Preparation and characterization of paclitaxel-loaded PLDLA microspheres

• Autor(a) principal: Martins,Kelly F.
• Data de Publicação: 2014
• Outros Autores: Messias,André D., Leite,Fábio L., Duek,Eliana A.R.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Materials research (São Carlos. Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392014000300016
• topic: chemotherapy; microspheres; paclitaxel; PLDLA

Paclitaxel (Taxol®), is a drug used to treat ovarian, breast, lung and bladder cancer. However, the low solubility of this drug in water is a major limitation in its clinical use. One strategy to overcome this limitation would be to encapsulate paclitaxel in polymeric microspheres that are biocompatible and can be used as drug carriers. The aim of this study was to use the bioresorbable, biocompatible copolymer poly-L-co-D,L-lactic acid (PLDLA) in the 70:30 rate to produce and characterize microspheres containing paclitaxel. The simple emulsion technique was used to obtain spherical microspheres that were studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The average size of PLDLA microspheres without and with paclitaxel was 10.3 ± 1.7 μm and 12.7 ± 1.3 μm, respectively, as determined by laser light scattering (LLS). Differential scanning calorimetry (DSC) showed that pure paclitaxel had an endothermic peak corresponding to a melting point of 220 °C, which indicated its crystalline nature. The same peak was observed in a physical mixture of PLDLA + paclitaxel in which both components were present in the same proportions used to prepare the microspheres . In contrast, this peak was not observed for the drug, indicating that paclitaxel did not crystallize in PLDLA microspheres. Differential scanning calorimetry (DSC) indicated that paclitaxel was homogeneously dispersed in the PLDLA microspheres, the incorporation of paclitaxel into the microspheres did not alter the thermal properties of PLDLA. The Fourier transform infrared spectroscopy (FTIR) analysis seems to indicate the absence of chemical interaction between polymer and drugs in microspheres and the presence of drugs as a molecular dispersion in the polymer matrix. The efficiency of paclitaxel encapsulation in PLDLA microspheres was 98.0 ± 0.3%, as assessed by high performance liquid chromatography (HPLC). A kinetic study of drug release in vitro using HPLC showed an initial burst release followed by a slower release characteristic of large diameter distribution systems. PLDLA microspheres released 90 ± 4% of the drug over a 30-day period. These findings indicate that PLDLA microspheres are promising carriers for paclitaxel, with a potential for future applications in drug delivery systems.