Magnesium Aluminum Silicate Research Articles

Novel composite blend microbeads of sodium alginate coated with chitosan for controlled release of amoxicillin

Composite blend microbeads of sodium alginate (NaAlg) with sodium carboxymethyl cellulose (NaCMC) containing magnesium aluminum silicate (MAS) particles and enteric coated with chitosan have been prepared to achieve controlled release (CR) of amoxicillin in stomach environment. The composite beads have been characterized by X-ray diffraction (XRD) to study drug distribution, DSC for understanding thermal stability and Fourier transform infrared (FTIR) spectroscopy to investigate chemical interactions as well as to assess the structure of the drug-loaded formulations. Surface morphology of the beads was investigated by scanning electron microscopy (SEM). The size distribution of beads loaded with drug as studied by particle size analyzer was in the range of 745–889μm. The beads exhibited quite widely varying encapsulation efficiencies from 52 to 92%. Equilibrium swelling of the beads measured in water and in vitro release of amoxicillin in pH 1.2 medium suggests that drug release depends on polymer blend composition, concentration of MAS and extent of enteric coating.

Aluminium - Magnesium Silicate enhances antibacterial activity of Ampicillin trihydrate, against Salmonella gallinarum

AbstractSolutions of different concentrations, of Ampicillin trihydrate (AT) and of a formulation of AT in Aluminium Magnesium Silicate (AMS), were used for sensitivity test on Salmonella gallinarum cultures. Also, S. gallinarum-infected chicks were treated with; 10 mg / Kg (AT), 10 mg / Kg (AT in AMS), 7.5 mg / Kg ( AT), 7.5 mg /Kg (AT in AMS). Mean inhibition area, 28.39 mm produced by AT did not vary significantly (P ) from 26.36 mm produced by AT in AMS. However, 17.5 105 Salmonella gallinarum culture forming units per ml of bile of the untreated chicks and 3.4 105 (80.58 % reduction), 2.5 105 (85.7 % reduction) , 5.4 105 (69.2 % reduction ) and 0.38 105 (97.8 % reduction ) of the respective treated groups, showed AMS significantly (P 0.01) improved AT`s ability to clear the infection, in vivo.

Ajuvant effect of a Synthetic Aluminium - Magnesium Silicate on chloroquine phosphate, against Plasmodium berghei.

AbstractAbstract effect of a synthetic Aluminium - Magnesium Silicate (AMS) on antiplasmodial activity of chloroquine was tested. Plasmodium berghei-infected mice were treated with 7 mg/kg, 5 mg/kg and 3 mg/kg chloroquine, respectively. The two subgroups in each experiment were treated with chloroquine alone and with chloroquine in AMS respectively. Parasitaemia (%) of the group treated with 7 mg/kg was higher than that of the control. At 5 mg/kg, chloroquine treatment significantly reduced parasitaemia from 3.60 to 2.46 (P =0.01). Incorporating chloroquine in AMS significantly improved its ability to reduce P. berghei parasitaemia at 5 mgkg and at 3 mg/kg, from 2.46 0.21 to 1.57 0.25 (P = 0.01) and from 3.82 0.06 to 2.12 0.08 (P =0.01 ). It also increased mortality of mice treated at 7 mg/kg from 20 to 80 %.

Antibacterial activity of Ampicillin trihydrate formulated in Aluminium-Magnesium Silicate, against <i>Salmonella gallinarum</i>

To test if stabilizing Ampicillin trihydrate (AT) with Aluminium-Magnesium Silicate (AMS) can enhance its antibacterial activities, different concentrations of AT solution and of a formulation of AT in the AMS, were made and used for sensitivity test on Salmonella gallinarum cultures. Also, S. gallinarum-infected chicks were treated with; 10 mg/Kg (AT), 10 mg/Kg (AT in AMS), 7.5 mg/Kg (AT), 7.5 mg/Kg (AT in AMS). Mean diameter of inhibition zone, 28.39 ± 2.07 mm produced by AT did not vary significantly (P > 0.05) from 26.36 ± 2.05 mm produced by AT in AMS. However, mean Salmonella gallinarum culture forming units per ml of bile, 17.6 ± 11 × 105of the untreated chicks and 3.4 ± 0.81 × 105(80.58% reduction), 2.4 ± 0.67 × 105(85.70% reduction), 5.4 ± 1.93 × 105(69.20% reduction ) and 0.38 ± 0.13 × 105(97.80% reduction ) of the respective treated groups, showed AMS significantly (P S. gallinarum infection, in vivo.

