Development and Characterization of DOPEPEG2000 Coated Oleic Acid Liposomes Encapsulating Anticancer Drugs

Abstract

Liposomes have been widely investigated as drug carriers for a broad range of anticancer drugs. However, their application as a drug delivery system may be challenging due to low encapsulation of active ingredient and poor stability which leads to uncontrolled delivery of bioactive ingredients. The present study aims at incorporating 1,2‐dioleoyl‐sn‐glycero‐3‐phosphoethanolamide‐N‐[methoxy(polyethylene glycol)‐2000 (DOPEPEG2000) into oleic acid (OA) liposomes in order to prolong the lifetime in blood circulation. The pH transition curve of oleic was obtained by titration of sodium oleate solution with 0.05 mol dm−3 HCl to determine the region where liposomes were abundantly present. The critical vesicle concentration (CVC) was then determined by surface tension measurements. Dry lipid liposomes were hydrated with phosphate buffer at just over twice the CVC value. Optical polarizing microscopy (OPM) showed the presence of liposomes while transmission electron microscopy (TEM) confirmed that the liposomes prepared were spherical in shape and less than 200 nm in size. The incorporation of DOPEPEG2000 into the oleic acid liposomes reduced the average particle size and zeta potential to mimic the red blood cells. The encapsulation efficiency of various anticancer drugs was more than 60% while more than 20% of the drugs were released after 24 h. The results suggest that DOPEPEG2000: oleic acid at a molar ratio of 1:50 fulfilled the requirements for intravenous drug delivery.