was placed in a disk and covered by a membrane then placed at the
bottom of the dissolution vessel.
The membrane was used to retain
the formula inside the disk. The dissolution medium used was
700 ml of hydro-alcoholic solution (1:1) to ensure sink condition.
The apparatus was equilibrated to 32 ± 0.5 C and the stirrer paddle
speed was set at 50 rpm. Aliquots were withdrawn at appropriate
time intervals (0.5, 1, 2, 3, 4, 5 and 6 h) and filtered through a syringe
filter having a pore size of 0.1 lm then analyzed spectrophotometrically
at wavelength of 250 nm (according to the method of
drug assay). The amount of drug released was calculated from the
standard curve. This procedure was performed in triplicates for
each formulation. Cumulative % drug released were calculated
out and plotted against time. ALA release from cubosomes in gels
has been shown to be primarily controlled by diffusion through
the matrix [18] and consequently can be described by the Higuchi
diffusion equation given by