STABILITY AND IN-VITRO CYTOTOXICITY OF PACLITAXEL LOADED C18-ADA2-RGD MICELLES
Purpose
To determine stability and in-vitro cytotoxicity of paclitaxel loaded micelles prepared from C18-ADA2-RGD amphiphiles.
Method
FRET (Förster Resonance Energy Transfer) pair, DiI (1,1’-dioctadecyl-3,3,3,3’-tetramethylindocarbocyanine perchlorate) and DiO (3,3’-dioctadecyloxacarbocyanine perchlorate) were loaded into micelles of C18-ADA2-RGD (stearic acid linked to RGD via 2 units of 8-amino-3,6 dioxoctanoic acid). DiO and DiI in ethanol (250 μg/mL each) were mixed in equal volume with 4 mg/mL solution of C18-ADA2-RGD amphiphiles. The solvent was evaporated by using nitrogen gas, and the formed film was hydrated by addition of water, followed by dialysis through a 1000 kDa membrane. The micelles were diluted with water from 2 to 10 fold and fluorescence spectra were recorded at excitation wavelength of 484 nm and emission wavelength range of 495 to 600 nm. Methanol was used to disassemble micelles. In vitro cytotoxicity of paclitaxel loaded C18-ADA2-RGD micelles was determined by SRB cytotoxicity assay in A2058 (melanoma cells) and Detroit 551 (normal cell line). The cells were plated at a density of 7000 cells/well for 24 hours and then treated with paclitaxel (free drug) and paclitaxel loaded micelles at concentrations ranging from 0.1 to 100 nM for 72 hours at 37°C. Cell viability was assessed and IC50 was determined using GraphPad Prism®.
Results
With FRET pair loaded micelles, upon 2X to 10X dilution, emission peak was always observed at 565 nm, indicating energy transfer and intact micelle structure. Emission peak was shifted to 501 nm when the micelle solution was diluted with methanol. When separate DiI micelles and DiO micelles were mixed with water as diluent, 501 nm peak was dominant, since no energy transfer occured. The IC50 of paclitaxel loaded in micelles decreased by 50% (4.704 nM) when compared to free paclitaxel (7.857 nM) in A2058 cells. In Detroit 551, IC50 of paclitaxel loaded in micelles was four fold higher (22.530 nM) when compared to free paclitaxel (4.765 nM).
Significance
The hydrophobic dyes were entrapped in the micellar core, which were stable upon 10X dilution. The toxicity of micellar systems was higher in cancer cells but lower in normal cells compared to free paclitaxel.
Location
DeRosa University Center, Stockton campus, University of the Pacific
Format
Poster Presentation
STABILITY AND IN-VITRO CYTOTOXICITY OF PACLITAXEL LOADED C18-ADA2-RGD MICELLES
DeRosa University Center, Stockton campus, University of the Pacific
