Physicochemical characterization of interaction of ibuprofen by solid-state milling with aluminum hydroxide

This present study is a preliminary exploration of the affinity between a carboxylic model drug ibuprofen and aluminum hydroxide. Ibuprofen was comilled with aluminum hydroxide in different weight ratios in the solid state and was characterized by scanning electron microscopy (SEM), X-ray powder diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), and in vitro dissolution studies. XRD and SEM studies indicated complete interaction of ibuprofen with aluminum hydroxide and complete amorphization of aluminum hydroxide-ibuprofen complexed salt as well, on comilling with aluminum hydroxide at 1:2 ratio. FTIR data showed the disappearance of acid carbonyl peak with the appearance and the corresponding increase in absorbance of new signal at 1,682 cm(-1) in the 1:1 and 1:2 ibuprofen-aluminum hydroxide-comilled powder. The accompanied increase in the absorbance of carboxylate peak in the ibuprofen-aluminum hydroxide physical mixture, and 1:0.1, 1:0.5, 1:1, and 1:2 (IBA(pm), and IB(1)A(0.1), IB(1)A(0.5), IB(1)A(1), and IB(1)A(2), respectively) comilled powder indicated an acid-base reaction between ibuprofen and aluminum hydroxide. On storage at 40 degrees C and 75% relative humidity (RH) for 10 weeks, XRD study showed the absence of reversion to the crystalline state and FTIR data revealed continued increase of new signal at 1,682 cm(-1) relative to carboxylic acid peak and no reappearance of carboxylic acid peak. In vitro dissolution studies revealed that the percent release of ibuprofen from the aluminum hydroxide-comilled powder is in the following order: IB(1)A(2) < IB(1)A(1) < ibuprofen crystal < ibuprofen milled alone < IB(1)A(0.1) < IB(1)A(0.5). Aluminum metal cation might have interacted to form a complex through the carboxyl and carbonyl groups of ibuprofen. Improved dissolution of drug associated with IB(1)A(0.1) and IB(1)A(0.5) is because of the absence of a new signal at 1,682 cm(-1) and improved amorphization of the drug to some extent. Dissolution of drug affected in IB(1)A(2) and IB(1)A(1) may be because of the insoluble stable complex formation.     

Isotherm and kinetic sorption of some lanthanides and iron from aqueous solution by aluminum silicotitante exchanger

Sorption of La³⁺, Eu³⁺, and Fe³⁺ onto new synthetic inorganic ion exchange material of aluminum silicotitante was investigated. The aluminum silicotitante (EX₁, EX₂, and EX₃) are synthetic with different concentration ratio (0.1:0.1:0.003, 0.1:0.1:0.1, and 0.1:0.1:0.1) at aging time 4, 4, and 1 day, respectively. The equilibrium kinetic for La³⁺, Eu³⁺, and Fe³⁺ onto EX₁, EX₂, and EX₃ materials takes about 120?min which is considered as a fast kinetic process. Sorption results were fitted using different kinetic models such as pseudo-first-order, pseudo-second order, and intraparticle diffusion models. The results indicated that the sorption of La³⁺, Eu³⁺, and Fe³⁺ onto EX₁, EX₂, and EX₃ materials is highly fit with the pseudo-second order model. Equilibrium data were described by the Langmuir, Freundlich isotherm models. The Langmuir isotherm model was fitted to the experimental data better than the Freundlich isotherm. The thermodynamics parameters (positive values of ΔH°, ΔS° and negative values of ΔG°) indicated the binding systems between the materials and adsorbate were endothermic, entropy gained and spontaneous in nature. The experimental data indicated that, aluminum silicotitante could be used as an efficient sorbent for La³⁺, Eu³⁺, and Fe³⁺. Maximum sorption % at equilibrium is 92.7, 99.0, and 78.5% for La³⁺, Eu³⁺, and Fe³⁺, respectively.     

