Structure determination of phase II of the antifungal drug griseofulvin by powder X-ray diffraction.

Two new crystalline polymorphs of the widely used antifungal drug griseofulvin (phases II and III), which originate from the crystallization of the melt, have been detected recently. The crystal structure of phase II of griseofulvin {systematic name: (2S,6'R)-7-chloro-2',4,6-trimethoxy-6'-methyl-3H,4'H-spiro[1-benzofuran-2,1'-cyclohex-2-ene]-3,4'-dione}, CHClO, has been solved by powder X-ray diffraction (PXRD). The PXRD pattern of this new phase was recorded at room temperature using synchrotron radiation.

A new protocol to determine the solubility of drugs into polymer matrixes.

In this paper we present a new protocol to determine faster the solubility of drugs into polymer matrixes. The originality of the method lies in the fact that the equilibrium saturated states are reached by demixing of supersaturated amorphous solid solutions and not by dissolution of crystalline drug into the amorphous polymer matrix as for usual methods. The equilibrium saturated states are thus much faster to reach due to the extra molecular mobility resulting from the strong plasticizing effect associated with the supersaturation conditions.

On the polymorphism of griseofulvin: identification of two additional polymorphs.

In this paper, we present an investigation of the polymorphism of griseofulvin. In addition to the only reported crystalline form (form I), two new polymorphic forms (II and III) have been identified and characterized by differential scanning calorimetry and powder X-ray diffraction. Reasons why these two polymorphs were isolated during the present study, but not detected during the numerous previous studies on this drug, are also discussed.

Characterization of the hidden glass transition of amorphous cyclomaltoheptaose.

An amorphous solid of cyclomaltoheptaose (β-cyclodextrin, β-CD) was formed by milling its crystalline form using a high-energy planetary mill at room temperature. The glass transition of this amorphous solid was found to occur above the thermal degradation point of the material preventing its direct observation and thus its full characterization. The corresponding glass transition temperature (T(g)) and the ΔC(p) at T(g) have, however, been estimated by extrapolation of T(g) and ΔC(p) of closely related amorphous compounds.