The stability of the different emulsions at 2071C
was evaluated by holding 10 ml samples in capped
graduated tubes (15 ml capacity) in which the volume of
the emulsion layer was measured 0–10 days after
preparation in relation to the sample volume (10 ml).
Ten tubes (replicates) per formulation were set up and
the experiment was repeated twice to confirm the
reproducibility of the results. The viscosity of the
emulsions was measured at the same time using a
viscometer (model: VT-03, Rion Co. Ltd., Japan;
accuracy of the viscometer=73% reading) using
200 ml samples in 250ml beakers. Ten samples representing
10 replicates per formulation were set up and the
experiment was repeated twice to confirm the reproducibility
of the results. The most stable formulation with
low viscosity (no. 9, Table 1) was selected for subsequent
stages of the present study