Efficacy of piperzine citrate, stabilized with Aluminium-Magnesium Silicate, against <i>Helignosomoides bakeri</i>

To test effect of a synthetic Aluminium-Magnesium Silicate (AMS) on anthelmintic efficacy of piperazine citrate (PC), 35 mice were infected by dosing each, 0.15 ml Helignosomoides bakeri sample which contained 200 infective larvae, per os. Following comfirmation of establishment of infection by faecal floatation, they were assigned into seven groups of 5 each, and were treated with piperazine citrate, per os, at rates of 110 mg/kg (PC), 110 mg/kg (PC in AMS), 82.5 mg/kg (PC), 82.5 mg/kg (PC in AMS), 55 mg/kg (PC) and 55 mg/kg (PC in AMS) respectively. The seventh group served as untreated control. Mean Eggs Per Gramm of faeces (EPG) were 375 ± 32.27, 175 ± 14.43, 830 ± 1.04, 70 ± 12.25, 850 ± 293.06, 370 ± 58.54 and 2,200 ± 2.55 respectively. This showed EPG reduction rates of 83%, 92%, 62%, 97%, 61% and 83% among the respective treated groups.

Adjuvant effect of a synthetic Aluminium-Magnesium Silicate on chloroquine phosphate, against Plasmodium berghei

Effect a synthetic Aluminium-Magnesium Silicate (AMS) has on chloroquine was tested. Thirty, Plasmodium berghei-infected mice, in three experimental groups (7 mg/kg, 5 mg/kg and 3 mg/kg) of 10 mice each, were treated. Two subgroups, in each experiment, were treated with chloroquine and with a chloroquine-AMS drug formulation, respectively. Five of the infected mice served as controls. Parasitaemia (%), Haemoglobin concentration (Hb), Red Blood Cells (RBC), rectal temperature and body weight were assessed. Parasitaemia of subgroups treated at 7 mg/kg were higher than that of the control. Also, at 7 mg/kg, there was mortality with chloroquine (20%) and with the chloroquine-AMS drug (80%). At 5 mg/kg and 3 mg/kg, the AMS significantly (P < 0.05) improved ability of chloroquine to reduce plamodial parasitaemia, from 2.46 ± 0.21 to 1.57 ± 0.25 and from 3.82 ± 0.06 to 2.12 ± 0.08. It also significantly (P < 0.05) improved means of Hb and RBC from 12.25 ± 0.27 and 88.99 ± 5.72 to 12.68 ± 0.18 and 92.91 ± 4.01 and from 10.18 ± 3.00 and 63.39 ± 18.02 to 12.98 ± 0.47 and 95.23 ± 5.32. Body weight increased at 5 mg/kg, from 29.06 ± 1.95 to 32.66 ± 2.10 kg (P < 0.05) while at 3 mg/kg, rectal temperature reduced from 37.35 ± 0.32 to 36.84oC ± 0.23oC (P < 0.05). These results suggest, AMS worsened chloroquine toxicity at 7 mg/kg but potentiated its antiplasmodial activities at the lower doses.

Effective treatment of resistant &amp;lt;i&amp;gt;Escherichia coli&amp;lt;/i&amp;gt; infection, with sulphadimidine stabilized in a synthetic Aluminium-Magnesium Silicate

To investigate if Aluminium-Magnesium Silicate (AMS) could make drugs regain effects against resistant pathogens, its effect was tested on sulphadimidine against sulphadimidine-resistant Escherichia coli. Two groups of chicks infected with sulphadimidine-resistant E. coli were treated at sulphadimidine dose rate of 1 g/litre of drinking water, with sulphadimidine and with an AMS-sulphadimidine drug formulation, respectively. Two other groups were similarly treated at sulphadimidine dose rate of 0.75 g/litre, while the fifth group served as control. Mean titres of the bacterium in bile of the chicks were compared. Titres, 119,200 ± 55,800 CFU/mL of the group treated with sulphadimidine at rate of 1 g/ litre and 14,800 ± 1700 CFU/mL of the group treated at rate of 0.75 g/litre, did not vary from 33,200 ± 5200 CFU/mL of the control (P > 0.05) but 295,200 ± 106,400 CFU/ml of the group treated at rate of 1 g/litre, with the AMS-sulpha- dimidine drug was significantly (P < 0.05) higher than that of the control while 5200 ± 1400 CFU/mL of the group treated at dose of 0.75 g/litre, with the AMS-sulphadimidine drug, reduced significantly (P < 0.05).

