Volumetric and heat capacity studies of heterocyclic compounds in aqueous amino acids buffer solutions at 298.15 K

Volumetric, Viscometric, and Refractive Index Studies of Drug Nicotinic Acid in Aqueous d-Xylose/l-Arabinose Solutions from 293.15 to 313.15 K: Insights into Solute–Solute and Solute–Solvent Interactions

“…hydrogen bond interactions between the hydrophilic sites (carboxylic acid and N atom of pyridine) of two nicotinic acid molecules , (positive contribution to volume);…”

“…According to Desnoyers’ cosphere overlap model, various types of interactions in the nicotinic acid + water + d -xylose/ l -arabinose ternary systems can be summarized as follows: hydrophobic–hydrophobic interactions between the nonpolar groups of two nicotinic acid molecules (negative contribution to volume); hydrogen bond interactions between the hydrophilic sites (carboxylic acid and N atom of pyridine) of two nicotinic acid molecules , (positive contribution to volume); hydrophilic–hydrophobic interactions between the nonpolar groups and hydrophilic groups of two nicotinic acid molecules (negative contribution to volume); hydrophilic–hydrophilic interactions between water or hydroxyl groups of the d -xylose/ l -arabinose molecule and the hydrophilic sites of nicotinic acid molecules (positive contribution to volume); hydrophilic–hydrophobic interactions between water or hydroxyl groups of the d -xylose/ l -arabinose molecule and the nonpolar groups of the nicotinic acid molecule (negative contribution to volume); hydrophobic–hydrophilic interactions between the nonpolar groups of the d -xylose/ l -arabinose molecule and the hydrophilic sites of the nicotinic acid molecule (negative contribution to volume); and hydrophobic–hydrophobic interactions between the nonpolar groups of the d -xylose/ l -arabinose molecule and the nonpolar groups of the nicotinic acid molecule (negative contribution to volume) …”

“…Nicotinic acid, also known as niacin, vitamin B3, and antileprosy factor, is one of the indispensable nutrients for the human body that acts as an antioxidant and plays an important role in promoting normal growth and development. − It is also an important hydrogen transporter and antileprosy factor in body tissues and can maintain skin and nerve health and promote digestion . Moreover, as a clinical drug, nicotinic acid can reduce the concentration of blood cholesterol, triglycerides, and β-lipoprotein. − Importantly, it is a well-established drug that is used as a vasodilator in the treatment of ischemic heart disease. Owing to the multiple effects of nicotinic acid, many researchers are interested in it and have devoted extensive research effort to it and achieved valuable results. ,,− For example, Pan et al and Yang et al .…”

“…Moreover, as a clinical drug, nicotinic acid can reduce the concentration of blood cholesterol, triglycerides, and β-lipoprotein. − Importantly, it is a well-established drug that is used as a vasodilator in the treatment of ischemic heart disease. Owing to the multiple effects of nicotinic acid, many researchers are interested in it and have devoted extensive research effort to it and achieved valuable results. ,,− For example, Pan et al and Yang et al . measured the density, viscosity, and electrical conductance of nicotinic acid in aqueous polyethanol solution and aqueous dextran solution and obtained the partial molar volume of nicotinic acid and the B coefficient of viscous flow.…”

“…Pandit et al studied the volumetric and viscometric properties of nicotinic acid in aqueous solutions of sodium malonate and explored various interactions in the studied aqueous solution . Tyunina et al studied the volumetric properties of nicotinic acid in aqueous phosphate buffer solutions (pH 7.35) and aqueous amino acid buffer solutions at 298.15 K, and all of the data were discussed in terms of intermolecular interactions operating in the system. However, physicochemical data on nicotinic acid are still limited. , It is well known that the aqueous solutions of carbohydrates constitute important solution systems in living systems, and the interaction of carbohydrates with nicotinic acid drugs plays an important role in biochemical processes.…”