A simple one-step protocol for preparing small-sized doxorubicin-loaded liposomes

A simple, single-step, extrusion-free protocol for preparing doxorubicin-loaded liposomes (100150 nm), based on the ethanol injection method (EIM), is described. Efficient encapsulation of doxorubicin (up to 98%) was obtained concomitantly with liposome preparation avoiding the need for an additional loading step. Parameters such as stock concentration of phospholipid, injection ratio, lipid composition, and drug-to-phospholipid ratio affected the resultant liposome size and magnitude of doxorubicin encapsulation. A lipid stock concentration (50 mM) and injection ratio (1:10) resulted in 96.0 +/- 2.92% encapsulation efficiency of doxorubicin (drug-to-lipid mole ratio: 0.192) and mean diameter of 135 +/- 2.32 nm for SCOL-2 formulation (DSPC/ cholesterol /oleic acid: 2/2/1; molar ratios). Replacement of phospholipid DSPC with DMPC or DPPC did not affect the mean liposome size and doxorubicin-encapsulation efficiency. These findings offer promise for scale-up and development on a large-scale production of doxorubicin-loaded liposomes for effective cancer therapy.