Powdered Particle Interactions: Suspension Flocculation and Caking I

Use of the Derjaguin, Landau, Verwey, and Overbeek Theory to Interpret Pharmaceutical Suspension Stability

“…One method which has been suggested for approaching this problem has been to use the principle of controlled flocculation (1). Although some workers (2) have questioned whether this procedure can be applied to macroscopic particles, the present authors have shown (3) that both flocculation, probably involving chemical bridging, and coagulation, resulting from zeta potential reduction, can be used to prevent impaction. It has also been shown (4) that comparisons may be made between coagulation in model monodisperse systems and in heterodisperse drug suspensions.…”

Use of the Coulter Counter and a Digital Computer for the Evaluation of Stability Ratios in Flocculating Monodisperse Systems

“…Further experiments are planned to evaluate more fully the factors which are likely to be of importance in governing the flocculation behavior of pharmaceutical suspensions. Such information is likely to be of great value in rationalizing the behavior of these systems and providing the pharmacist with a sound theoretical basis for formulation (13) to be compatible with aluminum salts, whereas more commonly used anionic surfactants such as sodium lauryl sulfate and sodium dioctyl sulfosuccinate cause precipitation (6,13). The results of two experiments are shown in Fig.…”

Aggregation Mechanisms in Pharmaceutical Suspensions

“…We would also like to answer an earlier criticism, by Wilson and Ecanow (4), of the validity of the concept of flocculation (or rather coagulation) of large particles by {-potential reduction and van der Waals' attraction. They refer to the statement by Kruyt (14) of the possibility of long-range London-van der Waals' forces between particles of 2-5 pm.…”

“…Intravenous administration of dextran solution has been suggested for treatment of hypercholesterolemia and atherosclerosis (l), and numerous investigations have been carried out to determine the effect of dextran on experimental hypercholesterolemia (2)(3)(4)(5)(6). Oral administrations of pectin and acacia have been studied for their hypocholesterolemic effects (7-14).…”