Comparison of DOX uptake levels in FSa-R and TAM-enriched FSa-N tumors after i.v. injection of free and liposomal drug1-a
| Formulation | Time | FSa-R | FSa-N | Uptake Ratio FSa-N/FSa-R |
|---|---|---|---|---|
| h | μg DOX/g tumor | |||
| Free | 1 | 7.8 ± 3.1 | 12.8 ± 1.2 | 1.6 (P = .050) |
| 4 | 6.2 ± 0.9 | 11.6 ± 1.2 | 1.9 (P = .008) | |
| 24 | 4.7 ± 1.1 | 7.7 ± 1.4 | 1.6 (P = .039) | |
| DSPC/Chol | 1 | 3.6 ± 0.6 | 5.2 ± 1.0 | 1.4 (P = .187) |
| 4 | 5.2 ± 0.2 | 14.1 ± 3.4 | 2.7 (P = .007) | |
| 24 | 16.3 ± 2.3 | 23.9 ± 2.7 | 1.5 (P = .050) | |
| PEG-PE/DSPC/Chol | 1 | 3.3 ± 0.7 | 5.3 ± 0.6 | 1.6 (P = .036) |
| 4 | 4.7 ± 1.0 | 9.8 ± 0.9 | 2.1 (P = .005) | |
| 24 | 15.7 ± 1.7 | 32.1 ± 4.7 | 2.0 (P = .017) | |
↵1-a Mice bearing bilateral 200- to 500-mg FSa-R or FSa-N tumors were injected i.v. with DOX (20 mg/kg) in free form or encapsulated in 100 nm DSPC/Chol or PEG-PE/DSPC/Chol liposomes as described under “Materials and Methods.” At the indicated times tumors were removed from mice (four mice per group) and processed for DOX determination as described under “Materials and Methods.” P values were determined by a Student’s t-test for independent variables with Statistica software.