheres with a serum albumin-alginate membrane: application to the encapsulation of a peptide

Hurteaux, Reynald; Edwards-Lévy, Florence; Laurent-Maquin, Dominique; Lévy, M.-C.

doi:10.1016/j.ejps.2004.10.010

Cited by 49 publications

(25 citation statements)

References 19 publications

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“…Larger size delivery systems may also offer larger drug loading capacities when compared to systems with smaller sizes. Among many different delivery systems, coating microspheres is a common method used to control drug release, since polymer networks of coatings can provide a diffusion barrier to retard the otherwise rapid drug release [2,3]. This is also a beneficial approach since specific ligands can be attached to the surface via the coating to target the delivery system [4].…”

Section: Introductionmentioning

confidence: 99%

Silk coatings on PLGA and alginate microspheres for protein delivery

Wang¹,

Wenk²,

Hu³

et al. 2007

Biomaterials

180

114

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Bombyx mori silk fibroin self-assembles on surfaces to form ultrathin nanoscale coatings based on our prior studies using layer-by-layer deposition techniques driven by hydrophobic interactions between silk fibroin protein molecules. In the present study, polylactic-co-glycolic acid (PLGA) and alginate microspheres were used as substrates and coated with silk fibroin. The coatings were visualized by confocal laser scanning microscopy using fluorescein-labeled silk fibroin. On PLGA microspheres the coating was ~1 μm and discontinuous, reflecting the porous surface of these microspheres determined by SEM. In contrast, on alginate microspheres the coating was ~10 μm thick and continuous. The silk fibroin penetrated into the alginate gel matrix. The silk coating on the PLGA microspheres delayed PLGA degradation. The silk coating on the alginate microspheres survived ethylenediamine tetraacetic acid (EDTA) treatment used to remove the Ca +2 -cross-links in the alginate gels to solubilize the alginate. This suggests that alginate microspheres can be used as templates to form silk microcapsules. Horseradish peroxidase (HRP) and tetramethylrhodamineconjugated bovine serum albumin (BSA) as model protein drugs were encapsulated in the PLGA and alginate microspheres with and without the silk fibroin coatings. Drug release was significantly retarded by the silk coatings when compared to uncoated microsphere controls, and was retarded further by methanol-treated silk coating when compared to silk water-based coatings on alginate microspheres. Silk coatings on PLGA and alginate microspheres provide mechanically stable shells as well as a diffusion barrier to the encapsulated protein drugs. This coating technique has potential for biosensor and drug delivery applications due to the aqueous process employed, the ability to control coating thickness and crystalline content, and the biocompatibility of the silk fibroin protein used in the process.

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Section: Introductionmentioning

confidence: 99%

Silk coatings on PLGA and alginate microspheres for protein delivery

Wang¹,

Wenk²,

Hu³

et al. 2007

Biomaterials

180

114

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“…O hidrogel de alginato-Ca é utilizado para aplicações endovasculares, no transplante de células, imobilização de enzimas, entre outras [5,6] . O grande interesse de muitos pesquisadores da área biomédica nos hidrogéis de alginato-Ca deve-se a sua comprovada biocompatibilidade, hidrofilicidade e baixo custo [7,8] . Outro polímero potencialmente viável para aplicações na área de biomateriais, é o PNIPAAm [9][10][11][12] .…”

Section: Determinação Da Morfologia Dos Hidrogéisunclassified

Morfologia de hidrogéis-ipn termo-sensíveis e ph-responsivos para aplicação como biomaterial na cultura de células

