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1.
Nanoscale ; 13(30): 12916-12928, 2021 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-34477775

RESUMO

One of the most realistic approaches for delivering actives (pharmaceuticals/cosmetics) deep into skin layers is encapsulation into nanoparticles (NPs). Nonetheless, molecular-level mechanisms related to active delivery from NPs to the skin have scarcely been studied despite the large number of synthesis and characterization studies. We herein report the underlying mechanism of active translocation and permeation through the outermost layer of skin, the stratum corneum (SC), via molecular dynamics (MD) simulations complemented by experimental studies. A SC molecular model is constructed using current state-of-the-art methodology via incorporating the three most abundant skin lipids: ceramides, free fatty acids, and cholesterol. As a potent antioxidant, ferulic acid (FA) is used as the model active, and it is loaded into Gelucire 50/13 NP. MD simulations elucidate that, first, FA-loaded NP approaches the skin surface quickly, followed by slight penetration and adsorption onto the upper skin surface; FA then translocates from the NP surface to the skin surface due to stronger NP-skin interactions compared to the FA-NP interactions; then, once FA is released onto the skin surface, it slowly permeates deep into the skin bilayer. Both the free energy and resistance to permeation not only indicate the spontaneous transfer of FA from the bulk to the skin surface, but they also reveal that the main barrier against permeation exists in the middle of the lipid hydrophobic tails. Significantly lower diffusion of FA is obtained in the main barrier region compared to the bulk. The estimated permeability coefficient (log P) values are found to be higher than the experimental values. Importantly, the permeation process evaluated via MD simulations perfectly matches with experiments. The study suggests a molecular simulation platform that provides various crucial insights relating to active delivery from loaded NP to skin, and it could facilitate the design and development of novel NP-based formulations for transdermal delivery and the topical application of drugs/cosmetics.


Assuntos
Simulação de Dinâmica Molecular , Nanopartículas , Administração Cutânea , Bicamadas Lipídicas , Lipídeos , Permeabilidade , Pele
2.
Pharmaceutics ; 13(2)2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33671970

RESUMO

The salt-dependent polymorphs of glycine crystals formed from bulk solutions have been a longstanding riddle. In this study, in order to shed fresh light, we studied the effects of seven common salts on primary nucleation of the metastable α-glycine and the stable γ-glycine. Our nucleation experiments and in-depth data analyses enabled us to reveal that (NH4)2SO4, NaCl and KNO3, in general, promote γ-glycine primary nucleation very significantly while simultaneously inhibiting α-glycine primary nucleation, thereby explaining why these three salts induce γ-glycine readily. In comparison, Ca(NO3)2 and MgSO4 also promote γ-glycine and inhibit α-glycine primary nucleation but not sufficiently to induce γ-glycine. More interestingly, Na2SO4 and K2SO4 promote not only γ-glycine but also α-glycine primary nucleation, which is unexpected and presents a rare case where a single additive promotes the nucleation of both polymorphs. As a result, the promoting effects of Na2SO4 and K2SO4 on γ-glycine do not enable γ-glycine nucleation to be more competitive than α-glycine nucleation, with γ-glycine failing to appear. These observations help us to better understand salt-governed glycine polymorphic selectivity.

3.
Colloids Surf B Biointerfaces ; 194: 111161, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32521462

RESUMO

Microemulsion can be a potential delivery vehicle to deliver skin care actives to deep skin layer for chronic skin care benefits. On top of skin care active, microemulsion vehicle composed of multiple skin beneficial oils can deliver additional skin care efficacies. In this study, microemulsions were developed using combinations of two skin beneficial oils, tea tree oil and medium chain triglyceride instead of single oil. For that, pseudo ternary phase diagrams were constructed on these oil combinations at different ratios of surfactant/co-surfactants. Ratio of oils and surfactant/co-surfactant combinations exhibited significant impact on the microemulsion region. A few compositions were selected from the single phase microemulsion regions of these phase diagrams for the preparation of resveratrol-loaded microemulsion and microemulsion gel formulations. The particle size of the resveratrol-loaded microemulsions were <50 nm. Cryogenic scanning electron microscope image clearly showed nano-droplets dispersed in continuous phase. Both physical and chemical stability of the formulations varied depending on their compositions, such as surfactant/co-surfactant combination and % total oil. The presence of chelating agent and anti-oxidant was also crucial to stabilize the formulations. The selected formulations demonstrated good physicochemical stability at 5 °C, 25 °C, and 40 °C/75 % RH (relative humidity) stability conditions. The results further showed that the % total oil and surfactant phase composition had huge influence on resveratrol release and skin permeation patterns from the microemulsion gels. In vitro skin permeation result indicated that the microemulsion gels can help resveratrol penetration into deep skin layer. Therefore, the developed resveratrol-loaded microemulsion gels can be utilized as skin care product with multiple skin care benefits.


