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Paclitaxel (PTX) is widely used as a first-line treatment for patients with metastatic breast cancer; however, its poor water solubility represents a major challenge for parenteral administration. The encapsulation of the PTX in drug-delivery systems with high affinity for tumor sites could improve the uptake and increase its therapeutic efficacy. In this work, long-circulating and pH-sensitive PEG-coated (SpHL-PTX) and PEG-folate-coated liposomes containing PTX (SpHL-FT-PTX) were prepared, and the physicochemical properties and in vitro cytotoxic activity were evaluated. Both formulations presented adequate physicochemical properties, including a mean diameter smaller than 200 nm, zeta potential values near the neutral range, and an encapsulation percentage higher than 93%. Moreover, SpHL-FT-PTX showed a good stability after storage for 100 days at 4 °C. The viability studies on breast cancer cell lines (MDA-MB-231 and MCF-7) demonstrated cytotoxic activity more pronounced for SpHL-FT-PTX than for SpHL-PTX or free drug for both tumor cell lines. This activity was reduced to a rate comparable to SpHL-PTX when the cells were previously treated with folic acid in order to saturate the receptors. In contrast, in the normal cell line (L929), cell viability was decreased only by free or liposomal PTX in the highest concentrations. A significantly higher selectivity index was obtained after SpHL-FT-PTX treatment compared to SpHL-PTX and free PTX. Therefore, the results of the present work suggest that SpHL-FT-PTX can be a promising formulation for the treatment of metastatic breast cancer. [ABSTRACT FROM AUTHOR]

Abstract: In the present study, anionic and pH-sensitive liposomes containing DNA were developed and characterized. These liposomes were obtained by binding the DNA with 6-monodeoxy-6-monoamine-β-cyclodextrin (Am-β-CD). This complex was encapsulated into the liposomes, which were characterized by encapsulation rate, diameter, zeta potential, and atomic force microscopy. The binding between Am-β-CD and the DNA was higher as of the +/− charge ratio. The amount of DNA encapsulated was approximately 10–14μg/mL. The mean diameter and zeta potential were 186.0nm and −56mV, respectively. Liposomes which did not contain the complex were more prone to collapse over the mica surface. The vesicles containing the complex presented a narrower size distribution. [Copyright &y& Elsevier]