For efficient drug design and development, employing a holistic method that combines insights gathered from structural, thermodynamic, and biological backgrounds is essential. Understanding the energetic principles underlying molecular interactions requires employing various thermodynamic methods and physicochemical, spectroscopic, and computational analyses, particularly in the early stages of the drug development process to achieve the best possible energy interaction profile and maintain a strong pharmacological assay. The present study focused on the various molecular interactions of L-Isoleucine, an essential amino acid, and L-Proline a nonessential amino acid within varying molalities (0.001, 0.003, 0.005 mol.kg−1) in an aqueous solution of an antiplatelet drug namely ticlopidine hydrochloride [TCP][HCl] at five distinct temperature (293.15 K, 298.15 K, 303.15 K, 308.15 K, and 313.15 K) and pressure at 0.1 MPa. The volumetric properties like apparent molar volume (ϕv), Limiting partial molar volume (ϕv0), Limiting the partial molar volume of transfer (Δϕv0), hydration number (nH), Hepler’s constant (∂ϕE0/∂T) are calculated using density data; The viscosity B-coefficient, temperature derivative of the B-coefficient (dB/dT), Free activation energy of the solvent and solute (Δμ10≠ and Δμ20≠), entropy and enthalpy of activation (ΔS20≠ and ΔH20≠), and solvation number (ns) are all determined using the viscosity data; Walden product (Λm0η0), limiting molar conductance (Λm0), molar conductance (Λm) was calculated using a specific conductance value; surface tension data calculates the Limiting Slope (∂σ/∂m). The UV–visible absorbance was measured, and the association constant was computed. The results of 1H NMR spectroscopy confirmed significant interactions among the protons of amino acids and Ticlopidine hydrochloride. These changes indicate a strong molecular interaction between them, which aligns with our theoretical studies.