Enhanced antiproliferative activity of the new anticancer candidate LPSF/AC04 in cyclodextrin inclusion complexes encapsulated into liposomes.

LPSF/AC04 (5Z)-[5-acridin-9-ylmethylene-3-(4-methyl-benzyl)-thiazolidine-2,4-dione] is an acridine-based derivative, part of a series of new anticancer agents synthesized for the purpose of developing more effective and less toxic anticancer drugs. However, the use of LPSF/AC04 is limited due to its low solubility in aqueous solutions. To overcome this problem, we investigated the interaction of LPSF/AC04 with hydroxypropyl-ß-cyclodextrin (HP-ß-CyD) and hydroxypropyl-γ-cyclodextrin (HP-γ-CyD) in inclusion complexes and determine which of the complexes formed presents the most significant interactions. In this paper, we report the physical characterization of the LPSF/AC04-HP-CyD inclusion complexes by thermogravimetric analysis, differential scanning calorimetry, infrared spectroscopy absorption, Raman spectroscopy, (1)HNMR, scanning electron microscopy, and by molecular modeling approaches. In addition, we verified that HP-ß-CyD complexation enhances the aqueous solubility of LPSF/AC04, and a significant increase in the antiproliferative activity of LPSF/AC04 against cell lines can be achieved by the encapsulation into liposomes. These findings showed that the nanoencapsulation of LPSF/AC04 and LPSF/AC04-HP-CyD inclusion complexes in liposomes leads to improved drug penetration into the cells and, as a result, an enhancement of cytotoxic activity. Further in vivo studies comparing free and encapsulated LPSF/AC04 will be undertaken to support this investigation.

The encapsulation of ß-lapachone in 2-hydroxypropyl-ß-cyclodextrin inclusion complex into liposomes: a physicochemical evaluation and molecular modeling approach.

The aim of this study was to encapsulate lapachone (ß-lap) or inclusion complex (ß-lap:HPß-CD) in liposomes and to evaluate their physicochemical characteristics. In addition, the investigation of the main aspects of the interaction between ß-lap and 2-hydroxypropyl-ß-cyclodextrin (HPß-CD), using both experimental and molecular modeling approaches was discussed. Furthermore, the in vitro drug release kinetics was evaluated. First, a phase solubility study of ß-lap in HPß-CD was performed and the ß-lap:HPß-CD was prepared by the freeze-drying technique. A 302-fold increase of solubility was achieved for ß-lap in HPß-CD solution with a constant of association K(1:1) of 961 M(-1) and a complexation efficiency of ß-lap of 0.1538. (1)H NMR, TG, DSC, IR, Raman and SEM indicated a change in the molecular environment of ß-lap in the inclusion complex. Molecular modeling confirms these results suggesting that ß-lap was included in the cavity of HPß-CD, with an intermolecular interaction energy of -23.67 kJ mol(-1). ß-lap:HPß-CD and ß-lap-loaded liposomes presented encapsulation efficiencies of 93% and 97%, respectively. The kinetic rate constants of 183.95±1.82 µg/h and 216.25±2.34 µg/h were calculated for ß-lap and ß-lap:HPß-CD-loaded liposomes, respectively. In conclusion, molecular modeling elucidates the formation of the inclusion complex, stabilized through hydrogen bonds, and the encapsulation of ß-lap and ß-lap:HPß-CD into liposomes could provide an alternative means leading eventually to its use in cancer research.

In vitrouptake and antimycobacterial activity of liposomal usnic acid formulation.

The cellular uptake and antimycobacterial activity of usnic acid (UA) and usnic acid-loaded liposomes (UA-LIPOs) were assessed on J774 macrophages. The minimal inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC) of UA and UA-LIPO against Mycobacterium tuberculosis were determined. Concentrations required to inhibit 50% of cell proliferation (IC(50)) were 22.5 (+/-0.60) and 12.5 (+/-0.26) microg/ml, for UA and UA-LIPO, respectively. The MICs of UA and UA-LIPO were 6.5 and 5.8 microg/mL, respectively. The MBC of UA-LIPO was twice as low (16 microg/mL) as that of UA (32 microg/mL). An improvement in the intracellular uptake of UA-LIPO was found (21.6 x 10(4) +/- 28.3 x 10(2) c.p.s), in comparison with UA (9.5 x 10(4) +/- 11.4 x 10(2) c.p.s). In addition, UA-LIPO remains much longer inside macrophages (30 hours). All data obtained from the encapsulation of usnic acid into liposomes as a drug delivery system (DDS) indicate a strong interaction between UA-liposomes and J774 macrophages, thereby facilitating UA penetration into cells. Considering such a process as ruling the Mycobacterium-transfection by magrophages, we could state that associating UA with this DDS leads to an improvement in its antimycobacterial activity.