Table 1.
Physicochemical characteristics of SN-38-loaded liposomes and SN-38 entrapment inside vesicles
| Sample
|
Physical parameters
|
Liposomal SN-38
|
||||
|---|---|---|---|---|---|---|
| Liposome composition | Lipid/SN-38 (molar ratio) | Particle sizea (nm) | PDIb | Zeta-potentialc (mV) | [SN-38]d (μM) | mg SN-38/mmol lipide |
| SLE | (7.5:1) | 355.3±13.2 | 0.472±0.011 | −47.7±8.8 | 1,770.0±10.2 | 52.2±0.3 |
| (10:1) | 332.8±19.6 | 0.525±0.058 | −54.3±10.3 | 1,329.0±11.3 | 39.2±0.3 | |
| (20:1) | 196.2±9.4 | 0.415±0.033 | −45.3±16.3 | 652.6±7.6 | 19.3±2.2 | |
| (40:1) | 119.1±1.9 | 0.398±0.081 | −36.1±8.7 | 331.3±8.2 | 9.8±0.2 | |
| DSPC/DOPS/CHOL (65:35:30) | (20:1) | 248.3±9.5 | 0.368±0.016 | −32.1±17.5 | 713.6±6.2 | 19.7±1.7 |
| EPC | (20:1) | 146.3±14.2 | 0.401±0.120 | −12.6±1.5 | 637.5±8.9 | 19.1±2.6 |
| EPC/DOPS (9:1) | (20:1) | 147.2±7.9 | 0.345±0.072 | −31.4±7.4 | 670.2±5.7 | 20.3±1.6 |
Notes:
a
Particle size measured as Z-average mean.
b
Polydispersity index.
c
Zeta potential.
d
Bulk SN-38 concentration in the liposome suspension.
e
Drug-loading efficiency, expressed as the amount of SN-38 relative to lipid (w/w). Lipid concentration in all the samples was 10 mg/mL. Three independent batches were processed and analyzed for physicochemical characterization. The data are the mean ± SD values corresponding to three independent preparations.
Abbreviations: SN-38, irinotecan metabolite; SLE, soy bean lipid extract; DSPC, L-α-distearoyl-phosphatidylcholine; DOPS, L-α-dioleoyl-phosphatidylserine; CHOL, cholesterol; EPC, egg yolk phosphatidylcholine.