Understanding the Drug-Polymer Interaction in Amorphous Solid Dispersion for BCS Class II Drug

Poor aqueous solubility of active pharmaceutical ingredients (API) is an enduring problem in developing pharmaceutical formulation of the BCS class II drug. Amorphous form of the drug poses a lot of problems like poor chemical and physical stability and difficulties in processing the amorphous material. For overcoming tendency of amorphous solids to crystallize to a more thermodynamically stable crystalline phase, amorphous drugs are formulated as solid dispersions whereby the addition of excipients is used to enhance the properties of the formulation. The stability of amorphous solid dispersions completely depends on the interaction of drug with the excipients (polymers) and indirectly to the thermodynamic properties of drug and polymers. Change in the melting point and glass transition temperature is a strong indication of good drug-polymer interaction resulting to a stable dispersion. In this study, it is aimed to formulate amorphous solid dispersion of crystalline drug of BCS class II with the addition of single or combination of polymers. Analytical techniques like Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and powder X-Ray Diffraction have been used to analyse the stability of amorphous solid dispersion in terms of change in its solid state characteristics and melting point. Drug-polymer miscibility has been studied further to ensure uniform mixing of the components in the formulation. In silico studies have been carried out to understand the interaction between drug and polymer at the molecular level. This stable dispersion will be further used to study the efficacy and toxicity of the formulation through in vitro and in vivo experiment.