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Recent advances in ceramic implants as drug delivery systems for biomedical applications.

Colilla M, Manzano M, Vallet-Regí M - Int J Nanomedicine (2008)

Bottom Line: Second, their capability of acting as delivery systems of a large variety of biologically active molecules, including drugs to treat bone infection, inflammation or diseases, and molecules that promote bone tissue regeneration, such as peptides, proteins, growth factors, and other osteogenic agents.The recent chemical and technological advances in the nanometer scale has allowed the design of mesoporous silicas with tailored structural and textural properties aimed at achieving a better control over molecule loading and release kinetics.Moreover organic modification of mesoporous silica walls has been revealed as a key strategy to modulate molecule adsorption and delivery rates.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Química Inorgánica y Bioinorgánica, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain.

ABSTRACT
Research in the development of new bioceramics with local drug delivery capability for bone regeneration technologies is receiving great interest by the scientific biomedical community. Among bioceramics, silica-based ordered mesoporous materials are excellent candidates as bone implants due to two main reasons: first, the bioactive behavior of such materials in contact with simulated body fluids, ie, a carbonate hydroxyapatite similar to the mineral phase of bone is formed onto the materials surfaces. Second, their capability of acting as delivery systems of a large variety of biologically active molecules, including drugs to treat bone infection, inflammation or diseases, and molecules that promote bone tissue regeneration, such as peptides, proteins, growth factors, and other osteogenic agents. The recent chemical and technological advances in the nanometer scale has allowed the design of mesoporous silicas with tailored structural and textural properties aimed at achieving a better control over molecule loading and release kinetics. Moreover organic modification of mesoporous silica walls has been revealed as a key strategy to modulate molecule adsorption and delivery rates.

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Related in: MedlinePlus

Alendronate adsorption on MCM-41 and SBA-15 mesoporous materials before and after functionalization with amino groups.
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f5-ijn-3-403: Alendronate adsorption on MCM-41 and SBA-15 mesoporous materials before and after functionalization with amino groups.

Mentions: Surface area influence was also shown when alendronate, a potent bisphosphonate used in osteoporosis treatments, was confined into MCM-41 and SBA-15 mesoporous matrices (Balas et al 2006). Both mesoporous matrices exhibited the same structure (2D hexagonal and p6mm symmetry) but different surface areas, SBET of 1157 and 719 m2/g for MCM-41 and SBA-15, respectively. When both matrices were loaded with alendronate under the same conditions, the maximum amounts of drug loaded were 14% and 8% for MCM-41 and SBA-15, respectively. This fact showed the clear dependence of maximum drug load on the matrix surface area in agreement with results reported later in the literature (Qu et al 2006). MCM-41 and SBA-15 were functionalized using amino groups with the aim of increasing the attracting host-guest interactions, and alendronate loading and release studies were carried out (Balas et al 2006). The amount of alendronate loaded followed the same trend that unmodified materials, ie MCM-41-NH2 loaded more alendronate (37%) than SBA-15-NH2 (22%) as a result of the higher surface area of MCM-41 (Table 2). In addition, it should be noticed that the amount of alendronate loaded in modified materials was almost 3 times larger than those of unmodified materials. This fact can be explained by the stronger attracting interactions between phosphonate groups and amino groups of modified materials compared to the weaker interaction taking place between phosphonate groups and silanol groups from unmodified matrices (Figure 5). Regarding alendronate release, it should be highlighted that in all cases an initial burst effect was observed. This fast release of the drug could be due to several reasons: alendronate that could be adsorbed in the outer surface of the matrix or by the existent alendronate gradient between mesoporous matrix and delivery medium. Therefore, after 24 h of assay, 28% of the total amount of alendronate adsorbed was delivered from MCM-41-NH2, whereas at the same time this percentage was 58% for unmodified MCM-41 (Table 2). On the other hand, 11% of the total alendronate loaded was released after 24 h of assay from SBA-15-NH2 matrix, whereas 55% of alendronate loaded was delivered after this time from SBA-15. After such burst effect, the alendronate was released to the medium in a sustained manner following first order kinetics for unmodified and modified MCM-41 materials and zero order or linear kinetics for unmodified and modified SBA-15 materials. Moreover, the increase in the total drug delivery time in functionalized materials compared with unmodified matrices (Table 2) can be ascribed to the stronger interactions between phosphonate groups from alendronate and amino groups covering the pore walls. This interaction led to a decrease in the alendronate delivery rate. This work evidences that the amount of alendronate adsorbed and drug delivery rate can be controlled by appropriately modifying the mesoporous carriers with amino groups. In this sense, organic functionalization allows a higher control over drug loading and release kinetics.


