Physicochemical studies on the sedimentation state of suspension particles. V. Studies on the effect of methylcellulose and sodium dodecyl sulphate on the dispersion and sedimentation state of griseofulvin (author's transl)

Abstract

Effects of methylcellulose and sodium dodecyl sulfate (SDS) on the dispersion and sedimentation bed of Griseofulvin (GR) was examined by the measurement of apparent degree of aggegation (γm/γo), amount of adsorption (X), ζ-Potential, porosity (ε), and tortxosity (q) of the sedimentation bed. When methylcellulose was added to the suspension prepared in water or SDS solution, γm/γo and ε decreased and q increased with the increasing amount of methylcellulose added in the case of water and 0.8 mM SDS solution, while each of the above quantities remained constant in 8 mM SDS solution. The ζ-potential in 10 mM NaCl decreased with the increase of methylcellulose, but gave a constant value against methylcellulose in the presence of SDS. The amount of methylcellulose adsorbed decreased with the increase of SDS concentration, and adsorption was not observed in 8 mM SDS solution. When SDS was added to the suspension prepared in water or methylcellulose solution, γm/γo and ε decreased and q increased with the increasing amount of SDS added in the case of water, while these values showed a maximum value against the SDS concentration at about 2.5 mM in the case of a suspension prepared in methylcellulose solution. The ζ-potential increased with the increase of SDS concentration in water or methylcellulose solution. Amount of SDS adsorbed was almost equal in both water and methylcellulose solution. Vertical tortuosity, qv, showed a higher value than horizontal tortuosity, qM, in all cases, and they were almost equal in concentrated dispersant solxtion. All the data plotted to see the relation between q and ε fell on the same line, showing that q decreased with the increase of ε. qv/qM took the value near 1 and increased with the increase of ε.