Doxorubicin-loaded phosphatidylethanolamine-conjugated nanoliposomes: in vitro characterization and their accumulation in liver, kidneys, and lungs in rats

Figures & data

Figure 1 Fourier transform infrared spectroscopy (FTIR) spectra of A) cholesterol (CHL); B) soya-L-α-lecithin (SPC); C) doxorubicin (DOX); D) phosphatidylethanolamine (PE); E) mixture of SPC, CHL, and DOX; F) mixture of SPC, CHL, DOX, and PE; and G) lyophilized formulation (DOX-PEL).

Figure 2 Differential scanning calorimetry (DSC) curve of A) cholesterol (CH L); B) soya-L-α-lecithin (SPC); C) phosphatidylethanolamine (PE); D) doxorubicin (DOX); and E) mixture of CHL, SPC, PE, and DOX.

Table 1 % yield, % loading and loading efficiency

Code name of the formulation	Molar ratio of phospholipids, cholesterol, and PE (for DOX-PEL) used	Drug: polymer ratio (w/w)	% yield	% loading (mean ± SD; n = 3)	Loading efficiency (% w/w) (mean ± SD; n = 3)
DOX-L	SPC:CHL = 23.32:15.52	1:40	50 2.46 ± 0.056	49.25 ± 1.05
DOX-PEL	SPC:CHL:PE = 233.2:155.2:6.7	1:41	44.72	2.65 ± 0.16	52.98 ± 3.22

Abbreviations: DOX-L, doxorubicin-loaded liposomes; DOX-PEL, PE-conjugated doxorubicin-loaded liposomes; PE, phosphatidylethanolamine; SPC, soya-L-α-lecithin; CHL, cholesterol; w/w, weight/weight; SD, standard deviation.

Figure 3 Field emission scanning electron microscopy (FESEM) of A) doxorubicin-loaded liposomes (DOX-L); and B) doxorubicin-loaded PE liposomes (DOX-PEL).

Figure 4 Energy dispersive X-ray (EDX) of A) doxorubicin-loaded liposomes (DOX-L); and B) doxorubicin-loaded PE liposomes (DOX-PEL).

Table 2 Weight % and atomic % of elements in various liposomes

	CK		OK		PK
	DOX-L	DOX-PEL	DOX-L	DOX-PEL	DOX-L	DOX-PEL
Weight %	53.66	46.85	42.06	47.58	4.28	5.57
Atomic %	61.75	55.30	36.34	42.15	1.91	2.55

Abbreviations: DOX-L, doxorubicin-loaded liposomes; DOX-PEL, PE-conjugated doxorubicin-loaded liposomes; CK, carbon counts; OK, oxygen counts; PK, phosphorous counts.

Figure 5 Particle size distribution of A) doxorubicin-loaded liposomes (DOX-L); and B) doxorubicin-loaded PE liposomes (DOX-PEL).

Table 3 Size distribution, PDI, and zeta potential of various liposomes

	Average size (d nm)	PDI	Zeta potential (mV)	Mobility (μmcm/Vs)	Conductivity (MS/cm)
DOX-L	32.67	0.221	−55.6	−4.36	0.0272
DOX-PEL	37.84	0.264	−50.2	−3.937	0.0356

Abbreviations: DOX-L, doxorubicin-loaded liposomes; DOX-PEL, PE-conjugated doxorubicin-loaded liposomes; PDI, polydispersity index.

Figure 6 Release of doxorubicin from doxorubicin-loaded liposomes (DOX-L) and doxorubicin-loaded PE liposomes (DOX-PEL).

Table 4 In vitro release kinetics with R² values for different formulations

	DOX-L	DOX-PEL
Zero order	Y = 0.1134 X + 23.302	Y = 0.1568 X + 22.19
kinetics	R^2 = 0.8342	R^2 = 0.9279
First order	Y = 0.0007 X + 1.918	Y = 0.0001 X + 1.944
kinetics	R^2 = 0.8865	R^2 = 0.9705
Higuchi	Y = 2.4371 X + 8.019	Y = 3.0508 X + 3.7397
kinetics	R^2 = 0.9254	R^2 = 0.9747
Korsmeyer	Y = 0.3188 X + 0.9133	Y = 0.382 X + 0.8022
kinetics	R^2 = 0.9375	R^2 = 0.9592
Hixon–Crowell	Y = −0.0021 X + 4.33	Y = −0.0029 X + 4.4096
kinetics	R^2 = 0.8766	R^2 = 0.9666

Abbreviations: DOX-L, doxorubicin-loaded liposomes; DOX-PEL, PEconjugated doxorubicin-loaded liposomes.

Figure 7 Fluorescence microscopic photographs of a) liver; b) kidneys; and c) lungs of rats treated with fluorescein isothiocyanate-phosphatidylethanolamine-doxorubicin (FITC-PE-DOX) liposomes (A = negative control; B = positive control; C = one hour after treatment; D = three hours after treatment).

Figure 8 Fluorescence microscopic photographs of liver a), kidneys b) and lungs c); of rats treated with phosphatidylethanolamine-doxorubicin (PE-DOX) liposomes (A = negative control; B = positive control; C = one hour after treatment; D = three hours after treatment).

Figure 9 Fluorescence microscopic photographs of liver a), kidneys b) and lungs c); of rats treated with free DOX (A = negative control; B = positive control; C = one hour after treatment; D = three hours after treatment).