Introduction: Pre-formulation research serves as the foundational gatekeeper in pharmaceutical development, ensuring an active ingredient possesses the necessary physicochemical profile for viable commercialization.

Objective: To perform a comprehensive preformulation study of cinnarizine and dimenhydrinate, characterizing their key physicochemical properties to guide rational formulation design.

Methods: The physiochemical characteristics of both medications were examined. Additionally, solubility was assessed in a range of pH-varying solvents, and FTIR and absorption maxima were used to assess purity. A standard calibration curve was created to support more analytical research investigations. Finally, research on the compatibility of drugs and excipients were conducted.

Results: Organoleptic characteristics showed that both medications were odorless and nearly white in color. The partition coefficient and melting point were noted in range. The infrared spectra, which displayed distinctive peaks, and UV spectroscopy, which displayed maxima at 253 nm for cinnarizine and 276 nm for dimenhydrinate, were used to establish the drug's purity. The derived standard curve was linear, with an equation of y = 0.0788 + 0.069 and a correlation coefficient of R2 = 0.996 & 0.999. Drug samples showed no discernible alterations in terms of coloring, liquefaction, or odor, indicating that there were no drug excipient interactions.