Water-soluble nanoparticles from random copolymer and oppositely charged surfactant, 3a -: Nanoparticles of poly(ethylene glycol)-based cationic random copolymer and fatty acid salts

In this report, we investigate the nanoparticle formation between random copolymers (RCPs) of methoxy-poly(ethylene glycol) monomethacrylate (MePEGMA) and (3-(riiethaeryloylamino)propyl)trimethylammonium chloride (MAPTAC and oppositely charged natural surfactants, sodidium oleate and sodium laurate, using turbidimetric titration, steady-state fluorescence, dynamic light scattering, and electron microscopy. Though sodium oleate and sodium laurate are sparingly soluble in water, the nanoparticle complexes formed between the RCPs and these surfactants are soluble in the entire range of compositions studied here, including the stoichiometric electronetural complexes. The spherical nature of these nanoparticle complexes is revealed by electron microscopic (EM) analysis. Dynamic light scattering (DLS) showed that the average diameters of the nano-particles are in the range 50 to 150 nm, which is supported by EM analysis. Pyrene fluorescence experiments suggested that these soluble nanoparticles have hydrophobic cores, which may solubilize hydrophobic drug molecules. The polarity index (I-1/I-3) obtained from the pyrene fluorescence spectra and the conductometric measurements showed that the nanoparticles are in the order of 10(-4) m. Further, the complexation of such poorly water-soluble amphiphilic surfactants with polymers offers a useful method for the immobilization of hydrophobic compounds towards water-soluble drug carrier formulations.