Micro- and nanoparticles

Xylans from beech wood, corncobs, and the alkaline steeping liquor of the viscose process have been shown to be applicable as pharmaceutical auxiliaries [3]. Micro- and nanoparticles were prepared by a coacervation method from xylan isolated from corncobs [150]. The process is based on neutralization of an alkaline solution in the presence of surfactant, which was shown to influence both the particle size and morphology. They are aimed at applications in drug delivery systems. 

A large variety of drug delivery systems are described in the literature, such as liposomes (Torchilin, 2006), micro and nanoparticles (Kumar, 2000), polymeric micelles (Torchilin, 2006), nanocrystals (Muller et al., 2011), among others. Microparticles are usually classified as microcapsules or microspheres (Figure 8). Microspheres are matrix spherical microparticles where the drug may be located on the surface or dissolved into the matrix. Microcapsules are characterized as spherical particles more than Ipm containing a core substance (aqueous or lipid), normally lipid, and are used to deliver poor soluble molecules... 

Xylan-based micro- and nanoparticles have been produced by simple coacervation (Garcia et al., 2001). In the study, sodium hydroxide and chloride acid or acetic acid were used as solvent and non-solvent, respectively. Also, xylan and surfactant concentrations and the molar ratio between sodium hydroxide and chloride acid were observed as parameters for the formation of micro- and nanoparticles by the simple coacervation technique (Garcia et al., 2001). Different xylan concentrations allowed the formation of micro- and nanoparticles. More precisely, microparticles were found for higher concentrations of xylan while nanopartides were produced for lower concentrations of the polymer solution. When the molar ratio between sodium hydroxide and chloride acid was greater than 1 1, the partides settled more rapidly at pH=7.0. Regarding the surfactant variations, an optimal concentration was found however, at higher ones a supernatant layer was observed after 30 days (Garda et al., 2001). 

S., Method for producing morphologically uniform micro and nanoparticles using micromixers, WO 00/72955, Schering AG, Priority 26.05.1999. 

Agnihori, S.A., Mallikarjuna, N.N. and Aminahhavi, T.M. (2004) Recent advances on chitosan-based micro and nanoparticles in drug delivery. Journal of Controlled Release, 100, 5—28. 

Champion JA, Katare YK, Mitragotri S (2007) Making polymeric micro- and nanoparticles of complex shapes. Proc Natl Acad Sci USA 104 11901-11904. 

BIOCONJUGATION OF BIODEGRADABLE POLY (LACTIC/GLYCOLIC ACID) TO PROTEIN, PEPTIDE, AND ANTI-CANCER DRUG AN ALTERNATIVE PATHWAY FOR ACHIEVING CONTROLLED RELEASE FROM MICRO- AND NANOPARTICLES TAE GWAN PARK... 

There are 22 chapters in the book and they cover the most important aspects of polymers as drugs, prodrugs, dmg delivery systems, and in situ prostheses. The major features promulgated are synthesis, derivatization, degradation, characterization, application, and evaluation techniques as well as new biodegradable materials, assemblies, hydrogels, telechelic polymers, derivatized polysaccharides, micro- and nanoparticles, mimetic... 

Bioconjugation of Biodegradable Poly (lactic/glycolic acid) to Protein, Peptide, and Anti-Cancer Drug An Alternative Pathway for Achieving Controlled Release from Micro- and Nanoparticles... 

Demirel M. et al.. Formulation and in vitro-in vivo evaluation of piribedil solid lipid micro- and nanoparticles, J. Microencapsulation, 18, 359, 2001. 

AB5 metal hydride particles have been dispersed in a polymer matrix in order to entrap the micro and nanoparticles produced by repeated fragmentation processes of the metal phase during the... 

As it was shown in the previous sections, there is at present a wide variety of available methods for the preparation of molecularly imprinted micro-and nanoparticles. Little has been done however to compare directly two or more of these various synthetic strategies in order to better ascertain their advantages and limitations, and in particular their capability to yield efficient MIPs. 

Gatti AM, Rivasi F. 2002. Biocompatibility of micro-and nanoparticles. Part 1 in liver and kidney. 

