Determination of the Solubility, Dissolution Enthalpy, and Entropy of Icariin in Acetone, Acetoacetate, Chloroform, and Light Petroleum

Abstract

The solubility of icariin in acetone, acetoacetate, chloroform, and light petroleum in the 283.2‐318.2 K range was measured by ultraviolet-visible spectrophotometry. As the temperature increased, the solubility of icariin in the 4 solvents gradually increased. The solubility data correlated with the modified Apelblat equation. The dissolution enthalpy and entropy of icariin were determined using van’t Hoff plots. The dissolution enthalpy and entropy of icariin in the 4 solvents increases as acetone >acetoacetate >chloroform >light petroleum, which can be explained by the difference of the polarity indices between them. The polarity indices of the solvents affect the solubility behavior.

Solubility and Thermodynamic Modeling of 5-Nitrofurazone in Pure Solvents and Binary Solvent Mixtures

“…In this work, the ultraviolet–visible spectrophotometric method was used to measure the solubility data of 5-nitrofurazone in 10 pure solvents (water, methanol, ethanol, acetonitrile, ethyl acetate, n -propanol, isopropanol, acetone, formamide, N , N -dimethylformamide) and two binary mixed solvents (water + N , N -dimethylformamide, acetonitrile + N , N -dimethylformamide) in the temperature range of 278.15–313.15 K. The experimental steps were as follows. First, excess 5-nitrofurazone (Form α) and an appropriate amount of different solvents were added to a 60 mL glass bottle with a stopper.…”

“…Therefore, the thermodynamic function of the actual dissolution process can be expressed by eq 10. 23−25 (10) where M denotes the thermodynamic function (including Gibbs energy (G), enthalpy (H), and entropy (S), etc.). x N is the equilibrium molar solubility of the solute.…”

Bioavailability Improvement Strategies for Icariin and Its Derivates: A Review

“…For orally administered drugs, their key pharmacokinetic property is their bioavailability [ 50 ]. While icariin and icariside II showed good solubility in organic solvents such as ethanol, ethyl acetate, acetone, or chloroform [ 51 , 52 ], they are insoluble/minimally soluble in water [ 53 ]. Besides their poor aqueous solubility, their insufficient membrane permeability (~10 −7 cm/s) contributes to their low oral bioavailability [ 54 ].…”