Pharmacokinetics and Tissue Distribution of Vinorelbine Bitartrate after Intraveous Administration of Liposomal and Injectable Formulations

A hydrophilic and temperature-induced degradation drug, vinorelbine bitartrate (VB)-loaded phosphatidylethanolamin liposomes (PSLs), was prepared by the thin-film hydration method. Liposomes were made of phosphatidylethanolamine: cholesteryl: oleic acid (PE: CHOL: OA, 3:3:1 mass/mass). The mean particle size of the PSLs ranged from 293.06 nm. The transmission electron microscope (TEM) images displayed that the shape of the PSLs was multilamellar vesicles with smooth surface. The highest entrapment efficiency (EE) and drug loading capacity (DL) could reach up to 68.5% and 6.23%, respectively. The PSLs was evaluated by comparing the rate of release of encapsulated VB in different phosphate buffer solution (PBS), and the result showed that the rate of drug release in acid medium was faster than in pH 7.4. Pharmacokinetic characteristics in vivo and the tissue distribution in mice were investigated, which provided experimental and theoretical basis for utilizing liposomes in malignant tumor chemotherapy.     

Development of Ciprofloxacin HCl-Based Solid Lipid Nanoparticles Using Ouzo Effect: An Experimental Optimization and Comparative Study

This study was performed to develop solid lipid nanoparticles of water soluble drug ciprofloxacin HCl using quick solvent diffusion evaporation technique (ouzo effect). A statistical central composite rotatable design was used to study the effect of independent variables. In the subsequent step, optimized SLN were further compared with nanostructured lipid carriers and nanoemulsion for particle size, zeta potential, drug entrapment, drug release, and stability. Comparative study revealed that the drug encapsulation efficiencies were enhanced by adding the Capmul MCM C8 into the solid lipid nanoparticles. The in vitro drug release study of all three formulations showed rapid release for nanoemulsion while controlled release for SLN. Stability study of all the formulation proved that nanostructured lipid carrier and SLN could prevent the drug expulsion during the storage period. Results of the study suggested that the SLN and nanostructured lipid carriers produced by the principle of ouzo effect could potentially be exploited for better drug entrapment efficiency and controlled drug release of water soluble actives.     

Polyacrylic Acid Modifies Local and Lateral Mobilities in Lipid Membranes

Polyacrylic acid (PAA) is a promising polymer for engineering lipid-based drug-delivery vesicles. Its unique properties allow lowering drug dose and delivery the drug close to the site of its release. To design a successful delivery scheme, however, it is important to understand on the molecular scale how the polymer interacts with lipids under various conditions in the human body. Some aspects of the PAA-lipid interaction can be revealed using physical methods, such as differential scanning microscopy, nuclear magnetic resonance spectroscopy, NMR-diffusometry, and infrared spectroscopy. This work discusses the use of these techniques as well as the peculiarities of preparing vesicular and microscopically aligned PAA-lipid systems.      

Poloxamer-Stabilized Topical Miconazole Nitrate-Loaded Microemulsion: Formulation Design and Characterization

Miconazole nitrate-loaded microemulsion based on Tween 80 and propylene glycol, castor oil and water with and without Poloxamer 407 was prepared and characterized with respect to drug content, stability, antifungal, and physicochemical properties and ex vivo drug release using a modified Franz diffusion apparatus. Results obtained revealed homogeneous and stable microemulsions with excellent physicochemical properties, permeation coefficients and fluxes, and increased in vitro antifungal activity (～1.2 times) against clinically isolated Candida albicans when compared to a commercial topical miconazole (Fungusol) solution. Poloxamer-stabilized microemulsion could offer a better and more reliable approach of delivering miconazole than both the unstabilized and Fungusol formulations.      

Application of a Laser Diffraction Method for Determination of Stability of Dispersion Systems in Food and Chemical Industry

Laser diffraction was used for determination of particle size of various emulsions. Mean particle size, fractions' number, and dispersion coefficients of tested systems are presented. Stability of greasing emulsions in relation to their pH was also tested. It was found out that determination of droplet size distribution in fat emulsions allows prediction of their properties (stability). The parameter may be helpful in selection of appropriate production process parameters, composition, and control of marketed emulsion systems during their storage. The purpose of the study was to determine applicability of a laser diffraction method for evaluation of stability of selected dispersion systems in food and chemical industry.     

