Table III.
Effect of Various Lipids on siRNA Complexation
| Formulation | Lipids | Lipid molar ratio | N/P | % siRNA complexeda | Remarks |
|---|---|---|---|---|---|
| D lipoplexes | DOTAP | 1 | 0.5 to 2 | − | Loosely bound complex formed at N/P = 1.25 and above |
| D2 lipoplexes | DOTAP/DOPE | 1:1 | 0.5 to 2 | − | Loosely bound complex formed at N/P = 1.25 and above. |
| D2H lipoplexes | DOTAP/DOPE/HSPC | 1:1:1.3 | 1.0 | 52.2 ± 1.68 | N/HSPC = 0.30 gave complete complexation at N/P = 2.0. |
| 1:1:1.3 | 1.5 | 60.5 ± 1.45 | |||
| 1:1:1.3 | 2.0 | 69.3 ± 0.98 | |||
| 1:1:2.6 | 1.0 | 55.5 ± 2.63 | |||
| 1:1:2.6 | 1.5 | 63.3 ± 2.40 | |||
| 1:1:2.6 | 2.0 | 73.3 ± 1.86 | |||
| 1:1:3.3 | 1.0 | 70.3 ± 1.56 | |||
| 1:1:3.3 | 1.5 | 85.2 ± 2.23 | |||
| 1:1:3.3 | 2.0 | 98.4 ± 1.53 | |||
| D2C Lipoplexes | DOTAP/DOPE/cholesterol | 1:1:1.3 | 1.0 | 40.2 ± 0.68 | At N/Chol = 0.38, siRNA complexation occurred at N/P = 2. |
| 1:1:1.3 | 1.5 | 52.3 ± 1.48 | |||
| 1:1:1.3 | 2.0 | 90.5 ± 1.23 | |||
| 1:1:2.6 | 1.0 | 43.2 ± 1.02 | |||
| 1:1:2.6 | 1.5 | 55.3 ± 1.63 | |||
| 1:1:2.6 | 2.0 | 97.5 ± 1.24 | |||
| 1:1:3.9 | Improper liposome formation | ||||
| D2CH lipoplexes | DOTAP/DOPE/HSPC/cholesterol (N/HSPC = 0.30) | 1:1:3.3:1.3 | 1.0 | 45.3 ± 1.65 | Complete complexation was achieved using combination of DOTAP, DOPE, HSPC and cholesterol (1:1:3.3:2.6) at N/P = 2.0. |
| 1:1:3.3:1.3 | 1.5 | 58.3 ± 1.06 | |||
| 1:1:3.3:1.3 | 2.0 | 87.5 ± 1.26 | |||
| 1:1:3.3:2.6 | 1.0 | 55.3 ± 1.09 | |||
| 1:1:3.3:2.6 | 1.5 | 85.6 ± 0.79 | |||
| 1:1:3.3:2.6 | 2.0 | 98.2 ± 1.57 | |||
| 1:1:3.3:3.9 | 1.0 | 33.3 ± 2.04 | |||
| 1:1:3.3:3.9 | 1.5 | 49.7 ± 1.63 | |||
| 1:1:3.3:3.9 | 2.0 | 63.2 ± 1.96 | |||
| D2CHP lipoplexes | DOTAP/DOPE/HSPC/cholesterol/DMPG (N/PC = 0.30), (N/Chol = 0.38) | 1:1:3.3:2.6:0 | 2.0 | 98.2 ± 0.86 | DMPG at all levels led to decreased siRNA complexation efficiency |
| 1:1:3.3:2.6:0.3 | 2.0 | 90.4 ± 1.21 | |||
| 1:1:3.3:2.6:0.5 | 2.0 | 74.5 ± 1.66 | |||
| 1:1:3.3:2.6:0.8 | 2.0 | 56.4 ± 2.13 | |||
| 1:1:3.3:2.6:1.0 | 2.0 | 37.5 ± 1.65 | |||
siRNA small interfering RNA, DOTAP dioleoyl-trimethylammoniumpropane, DOPE dioleoyl-sn-glycero-3-phosphoethanolamine, HSPC hydrogenated soya phosphocholine, Chol cholesterol, DMPG dimyristoyl-sn-glycero-3-phosphoglycerol, N/P represents ratio of quaternary nitrogen of DOTAP to phosphate of siRNA, N/PC represents molar ratio of DOTAP and HSPC, N/Chol represents molar ratio of DOTAP and cholesterol
aValues are represented as mean ± SD, n = 3