The present investigation was carried out to screen compatibility of some diluents with pefloxacin mesilate using differential
scanning calorimetry (DSC), isothermal stability studies, along with stability studies in liquid state and to assign relative
ranking to diluents. Compatibility was predicted with MCC101, MCC102, DCP anhydrous, Emcompress, while melting endotherm of
drug was lost in admixtures of dextrose anhydrous, Pearlitol, Lactopress spray dried, Lactochem fine powder and Lycatab indicating
possibility of interaction. Enthalpy changes were used for relative ranking of diluents.