ABSTRACT
BACKGROUND: Amphotericin B (AMB) is water-insoluble polyene, which has a broad spectrum of antifungal activity. The hydrophobic drug only exits in the phospholipid bilayer, leading to a low-drug liposomal loading capacity. OBJECTIVES: This study is designed to prepare water-soluble inclusion complex (IC) between AMB and cyclodextrin (CD) to formulate liposomal vesicles, double-loaded with drug molecules in the phospholipid bilayer and AMB/CD IC in the aqueous core. METHODS: Water-soluble AMB/CD IC was prepared by pH adjustment of the aqueous media and consequently characterized by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Liposomes double-loaded with AMB were formulated by the thin-film hydration method and accordingly evaluated for vesicle size, polydispersity index, entrapment efficiency, zeta potential, and in vitro drug leakage. RESULTS: Hydroxypropyl ß cyclodextrin (HP-ß-CD) better solubilized AMB than both α-CD and ß- CD e.g., the concentration of water-soluble AMB/HP-ß-CD IC could reach 465 µg/mL. Both DSC and SEM data illustrated that the drug no longer existed in its crystalline form, in AMB/HP-ß-CD IC. Liposomes double-loaded with hydrophilic AMB/HP-ß-CD IC and hydrophobic AMB had a diameter of 270 nm, polydispersity index less than 0.27, and zeta potential ca.-42.8 mV. Moreover, liposomes double-loaded with AMB enhanced drug-liposomal loading capacity by 25%, less leaked drug in phosphate buffer pH 7.4 at 37°C in comparison to liposomes loaded with only hydrophobic AMB. CONCLUSION: Liposomes double-loaded with AMB and AMB/HP-ß-CD IC increased drug-encapsulation ability and in vitro stability, suggesting potential drug delivery systems.
Subject(s)
Cyclodextrins , Liposomes , 2-Hydroxypropyl-beta-cyclodextrin , Amphotericin B , Drug Delivery SystemsABSTRACT
Lead-based ferroelectric ceramics with (1-x)Pb(B1 B2)O3-xPbTiO3 formula have emerged as a group of promising materials for various applications like ultrasonic sonars or medical imaging transducers. (1-x)PMN-xPT, (1-x)PIN-xPT and ternary solutions xPIN-yPMN-zPT ceramics are synthesised using the solid state reaction method. Our objective is to achieve higher structural transition temperatures than those of PMN-PT ceramics with as good dielectric, piezoelectric and electromechanical properties. Ceramics capacitance and loss tangent are measured when the ac field of measurement increases up to E=500 V/mm. Behaviours of these materials under ac field are related to their coercive field and Curie temperature.
ABSTRACT
As the alpha-cholesterol concentration decreased in blood plasma of healthy men, relative content of oleic and linoleic acids was also decreased in phospholipids of HDL2 subfraction without any alterations in HDL3 fraction. In the patients with ischemic heart disease content of linoleic acid was lower in the phospholipids and the ratio free cholesterol (HDL2 phospholipids was higher as compared with the group of healthy persons exhibiting the similar low content of cholesterol in HDL. The molar ratio free cholesterol) phospholipids was higher in the HDL3 fraction of the patients as compared with healthy persons, however composition of fatty acids was unaltered in the phospholipids Activity of lecithine cholesterol acyltransferase was lower in the patients as compared with healthy persons exhibiting the same content of cholesterol in HDL. Administration of heparin into the patients was responsible for an increase in the level of unsaturated phospholipids in HDL2 fraction (while they decreased in VLDL/as well as for a decrease in the ratio cholesterol/phospholipids. The data obtained suggest that alterations in the physico-chemical properties of the fraction studied might affect the antiatherogenic characteristics of HDL.