Semi-Solid o/w Emulsions Based on Sucrose Stearates: Influence of Oil and Surfactant Type on Morphology and Rheological Properties

Sucrose stearate blends of intermediate lipophilicity are mild surfactants with thermosensitive gelling behavior. Binary systems and emulsions with sucrose stearate S-970 or S-1170 were developed and investigated by thermoanalytical and rheological measurements. The presence of an oil phase promoted the gelling potential of the esters especially at higher production temperatures. Semi-solid emulsions with viscoelastic properties comparable to weak gels were obtained with different dermatologically acceptable oils. The complex internal structure as visualized by fluorescence microscopy exhibited changes during storage in dependence of oil and surfactant type. A combination of S-970 with cetearyl ethylhexanoate-based oil phases led to superior physical stability.     

Structures and oxygen storage/release capacities of Ce_xZr_(1-x)O_2: Effects of Zr content and preparation method

Ceria-zirconia solid solution has been prepared by the urea grind combustion and citric acid sol-gel methods for catalytic applications as oxygen storage/release materials in this study. The properties and oxygen storage/release capacities of samples with different Zr contents were characterized and evaluated by X-ray diffraction(XRD), N_2 adsorption, scanning electron microscopy(SEM), Raman spectroscopy, and insitu CO–CO_2 looping test. The results demonstrate that the samples prepared by two methods are all of excellent lattice [O] release/storage properties and maintain good long-term cycle stability. But the preparation method significantly impacts the homogeneity of samples related to their redox properties and the content of Zr over 20%, which greatly changed the properties of ceria-zirconia solid solutions and caused their changing of crystalline symmetry from cubic to tetragonal. The samples prepared by citric acid solgel method are of more homogeneous particle sizes and higher specific surface areas than that by urea grind combustion method, which is benefit to the oxygen release rather than oxygen storage. The bulk oxygen amount migrated to surface increases with the increasing Zr content, however, the amount of lattice oxygen migration decreases when Zr content is over 20%. When Zr content is 20%, the differences of storage/release capacities from two different preparation methods are reduced at high temperature in the long-term loop reaction.     

Vesicular release dynamics are altered by the interaction between the chemical cargo and vesicle membrane lipids

The release of the cargo from soft vesicles, an essential process for chemical delivery, is mediated by multiple factors. Among them, the regulation by the interaction between the chemical cargo species and the vesicular membrane, widely existing in all vesicles, has not been investigated to date. Yet, these interactions hold the potential to complicate the release process. We used liposomes loaded with different monoamines, dopamine (DA) and serotonin (5-HT), to simulate vesicular release and to monitor the dynamics of chemical release from isolated vesicles during vesicle impact electrochemical cytometry (VIEC). The release of DA from liposomes presents a longer release time compared to 5-HT. Modelling the release time showed that DA filled vesicles had a higher percentage of events where the time for the peak fall was better fit to a double exponential (DblExp) decay function, suggesting multiple kinetic steps in the release. By fitting to a desorption–release model, where the transmitters adsorbed to the vesicle membrane, the dissociation rates of DA and 5-HT from the liposome membrane were estimated. DA has a lower desorption rate constant, which leads to slower DA release than that observed for 5-HT, whereas there is little difference in pore size. The alteration of vesicular release dynamics due to the interaction between the chemical cargo and vesicle membrane lipids provides an important mechanism to regulate vesicular release in chemical and physiological processes. It is highly possible that this introduces a fundamental chemical regulation difference between transmitters during exocytosis.

The release of the cargo from soft vesicles, an essential process for chemical delivery, is mediated by multiple factors.     