Antiviral effects of a synthetic Aluminium-Magnesium Silicate, on Avian Influenza Virus

Effects a synthetic Aluminium-Magnesium Silicate [AMS] has on Avian Influenza Virus (AIV) were tested. Equal amounts of AIV samples and of the AMS were mixed, kept one hour at room temperature before centrifuging. The supernatants were remeasured and tested for, viral titre, Mean Death Time (MDT) and Mortality Rate of chicken Embryos (EMR). Volumes of the viral samples reduced at rate of 23.4% ± 5.48%. Viral titres reduced significantly (P < 0.01) from HA, 73 ± 32.72 to 1.4 ± 0.43. Also, EMR of infected chicken embryos reduced from 100% to 65%, while MDT of those that died,increased significantly (P < 0.01) from 76 ± 4.38 to 136 ±18.93 hours. When incubation with AMS was repeated on portions of an AIV sample, MDT increased from 64 to 104 hours with the portion incubated once. AIV portions on which incubation with AMS was repeated could not kill chicken embryos.

Effects of Aluminium–Magnesium Silicate on &lt;i&gt;Newcastle Disease Virus&lt;/i&gt; and on recovery of infected chicks

Effect of a synthetic Aluminium &ndash; Magnesium Silicate (AMS) on Newcastle Disease Virus (NDV) was tested. Equal amounts, of the AMS and of NDV, on a volume to weight (v/w) basis, were incubated for one hour at room temperature, and then centrifuged. The supernatant was tested for NDV titre. Portions of a virulent NDV were similarly incubated with the AMS, and their supernatants tested for morbidity rates on infected chicks. Also, two groups of chicks were infected with virulent NDV intramuscularly (I/m), and by introduction of infected chicks, respectively. Their subgroups were treated by administering AMS through drinking water, to assess its effect on mortality. Incubating NDV with AMS, reduced the viral titre from mean HA, 613 &plusmn;86 to 4. 5 &plusmn;0.72 (P &lt; 0.05). Also, incubating virulent NDV with the AMS, reduced its morbidity rate from 100% to 20% (P&lt; 0.05) when incubated once, and from 100% to zero, when incubated twice. NDV- infected chicks treated with AMS, had same 100% mortality as the controls, when route of infection was I/m (P &gt; 0.05) but when infection was by introduction of infected chicks, mortality reduced from 20% to zero (P &lt; 0.05).These results suggest AMS as NDV&rsquo;s antiviral agent.

Mechanical properties of pressure-less sintered zirconia–magnesium aluminum silicate glass composite

The main objective of the present study was to develop a high-strength machinable ceramic based on zirconia (ZrO2) and magnesium aluminum silicate (Mg3Al2Si6O18; MAS) glass system through pressure-less sintering. Pressure-less sintering of ZrO2, 3 mol% yttria-stabilized (YSZ) was carried out at 1450°C in air, using 10 wt% MAS glass as a sintering additive. The influence of glass on the microstructure and mechanical properties of the composite was investigated. The presence of glass into the ZrO2 matrix was substantiated using scanning electron microscopy (SEM). X-ray diffractometry (XRD) revealed no crystalline phases other than tetragonal ZrO2. The flexural strength of the composite was found to be ~30% higher than YSZ. The apparent crack resistance was determined by Vickers microindentations carried out at different loads ranging from 9.8 to 196 N. The apparent crack length on the surface at each load was found to be decreased (6–21%) in YSZ and the corresponding crack-resistance values increased by about 5–20%. Both YSZ and composite showed rising trend in crack-resistance values as the indentation load was increased. Improved properties of composite sample were attributed to the formation of a relatively larger process zone surrounding the crack, crack-arrest behavior due to the localized compressive stresses, and the crack-bridging phenomena.

