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FORMULATION AND EVALUATION OF RISPERIDONE-MANNITOL SOLID DISPERSIONS

VENKATESKUMAR KRISHNAMOORTHY^1*, VERMA PRIYA RANJAN PRASAD², SUCHANDRA SEN¹

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The aim of the study was to enhance the dissolution of Risperidone (RSP) by the solid dispersion technique using mannitol as hydrophilic carrier. Solid dispersions of RSP were prepared by the dispersion method in drug: carrier ratios of 1:1, 1:2, 1:4, 1:6, 1:8 and 1:10, and were evaluated by drug content, in-vitro release studies, Powder X- Ray diffraction (PXRD), Differential Scanning Calorimetry (DSC), Fourier Transform Infra Red Spectroscopy (FT-IR), Near Infra Red (NIR), Raman, Particle size analysis, wettability studies. Phase solubility results exhibited a linear increase in solubility with the increase in carrier content and temperature. The sign and magnitude of thermodynamic parameters like Gibbs free energy, enthalpy and entropy indicated the spontaneity of solubilization. All dispersions showed increased dissolution rate in comparison to pure RSP and dispersions with the highest concentration of mannitol exhibited the fastest dissolution among all samples. Dissolution parameters were used for comparing the dissolution profiles of all dispersions and pure RSP as follows: the amount of drug released at 05 and 30 min (Q05 and Q30), per cent dissolution efficiency (% DE), Dissolution rate constant (DRC), Dissolution half-life (t50 % and t85 % values were found to correlate with the release studies. The release data were found to fit best with the Korsemeyer-Peppas model. The results of XRD, DSC, FT-IR, Near Infrared, Raman and Particle size analysis revealed the reduction in drug’s crystallinity, particle size reduction and the compatibility of drug and carrier. Wettability studies proved the increased wettability of RSP in dispersions the change in surface morphology of dispersions was evident from in-vitro dispersion studies.