To determine the half-life for gemcitabine hydrochloride using microcalorimetry

The enthalpies of dissolution of gemcitabine hydrochloride in 0.9 % normal saline (medical) and citric acid solution were measured using a microcalorimeter at 309.65 K under atmospheric pressure. The differential enthalpy $$ \left( {\Updelta_{\text{dif}} H_{\text{m}}^{{{\theta}}} } \right) $$ and molar enthalpy $$ \left( {\Updelta_{\text{sol}} H_{\text{m}}^{{{\theta}}} } \right) $$ of dissolution were determined, respectively. The corresponding kinetic equation described the dissolution were elucidated to be da/dt = 10−3.84(1 − a)0.92 and da/dt = 10−3.80(1 − a)1.21. Besides, the half-life, $$ \Updelta_{\text{sol}} H_{\text{m}}^{{{\theta}}} ,\;\Updelta_{\text{sol}} G_{\text{m}}^{{{\theta}}} $$ and $$ \Updelta_{\text{sol}} S_{\text{m}}^{{{\theta}}} $$ of the dissolution were also obtained. Obviously, it will provide a simple and reliable method for the clinical application of gemcitabine hydrochloride.