Assuntos
Óleos , Resveratrol , Absorção Cutânea , Tensoativos , Administração Cutânea , Emulsões/metabolismo , Óleos/metabolismo , Resveratrol/administração & dosagem , Resveratrol/farmacocinética , Pele/metabolismo , Higiene da Pele , Tensoativos/metabolismo
4.
Colloids Surf B Biointerfaces ; 189: 110823, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32036331

RESUMO

The aim of this work was to develop microemulsions and microemulsion gels which can be used as vehicles for the topical delivery of ivermectin. Tea tree oil and ethyl butanoate were found to be suitable for ivermectin-loaded microemulsion formulations due to the higher solubility of ivermectin in these two oils than other tested oils. The pseudo-ternary phase diagrams were constructed based on these selected oils and combination of different surfactant/co-surfactant at different ratios. Ivermectin-loaded stable microemulsions and microemulsion gels were successfully formulated based on the selected compositions from the phase diagrams. Ivermectin-loaded microemulsions showed spherical nano-droplets dispersed in the continuous phase (via cryogenic field emission scanning electron microscope image) and the particle size was less than 100 nm (via dynamic light scattering measurement). Ethyl butanoate based microemulsion appeared to be the best microemulsion formulation considering the stability and permeation profiles while tea tree oil based microemulsion showed the best stability profile. Overall, microemulsion gel formulations exhibited better stability profiles than their microemulsion counterparts. All microemulsion gel formulations demonstrated significantly faster in vitro membrane permeation (release) rate of ivermectin than Soolantra cream (reference marketed product by Galderma, USA).The developed microemulsion and microemulsion gel formulations appear to be promising vehicles for topical delivery of ivermectin.


Assuntos
Antiparasitários/química , Butiratos/química , Ivermectina/química , Óleo de Melaleuca/química , Composição de Medicamentos , Sistemas de Liberação de Medicamentos , Emulsões/química , Tamanho da Partícula , Solubilidade , Propriedades de Superfície
5.
Int J Pharm ; 576: 118983, 2020 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-31874195

RESUMO

This study reports a novel quercetin nanorod/microcrystalline cellulose (MCC) formulation prepared by fluid bed coating crystallization technique. The process comprises fluidized bed spray coating of quercetin acetone solution onto MCC particles, solvent evaporation and crystallization of quercetin nanorods on MCC surface. Depending on the quercetin solution concentration, quercetin nanorods with 100-300 nm in diameter and 1-3 µm in length were obtained. Owing to the small particle size and large surface area, a higher dissolution rate was achieved for quercetin nanorods in contrast to the raw quercetin, which therefore led to higher antioxidant activities. In addition, the obtained quercetin nanorod/MCC formulation exhibited a good storage stability within 12 months. The developed quercetin nanorod/MCC formulation could be used for further pharmaceutical dosage or food supplements processing.