SiC nanowires reinforced MAS joint of SiC coated carbon/carbon composites to LAS glass ceramics

Abstract In order to improve the shear strength of the joints of carbon/carbon (C/C) composites to lithium aluminum silicate (LAS) glass ceramics, SiC coating and magnesium aluminum silicate (MAS) glass ceramics were used as transition layer and middle layer, respectively, and high quality SiC nanowires were applied as the reinforcement materials in MAS. The SiC nanowires reinforced MAS joint of SiC coated C/C composites to LAS glass ceramics was prepared by a three-step technique of pack cementation, CVD and hot-pressing. The microstructures of the as-prepared joints were characterized by SEM and EDS, and the shear strength of the joints was also examined. The shear strength of the SiC–MAS joint increased from 24.0 ± 2.0 MPa to 35.5 ± 5.5 MPa after adding SiC nanowires in MAS. The load decreases in step-style but not perpendicularly after the maximum value, which demonstrates good toughness of the joint with SiC nanowire porous layer.

Antiviral Effects of a Synthetic Aluminium-Magnesium Silicate on Avian Influenza Virus

AbstractEffects of a synthetic Aluminium-Magnesium Silicate (AMS) on Avian Influenza Virus (AIV) were tested. Equal amounts of H5N1 AIV samples and of AMS were mixed, left one hour, at room temperature before centrifuging. The supernatants were remeasured and tested for viral titre, for Mean Death Time (MDT) and Embryo Mortality Rate (EMR) of chicken eggs. Volumes of the viral samples reduced at rate of 23.4 &amp;177; 5.48 %. Viral titres reduced significantly (P from HA, 73 &amp;177; 32.72 to 1.4 &amp;177;0.43). Also, mortality of infected embryos reduced from 100 % to 65% while MDT of those that died, increased significantly (P = 0.001) from 76 &amp;177; 4.38 to 130 &amp;177;17.27 hours. When incubation with AMS was repeated on portions of the same sample, MDT increased from 64 to 104 hours with the portion incubated once. Two AIV portions on which incubation with AMS was repeated could not kill chick embryos.

Synthesis of an Attapulgite Clay@Carbon Nanocomposite Adsorbent by a Hydrothermal Carbonization Process and Their Application in the Removal of Toxic Metal Ions from Water

A new kind of attapulgite clay@carbon (ATP@C) nanocomposite adsorbent has been synthesized by a one-pot hydrothermal carbonization process under mild conditions using two cheap, ecofriendly materials (i.e., attapulgite clay (ATP), which is a magnesium aluminum silicate that is abundant in nature, and glucose, which is a green chemical obtained from biomass). Compared to carbon-based materials, this new ATP@C nanocomposite exhibits a high adsorption ability for Cr(VI) and Pb(II) ions with maximum adsorption capacities of 177.74 and 263.83 mg·g(-1), respectively. The results demonstrate that this nanocomposite is an exceptionally promising candidate as a low-cost, sustainable, and effective adsorbent for the removal of toxic ions from water.

Preparation and Characterization of Nicotine–Magnesium Aluminum Silicate Complex-Loaded Sodium Alginate Matrix Tablets for Buccal Delivery

Nicotine (NCT) buccal tablets consisting of sodium alginate (SA) and nicotine-magnesium aluminum silicate (NCT-MAS) complexes acting as drug carriers were prepared using the direct compression method. The effects of the preparation pH levels of the NCT-MAS complexes and the complex/SA ratios on NCT release, permeation across mucosa, and mucoadhesive properties of the tablets were investigated. The NCT-MAS complex-loaded SA tablets had good physical properties and zero-order release kinetics of NCT, which indicate a swelling/erosion-controlled release mechanism. Measurement of unidirectional NCT release and permeation across porcine esophageal mucosa using a modified USP dissolution apparatus 2 showed that NCT delivery was controlled by the swollen gel matrix of the tablets. This matrix, which controlled drug diffusion, resulted from the molecular interactions of SA and MAS. Tablets containing the NCT-MAS complexes prepared at pH 9 showed remarkably higher NCT permeation rates than those containing the complexes prepared at acidic and neutral pH levels. Larger amounts of SA in the tablets decreased NCT release and permeation rates. Additionally, the presence of SA could enhance the mucoadhesive properties of the tablets. These findings suggest that SA plays the important role not only in controlling release and permeation of NCT but also for enhancing the mucoadhesive properties of the NCT-MAS complex-loaded SA tablets, and these tablets demonstrate a promising buccal delivery system for NCT.

