In Vitro Dissolution Behavior of Gel-Derived Bioactive Glasses in the SiO2-CaO-P2O5-MgO System

2005 ◽  
Vol 288-289 ◽  
pp. 541-544
Author(s):  
Yurong Cai ◽  
Lian Zhou ◽  
Jian Hua Wei ◽  
Zhen Tao Yu ◽  
Jin Long Niu
Keyword(s):  
Calcium Phosphate ◽  
Ph Value ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Surface Characteristic ◽  
In Vitro Dissolution ◽  
Dissolution Behavior ◽  
Carbonate Apatite ◽  
High Concentration

Bioactive glass-ceramics of the SiO2-CaO-P2O5-MgO system were fabricated by sol-gel-self propagating method. Two Gel-derived materials discs， 5S and 3S， were prepared by compression of powders. The materials obtained were examined in vitro with regard to the dissolution behavior and the formation ability of calcium phosphate layer on the surfaces of samples in simulated body fluid (SBF). Concentration of ions and pH value in SBF were determined by ICP-AES and micro acidity meter after 3S and 5S were immerged in SBF for intervals from 6h to 15 days and the surface characteristic of 3S and 5S soaked were determined by SEM. Experiment results showed that the formation ability of calcium phosphate on the surface of gel-derived materials depended on the speed of dissolution of samples, which related to original chemical composition and size of crystal on the surface of materials. With decreasing of Si content and increasing of Ca content, smaller crystal could be formed on the surface of 3S, which tended to dissolve more quickly in SBF. Solubility product of calcium phosphate can be reached more easily in the solution with high concentration of Ca and P and bone-like carbonate apatite formed easily on the surface of 3S.

In Vitro Dissolution Behavior of Biphasic Tricalcium Phosphate Composite Powders Composed of α-Tricalcium Phosphate and β-Tricalcium Phosphate

2008 ◽  
Vol 368-372 ◽  
pp. 1206-1208 ◽  
Author(s):  
Yan Bao Li ◽  
Dong Xu Li ◽  
Wen Jian Weng
Keyword(s):  
Heat Treatment ◽  
Calcium Phosphate ◽  
Tricalcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Ph Value ◽  
In Vitro Dissolution ◽  
Dissolution Behavior ◽  
Buffer Solution ◽  
Composite Powders

Biphasic tricalcium phosphate (BTCP) powders composed of α-tricalcium phosphate (α-TCP) and β-tricalcium phosphate (β-TCP) were prepared using amorphous calcium phosphate (ACP) precursor after heat treatment at 800oC. The in vitro dissolution behavior of the powders was examined after soaked in 0.1M NaAc-HAc buffer solution for different times. It was revealed that the Ca2+ and PO4 3- concentration, and pH value of the BTCP-soaked solution are higher than those of the α-TCP- and β-TCP-soaked solutions. The dissolution behavior of BTCP powders was explained. The specific dissolution behavior of BTCP powders can widen the biodegradation range of calcium phosphate family.

scholarly journals Organic/Inorganic bioactive materials Part II: in vitro bioactivity of Collagen-Calcium Phosphate Silicate/Wollastonite hybrids

2009 ◽  
Vol 7 (4) ◽  
pp. 711-720 ◽  
Author(s):  
Lachezar Radev ◽  
Vladimir Hristov ◽  
Bisserka Samuneva ◽  
Dimitrina Ivanova
Keyword(s):  
Calcium Phosphate ◽  
Sol Gel ◽  
Ceramic Powder ◽  
Red Shift ◽  
Type I ◽  
Carbonate Apatite ◽  
Bioactive Materials ◽  
Carboxylate Groups ◽  
Phosphate Silicate

AbstractIn the present study, novel hybrid materials of Collagen (C) and Calcium Phosphate Silicate/Wollastonite (CPS/W) were synthesized. The CPS/W ceramic was prepared via polystep sol-gel method. The dissolution test of CPS/W ceramic was filled with TRIS-HCl buffer. FTIR depicts that hydroxyl carbonate apatite (OHCO3HA) was observed after 3 days of immersion in TRIS-HCl buffer. Biohybrids of C-CPS/W were produced from diluted hydrochloric acid collagen type I and ceramic powder with different ratios of C and CPS/W equal to 25:75 and 75:25 wt.%. The synthesized hybrids were characterized by FTIR, XRD and SEM. FTIR depicts a “red shift” if amide I could be attributed to the fact that the collagen prefers to chelate Ca2+ from partial dissolution of CPS/W ceramic. The growth of B-type carbonate containing hydroxyapatite (B-CO3HA) on the C-CPS/W hybrids soaked in 1.5SBF was observed. The negatively charged carboxylate groups from the collagen may be responsible for hydroxyapatite (HA) deposition. This fact was confirmed by the “red shift” of carboxylate groups of collagen in FTIR spectra. The formation of HA was observed by FTIR, XRD and SEM.

