OBJECTIVES The aim of this study was to improve flowability and compressibility characteristics of starch to use as a suitable excipient in direct compression tabletting. Quasi-emulsion solvent diffusion was used as a crystal modification method. MATERIALS AND METHODS Corn starch was dissolved in hydrochloric acid at 80°C and then ethanol as a non-solvent was added with lowering temperature u...

The self-diffusion of N a + , E t 4 N + and I in mixtures of water with n-propanol at 25 °C and with lert-butanol at 30 °C was measured as function of salt concentration and solvent composition. The limiting self-diffusion coefficients of the ions were used to compute the ionic radii. The influence of the composition of the solvent on the solvation of the ions is discussed. In aqueous solutions...

The generally used model for rotational diffusion, the Perrin-Stokes-Einstein model [l-3] , is based on hydrodynamics with the “stick” boundary condition. That is, the velocity of the solute molecule surface relative to the nearest solvent molecules is zero. Recently Hu and Zwanzig [4] have derived rotational friction coefficients for spheroids with the “slip” boundary condition. Here, the resi...

Thermal diffusion forced Rayleigh scattering results on thermal diffusion of poly(ethylene oxide) (PEO) in ethanol/water mixtures are presented. In water-rich solvent mixtures, PEO is found to migrate towards regions of lower temperature. This is typical for polymer solutions and corresponds to a positive Soret coefficient of PEO. In solvent mixtures with low water content, however, the polymer...

The effective treatment of diseases of the nail remains an important unmet medical need, primarily because of poor drug delivery. To address this challenge, the diffusion, in real time, of topically applied chemicals into the human nail has been visualized and characterized using stimulated Raman scattering (SRS) microscopy. Deuterated water (D2O), propylene glycol (PG-d8), and dimethyl sulphox...

Nonlinear wrinkling of a compressed film on a soft substrate in the presence of inhomogeneous swelling actuation strain caused by solvent diffusion is studied. The simulation relies on a continuum model which integrates phase field microelasticity and Föppl-von Kármán plate theory. We show that the wrinkling morphologies developed in the diffusive domain exceeding a critical compression are con...

Ethylcellulose/methylcellulose blends were produced using different precipitation techniques and impregnated with naproxen, a non-steroidal anti-inflammatory drug (NSAID). Solvent-evaporation technique was used not only for the preparation of ethylcellulose/methylcellulose microspheres but also to encapsulate naproxen. Supercritical fluid (SCF) impregnation was also performed to prepare naproxe...

Resorcin[4]arenes in an apolar solvent containing alcohols exist in three forms of self-assembled aggregates which have been characterised by the technique of diffusion NMR spectroscopy.