Theoretically nanoscale study on ionization of muscimol nano drug in aqueous solution

In the present work, acid dissociation constant (pKa) values of muscimol derivatives were calculated using the Density Functional Theory (DFT) method. In this regard, free energy values of neutral, protonated and deprotonated species of muscimol were calculated in water at the B3LYP/6-31G(d) basis sets. The hydrogen bond formation of all species had been analyzed using the Tomasi's method. It was revealed that the theoretically calculated pKa values were in a good agreement with the existing experimental pKa values, which were determined from capillary electrophoresis, potentiometric titration and UV-visible spectrophotometric measurements.

本研究中，蝇蕈醇（muscimol）衍生物的酸解离常数（pKa）采用密度泛函理论（Density Functional Theory，DFT）方法进行计算。在此基础上，于水溶液中采用B3LYP/6-31G(d)基组对蝇蕈醇的中性、质子化与去质子化物种的自由能值进行了计算。采用托马西（Tomasi）方法对所有物种的氢键形成情况进行了分析。结果表明，理论计算得到的pKa值与已有的实验pKa值具有良好的一致性，后者通过毛细管电泳、电位滴定及紫外-可见分光光度法测得。