Development of Fast Dissolving Tablets Containing Fexofenadine Hydrochloride Prepared by Lyophilization Technique

Objectives: To improve the aqueous solubility and dissolution of fexofenadine HCl, an attempt was made to prepare its fast dissolving tablets by lyophilization technique. Methods: For the preparation of lyophilized tablets (F1-F32), the drug was dispersed in a hydrated solution of water-soluble polymers (gelatin/maltodextrin/acacia) containing glycine and mannitol. The blend was pelted down into the patches of a blister pack, frozen down and then lyophilized. Different characterization parameters viz. differential scanning calorimetry, hardness, weight variation, X-ray diffraction (XRD), scanning electron microscopy (SEM), mercury porosimetry, solubility, wetting time and water absorption ratio, lyophilization tablet index, drug content, in vitro dissolution and stability were evaluated. Key findings: Tablets (F32) containing acacia were found to have fast disintegration and relatively higher mechanical strength with improved drug solubility. X-ray diffractogram and scanning electron micrograph indicated decrease in crystallinity of drug and a good porous structure property for prepared tablet, respectively. Dissolution study showed complete drug released within 5 min. Moreover, tablets (F32) were found to be stable for one month at 25 ± 2 °C/60 ± 5% relative humidity.