In vitro release of dexmedetomidine from silica xerogel monoliths: effect of sol-gel synthesis parameters

Kortesuo, Pirjo; Ahola, Manja; Kangas, Minna; Yli‐Urpo, Antti; Kiesvaara, Juha; Marvola, Martti

doi:10.1016/s0378-5173(01)00656-1

Cited by 89 publications

(60 citation statements)

References 17 publications

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“…50,52 Other studies investigating the use of silica xerogel for drug delivery reported that silica xerogels exhibited a weight loss of about 30% after several days in simulated body fluid. [53][54][55] In our study, the loss was 80% after 30 minutes -in comparison, a very fast exchange. Assuming that the silica matrix would be dissolved and not exchanged, the residual HA crystals would delaminate.…”

Section: Discussionsupporting

confidence: 42%

In vivo and in vitro investigations of a nanostructured coating material – a preclinical study

Adam¹,

Ganz²,

Xu³

et al. 2014

IJN

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Immediate loading of dental implants is only possible if a firm bone-implant anchorage at early stages is developed. This implies early and high bone apposition onto the implant surface. A nanostructured coating material based on an osseoinductive bone grafting is investigated in relation to the osseointegration at early stages. The goal is to transmit the structure (silica matrix with embedded hydroxyapatite) and the properties of the bone grafting into a coating material. The bone grafting substitute offers an osseoinductive potential caused by an exchange of the silica matrix in vivo accompanied by vascularization. X-ray diffraction and transmission electron microscopy analysis show that the coating material consists of a high porous silica matrix with embedded nanocrystalline hydroxyapatite with the same morphology as human hydroxyapatite. An in vitro investigation shows the early interaction between coating and human blood. Energy-dispersive X-ray analysis showed that the silica matrix was replaced by an organic matrix within a few minutes. Uncoated and coated titanium implants were inserted into the femora of New Zealand White rabbits. The bone-to-implant contact (BIC) was measured after 2, 4, and 6 weeks. The BIC of the coated implants was increased significantly at 2 and 4 weeks. After 6 weeks, the BIC was decreased to the level of the control group. A histological analysis revealed high bone apposition on the coated implant surface after 2 and 4 weeks. Osteoblastic and osteoclastic activities on the coating material indicated that the coating participates in the bone-remodeling process. The nanostructure of the coating material led to an exchange of the silica matrix by an autologous, organic matrix without delamination of the coating. This is the key issue in understanding initial bone formation on a coated surface.

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Section: Discussionsupporting

confidence: 42%

In vivo and in vitro investigations of a nanostructured coating material – a preclinical study

Adam¹,

Ganz²,

Xu³

et al. 2014

IJN

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“…Esta última técnica tem a vantagem de evitar uma possível ligação estável da substância à rede da sílica, o que reduziria a liberação do medicamento. A liberação de uma grande variedade de substâncias, incluindo esteróides 51 , fármacos anti-cancerígenos 52 , antibióticos [53][54][55] , anticoagulantes 56 , fármacos coronarianas 57 , fatores de crescimento 58 e proteínas 59 , tem sido testada. Em geral, a velocidade de liberação das espécies aprisionadas Tabela 1.…”

Section: Emprego Do Método Sol-gel Para Producão De Biocerâmicasunclassified

“…Concentração iônica do plasma sanguíneo humano e da solução que simula o fluido corporal (SBF) está relacionada à dissolução da matriz de sílica, embora possa ocorrer, também, simples difusão da substância a partir do vidro 60 . A velocidade de liberação das espécies pode ser regulada variando-se parâmetros tais como a concentração da espécie, a incorporação de aditivos 60 , as condições de secagem e o pH 52 do meio. O uso de materiais vítreos derivados do método sol-gel ainda não está autorizado para aplicações clínicas em humanos, mas, levando-se em conta que a formação da camada de HA é mais rápida nestes materiais que em vidros derivados de fusão, sua aplicação clínica em humanos provavelmente tomará o lugar dos vidros fundidos.…”

