Doxorubicin-incorporated polymeric micelles composed of dextran-b-poly(DL-lactide-co-glycolide) copolymer

Figures & data

Table 1 Characterization of DexbLG block copolymer

	MW by GPC			MW by ^1H-NMR
	Mw	Mn	PDIa	Theoreticalb	Experimentalb
Dextran	4800	4370	1.098
Dextran-NH2	5180	4880	1.061
PLGA	4920	4780	1.029
DexbLG				10,100	9580

a Notes: PDI = M_w/M_n;

b theoretical value was simply calculated from GPC data as follows: M_w of dextran-NH₂ + M_w of PLGA. Experimental value was calculated from ¹H NMR data of PLGA and dextran.

Abbreviations: GPC, gel permeation chromatography; PDI, polydispersity index; PLGA, poly(DL-lactide-co-glycolide); DexbLG, dextran and poly(DL-lactide-co-glycolide); MW, molecular weight; NMR, nuclear magnetic resonance imaging; dextran-NH₂, aminated dextran.

Figure 1 Synthesis schema for dextran and poly(DL-lactide-co-glycolide) block copolymer.

Figure 2 ¹H-NMR spectra of dextran and poly(DL-lactide-co-glycolide) block copolymer in dimethyl sulfoxide.

Table 2 Characterization of DexLG polymeric micelles incorporating doxorubicin

Polymer/doxorubicin weight ratio (mg/mg)	Drug contents (%, w/w)		Particle size (nm)
	Theoretical	Experimental	Intensity (mean ± SD)	Weight (mean ± SD)	Number (mean ± SD)
40/0	–	–	82.6 ± 17.3	75.6 ± 10.8	70.9 ± 8.7
40/5	11.1	7.6	122.1 ± 29.6	103.3 ± 24.0	91.4 ± 17.1
40/10	20	12.3	206.5 ± 49.7	177.5 ± 38.5	160.2 ± 27.2

Figure 3 Transmission electron micrograph of polymeric micelles composed of dextran and poly(DL-lactide-co-glycolide) block copolymer.

Figure 4 ¹H-NMR spectra of dextran and poly(DL-lactide-co-glycolide) polymeric micelle in D₂O (A) and dimethyl sulfoxide (B).

Figure 5 Fluorescence excitation of pyrene (6.0 × 10⁻⁷ M) versus the concentration of dextran and poly(DL-lactide-co-glycolide) copolymer in distilled water (λ_em = 390 nm) (A) plots of intensity ratios I₃₃₉/I₃₃₆ from the pyrene excitation spectra versus (B) log c of dextran and poly(DL-lactide-co-glycolide) copolymers in distilled water.

Figure 6 Drug release from polymeric micelles incorporating doxorubicin according to drug content.

Figure 7 Growth inhibition of doxorubicin-sensitive (A) and doxorubicin-resistant (B) HuCC-T1 cells by treatment of polymeric micelles incorporating doxorubicin. 1 × 10⁴ cells were exposed to doxorubicin or polymeric micelles for 2 days. Empty polymeric micelles were treated in a similar way to (C). Empty polymeric micelles did not significantly inhibit cell growth rate.

Figure 8 IC₅₀ of doxorubicin and polymeric micelles against doxorubicin-resistant HuCC-T1 cells.

Figure 9 Fluorescence images of doxorubicin-sensitive and doxorubicin-resistant HuCCT1 cells. HuCCT1 cells were exposed to doxorubicin or polymeric micelles (equivalent concentration of doxorubicin 1 μg/mL) for 1 hour. Fluorescence images of cells were observed with confocal laser scanning microscopy.

Figure 10 Flow cytometric analysis of doxorubicin-sensitive and doxorubicin-resistant HuCC-T1 cells. HuCCT1 cells were exposed to doxorubicin or polymeric micelles (equivalent concentration of doxorubicin 1 μg/mL) for 1 hour. 1 × 10⁶ cells were used for FACScan analysis. Doxorubicin-sensitive cells: (A) control, (B) doxorubicin, (C) polymeric micelles, (D) relative fluorescence intensity. Doxorubicin-resistant cells: (E) control; (F) doxorubicin; (G) polymeric micelles; (H) relative fluorescence intensity. The values were averaged over four separate experiments.

Notes: *P < 0.005; **P < 0.0001; ***P < 0.0001; ****P < 0.0001.