Separation of derivatized glucoside anomers using supercritical fluid chromatography.

Preparative scale supercritical fluid chromatography was used to separate derivatized anomeric monosaccharides. Methyl 2,3,4,6-tetra-O-benzoyl-α-d-glucopyranoside and methyl 2,3,4,6-tetra-O-benzoyl-ß-d-glucopyranoside were synthesized by benzoyl derivatization of the parent anomerically pure monosaccharides. The elution profiles of each anomer were studied, suggesting that separation was possible. Mixtures of the compounds were then prepared at different ratios and separation was achieved using carbon dioxide/ethanol mixtures as the mobile phase and GreenSep™ 5micron particle size silica as the stationary phase. Ethanol co-solvent in the mobile phase was required to give a successful separation of the anomers however over the range 6.5-10.4wt% ethanol concentration studied here there was little variation in the degree of separation. In fractionation trials, separation of mixtures into fractions with >98% purity was achieved, with recoveries greater than 96%.

Preparation and characterization of progesterone dispersions using supercritical carbon dioxide.

CONTEXT: Supercritical fluid methods offer an alternative to conventional mixing methods, particularly for heat sensitive drugs and where an organic solvent is undesirable. OBJECTIVE: To design, develop and construct a unit for the particles from a gas-saturated suspension/solution (PGSS) method and form endogenous progesterone (PGN) dispersion systems using SC-CO2. MATERIALS AND METHODS: The PGN dispersions were manufactured using three selected excipients: polyethylene glycol (PEG) 400/4000 (50:50), Gelucire 44/14 and D-α-tocopheryl PEG 1000 succinate (TPGS). Semisolid dispersions of PGN prepared by PGSS method were compared to the conventional methods; comelting (CM), cosolvent (CS) and physical mixing (PM). The dispersion systems made were characterized by Raman and Fourier transform infrared (FTIR) spectroscopies, X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), PGN recovery, uniformity and in vitro dissolution, analyzed by high-performance liquid chromatography (HPLC). RESULTS: Raman spectra revealed no changes in the crystalline structure of PGN treated with SC-CO2 compared to that of untreated PGN. XRPD and FTIR showed the presence of peaks and bands for PGN confirming that PGN has been incorporated well with each individual excipient. All PGN dispersions prepared by the PGSS method resulted in the improvement of PGN dissolution rates compared to that prepared by the conventional methods and untreated PGN after 60 min (p value < 0.05). CONCLUSION: The novel PGN dispersions prepared by the PGSS method offer the great potential to enhance PGN dissolution rate, reduce preparation time and form stable crystalline dispersion systems over those prepared by conventional methods.