Assuntos
Celulose/química , Nanotubos/química , Quercetina/química , Química Farmacêutica/métodos , Cristalização/métodos , Composição de Medicamentos/métodos , Tamanho da Partícula , Solubilidade
6.
Acta Crystallogr B Struct Sci Cryst Eng Mater ; 75(Pt 6): 969-977, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32830676

RESUMO

Polymorphism of active pharmaceutical ingredients (APIs) is of significance in the pharmaceutical industry because it can affect the quality, efficacy and safety of the final drug product. In this regard, polymorphic behavior of cocrystals is no exception because it can influence the development of cocrystals as potential drug formulations. The current contribution aims to introduce two novel polymorphs [forms (III) and (IV)] of agomelatine-hydroquinone (AGO-HYQ) cocrystal and to describe the thermodynamic relationship between the cocrystal polymorphs. All polymorphs were characterized using powder X-ray diffraction, differential scanning calorimetry, hot-stage microscopy and solubility measurements. In addition, the crystal structure of form (II), which has been previously solved from powder diffraction data [Prohens et al. (2016), Cryst. Growth Des. 16, 1063-1070] and form (III) were determined from the single-crystal X-ray diffraction data. Thermal analysis revealed that AGO-HYQ cocrystal form (III) exhibits a higher melting point and a lower heat of fusion than those of form (II). According to the heat of fusion rule, the polymorphs are enantiotropically related, with form (III) being stable at higher temperatures. Our results also show that the novel form (IV) is the most stable form at ambient conditions and it transforms into form (II) on heating, and therefore, the two polymorphs are enantiotropically related. Furthermore, solubility and van't Hoff plot results suggest that the transition points are approximately 339 K for the pair form (IV)-(II) and 352 K for the pair form (II)-(III).

7.
J Mech Behav Biomed Mater ; 91: 91-98, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30550989

RESUMO

To overcome the disadvantage of current antibiotic bone cements with low drug elution efficiency, the hollow nanostructured titanium-dioxide (TiO2) nanotubes (TNTs) were formulated with antibiotic loaded bone cement to create nano diffusion networks, enabling enhanced release of antibiotic. By incorporation of TNTs into Poly(methyl methacrylate) (PMMA) based bone cement, more than 50% of loaded antibiotic (such as gentamicin or vancomycin) could be released in two months. As comparison, only about 5% of total drug release was achieved in the absence of TNTs. The mechanical properties of PMMA-based bone cements were well preserved after incorporation of TNTs. Furthermore, the compression strength and bending modules of TNTs formulated antibiotic bone cements could be maintained after the drug release for 70 days or aging in PBS buffer for 3 months. The insoluble TNTs in bone cement is believed to support the mechanical properties after wet aging.


Assuntos
Antibacterianos/química , Cimentos Ósseos/química , Portadores de Fármacos/química , Fenômenos Mecânicos , Nanotubos/química , Polimetil Metacrilato/química , Titânio/química , Força Compressiva , Liberação Controlada de Fármacos
8.
Artigo em Inglês | MEDLINE | ID: mdl-24441128

RESUMO

Four solvates of an antifungal drug, griseofulvin (GF), were discovered. All the solvates were characterized by differential scanning calorimetry, thermogravimetric analysis, and their crystal structures were determined by single-crystal X-ray diffraction. The solvents that form the solvates are acetonitrile, nitromethane and nitroethane (2:1 and 1:1). It was found that all the solvates lose the solvent molecules from the crystal lattice between 343 and 383 K, and that the melting point of the desolvated materials matched the melting point of the solvent-free GF (493 K). The conformation of the GF molecule in solvent-free form was found to be significantly different from the conformations found in the solvates. Solution stability studies revealed that the GF-acetonitrile solvate transforms to GF and that GF-nitroethane (1:1) solvate transforms to GF-nitroethane (2:1) solvate. On the other hand, GF-nitromethane and GF-nitroethane (2:1) solvates were found to be stable in solution. Our results highlight the importance of the co-crystallization technique in the pharmaceutical drug development; it not only expands the solid form diversity but also creates new avenues for unraveling novel solvates.


Assuntos
Antifúngicos/química , Griseofulvina/química , Solventes/química , Acetonitrilas/química , Varredura Diferencial de Calorimetria , Cristalografia por Raios X , Etano/análogos & derivados , Etano/química , Humanos , Metano/análogos & derivados , Metano/química , Modelos Moleculares , Conformação Molecular , Nitroparafinas/química , Difração de Pó , Solubilidade , Soluções , Termodinâmica , Termogravimetria
9.
Mol Pharm ; 8(5): 1910-8, 2011 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-21875119

