We have examined the effect of stearylamine (SA) in liposomes on the viability of Plasmodium falciparum in culture by studying the inhibition of incorporation of [3H]-hypoxanthine in the nucleic acid of parasites. Stearylamine in liposomes significantly inhibits the growth of the parasites depending on the phospholipids composition. The maximum inhibition was observed when SA was delivered through Soya phosphatidylcholine (SPC) liposomes. The chain length of alkyl group and density of SA in liposomes play a significant role in inhibiting the growth of the parasites. Incorporation of either cholesterol or Distearylphosphatidylethanolamine？Methoxy-Polyethylene glycol-2000 (DSPE-mPEG-2000) in Soya phosphatidylcholine-stearylamine (SPC-SA) liposomes improves the efficacy. Intraerythrocytic entry of intact SPC-SA liposomes into infected erythrocytes was visualized using fluorescent microscopy. No hemolysis was observed in uninfected erythrocytes, and slight hemolysis was noted in infected erythrocytes at high concentrations of SPC-SA liposomes. Overall, our data suggested SA in SPC-liposomes might have potential application in malaria chemotherapy. 1. Introduction Malaria, a protozoan parasitic infection, is considered to be one of the most prevalent parasitic diseases afflicting the subtropical countries [1]. The quinoline group of antimalarial drugs such as chloroquine (CQ), mefloquine, and primaquine has been until recently, shown to be the most effective drugs for malaria chemotherapy because of their rapid onset of action and most important, their cost effectiveness, which have encouraged their wide use [2]. With the onset of CQ-resistant parasites, attempts have been made by several investigators to deliver chloroquine through liposomes for the treatment of chloroquine-resistant malaria [3–6]. The focus was also shifted either to develop novel chemotherapeutics or new modes of antimalarial drug delivery to overcome drug resistance mechanisms of the parasite [7]. Dramatic changes in the functional and structural characteristics of infected red blood cells (RBCs) are observed with Plasmodium infection and maturation. The alterations in lipid and protein composition-resulting from disturbance in membrane structure and function, ultimately lead to increased membrane fluidity [8]. The formation of “new permeable pathways” (NPPs) allows the entry of low molecular weight as well as nanosized molecules selectively to the parasitized RBCs [9, 10]. It has been previously reported by a number of investigators that liposomes consisting of stearylamine (SA) and
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