Synthesis,Properties, and Applications of Amino Acids Based Surfactants: A Review

Amino acids based surfactants belong to the class of surfactants with high biodegradability, low toxicity and excellent surface active properties. They possess excellent emulsifying, detergency properties and form fine lather. These surfactants are environment friendly, mild to skin and eyes, and have hard water tolerance. This article reviews types, synthesis, various surface properties such as cmc (critical micelle concentration), surface tension, phase behavior, Krafft temperature, and interfacial adsorption of these surfactants. The biological properties such as antimicrobial activity, aquatic toxicity, biodegradability and hemolytic activity have also been focused. The various applications of amino acid based surfactants in the area of life sciences such as gene transfection, formation of liposomes, and drug delivery systems have also been reviewed.     

High Yield of Supergiant Vesicles on Glyoxylic Acid Modified Aluminum Electrode

Supergiant vesicles are useful for investigating the interactions between lipid memebranes and collodial particles or macromolecules. Producing supergiant vesicles using the electroformation method lead to extraordinary findings in this work. The glyoxylic acid modified aluminum (GA-Al) electrode was prepared by the electro-reduction in an oxalic acid solution. High yield of supergiant vesicles with diameters >100 µm are successfully formed on a GA-Al electrode under an alternative current (AC) electric field. In contrast to platinum and indium tin oxide, which have been mainly used so far, this GA-Al electrode is preferable for the electroformation of egg phosphatidylcholine (EggPC) supergiant vesicles.     

Preparation of liposomes loaded with quantum dots, fluorescence resonance energy transfer studies, and near-infrared in-vivo imaging of mouse tissue

We report on a simple, fast and convenient method to engineer lipid vesicles loaded with quantum dots (QDs) by incorporating QDs into a vesicle-type of lipid bilayer using a phase transfer reagent. Hydrophilic CdTe QDs and near-infrared (NIR) QDs of type CdHgTe were incorporated into liposomes by transferring the QDs from an aqueous solution into chloroform by addition of a surfactant. The QD-loaded liposomes display bright fluorescence, and the incorporation of the QDs into the lipid bilayer leads to enhanced storage stability and reduced sensitivity to UV irradiation. The liposomes containing the QD were applied to label living cells and to image mouse tissue in-vivo using a confocal laser scanning microscope, while NIR images of mouse tissue were acquired with an NIR fluorescence imaging system. We also report on the fluorescence resonance energy transfer (FRET) that occurs between the CdTe QDs (the donor) and the CdHgTe QDs (the acceptor), both contained in liposomes. Based on these data, this NIR FRET system shows promise as a tool that may be used to study the release of drug-loaded liposomes and their in vivo distribution.

Natural Brazilian Raw Material to Develop O/W Emulsions Containing Lamellar Gel Phase (Development and Analysis of Emulsion with Vegetable Oils)

Oil-in-water emulsions were developed employing the HLB system and emulsion phase inversion (EPI) method. X-ray diffraction revealed that the anisotropic structures around the inner phase globules were lamellar gel network phases. The calculated distances between the lamellae made after preparation and 3 month latter showed that there was no swelling of the lamellar gel network indicating good stability and few changes during storage. The developed emulsions were stable and have potential to be employed for cosmetic and pharmaceutical purposes. The gel phase network and vegetal components seemed to be contributing factors.      

Preparation and Characterization of Cubosomal KIOM-C Suspension and Investigation on In Vitro Small Intestinal Absorption of Baicalin

KIOM-C suspension and cubosome/KIOM-C suspension were prepared in various buffer solution of different pHs by a sonication method. KIOM-C particles were unstable in terms of time-dependent change in the size and the zeta potential. The fluctuation in the size and the zeta potential of KIOM-C particles was effectively damped by cubosome. The shape of KIOM-C particles was irregular and the size was hundreds to thousands of nm. Cubosome/KIOM-C particles exhibited stripes on their surfaces and the size was hundreds of nm. Regardless of the pH values (pH 2.0–10.0) of media, baicalin, a major component of KIOM-C, was chemically stable for 48 hours at a room temperature. Cubosome markedly enhanced the stability of baicalin particles against sedimentation. EDTA significantly enhanced the in vitro small intestinal absorption of baicalin, but MO cubosome hardly promoted.