The following interactions between the soluble surfactant, @entity6000 9, and the very slightly soluble, finely powdered drug, @entity8821 , in aqueous suspension were investigated: adsorption/desorption of the surfactant, micellar solubilization of the drug, and deflocculation of its particles. The last effect, measured by the sedimentation volume of the suspensions, was also investigated for other @entity6000 . The adsorption of @entity6000 9 on solid @entity8821 was proportional to the equilibrium surfactant concentration up to the critical micelle concentration. It leveled off at higher concentrations, reaching saturation at completion of a close-packed surfactant monolayer. The adsorption was essentially completely reversible. The solubility of @entity8821 in water was very slight; its micellar solubilization was even less extensive. The sedimentation volume of @entity8821 suspensions decreased with increasing equilibrium concentration of @entity6000 9 and began to level off at the critical micelle concentration of 0.018%. At about twice that concentration, the sedimentation volume became almost constant, but reached its lowest value only at less than or equal to 0.5%. Slow rotation of suspensions prior to sedimentation promoted flocculation and higher sedimentation volumes between 0.01 and 0.03% @entity6000 9. @entity6000 with higher hydrophilic-lipophilic balance than @entity6000 9 produced considerably larger sedimentation volumes at comparable concentrations, due to a lower surface activity and a lesser tendency to adsorb on @entity8821 .

Effect of nonionic surfactants on aqueous XXXX suspensions.

@entity8821 :: ('MESH:D011324', 'Chemical') :: ['primidone'] @entity6000 :: ('MESH:D017830', 'Chemical') :: ['Octoxynols', 'octoxynols', 'octoxynol']
@entity8821 :: (MESH:D011324,Chemical) :: ['primidone']
