Preparation of amorphous carvedilol polymeric microparticles for improvement of physicochemical properties

The aim of the present study was to enhance the physicochemical properties of poorly aqueous soluble carvedilol (CRV) by preparing its microparticles in presence and/or in absence of a hydrophilic carrier. The polymeric microparticles of CRV were prepared with polyvinylpyrrolidone K30 with or without addition of adsorbents like Aerosil®200 and/or Sylysia®350 by using spray drying technique. The dissolution profiles revealed that the drug and polymer ratio and colloidal silica both played critical role in solubility enhancement. The spray dried microparticles and drug alone were characterized by differential scanning calorimetry (DSC), X-ray powder diffraction, Fourier transformation infrared spectroscopy (FTIR), particle size analysis and scanning electron microscopy (SEM). DSC analysis showed that CRV transformed from the crystalline state to amorphous state by spray drying, confirmed by disappearance of its melting peak. The results of the X-ray analysis were in agreement with the thermal analysis data. It did not show characteristic crystalline drug peaks which confirmed that the amorphous form of CRV was present in the CRV loaded microparticles. FTIR analysis demonstrated hydrogen bonding interaction with an absence of significant chemical interaction between CRV and polymer. Spherical microparticles were yielded with smooth surfaces as observed by SEM. All in all, this work reveals that spray drying is a suitable technique for preparation of microparticles with improved physicochemical properties of CRV.