In vitro studies on 5-florouracil-loaded DTPA-PE containing nanosized pegylated liposomes for diagnosis and treatment of tumor

Theranostic liposomes carry both the therapeutic active ingredients and the contrast agent into one delivery system. Codelivery of imaging contrast agent and chemotherapeutic drugs can provide real-time validation of the targeting strategy, resulting in an another step forward for individual-based therapy. The aim of this study was the incorporation of different drugs used in the diagnosis and treatment of tumors into one delivery system to develop nanosized, polyethylene glycol (PEG)-coated, different charged theranostic liposomes. Different charged liposomes consisting of 1,2-dipalmitoyl-sn-glycero-3- phosphocholine (DPPC) or Phospholipon® 90G (PL 90G; Phospholipid GmbH, Cologne, Germany), cholesterol, poly(ethylene glycol)2000/phosphatidyl ethanolamine (PEG2000-PE), stearylamine (SA) or dicetyl phosphate (DCP), and diethylenetriamine pentaacetate/PE (DTPA-PE) as bilayer ingredients and 5-florouracil (5-FU) as active substance were prepared by the film technique. Characterization, 5-FU in vitro release, cytotoxicity, and physical stability studies were performed. Particle size of all liposomes was 100-150°nm. Difference was not noted between encapsulation efficiency (EE%) of neutral DPPC and PL 90G liposomes containing 5-FU. EE% of charged DPPC liposomes was higher than that of charged PL 90G liposomes. PL 90G containing liposomes had a higher phospholipid amount than the same formulation of DPPC liposomes. DPPC containing different charged liposomes were selected for cytotoxicity studies. Different charged DPPC liposomes had the same antitumoral activity with the free 5-FU solution on MCF-7 cell lines. Liposome dispersions were more stable from the point of particle-size change and 5-FU leakage during storage at refrigerated temperature. The results of this study are very encouraging for the development of theranostic liposome formulations as a targeted delivery system for drugs, such as 5-FU, used both in therapy and imaging.