scholarly journals Sol-gel bioactive glass-ceramics Part I: Calcium phosphate silicate/wollastonite glass-ceramics

2009 ◽  
Vol 7 (3) ◽  
pp. 317-321 ◽  
Author(s):  
Lachezar Radev ◽  
Vladimir Hristov ◽  
Irena Michailova ◽  
Bisserka Samuneva
Keyword(s):  
Calcium Phosphate ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Molar Ratio ◽  
Structure Evolution ◽  
Apatite Formation ◽  
Sol Gel Process ◽  
Phosphate Silicate ◽  
Good Agreement

AbstractIn this work we present experimental results about synthesis, structure evolution and in vitro bioactivity of new calcium phosphate silicate/wollastonite (CPS/W) glass-ceramics. The samples obtained were synthesized via polystep sol-gel process with different Ca/P+Si molar ratio (R). The structure of the materials obtained was studied by XRD, FTIR spectroscopy and SEM. XRD showed the presence of Ca15(PO4)2(SiO4)6, β-CaSiO3 and α-CaSiO3 for the sample with R=1.89 after thermal treatment at 1200°C/2h. The XRD results are in good agreement with FTIR analysis. SEM denotes that apatite formation can be observed after soaking in simulated body fluid (SBF).

TTCP-DCPA Based Calcium Phosphate Cements Containing Hybrid Microparticles as Drug Carriers

2008 ◽  
Vol 396-398 ◽  
pp. 489-492 ◽  
Author(s):  
Hernán E. Romeo ◽  
María A. Fanovich
Keyword(s):  
Calcium Phosphate ◽  
Sol Gel ◽  
Drug Carriers ◽  
Cement Matrix ◽  
In Vitro Tests ◽  
29Si Nmr ◽  
Main Function ◽  
High Concentration ◽  
Calcium Phosphate Cements

In recent years, considerable attention has been focused on the development of new composite materials for application as drug delivery systems. In this field, calcium phosphate cements (CPCs) are often employed as support to delivery of drugs, but their behavior has some drawback related to the so-called burst effect. The aim of this work was to develop new CPCs formulations from synthesized tetracalcium phosphate (TTCP), dicalcium phosphate anhydrous TTCP and drug-containing hybrid microparticles (DCHM). The main function of these DCHM is providing nuclei of high concentration of drugs into the CPCs. The DCHM were synthesized via the sol-gel method from a bridged precursor of the type (H3CO)3 – Bridge – (OCH3)3 and aspirin (AS) as model drug. The inorganic polycondensation reached 89.5 % as calculated by 29Si NMR. The analysis by small angle X-ray scattering (SAXS) reveled a short range structural ordering in the DCHM at molecular level. Effective incorporation of AS inside the microspheres was detected by FTIR spectroscopy. In vitro tests of DCHM according to ISO 10993-5 revealed non-cytotoxic behavior. Four CPCs formulations containing 0, 1, 5 and 10 wt % of DCHM, were evaluated. The presence of DCHM did not modify neither the degree of conversion to low-crystallinity HA nor the measured setting times of the CPCs, however, the amount of incorporated microparticles considerably affected the degree of porosity (macropores of 200 µm) and interconnectivity of the cement matrix.

In Vitro Dissolution Behavior of Custom Made CaP Scaffolds for Bone Tissue Engineering

2007 ◽  
Vol 361-363 ◽  
pp. 7-10 ◽  
Author(s):  
Saartje Impens ◽  
Roosmarijn Schelstraete ◽  
Steven Mullens ◽  
Ivo Thijs ◽  
Jan Luyten ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Calcium Phosphate ◽  
Degradation Rate ◽  
In Vitro Dissolution ◽  
Dissolution Behavior ◽  
Degradation Behavior ◽  
Dissolution Tests ◽  
Custom Made

