Purpose: To characterize diclofenac sodium (DS) liposomes prepared using palm oil fractions. Methods: Reverse-phase evaporation method was used to prepare liposomes containing 10, 20, 30, 40 or 50% palm oil fractions. The effect of palm oil content on liposome formation, surface morphology, shape, size and zeta potential of the liposomes were studied using scanning electron microscopy (SEM) transmission electron microscopy (TEM) and particle analyzer. Drug loading, entrapment efficiency and in vitro drug release were measured in phosphate-buffered saline (PBS, pH 7.4) by UV spectrophotometry.

Results TEM and SEM images showed formation of liposomes for all formulations, However, increase in the proportion of palm oil in the formulations significantly reduced particle size and increased zeta potential. The effect on drug loading and drug release varied with palm oil fraction. The best release pattern with appropriate entrapment efficiency and stability was obtained with liposomes containing 33 % palm oil fraction. Introduction of 46 and 56 % of palm oil fractions yielded zeta potential of -42.8 and -50.7 mV, respectively, compared with -31.2 mV for the formulation without palm oil.

Conclusion: The results demonstrate the potentials of palm oil fractions in the preparation of suitable DS liposomes with good bioavailability.