FIGURE 13.

(A) The change of pyrene fluorescence intensity (I ₁) with pH at a constant micelle concentration (0.05 g L⁻¹). m-PHSM constructed with the different amounts of PLLA-b-PEG (5%, ▲; 10%, □; 20%, ●) was monitored in NaOH (or HCl)-Na₂B₄O₇ buffer solution (pH 8.0) with exposure to each pH for 24 h. (B) Cumulative amount of DOX for 12 h released from various m-PHSM at pH 6.5 (□) and pH 6.0 (■). (C) Cell viabilities determined by MTT assay of ovarian A2780 wild-type carcinoma cells treated with micelles: free DOX (white), DOX/PHIM (gray), and DOX/m-PHSM(20%) (dark gray). DOX dose was equivalent to 1,000 ng ml⁻¹ in each formulation (Kim et al., 2008). Abbreviation: m-PHSM, pH-sensitive mixed micelles containing poly(histidine (His)-co-phenylalanine (Phe))-b-poly(ethylene glycol) (PEG) and poly(L-lactic acid) (PLLA)-b-PEG; PHIM, pH-insensitive PLLA-b-PEG micelles.