UNLABELLED: The present study evaluates a new method to prepare nanoparticles of a poorly water-soluble drug, simvastatin, by evaporation of all solvents from spontaneously formed oil-in-water microemulsions. By this method, microemulsions containing a volatile solvent as an oil phase are converted into nanoparticles in the form of dry non-oily flakes by freeze-drying. The presence of simvastatin in nanoparticles was determined by dispersing the flakes in water and subsequent filtering through a 0.1-microm filter, followed by measuring the simvastatin concentration in the filtrate. It was found that after freeze-drying more than 95% of the drug was present in amorphous particles, smaller than 100 nm. It was found that tablets containing the flakes of simvastatin nanoparticles showed tremendous enhancement in dissolution profile compared with conventional tablets. X-ray diffraction revealed that in the resulting flakes simvastatin nanoparticles were initially amorphous, but a slow crystallization process took place when the product was stored at room temperature. FROM THE CLINICAL EDITOR: This paper describes a new method to prepare nanoparticles of a poorly water-soluble drug, simvastatin, by evaporation of all solvents from spontaneously formed oil-in-water microemulsions. Tablets containing the flakes of simvastatin nanoparticles showed tremendous enhancement in dissolution profile compared with conventional tablets.[on SciFinder (R)]
A review. Current approaches to the prepn. of nanoparticles in confined structures are described. The prepn. of inorg. and org. nanoparticles in nanometric confined structures, such as reverse micelles, water-in-oil and oil-in-water microemulsions, water-in-supercrit. liq. microemulsions, micelles of amphiphilic block copolymers, miniemulsions, dendrimers, polymeric capsules, pore channels of mesoporous solids, and nanoporous membranes, and liq. crystals are discussed. Examples of practical applications of the nanoparticles obtained are presented. [on SciFinder(R)]
Kamyshny A, Magdassi S. Microencapsulation. In: PS D Encyclopedia of Surface and Colloid Science. Taylor & Francis ; 2006.
Surface active antibodies were formed by covalent attachment of hydrophobic groups to the IgG mol. The modified antibodies reduced surface tension and adsorbed onto emulsion droplets at surface concns. higher than the native antibody. The chem. modification led to a decrease in the biol. activity; however, at specific conditions, surface-active antibodies, which retained their recognition ability, could be formed. By using these antibodies, a new emulsion, which has a specific recognition ability for HSV-1 infected cells, was formed. [on SciFinder(R)]
A review, with 42 refs., on (1) adsorption at fluid-fluid interfaces, (2) surface activity response to factors, (3) adsorption at solid-liq. interfaces, (4) proteins at interfaces of biol. interest, and other topics. Proteins at surfaces in pharmaceutical and food industries as well as in natural processes are discussed. [on SciFinder(R)]