Formation of size-controlled nano carrier systems by self-assembly

Nano carrier systems were prepared by forming self-assembled liposomes having a size distribution in the nano range through use of an ultrasonic homogenizer. Phosphatidylcholine and cholesterol were utilized as an amphiphilic compound and a shape stabilizer, respectively. The size of prepared samples was decreased (up to 150 nm) by elevating ratio of lecithin and extending homogenization time (2 ∼ 6 min). After secondary coating with alginic acid (0.1, 0.3 and 0.5, W/V), size was remarkably changed in the range of ±30 nm and zeta-potential was altered (only chitosan coating (molecular weight: 30 000 Da, 0.2, W/V): 10.3 mV, Alginic acid coating (0.5, W/V) after the chitosan coating: -21.8 mV). The low molecular weight chitosan (0.1, W/V)-coated nano-liposomes had a lower absolute value of zeta-potential than the high molecular weight chitosan (0.1, W/V)-coated nano-liposomes. The encapsulation efficiency was measured by gas chromatography. The efficiency was decreased slightly by elevating chitosan concentration (0.1 ∼ 0.5, W/V).