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The main objective of the present work was to enhance the solubility and dissolution rate of poorly water-soluble drug cefuroxime axetil (CA) by formulating it into solid dispersions (SDs) with water soluble carrier poloxamer 188. Different methods were employed to prepare the dispersion, such as: Solvent method (SM), Kneading method (KM), Melt evaporation method (MEM) and Physical mixture (PM) in different drug: carrier ratios 1:1, 1:2 and 1:3 (cefuroxime axetil: poloxamer 188). The physical mixture(s) and solid dispersion(s) were characterized for drug carrier interaction, drug content, solubility, dissolution rate, differential scanning calorimetry (DSC) and FT-IR study. The dissolution rate of the prepared solid dispersion systems was determined in phosphate buffer (pH 6.8) for 1 h. The solubility of drug from different systems was also determined in water. All SD formulations were found to have a higher dissolution rate comparatively to pure CA. The dissolution rate was enhanced in the following order SM > MEM > KM. The enhancement of dissolution rate may be caused by increase wettability, dispersibillity reduction in particle size or the formation of CA β crystalline. The FT-IR study probability revealed that there was no chemical interaction between drug and poloxamer 188.

In this work, various concentrations of ZnO nano particles, prepared by the coprecipitation method with a size range of 47-68 nm, have been investigated as antimicrobial agents. Dilution antimicrobial susceptibility tests were carried out on two kinds of microbes (Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli) according to the standard method recommended by Clinical and Laboratory Standards Institute, CLSI-2015-M07-A10. The results showed that the antimicrobial effect is larger, the higher the concentration of ZnO nano particles in solution. It was also found that Gram-positive microbes are more sensitive to ZnO nano particles when compared with the Gram-negative ones. The minimum inhibitory concentration (MIC) for E. coli was found to be 50 mg/mL while that for S. aureus was 25 mg/mL. The minimum bactericidal concentration (MBC) was 1600 mg/mL for E. coli and 800 mg/mL for S. aureus.

Liquid crystals (LCs) are soft materials that combine the fluidity of disordered liquids and the long-range orientational or positional order of crystalline solids, along one or two directions of space. A search for better stationary phases, including highly selective ones, is an important trend in chromatography development. Among the stationary phases under investigation are LC stationary phases that have been recently generated much interest. A variety of isomeric molecules were separated with high accuracy. Successfully, X-ray scattering is widely used to investigate and characterise the microscopic structure of most LCs. In this paper, a new liquid crystalline material that can be used potentially as stationary phase in gas chromatography was synthesised and characterised by means of nuclear magnetic resonance (NMR), infrared (IR) spectra, elemental analysis and X-ray diffraction.Keywords: liquid crystalline; Schiff base; nematic; X-ray diffraction; gas chromatography Introduction Liquid crystals (LCs) or mesophases are intermediate states of condensed matter; they combine long-range positional or orientational order along some directions of space (like in a crystal) and liquid-like disorder along other directions [1]. The most commonly obtained liquid crystalline phases are those with organic molecules or in solutions of surfactants.Presently, LCs can be divided into two categories: thermotropic and lyotropic according to the principal means of destroying the order in the parent solid state, probably thermotropic LC is the most widely studied category. Thermotropic LCs are formed by varying the temperature of the compounds and can be further classified as nematic (N) and smectic (S m ) structures [2,3].Since 1974, a number of studies have been centred on liquid crystalline materials with anisotropic properties. In particular, nematic LC materials based on Schiff base core have attracted considerable interest due to their unique solvent properties and potential applications in gas chromatography [4,5,[8][9][10][11][12][13][14][15][16].Increasing attention has been focused on important pollutants and phenols introduced into the environment through the discharge of industrial waste and the decomposition of various pesticides and herbicides [5][6][7]. The determination of substituted phenol isomers by ordinary stationary phases presents some difficulties, since these isomers have similar boiling points and polarities.A stationary phase able to separate on a basis other than boiling point or polarity is essential. Several studies have centred on liquid crystalline