BIOPHYSICAL CHARACTERIZATION OF VALRUBICIN INCORPORATED RHDL NANOPARTICLES.

Purpose: The purpose of this investigation is to study the biophysical properties of anticancer drug valrubicin, loaded in reconstituted high density lipoprotein (rHDL) nanoparticles by UV- visible and fluorescent spectroscopy along with time resolved measurements and to show its potential application as an imaging agent. Methods: Spectroscopy techniques have been used to study the photophysical properties of free valrubicin and valrubicin incorporated rHDL nanoparticles. UV-Vis absorption and fluorescence measurements were obtained using a Cary 50 UV-visible spectrophotometer (Varian Inc.) and Cary Eclipse Spectrofluorometer (Varian Inc.) respectively. Biological application of rHDL valrubicin nanoparticles as an imaging agent was observed using confocal microscopy. Results: Steady state anisotropy of rHDL valrubicin is higher than free valrubicin drug particles. Fluorescence lifetime of rHDL valrubicin is 0.78 ns and of free valrubicin is 1.01ns. rHDL valrubicin also shows temperature dependent decrease in anisotropy with increase in temperature. Confocal image shows the engulfed rHDL valrubicin particles inside the cells. Conclusions: This rHDL valrubicin nanoparticle provides a targeted delivery approach to treat cancer and since this drug possesses fluorescent properties, these valrubicin rHDL nanoparticles can be tracked inside the cells and In-vivo.