Recent advances in ceramic implants as drug delivery systems for biomedical applications.

Colilla M, Manzano M, Vallet-Regí M - Int J Nanomedicine (2008)

Alendronate adsorption on MCM-41 and SBA-15 mesoporous materials before and after functionalization with amino groups.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2636592&req=5

f5-ijn-3-403: Alendronate adsorption on MCM-41 and SBA-15 mesoporous materials before and after functionalization with amino groups.
Mentions: Surface area influence was also shown when alendronate, a potent bisphosphonate used in osteoporosis treatments, was confined into MCM-41 and SBA-15 mesoporous matrices (Balas et al 2006). Both mesoporous matrices exhibited the same structure (2D hexagonal and p6mm symmetry) but different surface areas, SBET of 1157 and 719 m2/g for MCM-41 and SBA-15, respectively. When both matrices were loaded with alendronate under the same conditions, the maximum amounts of drug loaded were 14% and 8% for MCM-41 and SBA-15, respectively. This fact showed the clear dependence of maximum drug load on the matrix surface area in agreement with results reported later in the literature (Qu et al 2006). MCM-41 and SBA-15 were functionalized using amino groups with the aim of increasing the attracting host-guest interactions, and alendronate loading and release studies were carried out (Balas et al 2006). The amount of alendronate loaded followed the same trend that unmodified materials, ie MCM-41-NH2 loaded more alendronate (37%) than SBA-15-NH2 (22%) as a result of the higher surface area of MCM-41 (Table 2). In addition, it should be noticed that the amount of alendronate loaded in modified materials was almost 3 times larger than those of unmodified materials. This fact can be explained by the stronger attracting interactions between phosphonate groups and amino groups of modified materials compared to the weaker interaction taking place between phosphonate groups and silanol groups from unmodified matrices (Figure 5). Regarding alendronate release, it should be highlighted that in all cases an initial burst effect was observed. This fast release of the drug could be due to several reasons: alendronate that could be adsorbed in the outer surface of the matrix or by the existent alendronate gradient between mesoporous matrix and delivery medium. Therefore, after 24 h of assay, 28% of the total amount of alendronate adsorbed was delivered from MCM-41-NH2, whereas at the same time this percentage was 58% for unmodified MCM-41 (Table 2). On the other hand, 11% of the total alendronate loaded was released after 24 h of assay from SBA-15-NH2 matrix, whereas 55% of alendronate loaded was delivered after this time from SBA-15. After such burst effect, the alendronate was released to the medium in a sustained manner following first order kinetics for unmodified and modified MCM-41 materials and zero order or linear kinetics for unmodified and modified SBA-15 materials. Moreover, the increase in the total drug delivery time in functionalized materials compared with unmodified matrices (Table 2) can be ascribed to the stronger interactions between phosphonate groups from alendronate and amino groups covering the pore walls. This interaction led to a decrease in the alendronate delivery rate. This work evidences that the amount of alendronate adsorbed and drug delivery rate can be controlled by appropriately modifying the mesoporous carriers with amino groups. In this sense, organic functionalization allows a higher control over drug loading and release kinetics.

Bottom Line: Second, their capability of acting as delivery systems of a large variety of biologically active molecules, including drugs to treat bone infection, inflammation or diseases, and molecules that promote bone tissue regeneration, such as peptides, proteins, growth factors, and other osteogenic agents.The recent chemical and technological advances in the nanometer scale has allowed the design of mesoporous silicas with tailored structural and textural properties aimed at achieving a better control over molecule loading and release kinetics.Moreover organic modification of mesoporous silica walls has been revealed as a key strategy to modulate molecule adsorption and delivery rates.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Química Inorgánica y Bioinorgánica, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain.

ABSTRACT
Research in the development of new bioceramics with local drug delivery capability for bone regeneration technologies is receiving great interest by the scientific biomedical community. Among bioceramics, silica-based ordered mesoporous materials are excellent candidates as bone implants due to two main reasons: first, the bioactive behavior of such materials in contact with simulated body fluids, ie, a carbonate hydroxyapatite similar to the mineral phase of bone is formed onto the materials surfaces. Second, their capability of acting as delivery systems of a large variety of biologically active molecules, including drugs to treat bone infection, inflammation or diseases, and molecules that promote bone tissue regeneration, such as peptides, proteins, growth factors, and other osteogenic agents. The recent chemical and technological advances in the nanometer scale has allowed the design of mesoporous silicas with tailored structural and textural properties aimed at achieving a better control over molecule loading and release kinetics. Moreover organic modification of mesoporous silica walls has been revealed as a key strategy to modulate molecule adsorption and delivery rates.

Show MeSH
Related in: MedlinePlus