RESUMO

The effects of polyvinylpyrrolidone (PVP), hydroxypropyl methyl cellulose (HPMC), and lecithin additives on salbutamol sulfate (SS) crystal growth are studied using molecular dynamics (MD) simulation, to provide an insight into the interaction between the additives and SS crystal faces at the atomistic level. The interaction energy between additives and crystal faces is presented. The intermolecular contacts between the additives and the crystal faces are analyzed by calculating the average number of contacts between O atoms of the additives and the H atoms of the first layer of the SS crystal. The mobility of each additive on SS crystal faces is also reported by determining the mean square displacement. Our results suggest that PVP is the most effective among the three additives for the inhibition of SS crystal growth. The methodology used in this study could be a powerful tool for selection of habit-modifying additives in other crystallization systems.


Assuntos
Agonistas de Receptores Adrenérgicos beta 2/química , Albuterol/química , Broncodilatadores/química , Excipientes/química , Composição de Medicamentos , Estabilidade de Medicamentos , Derivados da Hipromelose , Lecitinas/química , Metilcelulose/análogos & derivados , Metilcelulose/química , Conformação Molecular , Simulação de Dinâmica Molecular , Povidona/química
10.
Acta Crystallogr Sect E Struct Rep Online ; 67(Pt 5): o1227, 2011 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-21754525

RESUMO

The cation of the title salt, C(7)H(11)N(2) (+)·C(12)H(13)O(2) (-)·H(2)O, is planar (r.m.s. deviation = 0.0184 Å). In the crystal, the cation, anion and water mol-ecule are linked by O-H⋯O and N-H⋯O hydrogen bonds, forming a chain running along the a axis.

11.
Int J Pharm ; 415(1-2): 110-8, 2011 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-21645601

RESUMO

The ability to detect and quantify polymorphism of pharmaceuticals is critically important in ensuring that the formulated product delivers the desired therapeutic properties because different polymorphic forms of a drug exhibit different solubilities, stabilities and bioavailabilities. The purpose of this study is to develop an effective method for quantitative analysis of a small amount of one polymorph within a binary polymorphic mixture. Sulfamerazine (SMZ), an antibacterial drug, was chosen as the model compound. The effectiveness and accuracy of powder X-ray diffraction (PXRD), Raman microscopy and differential scanning calorimetry (DSC) for the quantification of SMZ polymorphs were studied and compared. Low heating rate in DSC allowed complete transformation from Form I to Form II to take place, resulting in a highly linear calibration curve. Our results showed that DSC and PXRD are capable in providing accurate measurement of polymorphic content in the SMZ binary mixtures while Raman is the least accurate technique for the system studied. DSC provides a rapid and accurate method for offline quantification of SMZ polymorphs, and PXRD provides a non-destructive, non-contact analysis.


Assuntos
Varredura Diferencial de Calorimetria/métodos , Contaminação de Medicamentos , Preparações Farmacêuticas , Difração de Pó/métodos , Análise Espectral Raman/métodos , Difração de Raios X/métodos , Antibacterianos/análise , Antibacterianos/química , Antibacterianos/normas , Calibragem , Cristalização , Análise Multivariada , Preparações Farmacêuticas/análise , Preparações Farmacêuticas/química , Preparações Farmacêuticas/normas , Valor Preditivo dos Testes , Sulfamerazina/análise , Sulfamerazina/química , Sulfamerazina/normas , Termodinâmica
12.
Acta Crystallogr Sect E Struct Rep Online ; 67(Pt 3): o550-1, 2011 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-21522317

RESUMO

The anti-biotic nitro-furan-toin {systematic name: (E)-1-[(5-nitro-2-fur-yl)methyl-idene-amino]-imidazolidine-2,4-dione} crys-tallizes as a methanol monosolvate, C(8)H(6)N(4)O(5)·CH(4)O. The nitro-furan-toin mol-ecule adopts a nearly planar conformation (r.m.s. deviation = 0.0344 Å). Hydrogen bonds involve the co-operative N-H⋯O-H⋯O heterosynthons between the cyclic imide of nitro-furan-toin and methanol O-H groups. There are also C-H⋯O hydrogen bonds involving the nitro-furan-toin mol-ecules which support the key hydrogen-bonding synthon. The overall crystal packing is further assisted by weak C-H⋯O inter-actions, giving a herringbone pattern.

