Solvent effects on chemical processes. 11. Solvent effects on the kinetics of decarboxylative dechlorination of N-chloro amino acids in binary aqueous-organic solvents

Mathematical representation of xanthine oxidase activity in hydro-organic mixtures

A mathematical model is proposed to calculate the enzyme activity in different concentrations of the organic solvent in hydro-organic mixtures. The accuracy and predictability of the model have been evaluated employing experimentally determined xanthine oxidase activity in five hydro-organic mixtures by using absolute percentage mean deviation (APMD). The obtained APMD for correlative and predictive studies were 5.3% and 7.6%, respectively.

A model to represent solvent effects on the chemical stability of solutes in mixed solvent systems

The applicability of the combined nearly ideal binary solvent/Redlich-Kister (CNIBS/R-K) equation for quantification of solvent effects on the stability of a solute is shown employing the experimental data of three solutes in different aqueous binary solvents. The proposed model provides a simple computational method to correlate/predict the instability rate constant of a drug in mixed solvent systems. The accuracy of the model is compared with that of a model proposed by Connors and co-workers employing various methods including mean percentage deviation (MPD) as comparison criteria. The obtained overall MPD values for the proposed model to correlate and predict the instability rate constants are 2.05 +/- 1.44 and 4.41 +/- 3.21%, respectively, where the corresponding values for Connors' model are 4.34 +/- 3.28 and 10.74 +/- 9.86%. The results suggest that by using only five experimental instability rate constants at different concentrations of the cosolvent in a binary mixture, it is possible to predict unmeasured values falling between data points within an acceptable error range.