Design Of Vesicles Research Articles

Niosomes: A Promising Approach in Drug Delivery Systems

Design of vesicles as a tool to enhance drug delivery has created a lot of interest among humans operating within drug delivery systems space over the past decade. Niosomes are formations of vesicles by a hydrating mixture of cholesterol and nonionic surfactants. Completely different novel approaches used to deliver these medicines include liposomes, microspheres, engineering science, small emulsions, antibody-loaded drug delivery, magnetic microcapsules, implantable pumps and niosomes. Design and development of novel drug delivery system (NDDS) has two prerequisites. First, it should distribute the drug in accordance with a predetermined rate and second it should release therapeutically effective amount of drug at the site of action. Conventional dosage forms are unable to meet these requisites. Niosomes are basically non-ionic surfactant based vesicles in which an aqueous solution of solute is completely sealed off by a membrane resulting from the group of surfactant macromolecules as bilayer. Niosomes remain in the bloodstream for a reasonable time, which is useful for targeted drug delivery. This review additionally presents an overview of the strategies of preparation of niosome, types of niosomes, characterization and their applications. Keywords: Niosomes, Vesicles, NDDS, Conventional, Micromolecules.

Calixarenes: Generalities and Their Role in Improving the Solubility, Biocompatibility, Stability, Bioavailability, Detection, and Transport of Biomolecules.

The properties and characteristics of calix[n]arenes are described, as well as their capacity to form amphiphilic assemblies by means of the design of synthetic macrocycles with a hydrophilic head and a hydrophobic tail. Their interaction with various substances of interest in pharmacy, engineering, and medicine is also described. In particular, the role of the calix[n]arenes in the detection of dopamine, the design of vesicles and liposomes employed in the manufacture of systems of controlled release drugs used in the treatment of cancer, and their role in improving the solubility of testosterone and anthelmintic drugs and the biocompatibility of biomaterials useful for the manufacture of synthetic organs is emphasized. The versatility of these macrocycles, able to vary in size, shape, functional groups, and hydrophobicity and to recognize various biomolecules and molecules with biological activity without causing cytotoxicity is highlighted.

Design of Vesicles Using Capillary Microfluidic Devices: From Magnetic to Multifunctional Vesicles

In the core, in the shell, or both: a microfluidic device is used to design magnetic vesicles (liposomes and polymersomes) through chemical modification of the nanoparticle surface. Hydrophilic, hydrophobic and fluorescent quantum dot nanoparticles are used for elaborating the vesicles. Hybrid vesicles are easily obtained with a very high yield and excellent monodispersity.

Theory of Tunable pH-Sensitive Vesicles of Anionic and Cationic Lipids or Anionic and Neutral Lipids

The design of vesicles that become unstable at an easily tuned value of pH is of great interest for targeted drug delivery. We present a microscopic theory for two forms of such vesicles. A model of lipids introduced by us previously is applied to a system of ionizable anionic lipid and permanently charged cationic lipid. We calculate the pH at which the lamellar phase becomes unstable with respect to an inverted hexagonal one, a value that depends continuously on the system composition. Identifying this instability with that displayed by unilamellar vesicles undergoing fusion, we obtain very good agreement with the recent experimental data of Hafez, Ansell, and Cullis, (2000, Biophys. J. 79:1438–1446) on the pH at which fusion occurs versus vesicle composition. We explicate the mechanism in terms of the role of the counterions. This understanding suggests that a system of a neutral, nonlamellar-forming lipid stabilized by an anionic lipid would serve equally well for preparing tunable, pH-sensitive vesicles. Our calculations confirm this. Further, we show that both forms of vesicle have the desirable feature of exhibiting a regime in which the pH at instability is a rapidly varying function of the vesicle composition.