13.
Acta Crystallogr Sect E Struct Rep Online ; 67(Pt 3): o552-3, 2011 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-21522318

RESUMO

In the crystal structure of the title co-crystal, C(4)H(5)N(3)·C(12)H(14)O(2), the components are linked by N-H⋯O and O-H⋯N hydrogen bonds. Self-assembly of these dimeric units results in a four-component supra-molecular unit featuring a homosynthon between two mol-ecules of the pyrimidin-2-amine involving two N-H⋯O hydrogen bonds, and two heterosynthons between each one mol-ecule of pyrimidin-2-amine and 1-phenyl-cyclo-pentane-1-carb-oxy-lic acid involving N-H⋯O and O-H⋯N hydrogen bonds.

14.
Chem Commun (Camb) ; 46(32): 5924-6, 2010 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-20601977

RESUMO

The importance of relative growth rates in the preponderance of alpha- over gamma-glycine during solution crystallisation has been confirmed. Most surprisingly tailor-made additives drastically accelerated the growth of gamma-glycine--an unexpected and key factor in the polymorphic outcome of glycine crystallisation.

15.
J Pharm Sci ; 99(7): 2975-90, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20091821

RESUMO

Crystal polymorphism of the anti-diabetic drug Tolbutamide (TB) has been studied using various analytical techniques. TB crystallizes in four polymorphic forms (Forms I-IV), which differ in their mode of packing and in molecular conformation but with similar hydrogen bonding synthon (urea tape motif). All the structures were solved from single crystal X-ray data, except for Form IV, which was solved using conventional powder X-ray diffraction (PXRD) data. The conformational differences in the TB molecule arise primarily from torsional variations in the alkyl tail which result in two types of conformers (U and chair). The packing differences are mainly due to the orientation of adjacent molecules in the hydrogen bonding networks. Based on the DSC data, thermodynamic stability relationships of polymorphic pairs were evaluated and graphically visualized in a schematic energy-temperature diagram. Form II is found to be the thermodynamically stable polymorph from absolute zero to approximately 353 K and beyond which Form I(H) is the stable polymorph. The anisotropic lattice contraction of TB polymorphs which resulted in severe variations in PXRD patterns at ambient and low temperature was highlighted. The present work also highlights and resolves several discrepancies in the published data on the structural and thermodynamic features of TB polymorphs.


Assuntos
Hipoglicemiantes/química , Tolbutamida/química , Cristalização , Cristalografia por Raios X , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Conformação Molecular , Espectrofotometria Infravermelho , Termodinâmica
16.
Acta Crystallogr Sect E Struct Rep Online ; 66(Pt 12): o3339-40, 2010 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-21589613

RESUMO

In the title salt, C(5)H(7)N(2) (+)·C(10)H(9)O(2) (-), 2-amino-pyridine and 1-phenyl-cyclo-propane-1-carb-oxy-lic acid crystallize together, forming a 2-amino-pyridinium-carboxyl-ate supra-molecular heterosynthon involving two N-H⋯O hydrogen bonds, which in turn dimerizes to form a four-component supra-molecular unit also sustained by N-H⋯O hydrogen bonding. A C-H⋯π inter-action between a pyridine C-H group and the centroid of the phenyl ring of the anion further stabilizes the four-component supra-molecular unit. The overall crystal packing also features C-H⋯O inter-actions.

17.
Acta Crystallogr Sect E Struct Rep Online ; 66(Pt 5): o1045-6, 2010 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-21579106

RESUMO

In the title co-crystal solvate, 2-ethoxy-benzamide-2,5-dihydroxy-benzoic acid-ethanoic acid (2/1/1), 2C(9)H(11)NO(2)·C(7)H(6)O(4)·C(2)H(4)O(2), two nonsteroidal anti-inflammatory drugs, ethenzamide (systematic name: 2-ethoxy-benzamide) and gentisic acid (systematic name: 2,5-dihydroxy-benzoic acid), together with acetic acid (systematic name: ethanoic acid) form a four-component mol-ecular assembly held together by N-H⋯O and O-H⋯O hydrogen bonds. This assembly features two symmetry-independent mol-ecules of ethenzamide, forming supra-molecular acid-amide heterosynthons with gentisic acid and acetic acid. These heterosynthons involve quite strong O-H⋯O [O⋯O = 2.5446 (15) and 2.5327 (15) Å] and less strong N-H⋯O [N⋯O = 2.9550 (17) and 2.9542 (17) Å] hydrogen bonds. The overall crystal packing features several C-H⋯O and π-π stacking inter-actions [centroid-centroid distance = 3.7792 (11) Å].