Novel chitosan−magnesium aluminum silicate nanocomposite film coatings for modified-release tablets

Chitosan (CS), a positively charged polysaccharide, and magnesium aluminum silicate (MAS), a negatively charged clay with silicate layers, can electrostatically interact to form nanocomposite films. In this study, CS–MAS nanocomposite films were evaluated for use in tablet film coating. Effects of CS–MAS ratio and coating level on water uptake and drug release from the coated tablets were investigated. Surface and film matrix morphology of the coated film and the effect of enzymes in the simulated gastro-intestinal fluid on drug release were also examined. The results demonstrated that the CS–MAS coated tablets had a rough surface and a layered matrix film, whereas a smooth surface and dense matrix film on the CS coated tablets was found. However, the CS–MAS coated tablets provided fewer film defects than the CS coated tablets. Nanocomposite formation between CS and MAS could retard swelling and erosion of CS in the composite films in acidic medium. The higher MAS ratio of the CS–MAS coated tablets gave lower water uptake and slower drug release when compared with the CS coated tablets. Moreover, the CS–MAS films on the tablets presented good stability towards enzymatic degradation in simulated intestinal fluid. The release of drug from the CS–MAS coated tablets could be modulated by varying CS–MAS ratios and coating levels. Additionally, drug solubility also influenced drug release characteristics of the CS–MAS coated tablets. These findings suggest that the CS–MAS nanocomposites displays a strong potential for use in tablet film coating intended for modifying drug release from tablets.

The roughness, microhardness, and surface analysis of nanocomposites after application of topical fluoride gels

Objectives Application of acidulated phosphate fluoride (APF) gels has long been considered to cause deterioration of composite surfaces. The aims of this study were to demonstrate that nanocomposite surfaces were not affected by some APF gels and to investigate the possible underlying mechanisms. Methods The elemental composition and viscosity of 3 acidulated phosphate fluoride (APF) agents (60 Second Taste Gel, Topex, and Zap) and 1 neutral fluoride agent (pH7 Gel) were analyzed. Subsequently, 320 specimens of 3 nanocomposites (Premisa, Filtek Z350, and Grandio) and a microhybrid composite (Estelite Sigma) with 80 specimens for each composite were randomly divided into 5 groups ( n = 16) and treated with 4 fluoride gels as well as distilled water which served as the control. Fluoride gels were applied on composite resin surfaces 4 times, 30 min each time. The roughness and microhardness were measured after treatments. Qualitative examination of the surface degradation of the composites was carried out with Fourier transforming infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Results Topex and Zap did not cause surface changes of composite resins, the possible reason being ascribed to the presence of magnesium aluminum silicate (MAS) clays. In contrast, 60 Second Taste Gel treatments caused significant roughness increase, microhardness decrease, more prominent filler dissolution, and IR spectral changes of Premisa, Filtek Z350, and Grandio. Estelite Sigma was less affected by the 4 fluoride gels. Significance The composite surfaces were not affected by Topex or Zap even after extended treatments. These two APF gels may be more suitable for clinical applications.

Standardization of the Peste des Petits Ruminants (PPR) Haemagglutinin antigen for Haemagglutination-Inhibition Test

Ezeibe, M.C.O., Eze, J.I., Ijabo, O., Ngene, A.A., Okoroafor, O.N., Chukwu, O.S., Ukomadu, N.M., Sanda, E.M., Eze, I.C. and Ugonabo, J.A.C. 2010. Standardization of the peste des petits ruminants (PPR) haemagglutinin antigen for haemagglutination-inhibition test. J. Appl. Anim. Res., 38: 113–115. Samples of tisssue culture Peste des Petits Ruminants (PPR) monospecific vaccine were incubated with equal volume of aluminium-magnesium silicate. The cultured PPR virus which were haemagglutination negative became haemagglutination positive following the incubation with AMS. The haemagglutination was in each case inhibited by a known PPR antiserum. It has been concluded that incubation with AMS can be adopted to convert cultured PPR virus to standard PPR haemagglutinin antigin for use in haemagglutination inhibition test to confirm diagnosis of PPR.

