emulsion at both storage temperatures indicated the ability of the
emulsifier to retard changes in the oil droplet sizes; the emulsion
stabilized with BN40M appeared to retain the initial distribution at
37 C better than at 25 C (data not shown).
The stability of BN40M emulsions may be explained by viscosity
effects, improved adsorption to the oil surface due to the high M:HP
ratio, and the enhancement of hydrophobic interactions at higher
temperatures. When a solution of HPMC is heated above its lower
critical solution temperature, HPMC precipitates due to enhanced
hydrophobic interactions as temperature increases (Sarkar, 1995).
The smaller particle sizes in the emulsion produced by AN6 at 37 C
as compared to 25 C and the retention of the initial particle distribution
in BN40M over 12 days at 37 C may suggest the role of higher
temperatures in generating stable emulsions by promoting stronger
hydrophobic interactions between the oil droplet and emulsifier