18.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 9): o2126-7, 2009 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-21577539

RESUMO

In the title 1:1 cocrystal, C(7)H(8)N(4)O(2)·C(7)H(6)O(4), the anti-asthmatic drug theophylline (systematic name: 1,3-dimethyl-7H-purine-2,6-dione) and a non-steroidal anti-inflammatory drug, gentisic acid (systematic name: 2,5-dihydroxy-benzoic acid) crystallize together, forming two-dimensional hydrogen-bonded sheets involving N-H⋯O and O-H⋯N hydrogen bonds. The overall crystal packing features π-π stacking inter-actions [centroid-centroid distance = 3.348 (1) Å]. The cocrystal described herein belongs to the class of pharmaceutical cocrystals involving two active pharmaceutical ingredients which has been relatively unexplored to date.

19.
J Phys Chem B ; 112(32): 9890-5, 2008 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-18646803

RESUMO

Pharmaceutical cocrystals have rapidly emerged as a new class of API solids with great promise and advantages. Much work has been focused on exploring the crystal engineering and design strategies that facilitate formation of cocrystals of APIs and ligands/cocrystal formers. However, fewer attempts have been made to understand the equilibrium phase behavior and phase transition kinetics of the cocrystallizing solutions. This limited knowledge on the solution physical chemistry often leads to difficulty in screening for potential molecular pairs of API and ligand that form cocrystals effectively. In this study, the long-time self-diffusivities measured using pulsed gradient spin-echo nuclear magnetic resonance (PGSE NMR) are used to characterize the particle interactions in solutions for pharmaceutical cocrystallizing systems. For the pairs of API and ligand that produce cocrystals, the heteromeric attractions between API and ligand are found to be stronger than the homomeric attractions between API molecules and between ligand molecules, suggesting that an energetically favorable condition is induced for the formation of cocrystals. To the best of our knowledge, this is the first report of using the pair contribution of the self-diffusivity as a screening tool for cocrystal formation.


Assuntos
Cristalização , Cinética , Espectroscopia de Ressonância Magnética , Preparações Farmacêuticas/química , Soluções , Difração de Raios X
20.
J Colloid Interface Sci ; 321(2): 365-72, 2008 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-18328495

RESUMO

Carboxyl-modified SBA-15 rod-like mesoporous materials have been synthesized by a facile rapid co-condensation of tetraethylorthosilicate (TEOS) and 2-cyanoethyltriethoxysilane (CTES), followed by hydrolysis of cyanide groups in sulfuric acid. The concentration of carboxylic groups was varied by changing the silica source ratio of CTES/TEOS from 0.05 to 0.3. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the uniform ordered mesoporous structure and rod-like morphology of SBA-15 have been preserved even at the high concentration of carboxylic groups employed. Characterization by Fourier transformed infrared spectroscopy (FTIR), solid-state NMR investigation indicated that carboxylic groups have been successfully grafted onto the surface of SBA-15 through siloxane bonds [(O(3))SiCH(2)CH(2)COOH. The negative charges of the modified SBA-15 materials were enhanced by the presence of the carboxylic groups on the surface. The capacity of lysozyme adsorption of the modified SBA-15 materials were found to be significantly improved as compared with pure silica SBA-15. The maximum amount of lysozyme adsorption on carboxyl-modified was increased with the pH of solution increased from 5.5 to 9.0.


Assuntos
Dióxido de Silício/síntese química , Adsorção , Ácidos Carboxílicos/química , Espectroscopia de Ressonância Magnética , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Estrutura Molecular , Muramidase , Nitrilas , Silanos , Dióxido de Silício/química , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Difração de Raios X
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