Preparation and characterization of Enoxaparin nano-liposomes

Abstract

Introduction: Enoxaparin is a low molecular weight heparin with an average molecular weight of 4.5 KD. Orally administrated Enoxaparin can not cross the gastrointestinal barrier due to its high water solubility, high molecular weight and significant negative charge. Therefore, it is used by injection; which may cause patient discomfort, pain, hematoma and infection. Aim: Enoxaparin as a hydrophilic drug can be incorporated in the aqueous core of the nano-liposomes. These carriers not only have the ability to enhance bioavailability and stability of oral delivery drugs, but also minimize their unwanted interactions. Methods and materials: The nano-liposomes were prepared by three methods including ethanol injection, thin film hydration and double emulsion/solvent evaporation technique. Size distribution and zeta potential of the nano-liposomes were characterized by DLS (dynamic light scattering). In order to separate the loaded nano-liposomes from the free drug, ultracentrifugation technique was done. Enoxaparin concentration was assessed through a calibration curve constructed by UV/visible spectrophotometer at 513 nm. Release study was done by dialysis method. Results: The mean vesicle size in diameter was obtained under 100 nm for three methods. Also, 17.8±2.1%, 27±3.1% and 42.3±4.4 % of the drug was loaded in nano-liposomes made by ethanol injection, thin film layer hydration and double emulsion/ solvent evaporation methods. Zeta potential was achieved -30.7±7.25, -26.7±5.06 and -27.9 ± 7.41, respectively. Also Drug release from liposomes was obtained 42.17±1.72, 29.43±0.34 and 32.27±0.14% in 24 hours, respectively. Discussion: This size range can create high surface area for absorption. Double emulsion method has advantages in encapsulating hydrophilic drugs with high entrapment efficiencies. Nano-liposomes made by double emulsion/solvent evaporation method could show good results of drug release for this simple liposomal composition.