Solubility and Model Correlation of Doxofylline in Pure Solvents at the Temperature Range of 283.15–323.15 K

Abstract

Doxofylline (DFL) is a theophylline derivative with poor solubility in water. In this paper, the solubility of DFL (as mole fraction) in 17 organic solvents including 4 esters (ethyl acetate, n-propyl acetate, n-butyl acetate, methyl propionate), 8 alcohols (methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, n-pentanol), 3 ketones (acetone, 2-butanone, cyclohexanone), acetonitrile, and water was studied at the temperatures ranging from “T = 283.15 to 323.15 K”. The solubility of DFL in pure solvents was simulated using three semiempirical models (modified Apelblat, λh, and three-parameter Van’t Hoff) and two activity coefficient models (Wilson and NRTL). In addition, the thermodynamic mixing properties (Δmix G, Δmix H, Δmix S, ln (γ1 ∞) and H 1 E,∞) were evaluated using the solubility data and the Wilson model.

Solubility and Thermodynamic Properties of Clotrimazole in 16 Organic Solvents at Temperature of 283.15 to 323.15 K

“…The thermodynamic mixing properties of the real solution can be described by eqs and . normalΔ mix M = M normalE + normalΔ mix M id M = G , H 0.25em and 0.25em S where Δ mix M is the thermodynamic mixing property of the real solution; Δ mix M id is the thermodynamic mixing property of the ideal solution; and M E is the thermodynamic excess properties of the solution, which can be estimated using eqs −. , G normalE = R T ( x 1 ln ⁡ γ 1 + x 2 ln ⁡ γ 2 ) = prefix− R T [ x 1 ln false( x 1 + normalΛ 12 x 2 false) + x 2 ln false( x 2 + normalΛ 21 x 1 false) ] …”

“…The infinite dilution activity coefficient (γ 1 ∞ ) and the reduced excess enthalpy ( H 1 E, ∞ ) at an infinitesimal concentration can also be estimated using eqs and ln nobreak0em.25em⁡ γ 1 ∞ = 1 − ln nobreak0em.25em⁡ normalΛ 12 − normalΛ 21 H 1 normalE , ∞ = true( H normalE x 1 x 2 true) x 1 → 0 = R ( b 12 + b 21 Λ 21 ) …”

“…The thermodynamic mixing properties of the real solution can be described by eqs and . where Δ mix M is the thermodynamic mixing property of the real solution; Δ mix M id is the thermodynamic mixing property of the ideal solution; and M E is the thermodynamic excess properties of the solution, which can be estimated using eqs −. , …”

“…The infinite dilution activity coefficient (γ 1 ∞ ) and the reduced excess enthalpy ( H 1 E, ∞ ) at an infinitesimal concentration can also be estimated using eqs and …”

Determination and Simulation of the Solubility of Bifonazole in 14 Pure Solvents at 283.15–323.15 K

“…The excess property M E can be calculated from the parameters of the Wilson model by eqs 20−22: 38,39 ( ln ln ) ln( ) ln( )…”