The degradation rate of custom made calcium phosphate scaffolds, designed for bone tissue engineering applications, influences the healing process of critical size bone defects. An optimal degradation rate exists at which the neo-formed bone replaces the CaP (calcium phosphate) scaffold [1]. Consequently investigating the complex degradation behavior (dissolution, reprecipitation, osteoclast activity) of custom made CaP structures gains interest. In this work different in vitro dissolution experiments were performed to study the degradation behavior of 4 by composition different calcium phosphates. Ideally these experiments should have a predictive power regarding the in vivo degradation behavior. In vitro dissolution tests still lack standardization. Therefore this study focuses on the influence of two dissolution constraints: (i) the material’s macrostructure (porous - dense), (ii) the regenerated fluid flow (bath shaking - perfusion). From 4 different CaP compositions porous structures and as a reference dense disks were produced, using the same starting powder and heat treatment. To compare the different dissolution tests, all data was normalized to the CaP surface area. Results show that besides the structural appearances of the CaP structures, also the design of the dissolution test influences the in vitro dissolution behavior. Moreover there is a need to take the morphology of the dissolved material into account. The CaP perfusion tests show dissolution dynamics that resemble the in vivo reality more closely than the shaking bath experiments.

scholarly journals Long-Acting Risperidone Dual Control System: Preparation, Characterization and Evaluation In Vitro and In Vivo

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1210
Author(s):  
Xieguo Yan ◽  
Shiqiang Wang ◽  
Kaoxiang Sun
Keyword(s):  
Drug Loading ◽  
Entrapment Efficiency ◽  
In Vitro Dissolution ◽  
Dissolution Behavior ◽  
In Vivo Evaluation ◽  
Long Term Treatment ◽  
Long Acting

Schizophrenia, a psychiatric disorder, requires long-term treatment; however, large fluctuations in blood drug concentration increase the risk of adverse reactions. We prepared a long-term risperidone (RIS) implantation system that can stabilize RIS release and established in-vitro and in-vivo evaluation systems. Cumulative release, drug loading, and entrapment efficiency were used as evaluation indicators to evaluate the effects of different pore formers, polymer ratios, porogen concentrations, and oil–water ratios on a RIS implant (RIS-IM). We also built a mathematical model to identify the optimized formulation by stepwise regression. We also assessed the crystalline changes, residual solvents, solubility and stability after sterilization, in-vivo polymer degradation, pharmacokinetics, and tissue inflammation in the case of the optimized formulation. The surface of the optimized RIS microspheres was small and hollow with 134.4 ± 3.5 µm particle size, 1.60 SPAN, 46.7% ± 2.3% implant drug loading, and 93.4% entrapment efficiency. The in-vitro dissolution behavior of RIS-IM had zero-order kinetics and stable blood concentration; no lag time was released for over three months. Furthermore, the RIS-IM was not only non-irritating to tissues but also had good biocompatibility and product stability. Long-acting RIS-IMs with microspheres and film coatings can provide a new avenue for treating schizophrenia.

Material Properties of Strontium Doped Bioactive Glasses/Hydroxyapatite Composite and Its Mechanism of Promoting Bone Repair

2021 ◽  
Vol 11 (12) ◽  
pp. 2313-2320
Author(s):  
Jian Zhao ◽  
Wei Li ◽  
Xin Dong ◽  
Jiying Chen
Keyword(s):  
Bone Repair ◽  
Sol Gel ◽  
Precipitation Method ◽  
Dissolution Behavior ◽  
Immersion Method ◽  
Bioactive Glasses ◽  
Strontium Content ◽  
M2 Polarization ◽  
Good Ability

Based on bioactive glasses (BG) of 58S, sol–gel method is used to prepare strontium oxide substituted bioactive glasses (SrO-BG) with different strontium content. SrO-BG and nano hydroxyapatite (HAp) composite materials were synthesized using precipitation method. The phase composition and morphologies of the prepared materials were examined by x-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The dissolution and bio-mineralization of SrO-BG and SrO-BG/HAp composites in SBF are investigated by immersion method. The effects of secretion components of macrophages regulated by strontium doped SrO-BG/HAp composites on the osteogenic differentiation (OD) of bone marrow mesenchymal stem cells (BMSCs) are analyzed. The results demonstrate that the SrO-BG can inhibit the dissolution of BG. Different proportions of SrO-BG/HAp composites show good ability to induce HAp in SBF. The bio-mineralization ability of SrO-BG/HAp composites increases with the increase of SrO-BG content. The results of dissolution behavior and bio-mineralization of SrO-BG/HAp composite show that the dissolution rate of each ion can be controlled by adjusting the content of SrO-BG in the composite, and then the degradation rate can effectively be controlled. The results of in vitro experiments show that SrO-BG/HAp composites with 2%, 5% and 8% strontium content are more effective in promoting M2 polarization of macrophages than SrO-BG/HAp composites with 0% strontium content. Among them, 5% strontium doped SrO-BG/HAp has the strongest effect on M2 polarization of macrophages, and the secretion of macrophages regulated by 5% strontium doped SrO-BG/HAp composite is more conducive to bone repair.

