Document Studies of ternary systems of sulfadiazine with β-cyclodextrin and aminoacids

DELRIVO A.; ZOPPI A; GRANERO GE; LONGHI MR

Ars Pharmaceutica

Universidad de Granada

Lugar: Granada; Año: 2016 vol. 57 p. 167 - 176

0004-2927

Introduction: Cyclodextrins (CD), are known to form inclusion complexes with a variety of guest moleculesboth in solution and in the solid state. This can lead to the alteration of properties of guest molecules.Unfortunately, the complexation efficiency of CD is rather low, and can be enhanced by formationof ternary complexes using aminoacids (AA). Sulfadiazine (SDZ) is an antibiotic with extremely lowwater solubility which limits its therapeutic applications and bioavailability.Objetives: The aim of this work was to increase the aqueous solubility of SDZ by preparing ternarycomplexes of this drug with β-cyclodextrin (βCD) and an AA as a third auxiliary substance.Materials y Methods: Complex formation was studied by phase solubility analysis (PSA), nuclear magneticresonance (NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TG) andscanning electron microscopy (SEM).Results: The apparent stability constants (KC) of the multicomponent complexes were calculated fromthe solubility diagrams. By the analysis of the NMR spectra, it could be said that the shifts of some protonsevidenced the important role of the AA in the formation of multicomponent complexes. Among theAA, Arginine (ARG) proved to have better solubilizing properties for SDZ, reaching an improvementup to 70 times. The use of DSC, TG and SEM suggested the formation of new solid phases betweenSDZ:βCD:AA.