Initial Salt Screening Procedures for Manufacturing Ibuprofen

The aim of this paper is to design initial salt screening procedures for manufacturing ibuprofen. Salt forms of a pharmaceutical acid racemic (R,S)-(±)-ibuprofen and their “developable” synthetic routes were ferreted out simultaneously through the screening of seven bases of sodium hydroxide, potassium hydroxide, l-arginine, l-histidine, l-lysine, diethanolamine, and tris(hydroxymethyl)aminomethane (THAM), and the match with the use of nine organic solvents of methanol, dimethyl sulfoxide, ethanol, N,?N-dimethylformamide, acetonitrile, isopropyl alcohol, 1,4-dioxane, acetone, and tetrahydrofuran mainly in the presence of water in 20 mL scintillation vials. Racemic (R,S)-(±)-sodium ibuprofen dihydrate, a well-known ibuprofen salt and the newly discovered racemic (R,S)-(±)-THAM ibuprofen, appeared as white-squared powders with a molecular weight of 327.42 g/mol, a melting point of 160.17°C, and the apparent solubility product, K′_sp, of 6.0 × 10^?4 M² at 25°C were successfully synthesized by the initial salt screening methods. The new amine salt of ibuprofen was monoclinic and had a space group of P2₁/c and lattice parameters of a = 17.578(8)°, b = 10.428(4)°, c = 9.991(4) Å, α = 90.00°, β = 97.17(1)°, γ = 90.00°, and V = 1,817.05(244) ų. The aspect ratio of the amine salt crystals of ibuprofen of ≈ 1.0 implied that the crystals had a better flowability than the sodium salt counterparts. This amine salt of ibuprofen was more stable in moist or dried atmospheres and was more hydrophobic than the sodium salt of ibuprofen. Moreover, the slow dissolution of this amine salt of ibuprofen might have made it less bitter and more suitable as a sustained release drug than the sodium salt of ibuprofen. The future work is to search for the different polymorphs of this amine salt of ibuprofen and to extend the initial salt screening working logics to the formation of co-crystals.     

Crystal data on ytterbium chlorosilicate,Yb3(SiO4)2Cl

Ytterbium chlorosilicate, Yb₃(SiO₄)₂Cl, was obtained in the form of single crystals up to 1.5 × 1.5 × 0.5 mm³ as by-product of the synthesis of ytterbium oxychloride. The compound has orthorhombic symmetry (space group Pnma - D_2h¹⁶). The unit cell parameters are: $\text{a}\text{= 6.753}\text{A}\text{?}\text{, b}\text{= 17.583}\text{A}\text{?}\text{, c}\text{= 6.137}\text{A}\text{?}$. The substance is characterized by means of morphology and X-ray powder data.     

Crystal growth and scintillation properties of Er-doped Lu3Al5O12 single crystals

Er-doped Lu₃Al₅O₁₂ (Er:LuAG) single crystalline scintillators with different Er concentrations of 0.1, 0.5, 1, and 3% were grown by the micro-pulling-down (μ-PD) method. The grown crystals were composed of single-phase material, as demonstrated by powder X-ray diffraction (XRD). The radioluminescence spectra measured under ²⁴¹Am α-ray excitation indicated host emission at approximately 350 nm and Er³⁺ 4f-4f emissions. According to the pulse height spectra recorded under γ-ray irradiation, the 0.5% Er:LuAG exhibited the highest peak channel among the samples. The γ-ray excited decay time profiles were well fitted by the two-component exponential approximation (0.8 μs and 6-10 μs).     

A new route to mass production of metal hydroxide/oxide hydroxide nanoparticles

Aluminum hydroxide/oxide hydroxide nanofibers were self-assembled by hydration of highly activated aluminum powder using no surfactants or templates. The activation was performed by milling aluminum powder with sodium chloride as nano-miller. Transmission electron microscopy images and X-ray diffraction patterns confirm that this method leads to smaller size of aluminum particles (less than 50 nm) and increases the lattice strain. These factors provide conditions under which hydration procedure proceeds until it reaches the core of aluminum particles. The synthesized powder consists of nanofibers with thickness less then 10 nm and average length of 120 nm and specific surface area of 309 m² g⁻¹. The process is convenient, highly efficient and capable to be implemented in mass production. It may be extended to produce hydroxide/oxide hydroxide nanopowders of other metals, as well.     