Chitosan–magnesium aluminum silicate nanocomposite films: Physicochemical characterization and drug permeability

Chitosan–magnesium aluminum silicate (CS–MAS) films were prepared and the effects of MAS content and heat treatment of the CS–MAS dispersion before film casting on the physicochemical and drug permeability properties of the films were investigated. CS could interact with MAS via electrostatic interaction and intermolecular hydrogen bonding mechanisms, resulting in nanocomposite formation, for which it was not necessary to apply the heat treatment on the composite dispersions. The nature of the exfoliated and intercalated nanocomposite films formed was depended on the MAS content added. The heat treatment on the composite dispersions caused an increase in tensile strength, but reduced %elongation of the CS–MAS nanocomposite films. The exfoliated nanocomposite films showed higher flexibility, water uptake, and drug permeability compared to the CS and intercalated CS–MAS nanocomposite films. At higher MAS content, the CS–MAS films prepared using heat treatment had a lower water uptake, resulting in lower drug permeability when compared with those prepared using non-heated dispersions. The permeation mechanism of non-electrolyte and negatively charged drugs across the CS–MAS nanocomposite films was predominantly controlled by diffusion in water-filled microchannels, whereas both adsorption onto MAS and diffusion processes occurred concurrently for the film permeation of positively charged drugs. The findings of this study suggest that CS–MAS nanocomposite films can be formed without heating of the composite dispersion before casting. CS–MAS nanocomposites showed strong potential to be used as a film former for coated tablets intended for modulating drug release.

Enhanced entrapment efficiency and modulated drug release of alginate beads loaded with drug–clay intercalated complexes as microreservoirs

Calcium alginate (CA) beads loaded with intercalated complexes of propranolol HCl (PPN) and magnesium aluminum silicate (MAS), which serve as microreservoirs, were prepared using an ionotropic gelation method. The surface and matrix morphology, drug entrapment efficiency, thermal behavior, mechanical properties, and PPN release of the CA beads were characterized. The results showed that the molecular interaction of MAS with PPN and sodium alginate (SA) resulted in PPN–MAS intercalated complex particles as microservoirs and denser matrix structure formation in the CA beads. The small particles of the PPN–MAS complexes were embedded on the surface and in the matrix of the CA beads, which was revealed using SEM and EDX. The PPN entrapment efficiency of the PPN–MAS complex-loaded CA beads was significantly higher than that of the PPN-loaded CA beads. Increased MAS content caused an increase in PPN entrapment efficiency, thermal stability, and the strength of the CA beads. Moreover, the PPN–MAS complexes in the CA beads could remarkably reduce the initial burst of PPN release as well as its release rate in both 0.1 M HCl and phosphate buffer at pH 6.8, depending on the MAS content added. Additionally, the PPN–MAS complex-loaded CA beads also produced a sustained release pattern of PPN in simulated gastro-intestinal conditions. In conclusion, the CA beads containing drug–clay intercalated complexes as microreservoirs could enhance drug entrapment efficiency, reduce initial burst release and modulate drug release. Furthermore, these beads represent a promising oral drug delivery system for highly water-soluble cationic drugs.

Density and Cell Morphology of Rigid Foam PVC-Clay Nanocomposites

Rigid PVC foam is becoming increasingly popular in the building materials industry due to recent advances in compound formulations and extrusion technologies. Amongst the most critical physical properties of rigid foams is the foam density. It not only determines the weight of the foam product, but it also controls its mechanical strength, stiffness, dimensional stability, and more importantly its cost. Foam density is usually maintained, through compound formulations and processing conditions, within a narrow range to ensure adequate product performance at a minimum material cost. The objective of this work is to investigate the effect of using different types of nanoclay fillers on the density and cell morphology of rigid PVC foam. Four different types of commercially available nanoclays were used: Natural Calcium Montmorillonite (unmodified), Sodium Montmorillonite modified with a quaternary ammonium salt, Aluminium Magnesium Silicate clay, and Magnesium Lithium Silicate clay. The individual and combined effect of nanoclay concentration and blowing agent content in the polymer melt on the foam density are reported. Optical Microscopy, SEM, XRD, and TEM imaging were used in the analysis of foam cell morphology and the dispersion and exfoliation of nanoclays in the polymer matrix.