Rifampicin-Carrying Poly(D, L-Lactide) Microspheres: Loading and Release

Rifampicin-loaded poly(D, L-lactide) (PDLLA) microspheres in the size range of 0.8—8.0//m were prepared by a modified solvent evaporation method. Rifampicin loading was changed by using different types of solvents (i.e. methylene chloride, chloroform, and carbon tetrachloride) with different solvent/polymer ratios and different emulsifiers (i.e. methyl cellulose, gelatin, and Tween-20), and by changing the initial drug/polymer ratio. These rifampicin-loaded PDLLA microspheres degraded much faster in the medium at basic pH (9.8) and at high temperatures (55°C). Rifampicin release was also high under these conditions. It was concluded that rifampicin release was both degradation-and diffusion- controlled.