Physicochemical and spectral investigation of interactions between hydralazine hydrochloride and dextrose in aqueous solutions

• The interactional behaviour of HHC with dextrose was studied. • Thermophysical and transfer parameters were evaluated. • Hydrophobic/ion-hydrophobic interactions predominate in the studied systems. • HHC behaves as a structure-former in water and dextrose. • UV, Fluorescence and FTIR spectral studies have been conducted. Hydralazine hydrochloride (HHC) is an antihypertensive drug prescribed to hypertension patients during heart failure and pregnancy. In this work, we have introduced a novel approach to understand the molecular basis of HHC-dextrose interactions, paving the way for tailored therapeutic strategies in hypertension management. For this purpose, the physicochemical properties of HHC ( m /mol.kg −1 = 0.001–0.010) in water and 5 % w/v dextrose solution (D5W) have been studied by measuring densities ( ρ ), sound velocities ( u ), molar conductance ( Λ m ) and viscosities ( η ) for HHC at four temperatures ( T /K = 300.15–315.15) under atmospheric pressure ( P/ kPa = 101.325). The experimentally measured data were then used to calculate apparent molar parameters ( Φ V , Φ K ), partial molar parameters ( Φ V 0 , Φ K 0 ) and transfer parameters ( Δ tr Φ V 0 , Δ tr Φ K 0 , Δ tr B ). At 300.15 K, on transposing to D5W solvent from water, Φ V 0 decreased from 144.05 to 117.21, Φ K 0 decreased from −15.89 to −18.73 and B- coefficient decreased from 5.62 to 5.60, generating negative transfer parameters. A similar trend prevailed at other temperatures also and the negative values of transfer parameters advocate the dominance of ion-hydrophobic, hydrophobic-hydrophobic and hydrophilic-hydrophobic interactions in the solutions. Moreover, the structure-making behaviour of HHC in water and D5W was confirmed by positive values of Hepler’s constant ( ∂ 2 Φ V 0 /∂T 2 ) P and Walden product d ( Λ m 0 η 0 ) dT P as well as from the negative values of dB/dT . Furthermore, hyperchromic shift in UV–visible spectra, decrease in fluorescence intensity, and disarticulation in FTIR spectra (recorded at T = 298.15 K and P = 101.325 kPa) strengthen the physicochemical outcomes. Comprehending these interactions is crucial for developing optimized formulations that enhance drug delivery, drug absorption and ultimately improve blood pressure control and patient outcomes. Further, these findings could also be helpful in determining various pharmacodynamic and pharmacokinetic parameters like therapeutic efficacy, stability, solubility and bioavailability of drug HHC.