scholarly journals In Silico Prediction of Plasma Concentrations of Fluconazole Capsules with Different Dissolution Profiles and Bioequivalence Study Using Population Simulation

Pharmaceutics ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 215 ◽  
Author(s):  
Marcelo Dutra Duque ◽  
Daniela Amaral Silva ◽  
Michele Georges Issa ◽  
Valentina Porta ◽  
Raimar Löbenberg ◽  
...  
Keyword(s):  
Reference Product ◽  
Plasma Concentrations ◽  
Drug Dissolution ◽  
In Vitro Dissolution ◽  
Dissolution Behavior ◽  
Dissolution Profile ◽  
Time Data ◽  
Simulation Results ◽  
Population Simulation

A biowaiver is accepted by the Brazilian Health Surveillance Agency (ANVISA) for immediate-release solid oral products containing Biopharmaceutics Classification System (BCS) class I drugs showing rapid drug dissolution. This study aimed to simulate plasma concentrations of fluconazole capsules with different dissolution profiles and run population simulation to evaluate their bioequivalence. The dissolution profiles of two batches of the reference product Zoltec® 150 mg capsules, A1 and A2, and two batches of other products (B1 and B2; C1 and C2), as well as plasma concentration–time data of the reference product from the literature, were used for the simulations. Although products C1 and C2 had drug dissolutions < 85% in 30 min at 0.1 M HCl, simulation results demonstrated that these products would show the same in vivo performance as products A1, A2, B1, and B2. Population simulation results of the ln-transformed 90% confidence interval for the ratio of Cmax and AUC0–t values for all products were within the 80–125% interval, showing to be bioequivalent. Thus, even though the in vitro dissolution behavior of products C1 and C2 was not equivalent to a rapid dissolution profile, the computer simulations proved to be an important tool to show the possibility of bioequivalence for these products.

scholarly journals Influence of Fluoride Concentration and pH Value of 35% Hydrogen Peroxide on the Hardness, Roughness and Morphology of Bovine Enamel

2014 ◽  
Vol 15 (4) ◽  
pp. 392-398 ◽  
Author(s):  
Wilcilene Costa Nascimento ◽  
Yasmin do Socorro Batista de Lima Gomes ◽  
Larissa Dias Alexandrino ◽  
Hilton Tulio Costi ◽  
José Otávio Carrera Silva ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Ph Value ◽  
Morphological Changes ◽  
Fluoride Concentration ◽  
Knoop Hardness ◽  
Scanning Electron Micrographs ◽  
High Concentration ◽  
Acidic Group ◽  
Bovine Enamel

ABSTRACT Aim The aim of this in vitro study was to evaluate the effects of different sodium fluoride (NaF) concentrations and pH values on the Knoop hardness (KHN), surface roughness (SR), and morphology of bovine incisors bleached with 35% hydrogen peroxide (HP). Materials and methods Sixty-five bovine incisors were fragmented (5 mm2 × 2 mm) and distributed in 5 groups: Control (unbleached), Low NaF/Acidic (35% HP + 1.3% NaF, pH 5.5), Low NaF/Neutral (35% HP + 1.3% NaF, pH 7.0), High NaF/ Acidic (35% HP + 2% NaF, pH 5.5), and High NaF/Neutral (35% HP + 2% NaF, pH 7.0). KHN analysis was performed with a microhardness tester under a load of 25 gf for 5 seconds. The average SR was obtained with a rugosimeter. KHN and SR were analyzed before and after treatments. For morphological analysis, specimens were dehydrated and gold-sputtered, and scanning electron micrographs were obtained and analyzed by 3 examiners with a double-blinded technique. KHN and SR results were analyzed by one-way ANOVA and Tukey's test (p < 0.05). Results Only the Low NaF/Acidic and Low NaF/Neutral groups showed significant differences between the initial and final KHN values. All bleached groups presented significant differences between the initial and final SR values. Among the bleached groups, the least and most morphological changes were shown by the High NaF/Neutral and the Low NaF/Acidic group, respectively. Conclusion Treatment with 35% HP and 2% NaF at pH 7.0 promoted the least changes in morphology, hardness and roughness among the bleached groups. Clinical significance In-office bleaching with high-concentration HP and 2% NaF at neutral pH promoted the least changes in enamel hardness, SR, and morphology compared to other treatments. How to cite this article Nascimento WC, Gomes YSBL, Alexandrino LD, Costi HT, Silva JOC Jr, Silva CM. Influence of Fluoride Concentration and pH Value of 35% Hydrogen Peroxide on the Hardness, Roughness and Morphology of Bovine Enamel. J Contemp Dent Pract 2014;15(4):392-398.

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