Influence of Polymers on the Crystal Growth of Metformin Hydrochloride

Crystallization of metformin hydrochloride by solvent evaporation method was carried out in the presence of hydrophilic and hydrophobic polymers to investigate the influence of polymer in the agglomeration of the crystallites in–vitro. Transparent, prismatic shaped crystals (of size: 7 × 2 × 1.5 mm3) were crystallized in hydrophilic polymer hydroxypropyl methylcellulose (HPMC) and long rod shaped crystal (of size: 20 × 2 × 1.5 mm3) habits in hydrophobic polymer polyvinylpyrrolidone (PVP K30). The crystal structures were determined using single crystal X–ray diffraction method. Morphology studies revealed that the growth is prominent along a– axis and the prominent face is {001} for both the habits. Prismatic crystal habit is bounded by side faces {020} and corner faces {110}. FTIR spectral assignments were made and the fingerprint absorption band was identified. Thermal stability and thermal decomposition were analyzed using thermo calorimetry in the temperature range 30 -700°C.