Rubira¹,

Muniz²,

Guilherme

et al. 2009

Polímeros

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Resumo:No presente trabalho, foram sintetizados hidrogéis com ambas as propriedades, termo-sensíveis e pH-responsivos, pela formação de redes de alginato de cálcio (alginato-Ca) dentro de redes de poli(N-Isopropil Acrilamida) (PNIPAAm), resultando em um sistema IPN (sistema de redes poliméricas interpenetradas). Através das análises por microscopia de varredura eletrônica (MEV) e ensaios de intumescimento foi possível observar que os hidrogéis IPN exibiram forte contração quando aquecidos acima da LCST (temperatura critica inferior de solubilização) da PNIPAAm, ou seja, acima de temperaturas de 30-35 °C. Observou-se ainda que devido à contração do hidrogel, houve uma diminuição significativa nos tamanhos de poros os quais foram observados pelas micrografias. Observou-se também que no intervalo de pH estudado os hidrogéis de IPN sofreram significativa variação da estrutura com a variação desse parâmetro. Tal efeito foi atribuído à presença de grupos químicos carregados com alginato, os quais possuem carga elétrica negativa. Os resultados indicaram que o hidrogel formado por alginato-Ca e PNIPAAm possuíram características especificas após variação de pH e temperatura, e que tais características são derivadas dos compostos individuais envolvidos na síntese. Nesse caso, as propriedades de alginato-Ca e PNIPAAm livres foram preservadas dentro do hidrogel. Tal hidrogel ficou mais resistente à aplicação de uma tensão de compressão. Como conclusão, observou-se que os hidrogéis apresentaram morfologia característica para variações controladas de pH e temperatura, podendo ser eficientemente aplicados como biomaterial na cultura de células. Palavras-chave: Hidrogel, termo-sensível, pH-responsivo, morfologia, cultura de células. Morphology of Temperature-sensitive and pH-responsive IPN-hydrogels for Application as Biomaterial for Cell GrowthAbstract: In the present investigation, hydrogels with pH-responsive and temperature-sensitive properties were obtained by formation of alginate-Ca network inside the PNIPAAm network resulting in an interpenetrated network system (IPN). From scanning electron microscopy (SEM) images and water uptake (WU) tests one observed that IPN hydrogels exhibited a drastic shrinking when heated above 30-35 °C. The shrinking resulted in decreased average pore size, thus affect the hydrogel morphology significantly. In the pH range studied, IPN hydrogels showed significant pH dependence, which was attributed to the charged alginate groups. The results indicated that the pH-responsiveness and temperature-dependence of alginate and PNIPAAm, respectively, were preserved in IPN hydrogels. In addition, such hydrogels become less deformable when subjected to compressive stress. These hydrogels presented porous morphology that may be tuned by controlling the temperature, and this makes them attractive for applications as biomaterial in cell growth.

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“…The formed hydrogel is expected to be more stable mechanically over long-term storage and exhibits sustained drug release property. Propylene glycol alginate [127][128][129][130] The propylene glycol alginate forms a membrane with albumin via transacylation reaction between ester group of propylene glycol alginate and amino group of albumin, initiated by alkaline pH. Peptide drug is released at a slower rate when microparticles are coated with such membrane.…”

Section: Graft Copolymer Physicochemical and Drug Release Propertiesmentioning

confidence: 99%

Alginate graft copolymers and alginate–co-excipient physical mixture in oral drug delivery

Wong

2011

Journal of Pharmacy and Pharmacology

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Objectives Use of alginate graft copolymers in oral drug delivery reduces dosage form manufacture complexity with reference to mixing or coating processes. It is deemed to give constant or approximately steady weight ratio of alginate to covalently attached co-excipient in copolymers, thereby leading to controllable matrix processing and drug release. This review describes various grafting approaches and their outcome on oral drug release behaviour of alginate graft copolymeric matrices. It examines drug release modulation mechanism of alginate graft copolymers against that of co-excipients in non-grafted formulations. Key findings Drug release from alginate matrices can be modulated through using either co-excipients or graft copolymers via changing their swelling, erosion, hydrophobicity/ hydrophilicity, porosity and/or drug adsorption capacity. However, it is not known if the drug delivery performance of formulations prepared using alginate graft copolymers is superior to those incorporating graft-equivalent co-excipient physically in a dosage form without grafting but at the corresponding graft weight, owing to limited studies being available. Conclusions The value of alginate graft copolymers as the potential alternative to alginate-co-excipient physical mixture in oral drug delivery cannot be entirely defined by past and present research. Such an issue is complicated by the lack of green chemistry graft copolymer synthesis approach, high grafting process cost, complications and hazards, and the formed graft copolymers having unknown toxicity. Future research will need to address these matters to achieve a widespread commercialization and industrial application of alginate graft copolymers in oral drug delivery

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Coating alginate microspheres with a serum albumin-alginate membrane: application to the encapsulation of a peptide

Cited by 49 publications

References 19 publications

Silk coatings on PLGA and alginate microspheres for protein delivery

Silk coatings on PLGA and alginate microspheres for protein delivery

Morfologia de hidrogéis-ipn termo-sensíveis e ph-responsivos para aplicação como biomaterial na cultura de células

Alginate graft copolymers and alginate–co-excipient physical mixture in oral drug delivery

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