Methanol was obtained from Fisher S

Methanol was obtained from Fisher Scientific, UK. Glacial acetic acid was purchased
from R & M Marketing, Essex, UK. The organic solvents and chemicals used were either of analytical reagent or high performance liquid chromatography grade. Isopropyl myristate was purchased from Derifats Chemicals Sdn Bhd, Malaysia. Tween 80 and Span 80 were purchased from Sigma–Aldrich, USA.