The utility of rat jejunal permeability for biopharmaceutics classification system

Purpose: The biopharmaceutical classification system has been developed to provide a scientific approach for classifying drug compounds based on their dose/solubility ratio and human intestinal permeability. Therefore in this study a new classification is presented, which is based on a correlation between rat and human intestinal permeability values. Methods: In situ technique in rat jejunum was used to determine the effective intestinal permeability of tested drugs. Then three dimensionless parameters—dose number, absorption number, and dissolution number (D_o, A_n, and D_n)—were calculated for each drug. Results: Four classes of drugs were defined, that is, class I, D₀ < 0.5, P_eff(rat) > 5.09 × 10^?5 cm/s; class II, D_o > 1, P_eff(rat) > 5.09 × 10^??5 cm/s; class III, D₀ < 0.5, P_eff(rat) < 4.2 × 10^?5 cm/s; and class IV, D_o > 1, P_eff(rat) < 4.2 × 10^?5 cm/s. A region of borderline drugs (0.5 < D_o < 1, 4.2 × 10^?5 < P_eff(rat) < 5.09 × 10^?5 cm/s) was also defined. Conclusion: According to obtained results and proposed classification for drugs, it is concluded that drugs could be categorized correctly based on dose number and their intestinal permeability values in rat model using single-pass intestinal perfusion technique. This classification enables us to remark defined characteristics for intestinal absorption of all four classes using suitable cutoff points for both dose number and rat effective intestinal permeability values.     

Role of Mg dopant on the electrochemical performance of LiNi0.5Co0.5O2 cathode materials for lithium rechargeable batteries

Positive electrode materials, LiMg _x Ni_0.5−x Co_0.5O₂ (x = 0 < x < 0.5), have been successfully synthesized by microwave-assisted solution technique. The precursor has been analyzed by TG/DTA and the powder was calcined at 850 °C. The XRD patterns reveal that the synthesized materials exhibit hexagonal layered structure corresponding to space group. Coin cells of 2016 type have been fabricated using the synthesized layered material as cathode active material and lithium foil used as counter and reference electrode. Test cells were operated in the potential limits between 2.7 and 4.3 V using 1 M LiPF₆ in 1:1 EC/DEC as electrolyte. LiMg_0.2Ni_0.3Co_0.5O₂ material delivers an average discharge capacity of around 165 mA hg⁻¹ at 0.1 C rate over the investigated 20 cycles.     

Trivalent chromium in the solid solution system CrxMo1-xO2 (x ≤ 0.5)

the solid solution system Cr_xMo_1-xO₂ for x ≤ 0.5 was investigated. The following three phases were identified from x-ray powder diffraction analyses: monoclinic distorted rutile (CrMoO₄) for 0.36 ≤ x ≤ 0.5, tetragonal rutile for 0.12 ≤ x < 0.36 and monoclinic (MoO₂) for 0 ≤ x < 0.12. From magnetic data it was shown that throughout the whole range the magnetic ion was trivalent chromium (d³) and the pentavalent molybdenum (d¹) due to its metallic Mo-Mo interactions does not contribute to the magnetic moment.     

Synthesis of ammonium aluminum oxalate from Bayer aluminum hydroxide

The synthesis of ammonium aluminum oxalate was performed using Bayer aluminum hydroxide as a raw material. For this aim, Bayer aluminum hydroxide of 99.7% purity was dissolved in oxalic acid to produce an aqueous aluminum solution. As a result, it was found that a mixing ratio of ethanol to Al solution exceeding 2:1 and a pH adjusted to greater than 8.0 should be employed in the synthesis of ammonium aluminum oxalate. From the chemical analysis of ammonium aluminum oxalate prepared in this work, the NH₄, Al and C content were found to be 14.5, 7.18 and 17.4%, respectively which are very close to the theoretical values of (NH₄)₃Al(C₂O₄)₃3H₂O.     

New rutile solid solutions,Ti1−4xLixM3xO2: M = Nb,Ta, Sb

Three extensive new rutile solid solution series have been prepared in which Ti⁴⁺ is replaced by a combination of Li⁺ and a pentavalent cation: Nb⁵⁺, Ta⁵⁺, Sb⁵⁺. The formulae are Ti_1?4xLi_xM_3xO₂: 0 < x ? 0.15, M = Ta; 0 < x ? 0.17, M = Nb; 0 < x ? 0.12, M = Sb. The solid solutions were characterised by X-ray powder diffraction and density measurements. In addition to the rutile solid solutions, LiNb₃O₈ forms a limited range of solid solutions, Li_1?yNb_3?3yTi_4yO₈: 0 < y ? 0.06.     

