Preparation and evaluation of microencapsulated fast melt tablets of ambroxol hydrochloride

Natural resources in general and plant materials in particular are receiving more attention due to their safety as pharmaceutical excipients. Present work assessed the potential of a natural polysaccharide, pectin to mask the bitter taste of ambroxol hydrochloride, by microencapsulation technique, and its possibility to formulate as a fast disintegrating dosage form. Taste masking is an important developmental challenge in fast dissolving drug delivery system since it dissolves or disintegrates in the patient's mouth in close proximity to the taste buds. The prepared microspheres by emulsion solvent evaporation technique possessed good sphericity, smooth surface morphology, uniform and narrow size distribution (10-90 mum), when analyzed by scanning electron microscopy, laser diffraction and optical microscopy. Method of preparation has influenced the particle size and drug loading efficiency. Drug-polymer compatibility was confirmed by Fourier transform infrared spectroscopy and thin layer chromatography. DSC and X-ray diffraction studies revealed that the drug was dispersed inside the microspheres in the form of an insoluble matrix. The formation of microspheres was affected by glass transition temperature of the polymer, surfactant, type of plasticizers, volume of internal phase, stirrer speed etc. Fast dissolving tablets were prepared by the modification of melt granulation technique. The resulting granules were found to melt fast at body temperature, have smooth mouth feel and good physical stability. This study demonstrated that pectin could be a right choice in developing patient favored formulations for bitter drugs and can be utilized in fast disintegrating dosage forms as well.