In the present study, release properties of antibiotic-loaded cement-type nanocomposites of biomimetic apatite and calcium sulfate were studied. Nanocrystalline component of the nanocomposite was synthesized by soaking a mixture of calcium phosphate reactants in tris-buffered simulated body fluid (SBF). The release patterns of cephalexin and gentamicin from both pure calcium sulfate and nanocomposite cements into SBF were collected up to 144 h and fitted by Higuchi and Weibull equations. The effect of loaded antibiotics on physical properties of the cements was also evaluated. Fast release behavior of both antibiotics was obtained from calcium sulfate matrix, in which 80-85% of the loaded antibiotics were liberated during the first 10 h of elution. In contrast, an administered elution was acquired from nanonocomposite materials so that the release was controlled, in all cases, by a combined mechanism; major mechanism was drug diffusion through the matrix and the minor was matrix dissolution. The results showed that the initial setting time and injectability of cements were increased from 7 min and 71% for pure calcium sulfate cement (powder-to-liquid ratio = 2.5 g/mL) to 33 min and 95% for the nanocomposite cement containing 60 wt % apatite, respectively. The compressive strength of nanocomposite was about 0.9 MPa, nearly four times lower than that of pure calcium sulfate. In addition, the use of cephalexin monohydrate did not influence the setting time and compressive strength of the cements, whereas (adding) gentamicin sulfate significantly improved these properties.
Different types of calcium phosphate cements (CPCs) have been studied as potential matrices for incorporating different types of antibiotics. All of these matrices were morphologically microporous whereas macroporosity is essential for rapid cement resorption and bone replacement. In this study, liberation of cephalexin monohydrate (CMH) from a macroporous CPC was investigated over 0.5-300 h in simulated body fluid and some mathematical models were fitted to the release profiles. Macroporosity was introduced into the cement matrix by using sodium dodecyl sulfate molecules as air-entraining agents and the effect of both surfactant and CMH on basic properties of the CPC was studied. Incorporation of CMH into the CPC composition increased the setting time, decreased the crystallinity of the formed apatite phase, and improved the injectability of the paste. The use of both CMH and sodium dodecyl sulfate did not affect the rate of conversion of the reactants into apatite phase while soaking the cements in simulated body fluid. Results showed that the liberation rate of the drug from porous CPC was higher than that of the nonporous CPC but same release patterns were experienced in both types of cements, that is, like to nonporous CPC, a time-dependent controlled release of the incorporated drug was obtained from macroporous CPC. The Weibull model was the best fitting-equation for release profiles of all cements. The liberated CMH was as active as fresh cephalexin. It is concluded that this macroporous CPC can be successfully used as drug carrier with controlled release profile for the treatment of bone infections.
The patient satisfaction questionnaire strives to be a valid and reliable instrument for assessing in-patient satisfaction with hospital services in Iran.
This study investigated the release of cephalexin monohydrate (CMH) antibitic from macroporous calcium phosphate cement (CPC) over 0?5-300 h in simulated body fluid. Macroporosity was introduced into the cement matrix by using sodium dodecyl sulphate molecules as air entraining agents. The effect of both surfactant and CMH on basic properties of the CPC has been also elaborated. The results showed that the release rate of the drug from a porous CPC was higher than that of the non-porous CPC; however the same release patterns observed for both morphologies indicated a time dependent controlled release. Incorporation of CMH into the cement composition increased the setting time, while the crystallinity of the formed apatite decreased and injectability of the paste improved. In addition, the rate of hydraulic reactions, leading to conversion of the reactants into apatite phase, did not influenced by incorporating both CMH and surfactant into the cement.
In this study, the compressive strength and bioactivity of strong polymeric calcium phosphate cement (PCPC), made by mixing a calcium phosphate powder (a mixture of tetracalcium phosphate and dicalcium phosphate dihydrate) and an aqueous solution of poly(acrylic/itaconic) acid, were investigated. The characteristics of the cement such as phase composition, setting reaction products and microstructure were analysed and compared to those of a control sample made by the same solid phase and water as a liquid. The hard tissue healing capability of PCPC was tested in a rabbit model by radiographical observations of the healing process as well as the cement condition. The results showed that the compressive strength of the set PCPC was y35 MPa before soaking in a simulated body fluid (SBF), which was much higher than that of the control specimen. However, it sharply decreased when the cement was immersed in the SBF. Xray diffraction analysis revealed that tricalcium phosphate was formed in the set PCPC and only a small amount of hydroxyapatite was produced after seven days soaking. In contrast, hydroxyapatite was almost the only phase of the control specimen after the soaking period. Radiography tests showed a cement (PCPC) with an irregular macrostructure after three months implantation, with a decreased radiopacity, and without any periosteal or intercortical callus formation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.