TABLE 1.
Representative formulations of rifampin-loaded microspheres
| Formulation no. (lot no.) | Excipient | Excipient solvent | Rifampin content (% [wt/wt])
|
Microsphere size (μm)a | In vitro release (%) after 2 days | |
|---|---|---|---|---|---|---|
| Theoretical | Observed | |||||
| 1 | 60:40 DL-PLG | Ethyl acetate | 30 | 1.38 | 101.1 | NDb |
| 2 | 60:40 DL-PLG | Ethyl acetate | 30 | 18 | 106.1 | 2 |
| 3 | 50:50 DL-PLG | Methylene chloride | 30 | 19 | 110.7 | 5 |
| 4 | 65:35 DL-PLG | Ethyl acetate | 30 | 17.6 | 68.4 | 15 |
| 5 | 60:40 DL-PLGc | Ethyl acetate | 30 | 17 | 106.1 | 25 |
| 6 | 60:40/50:50 DL-PLGd | Ethyl acetate | 30 | 27 | 101.1 | 2.5 |
| 7 | 60:40/50:50 DL-PLGd | Ethyl acetate | 30 | 25.7 | 130.2 | 1.8 |
a
Data reported as 90 volume percentiles.
b
ND, not done.
c
Microspheres prepared by incorporating dextrose.
d
Excipient is a blend of 60:40 DL-PLG and low-molecular-weight 50:50 DL-PLG.