An experimental and theoretical study on the hydration in aqueous medium of the antihypertensive agent tolazoline hydrochloride

A structural and vibrational investigation on the antiviral deoxyribonucleoside thymidine agent in gas and aqueous solution phases

“…Table show the uncorrected solvation energy (Δ G u ), calculated as relative energy (Δ E ), and defined as the difference between the total energies in aqueous solutions and the values in gas phase. The Δ G ne values in aqueous solution were obtained using the PCM/SMD model, as reported for other compound in aqueous medium . Note that the Δ G c values for the C2 conformer increase significantly in aqueous solution in accordance with a higher volume variation, as seen in Supporting Information, Table S4.…”

“…The results for both media using the 6–31G* basis sets show for C1 and C2 in the two phases two BCPs while for C3 in both media are observed three BCPs. These BCPs have the typical properties of the closed‐shell interaction, which implies values of ρ (r) relatively low, the relationship |λ 1 |/λ 3 <1 and ▿ 2 ρ(r) positive indicating thus that the interaction is dominated by the charge contraction away from the interatomic surface toward each nucleus . A very important result for the three conformers is that the values of the properties decrease in aqueous solution as consequence of the hydration.…”

“…The experimental and calculated wavenumbers for all the normal vibration modes by using 6–31G* basis set together to the corresponding assignments for C1, C2, and C3 in both media are shown in Table . The vibrational assignments of the experimental bands to the normal thymidine vibration modes are based on the comparison with the previous partial assignments, with related molecules and with the results of the calculations performed here (Supporting Information, Tables S13, S14, and S15). It is important to note that in general in all spectra, there is good agreement between the experimental and theoretical spectra, especially in the higher wavenumbers regions.…”

Correlations in hydrochloride drugs with diverse pharmacological activities. Role of N-H…Cl bonds

“…In pharmacology and medicine, the hydrochloride / hydrobromide species are generally used as drugs in multiple and clinical applications, including in dosage, because these species present higher solubilities than their free bases, this way, they can be easily absorbed and assimilated in the human organism [1][2][3][4][5][6][7][8][9][10]. Veber et al [9] have studied important molecular properties necessary to the oral bioavailability of drugs while Lipinski et al have predicted the absorption or permeation of a drug taking into account the presence of H bonds acceptors (N-H or OH groups) and donors (N and O atoms) and, also, the molecular weights, among other factors [10].…”

“…Moreover, from that point of view, it is interesting to know the properties of different hydrochloride forms to evaluate if these species are better as drugs than the hydrobromide ones. Taking into account that in the literature there are a large number of hydrochloride species with many applications, in this study, only ten alkaloids, including a psychotropic species, three antihistaminic and three antihypertensive agents were considered because their properties were in general already published [6][7][8][11][12][13][14][15][16][17][18][19][20][21][22][23][24].…”