Correlation of dielectric constant and solubilizing properties of tetramethyldicarboxamides.

The dielectric constants of aqueous solutions of four tetramethyldicarboxamides (tetramethylpimelamide, tetramethylsuberamide, tetramethylazelamide, and tetramethylsebacamide) were measured at 25 degrees. The values obtained were utilized in assessing the solubility behavior patterns of glutethimide, a semipolar, water-insoluble drug in these amide-water systems. At equimolar concentrations of water-rich amide solutions, the solubilizing power paralleled the chain length of the amides.

Residues in antibiotic preparations, ii: effect of pH on the nature and level of particulate matter in sodium cephalothin intravenous solutions.

The effect of pH on the extent and nature of particulate contamination in sodium cephalothin intravenous solutions was studied. The extent of particulate contamination was determined by microscopic and automatic electronic counting procedures, and the physical nature of the particles was determined using scanning electron microscopy. At low pH values (i.

Residues in antibiotic preparations, i: scanning electron microscopic studies of surface topography.

The surface characteristics of residues obtained from several commercial antibiotic products were studied using scanning electron microscopy. The photomicrographs showed the presence of particulates possessing crystalline or amorphous properties with particle sizes ranging from 1 mum to several mum. Small, well-defined, granular crystalline particulates seemed to predominate in residues of products which were processed under optimum pH conditions.