Section: Emprego Do Método Sol-gel Para Producão De Biocerâmicasunclassified

Cerâmicas bioativas: estado da arte

Andrade

Domingues

2006

Quím. Nova

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Recebido em 13/10/04; aceito em 27/4/05; publicado na web em 24/8/05 BIOACTIVE CERAMICS: STATE OF THE ART. Bioactive glasses undergo corrosion with leaching of alkaline ions when exposed to body fluids. This results in the spontaneous formation of a layer of hydroxyapatite (HA) , the mineral component of natural bone, which in turn can induce bone growth in vivo. This paper describes the different types of bioactive glasses, the characterization methods currently used, and the main factors that influence their bioactivity. Nucleation and crystallization, the main mechanisms involved in the formation of hydroxyapatite, Ca 10 (PO 4 ) 6 (OH) 2, are discussed as a function of the chemical composition and the reactivity of the surface of the material. Finally, promising applications are considered.Keywords: sol-gel; bioactive glass; in vitro tests. INTRODUÇÃOO aprimoramento técnico-científico na área médica faz-se necessário devido à busca incansável do ser humano pela longevidade e por padrões de vida superiores, o que gera a necessidade de alternativas para reparo e substituição de tecidos vivos vitimados por traumas, patologias e fraturas, dentre outros 1 . Devido a problemas como disponibilidade limitada, dificuldade de armazenamento e um tempo cirúrgico maior dos enxertos autógenos e alógenos, os pesquisadores buscam materiais sintéticos que facilitem a reparação óssea visando o restabelecimento rápido das funções fisiológicas 2 . Dentre os materiais sintéticos usados para biorreparação do tecido ósseo, as cerâmicas, também conhecidas como biocerâmicas, são as mais empregadas. As biocerâmicas apresentam-se na forma de pós, revestimentos ou próteses usados para reparo, aumento ou substituição de tecidos doentes ou danificados, como ossos, juntas e dentes 3,4 . Embora muitas composições de cerâmicas tenham sido testadas para uso médico, poucas são usadas clinicamente. Destas, pode-se citar a Al 2 O 3 e ZrO 2, usadas, inicialmente, na substituição total de juntas dos quadris e fêmur; os fosfatos de cálcio usados como revestimento de ligas metálicas e em formato de granulados ou de pequenas peças porosas para reparo ósseo; os vidros e vitrocerâmicas bioativos usados para substituição e reparo de ossículos do ouvido interno, dentes e vértebras 3,5 . CERÂMICAS BIOATIVAS (CBAs)Atualmente, o uso de cerâmicas bioativas como implantes ósse-os tem sido muito estudado. O termo bioatividade foi usado primeiro para descrever a habilidade que certas composições de vidros, desenvolvidos no fim da década de 60 e início da de 70 6 , têm de se ligarem ao tecido ósseo circundante ao implante, induzindo a formação de uma camada de hidroxiapatita (HA) em sua superfície. Hoje, sabe-se que outros materiais cerâmicos como a HA sintética, o fosfato tri-cálcio sinterizado e algumas vitro-cerâmicas 7-11 também podem ser bioativos sob certas condições de síntese.Sabe-se que a superfície de uma cerâmica bioativa (CBA) induz a biomineralização do fosfato de cálcio (HA) através da interação com o plasma sanguíneo, que é a primeira fase que int...

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“…Herein we will describe mesoporous materials, specifically silicates, such as MCM-41 and SBA-15 (1)(2)(3). According to literature, these materials are also biodegradable and biocompatible (12)(13)(14).…”

mentioning

confidence: 99%

Ordered mesoporous silicates as matrices for controlled release of drugs

Ukmar

Planinšek

2010

Acta Pharmaceutica

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According to the International Union of Pure and Applied Chemistry (IUPAC), porous materials are classified into three categories: microporous with pore diameters less than 2 nm, mesoporous having pore diameters between 2 and 50 nm, and macroporous with pore sizes larger than 50 nm. Highly ordered mesoporous silicates such as MCM (Mobil Composition of Matter No. 41, 48,...) and SBA (Santa Barbara Amorphous material No. 1, 3, 15,...) have been long recognized as very promising materials with a rich variety of possible applications (1). The various types of MCM and SBA silicates can be distinguished by the number after the acronym. The three most important MCM materials are: MCM-41 (hexagonal), MCM-48 (cubic) and MCM-50 (lamellar). Also a wide variety of SBA materials has been prepared, such as SBA-1 (cubic), SBA-11 (cubic), SBA-12 (3D hexagonal network), SBA-14 (lamellar), SBA-15 (2D hexagonal) and SBA-16 (cubic cage-structured). They show ordered arrangements of channels and cavities of different geometry confined between walls built up from SiO 2 units. Among all numerous applications of mesoporous materials, ranging from separation technology, catalysis, hydrogen Interest in and thereby also development of ordered mesoporous silicates as drug delivery devices have grown immensely over the past few years. On hand selected cases from the literature, the power of such systems as delivery devices has been established. Specifically, it is shown how it is possible to enhance the release kinetics of poorly soluble drugs by embedding them in mesoporous silicates. Further critical factors governing the structure and release of the model drug itraconazole incorporated in an SBA-15 matrix are briefly reviewed. The possibility of functionalizing the surface of mesoporous matrices also under harsher conditions offers a broad platform for the design of stimuli-responsive drug release, including pH responsive systems and systems which respond to the presence of specific ions, reducing agents, magnetic field or UV light, whose efficiency and biocompatibility has been established in vitro.

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In vitro release of dexmedetomidine from silica xerogel monoliths: effect of sol-gel synthesis parameters

Cited by 89 publications

References 17 publications

In vivo and in vitro investigations of a nanostructured coating material – a preclinical study

In vivo and in vitro investigations of a nanostructured coating material – a preclinical study

Cerâmicas bioativas: estado da arte

Ordered mesoporous silicates as matrices for controlled release of drugs

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In vitro release of dexmedetomidine from silica xerogel monoliths: effect of sol-gel synthesis parameters

Cited by 89 publications

References 17 publications

In vivo and in vitro investigations of a nanostructured coating material &ndash; a preclinical study

In vivo and in vitro investigations of a nanostructured coating material &ndash; a preclinical study

Cerâmicas bioativas: estado da arte

Ordered mesoporous silicates as matrices for controlled release of drugs

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Product

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In vivo and in vitro investigations of a nanostructured coating material – a preclinical study

In vivo and in vitro investigations of a nanostructured coating material – a preclinical study