Physicochemical characterization and dissolution enhancement of loratadine by solid dispersion technique

The purpose of this investigation was to enhance the dissolution rate of loratadine using polyethylene glycol 6000 (PEG) solid dispersions (SDs). The solubility behavior of loratadine in the presence of polyethylene glycol 4000 and polyethylene glycol 6000 in water showed linear increase with increasing concentrations of PEG, indicating AL type solubility diagrams. SDs of loratadine with PEG 6000 were prepared at 1: 1, 1: 3, 1: 5, 1: 7 and 1: 9 ratios by the solvent evaporation method. Solid dispersions were characterized for drug content, dissolution behavior and for physicochemical characteristics. The dissolution rate of loratadine was enhanced rapidly with increasing concentrations of PEG 6000 in SDs. Fourier transform infrared (FTIR) studies showed the stability of loratadine and the absence of a well-defined loratadine — PEG 6000 interaction. Differential scanning calorimetry (DSC) and X-ray powder diffractometry (XRD) studies revealed the amorphous state of loratadine in SDs of loratadine with PEG 6000 which was further confirmed from scanning electron microscopy (SEM) studies. The flow properties of the blend, physical characteristics and disintegration time of the tablets formulated indicated that PEG 6000 SD can be used to formulate fast release loratadine tablets.