OLANZAPINE-PEG 6000 BINARY SYSTEMS: IN VITRO DISSOLUTION BEHAVIOR, PHYSICOCHEMICAL CHARACTERIZATION AND MATHEMATICAL...

The objective of the present work is to study the dissolution behavior of olanzapine from its solid dispersions with PEG 6000. Solid dispersions were prepared by melt dispersion method and characterized by phase solubility studies, drug content and in vitro dissolution studies. The best releasing dispersions were characterized by X-ray diffraction, differential scanning calorimetry, FT-IR spectroscopy, Near Infrared, Raman analysis and wettability studies. The phase solubility studies and its thermodynamic parameters indicated the spontaneity and solubilization effect of the carrier. The release study results showed greater improvement of drug release from solid dispersions than pure drug and a linear increase in drug release was observed with an increase in carrier content. XRD, DSC, FT-IR, NIR and Raman analysis revealed the crystallinity reduction of olanzapine and its compatibility with the carrier. Wettability studies proved the increased wettability in samples due to water absorbing nature of the carrier. The possible mechanisms for increased release rate are attributed to solubilization effect of the carrier, formation of solid solution, prevention of agglomeration or aggregation of drug particles, change in surface hydrophobicity, increased wettability and dispersability of drug in dissolution medium. The suggested reasons for such release behavior were found to be well supported by results of the evaluation techniques.