152 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Results for salicylamide suspensions are shown in Fig. 2. These suspensions were deflocculated (and exhibited caking) in the absence of a hydrophilic additive. Lower concentrations of the additives were sufficient to induce a rise in sedimentation volumes (signifying the onset of flocculation) than with sulfamerazine. o.4 f 0.3 0.2 0.1 I I I 20 40 60 POLYOL CON. (% V/v ) Figure 2. Sedimentation volume (F) of logo salicylamide suspensions containing various polyols. v propylene glycol O polyethylene glycol 400 [] sorbitol solution Only sorbitol was used in the butamben suspensions (Fig. 3) Sedimentation volume was increased even at low sorbitol concentration. The suspension containing no sorbitol was caked. Interestingly, none of the other suspensions, regardless of sedimentation volume, was completely redispersible either. The suspensions had a coarse appearance suggesting that recrystallization occurred on standing. This may have resulted in a

SUSPENSIONS CONTAINING NONIONIC SURFACTANT !55 0.2 0 I i I I 20 40 POLYOL CON. (% v/v ) Figure •. Sedimentation volume (F) of 10% butamben suspensions cor•t•irfir•g sorbitol. 4ø I •. 20 • - o o 0 I I I I I I l 20 40 60 POLYOL CON. (% v/v ) Figure 4. Solubility of sulfamerazine as a function of polyol concentration. v propylene glycol O polyethylene glycol 400 [] sorbitol solution