In this communication, lipase A from Candida antarctica (CALA) was immobilized by covalent bonding on magnetic nanoparticles coated with chitosan and activated with glutaraldehyde, labelled CALA-MNP, (immobilization parameters: 84.1% ± 1.0 for immobilization yield and 208.0 ± 3.0 U/g ± 1.1 for derivative activity). CALA-MNP biocatalyst was characterized by X-ray Powder Diffraction (XRPD), Fourier Transform Infrared (FTIR) spectroscopy, Thermogravimetry (TG) and Scanning Electron Microscope (SEM), proving the incorporation of magnetite and the immobilization of CALA in the chitosan matrix. Besides, the immobilized biocatalyst showed a half-life 8–11 times higher than that of the soluble enzyme at pH 5–9. CALA showed the highest activity at pH 7, while CALA-MNP presented the highest activity at pH 10. The immobilized enzyme was more active than the free enzyme at all studied pH values, except pH 7.

Sbstract Pluronics molecules self-assemble in aqueous solution providing a core/shell architecture that improves the solubility of hydrophobic drugs. Binary mixtures of Pluronics  have been studied as drug nanocarriers in order to combine their advantages, like high colloidal stability, small particle size and good solubilisation capacity (S cp ). In this work we studied Pluronics  binary mixture, P123 and F127, as nanocarriers of the hydrophobic drug griseofulvin. P123 (E 21 P 67 E 21 ) shows a relative good S cp , whereas F127 (E 98 P 67 E 98 ) shows a good colloidal stability. According to data, these binary mixtures form stables nano-sized comicelles in aqueous solution. The S cp of the P123/F127 systems at 25 and 37 °C was monitored by UV/Visible spectroscopy, showing good results at both temperatures, as would be expected, since P123/F127 have similar length hydrophobic block. Hydrophobic-dependence and temperature-responsive of the systems were evaluated by CMC, particle size and colloidal stability. Hence, stables P123/F127 comicelles may have potencial as hydrophobic drug delivery.

Binary mixtures of block copolymers E 114 CL 20 and E 97 P 69 E 97 (F127 ® ) were prepared in order to tailor a drug delivery system with synergistic effect, concerning dilution stability and high drug solubility. Both reduction of the critical micelle concentrations (CMC) values and enhance hydrophobic drug solubility in F127/E 114 CL 20 mixtures (30-50 wt.%) were observed by addition of the diblock E 114 CL 20 , also reaching the best enhancement of drug solubility for mangiferin and carbamazepine. Experimental MaterialsCopolymer E 114 CL 20 (CL 20 ) (E = ethylene oxide and CL = ε-caprolactone blocks) was synthesized and Synergistic Effect in Drug Solubility by New Binary Micelles of Poly(ε-caprolactone)-poly(ethylene oxide) and F127 ® J. Braz. Chem. Soc. 1342