Showing papers on "Nanoparticle published in 1986"

A solid colloidal drug delivery system for the eye: encapsulation of pilocarpin in nanoparticles

Abstract: The present study was undertaken in order to encapsulate pilocarpin into nanoparticles. Two principally different methods for manufacturing these particles were investigated. Firstly, pilocarpin was dissolved in an aqueous medium in which the polymerization was carried out, and secondly, the polymerizing monomer was kept saturated with the drug solution under acidic conditions resulting in an incorporation into the nanoparticles in an aqueous environment. The amount of pilocarpin that could be incorporated into the nanoparticles was found to be largely influenced by the temperature at which the nanoparticles were produced and by the stabilizers used. At low temperatures, up to 60 per cent of pilocarpin nitrate could be encapsulated into butylcyanoacrylate nanoparticles using emulsion polymerization techniques. Larger amounts of pilocarpin could not be incorporated because of the hydrophilicity of the salts of this drug. The physico-chemical characteristics of the nanoparticles are reported: the particle size and morphology were determined by scanning and transmission electron microscopy and photon correlation spectrometry. The average particle size was about 100 nm. The results obtained in this study show that photon correlation spectrometry is a suitable method for the sizing of nanoparticles.

Interfacial Polymerization, A Useful Method for the Preparation of Polymethylcyanoacrylate Nanoparticles

Abstract: An interfacial polymerization procedure was developed for the preparation of polymethylcyanoacrylate (PMCA) nanoparticles loaded with triamcinolone acetonide. The nanoparticles were characterized concerning their interior structure, size distribution, drug content, drug release and in vivo distribution. These results (except those for the in vivo distribution) were compared with those obtained with nanoparticles prepared by micell polymerization [5]. Both preparation procedures yielded particles with a mean diameter below 500 nm. The drug content of the nanoparticles prepared by interfacial polymerization ranged from 6,5% w/w to 1,9% w/w depending on the employed monomer concentration in contrast to 0,045% w/w for nanoparticles prepared by micell polymerization [5]. In comparison to microcrystalline substance the drug release from the nanoparticles could be sustained in all cases, but there was no difference in drug release between the nanoparticles prepared by both methods.After removal of surfac...

Radiolabelling of poly(butyl 2‐cyanoacrylate) nanoparticles with a technetium‐99m‐dextran complex

Abstract: Poly(butyl 2-cyanoacrylate) nanoparticles have been radiolabelled with a 99mTc-dextran complex to allow their pattern of biodistribution to be followed by using the technique of gamma scintigraphy. The method involves the preforming of a 99mTc-dextran complex and using this as a polymerie stabiliser during the formation of nanoparticles. Copolymerisation of this complex with the cyanoacrylate monomer results in the radiolabel being covalently linked to the nanoparticle matrix with a labelling efficiency of approximately 18%. The radiolabelled nanoparticles slowly degrade and release the activity into buffer solution. The release rate was relatively unaffected by the presence of plasma proteins indicating that the system should be suitable for use in vivo.