Mechanochemical Synthesis of Double Hydroxides

It has been demonstrated that the formation of magnesium-aluminium double hydroxides [Mg_{(1 – X)}Al _X (OH)₂] ^X+(A ^n– _X/n ) m H₂O, (A–Cl^–, NO^– ₃, SO^2– ₄) occurs during mechanical activation of the mixture of magnesium hydroxide (brucite) with aluminium chloride, nitrate and sulphate in high-energy planetary-type activators. The effect of activation time on the formation of the double hydroxide has been investigated. Thermal decomposition of the chloride form of the double hydroxide has been studied.     

Crystal growth and scintillation properties of Nd-doped Lu3Al5O12 single crystals with different Nd concentrations

Nd 0.1%, 0.5%, 1% and 3% doped Lu₃Al₅O₁₂ (Nd:LuAG) single crystals were grown in the nitrogen atmosphere by the micro-pulling down (μ-PD) method. The grown crystals had a single-phase confirmed by powder XRD analysis. In absorption spectra, some weak absorption lines due to Nd³⁺ 4f-4f transitions were observed and their intensity increased with the increase of Nd concentration. When excited by ²⁴¹Am α-ray, a broad emission peak due to defects in the host lattice at 320 nm and some sharp lines due to Nd³⁺ 4f-4f transitions at wavelength longer than 400 nm were observed. The decay time profiles of Nd:LuAG under γ-ray excitation were well approximated by two exponential function of 340-760 ns and 3-5 μs for each sample. By pulse height measurement using ¹³⁷Cs, Nd 0.5%:LuAG showed the highest light yield of 7600 ± 760 photons/MeV.     

Existence de la structure triramsdellite : Li3FeSb2O8

An ordered ramsdellite Li₃FeSb₂O₈, called triramsdellite, was synthesized for the first time. This phase crystallizes in the orthorhombic system, with the possible space groups Pmcn and P2₁ cn and with the parameters $\text{a}\text{= 9.017(4)}\text{A}\text{?}$, $\text{b}\text{= 5.013(2)}\text{A}\text{?}$ and $\text{c}\text{= 9.841(4)}\text{A}\text{?}$. The X-ray powder diffraction study shows that a 1–2 type order appears between the cations belonging to the two sorts of octahedral sites A and B; these sites are preferentially occupied by lithium and antimony respectively according to the formulation |Li₃|_tet|Li_1.5Fe_0.5|^A_oct|FeSb₃|^B_octO₁₂. This structure, which can be described as built up from A₂B₄O₁₂ octahedral units, is compared to the LiSbO₃ and trirutile structures.     

Electrolytic preparation of Al3Ni fibers from the eutectic alloy,AlAl3Ni

An electrolytic procedure was developed to remove the trialuminum nickel fibers from the aluminum matrix in the eutectic alloy, AlAl₃Ni. The procedure consists of electrolyzing the aluminum matrix at potentials ranging from ?0.8 to +0.5 volts (vs S.C.E.) in a 1$\text{M}$ potassium hydroxide electrolyte. Scanning electron photomicrographs showed that the separated Al₃Ni fibers are intact. Anodic polarization studies with aluminum-nickel alloys illustrated that the presence of nickel protects aluminum from oxidation. Studies with a special fabricated platinum electrode demonstrated that the Al₃Ni fibers are not oxidized within the potential range of ?0.8 to +0.5 (vs. S.C.E.) in a 1$\text{M}$ potassium hydroxide electrolyte. This decreased rate of oxidation of aluminum in the Al₃Ni fibers is correlated with the low rate of diffusion of the aluminum in the Al₃Ni orthorhombic crystals.     

