Journal of Pharmaceutical Chemistry and Drug formulation ISSN: 3108-0782 (Online)

Authors: Megha Sharma, Dr. Arvind Rao

Abstract: Formulation stability is a critical determinant of the efficacy and shelf-life of pharmaceutical products. Drug–excipient interactions can significantly influence the physical, chemical, and therapeutic stability of formulations. This study investigates various types of interactions between drugs and excipients, their detection methods, and the resultant impact on formulation stability. Techniques such as Differential Scanning Calorimetry (DSC), Fourier-Transform Infrared Spectroscopy (FTIR), and High-Performance Liquid Chromatography (HPLC) are used to detect and quantify interactions. The influence of environmental factors like temperature, humidity, and light is discussed in relation to stability outcomes. Additionally, case studies on commonly used excipients such as lactose, microcrystalline cellulose, and polyethylene glycol provide insights into their compatibility profiles with different classes of drugs. A comparative table summarizes key drug–excipient interactions and associated stability challenges. Understanding these interactions enables rational selection of excipients, optimization of formulation design, and improved product performance. The findings highlight the necessity for systematic compatibility studies to ensure safe, effective, and stable pharmaceutical formulations.

Keywords: Drug–excipient interactions, formulation stability, compatibility studies, DSC, FTIR, HPLC, excipient selection, stability analysis