Silica sol-gel for the controlled release of antibiotics. I. Synthesis, characterization, andin vitro release

Abstract

Room temperature processed silica sol-gel (xerogel) was investigated as a novel controlled release carrier of antibiotics (vancomycin). Xerogel characteristics, in vitro release properties, and bactericidal efficacy of the released antibiotic were determined. The xerogel/vancomycin composite showed a long-term sustained release (up to 6 weeks). In addition, bactericidal efficacy of released vancomycin was retained. The kinetics of release and the amount released were dose dependent. The initial, first-order release was followed by a near-zero-order release. The time to transition from the first- to zero-order release increased with vancomycin load (from 2 to 3 weeks with load increase from 2.2 to 11.1 mg/g). Regardless of the load, about 70% of the original vancomycin content was released by the transitional point, and the cumulative release after 6 weeks of immersion was about 90%. This study, combined with other reports documenting biocompatibility and controlled resorbability of the xerogel/drug composite in vivo, suggests that silica xerogel is a promising controlled release material for the treatment of bone infections.

Polymer–xerogel composites for controlled release wound dressings

“…Silica xerogels containing either bupivacaine hydrochloride (BP) or mepivacaine hydrochloride (MP) (Sigma Aldrich) were prepared at room temperature via a one-step acid catalyzed sol-gel process with tetraethoxysilane (TEOS, Strem Chemicals, Newburyport, MA) as previously described [21][22][23][24]. The dried xerogel disks were then crushed into granules using mortar and pestle.…”

“…The continuous polymeric phase can include biopolymers such as collagen [12] and chitosan [13] or synthetic polymers such as poly(lactic acid) (PLA) [14], poly(lactide-co-glycolide) (PLGA) [15], polyhydroxyalkanoates [16], polyurethanes [17], polyvinyl alcohol [18] or poly(methyl methacrylate) [19]. Certain ceramic particles, particularly sol-gel processed silicon oxide (xerogel) microparticles, can provide controlled release properties including zero-order kinetics for a broad range of therapeutic agents such as anesthetics, antibiotics and growth factors [20][21][22][23][24][25][26][27][28][29][30][31] but by themselves the ceramics do not provide for a flexible, absorbent wound covering. Polymer-ceramic composites based upon PLA and PLGA have been investigated for controlled drug delivery [32,33] but their use is limited by the inherently acidic, pro-inflammatory polymeric degradation products and by their relatively high rigidity and lack of flexibility [34].…”

“…They bind and release a variety of bioactive agents and, unlike polyesters such as PLA and PLGA, they do not produce significant amounts of inflammatory degradation products [35,36]. The silica-based xerogel particles synthesized here also display excellent local tissue response, their degradation products are safely excreted [37][38][39] and they allow highly tunable controlled release for a broad range of bioactive compounds [21,24,26,27].…”

Cerâmicas bioativas: estado da arte

“…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.…”

Desarrollo de recubrimientos híbridos osteoinductores para implantes dentales

“…Por ejemplo, Radin y colaboradores [83][84][85]93, 100] incorporaron fármacos solubles en agua, como la vancomicina, en la etapa sol. El procedimiento que siguieron para controlar la liberación se basó en la incorporación distintas concentraciones de fármaco adicionado al sol y la posterior deposición de distintas capas.…”