500908-53-2Relevant articles and documents
Host-guest interactions between dapsone and β-cyclodextrin (Part II): Thermal analysis, spectroscopic characterization, and solubility studies
Martins,Calderini,Pessine
, p. 109 - 116 (2012)
The complex of dapsone with β-cyclodextrin was prepared by the co-precipitation/freeze-drying method. The physical-chemical characteristics of the complex were investigated by different methods and compared with those of the physical mixture and of the isolated compounds. The methods used were infrared spectroscopy, X-ray diffractometry and differential scanning calorimetry. The stability constant was calculated from phase solubility diagram (Higuchi-Connors) and fluorescence spectroscopy. The stoichiometry of the complex was confirmed by Job's plot. Fluorescence measurements at different temperatures provided the thermodynamic parameters of the complexation. The infrared spectrum showed the disappearance of the SO2 asymmetric stretching band of the drug at 1275 cm-1 after complexation. The amorphization of the samples, as revealed by the X-ray diffraction patterns, was an indirect proof of the inclusion complex. The thermal analysis showed that the curves of the physical mixture are combination of the curves of both constituents (dapsone and β-cyclodextrin) while the absence of the melting peak of the drug in the DSC curve of the complex suggests the inclusion of the drug molecule in the host cavity as a 1:1 complex as indicated by Job's plot. There was a linear increase in its solubility with the increase of the cyclodextrin concentration and the complex was classified as an A L-type. The value of the stability constant was 3,998 L mol -1 calculated by the Higuchi-Connors diagram and around 18,100 L mol-1 from the fluorescence method indicating a strong interaction between the host and the guest. Complex formation was a spontaneous and enthalpy directed process.
Host-guest interactions between dapsone and β-cyclodextrin (part I): Study of the inclusion compound by nuclear magnetic resonance techniques
Calderini, Adriana,Martins, Milene H.,Pessine, Francisco B. T.
, p. 77 - 86 (2013)
Dapsone (4,4′diaminodiphenylsulfone) is a very effective drug to treat leprosy and a broad range of infectious conditions such as Pneumocystis carinii pneumonia, toxoplasmosis and tuberculosis. However, the oral administration of this drug generally is related to serious side effects and treatment failures. It is believed that the inclusion compound of this drug and cyclodextrins would increase the wettability and the solubility of the encapsulated drug for a supported and gradual release, maximizing its biodisponibility over time. The encapsulation of dapsone in β-cyclodextrin was investigated by five nuclear magnetic resonance spectroscopy techniques. The data obtained for the complex in aqueous solution and in solid-state revealed a strong interaction between host and guest, showing that the drug molecule is deeply inserted in the CD cavity. The diffusion experiments (diffusion ordered spectroscopy) showed a high percentage of complexation (86 %) and that the drug molecule is preferentially interacting with the large side of the β-cyclodextrin cavity.
