Rifampicin-loadedpoly(e-caprolactone)-b-poly(ethylene glycol) -poly(e-caprolactone) flower-like polymeric micelles display low aqueous physical stability over time and undergo substantial secondary aggregation. To improve their physical stability, the lyoprotectionlyophilization process was thoroughly characterized. The preliminary cryoprotectant performance of mono-and disaccharides (e.g. maltose, glucose), hydroxypropyl-bcyclodextrin (HPbCD) and poly(ethylene glycol) (PEG) of different molecular weights was assessed in freeze -thawing assays at 2208C, 2808C and 21968C. The size and size distribution of the micelles at the different stages were measured by dynamic light scattering (DLS). A cryoprotectant factor ( f c ) was determined by taking the ratio between the size immediately after the addition of the cryoprotectant and the size after the preliminary freeze -thawing assay. The benefit of a synergistic cryoprotection by means of saccharide/ PEG mixtures was also assessed. Glucose (1 : 20), maltose (1 : 20), HPbCD (1 : 5) and glucose or maltose mixtures with PEG3350 (1 : 20) (copolymer:cryoprotectant weight ratio) were the most effective systems to protect 1 per cent micellar systems. Conversely, only HPbCD (1 : 5) cryoprotected more concentrated drug-loaded micelles (4% and 6%). Then, those micelle/ cryoprotectant systems that displayed f c values smaller than 2 were freeze-dried. The morphology of freeze-dried powders was characterized by scanning electron microscopy and atomic force microscopy and the residual water content analysed by the Karl Fisher method. The HPbCD-added lyophilisates were brittle porous cakes (residual water was between 0.8% and 3%), easily redispersable in water to form transparent systems with a minimal increase in the micellar size, as determined by DLS.