Thermodynamics of risperidone and solubility in pure organic solvents

Abstract

The solid-liquid solubility of the thermodynamically stable form I of the drug risperidone has been determined by a gravimetric method in nine pure organic solvents in the temperature range 278.15-323.15 K. The melting temperature and associated enthalpy of fusion of risperidone form I has been determined by differential scanning calorimetry (DSC) to be 442.38 K and 43.94 kJ mol -1 , respectively. The heat capacity of the solid form I and the melt have been determined over a range of temperatures by temperature-modulated DSC, and extrapolated data has been used to calculate the Gibbs energy, enthalpy and entropy of fusion from ambient temperature up to the melting point. The ideal solubility within a Raoult's law framework is obtained from the Gibbs energy of fusion, and the solution activity coefficient at equilibrium in the nine solvents quantified. Solutions in all solvents exhibit positive deviation from Raoult's law, with the highest solubility (closest to ideality) in toluene, an aprotic apolar solvent. The solubility curves plotted in a van't Hoff graph show non-linear behaviour and are well-approximated by a second order polynomial.

Controlled release formulations of risperidone antipsychotic drug in novel aliphatic polyester carriers: Data analysis and modelling

“…The prepared blends have been used for the preparation of RISP patches via solvent 39 evaporation method, containing 5, 10 and 15 wt% RISP. These formulations were characterized using 40 FT-IR spectroscopy, DSC and WAXD in order to evaluate interactions taking place between polymer 41 matrix and drug, as well as the dispersion and the physical state of the drug inside the polymer matrix. 42 In vitro drug release studies were performed using as dissolution medium phosphate buffered saline sim- 43 ulating body fluids.…”

Determination and Correlation of Ethyl Vanillin Solubility in Different Binary Solvents at Temperatures from 273.15 to 313.15 K

“…To obtain product with high purity and yields, we need accurate equilibrium solubility to optimize this process. 6 Therefore, it is necessary to obtain accurate solubility data of ethyl vanillin in different solvents.…”

“…In the manufacturing process of ethyl vanillin, as a separation process, crystallization is a vital step to obtain solid products. To obtain product with high purity and yields, we need accurate equilibrium solubility to optimize this process . Therefore, it is necessary to obtain accurate solubility data of ethyl vanillin in different solvents.…”

Solubility and Thermodynamic Behavior of Veramoss in Different Pure Solvents and {Ethanol + Water} Mixtures from T = 283.15 to 333.15 K

“…Solubility and thermodynamic properties are important physicochemical parameters which are useful in crystallization, purification, formulation development, and preformulation studies. − The solubility data and thermodynamic properties of veramoss are unavailable in the literature and are needed to control the supersaturation, particle size, and desired polymorphic form in the crystallization process . Therefore, much more attention should be paid to the solubility and thermodynamic parameters of veramoss.…”