Desenvolvimento de formas lipossomais contendo levana

AUTOR(ES)

Agenor Tavares JÃcome JÃnior

DATA DE PUBLICAÇÃO

2006

RESUMO

The present study proposes the manufacture of liposomes containing levan as an antitumor and immunomodulator for the cancer therapy. Levan-loaded liposomes (Lev-LIPO) were prepared according to the thin film formed method. Physicochemical characterization was performed immediately after their preparation. Additionally, both accelerated and long-term stability testing of Lev-LIPO were carried out. The size distribution and surface charge of particles were determined using a zetasizerÂ. The assessment of levan content into liposomes was performed after the extraction of levan from liposomes with methanol and acid hydrolysis yielding fructose constituents, which were detected by spectrocolorimetry at 530 nm, and HPLC, using Refraction Index Detector, to make a comparative analysis each other. The encapsulation ratio of levan into liposomes was determined in the filtrated after ultrafiltration by centrifugation of samples. The in vitro release profile of Lev-LIPO was evaluated using dialysis method. Lev-LIPO (1.8 mg/ml) presented a bluish milky opalescent appearance and maintained its initial characteristics over 180 days when stored at 4ÂC Â 1ÂC. Lev-LIPO had a mean diameter of 145 Â 75 nm. The Lev-LIPO Zeta potential decreased (21.33 to 2.51 mV) when levan content was increased. The encapsulation ratio of levan into liposomes was 87.6 Â 1.2% determinated by spectrocolorimetry and 88.67 Â 1.69% by HPLC. The in vitro kinetics of Lev-LIPO showed an initial burst of 10.59 Â 3.49% at the first hour followed by a slow and controlled drug release during the second stage (8 â 72 h) with 0.27 mg/h rate. The loaded levan amount diffused out (98.70 Â 0.85 %) within 96 h. Lev-LIPO suggest a potential drug delivery system that can be used in the cancer therapy

ASSUNTO(S)

quimica dos produtos naturais fosfolipÃdeos lipossomas lipossomas terapia polissacarÃdeo cÃncer sistema de liberaÃÃo controlada levana

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