ORIGINAL ARTICLES  NEW TRENDS IN BIOENCAPSULATION - Part 2 

Minerva Biotecnologica 2006 March;18(1):3-9

Copyright © 2006 EDIZIONI MINERVA MEDICA

lingua: Inglese

New PHB/PHPE microspheres obtained from Burkholderia cepacia as biodegradable drug delivery systems for photodynamic therapy

Ré M. I. ¹, Rodrigues F. A. ², Silva E. S. ², Castro I. M. ³, Simioni A. R. ³, Pelisson M. M. M. ⁴, Beltrame M.Jr. ⁴, Tedesco A. C. ³

¹ Lab. of Chemical Processes and Technology Institute for Technological Research of the State of São Paulo, Brazil 2 Lab. of Industrial Biotechnology Institute for Technological Research of the State of São Paulo, Brazil 3 São Paulo University, FFCLRP-USP, Rib. Preto-SP, Brazil 4 Vale do Paraíba University, IP&D, São José dos Campos, Brazil

The potential use of PHB/PHPE, a new polyhydroxyalkanoate synthesized by the bacteria Burkholderia cepacia, was investigated in this paper to prepare drug-loaded microspheres by spray-drying. NzPC, a photosensitizer dye, whose application in photodynamic therapy (PDT) against cancer has been investigated, was incorporated into the PHB/PHPE microspheres as a model drug. PHB/PHPE was produced by a fed-batch culture of Burkholderia cepacia strain IPT 64 using sucrose as sole carbon source. After polymer accumulation, cells were inactivated by heat and the polymer was extracted under mild conditions in aqueous medium by enzymatic action. A new microencapsulation process without organic solvent was employed to prepare NzPC-loaded PHB/PHPE microspheres by spray-drying. Microspheres were characterized by optical microscopy and scanning electron microscopy for particle size and morphology, respectively. Microspheres with a relatively small size and a narrow size distribution (0.8 to 8.0 (mm) were obtained. The photophysical and photochemical properties of the NzPC-loaded PHB/PHPE microspheres were also determined to investigate the effects of the incorporation of this dye into the polymeric microspheres. It could be demonstrated that the biopolymer PHB/PHPE, due to their unsaturation, may present good biodegradable properties to control the release of NzPC in biological medium, and that NzPC-loaded PHB/PHPE microspheres could be an interesting system to release NzPC for Photodynamic therapy