Sol-gel synthesis of lead-free (K0.5Bi0.5)0.4Ba0.6TiO3 nanorods

A kind of lead-free ferroelectric nanorods, (K_0.5Bi_0.5)_0.4Ba_0.6TiO₃, has been prepared by the sol-gel process. The phase formation, structure and morphological analyses of (K_0.5Bi_0.5)_0.4Ba_0.6TiO₃ were investigated by XRD, FTIR, Raman and TEM. The results revealed that single-crystalline (K_0.5Bi_0.5)_0.4Ba_0.6TiO₃ nanorods with width around 80 to 120 nm, and length around 200-300 nm were obtained by calcining dried gels at 800 °C for 2 h. Raman analysis of (K_0.5Bi_0.5)_0.4Ba_0.6TiO₃ nanorods indicated that A₁(TO₂) and E(TO) mode incorporated into one broad peak at around 285 cm^− 1, which can be attributed to the cation disorder (Bi, K, Ba) on the 12-fold coordinated A site of ABO₃ structure.     

Reduced titanium oxide Ti3O5 powder as a promising conductive additive for LiFePO4-based lithium-ion batteries

Reduced titanium oxide Ti₃O₅ powder which was fabricated by a sol–gel process was added to lithium iron phosphate (LiFePO₄) cathode electrodes for use in lithium-ion batteries and its performance was investigated. First discharging of the cathode electrode with Ti₃O₅ powder as the conductive additive keeps the capacity of 170.9 mAh g^?1 at 0.1 C, 150.8 mAh g^?1 at 0.5 C, 134.6 mAh g^?1 at 1 C, and 107 mAh g^?1 at 2 C, respectively, which is higher than that of the cathode electrode with acetylene black as the conductive additive, who keeps the capacity of 162 mAh g^?1 at 0.1 C, 142.8 mAh g^?1 at 0.5 C, 126.9 mAh g^?1 at 1 C, and 105.8 mAh g^?1 at 2 C, respectively. Over 100 cycles at 0.5 C, the LiFePO₄ cathode electrode with Ti₃O₅ powder can maintain 77.5 % of its initial capacity, and the electrode with acetylene black shows 73.6 % capacity retention. The reason why the electrode with Ti₃O₅ additive shows better rate capability is that the Ti₃O₅ powder exhibits a relatively good electrical conductivity and shows a more homogeneous dispersion than acetylene black among the LiFePO₄ particles during the cycles, in the investigation, a layer of suspected titanium oxide yarn-like thin film is discovered coating on the LiFePO₄ particles of the cathode electrode with Ti₃O₅ powder after 100 cycles at 0.5 C.     

Synthesis of Ca-α-SiAlON:Eux phosphor powder by carbothermal-reduction–nitridation process

Yellow-emitting Ca-α-SiAlON:Eu_x phosphor powders have been synthesized by the carbothermal-reduction–nitridation of a homogeneous Ca–Si–Al–Eu–C–O mixture at 1550 °C in flowing nitrogen. The resulting phosphor powder emits yellow luminescence with a peak wavelength at 575–590 nm under ultraviolet excitation at 370 nm. Compared with commercial Ce³⁺-doped yttrium aluminum garnet (YAG:Ce³⁺) phosphor powder, the synthesized Ca-α-SiAlON:Eu_x phosphor powder exhibits better thermal stability.     

Preparation of magnetic coatings from strontium hexaferrite on tin and cardboard by cold rolling

A finely dispersed powder of strontium hexaferrite doped with aluminum of the composition SrFe_12?x Al _x O₁₉ with an aluminum content x = 0.6 ± 0.1 is prepared through crystallization of oxide glasses. The powder is characterized by a saturation magnetization of 60.2 A m²/kg and a coercive force of 550 kA/m. The hexaferrite particles predominantly have the shape of thick hexagonal platelets with a diameter ranging from 300 to 500 nm and a thickness-to-diameter ratio varying from 0.3 to 0.5. Magnetic coatings on tin and cardboard substrates are produced by cold rolling of strontium hexaferrite powders. It is shown that hexaferrite particles in the magnetic coatings have the preferred orientation of the well-developed facets along the rolling plane, which manifests itself in anisotropy of the magnetic properties of the coatings. The degree of texturing in the strontium hexaferrite coatings on cardboard and tin substrates is equal to 44 and 66%, respectively.