Florence, A. T. The oral absorption of micro- and nanoparticles Neither exceptional nor unusual. Pharm. Res. 14 259—266, 1997. 

In general, thin layers, beads, micro-, and nanoparticles made of ceramics, glasses, nitrocellulose, polystirene, and gold, have been exploited, and the concept of multivalency has been widely applied.77... 

Micro- and Nanoparticles Manufactured by Dextran Esterification with CDI... 

Durr, M., Kentsch, J., Muller, T., Schnelle, T., Stelzle, M., Microdevices for manipulation and accumulation of micro- and nanoparticles by dielectrophoresis. Electrophoresis 2003, 24, 722-731. 

Properties of Micro- and Nanoparticles 9.3.1 Membrane-Passing Properties... 

Agnihotri SA, Mallikarjuna NN, Aminabhavi TM (2004) Recent advances on chitosan-based micro- and nanoparticles in drug delivery. J Control Rel 100(l) 5-28 Akiyama Y, Nagahara N, Kashihara T, Hirai S, Toguchi H (1995) In vitro and in vivo evaluation of mucoadhesive microspheres prepared for the gastrointestinal tract using polyglycerol esters of fatty acids and a poly(acrylic acid) derivatives. Pharm Res 12 397-405... 

The use of synergists (micro- and nanoparticles) was also investigated in intumescent coatings. The most recent work conducted is based on the studies done in intumescent bulk polymer (see reaction to fire part). Li et al.108 suggested combining EG and/or molybdenum disilicide (MoSij) in an intumescent system based on APP/PER-melamine. The results show that incorporating the... 

Abstract. The paper presents results of theoretical and experimental investigations of the process of electrochemical conversion of organic dielectrics into nanosized carbon structures. A new low-temperature method for the synthesis of fractal carbon materials with micro- and nanoparticles having a fibrous, spheroidal, dendritic, and other structure has been briefly characterized. 

Abstract. Surface pressure/area isotherms of monolayers of micro- and nanoparticles at fluid/liquid interfaces can be used to obtain information about particle properties (dimensions, interfacial contact angles), the structure of interfacial particle layers, interparticle interactions as well as relaxation processes within layers. Such information is important for understanding the stabilisation/destabilisation effects of particles for emulsions and foams. For a correct description of II-A isotherms of nanoparticle monolayers, the significant differences in particle size and solvent molecule size should be taken into account. The corresponding equations are derived by using the thermodynamic model of a two-dimensional solution. The equations not only provide satisfactory agreement with experimental data for the surface pressure of monolayers in a wide range of particle sizes from 75 pm to 7.5 nm, but also predict the areas per particle and per solvent molecule close to the experimental values. Similar equations can also be applied to protein molecule monolayers at liquid interfaces. 

The aim of the present study is to demonstrate that the corresponding equations can be derived similarly to expressions for the surface tension of mixed solutions of molecules with different sizes.29 The same approach was also applied to protein solutions.30 The derived equations are compared with some experimental Il-A isotherms of monolayers of micro- and nanoparticles and proteins reported in the literature. 

Introducing the area of surface layer per one micro- or nanoparticle A via the relation 0 = (o/A, and using, instead of Eq. (11) which expresses the enthalpy contribution to the solvent activity coefficient, the assumption that this contribution is independent of 0 (i.e., taking lnf0H to be constant, which corresponds better to the liquid-expanded monolayer33), with the condition n = (o/(0o 1 which is true for micro- and nanoparticles, one obtains from Eq. (13) the expression for the II-A isotherm valid for a monolayer of particles ... 

Particulates are commonly classified into micro- and nanoparticles based on the size of the particles. Nanoparticles are colloidal particles ranging from 10 to 1,000 run, in which drag may be entrapped, encapsulated, and/or absorbed. Microparticulates are drag-containing small polymeric particles (erodible, non-erodible or ion-exchange resins) within the size of 1-10 /on, which are suspended in a liquid carrier medium. 

Hydrogel micro- and nanoparticles composed of biopolymer matrixes have gained a lot of attention in recent years due to their application in drug delivery and tissue engineering [10,14,45 17], The biopolymers used for these purposes are nontoxic,... 

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