[Compatibility evaluation of Chinese medicines injections based on isothermal titration calorimetry]

The paper is to report the establishment of a method for quickly evaluating compatibility of Chinese medicines injections. Isothermal titration calorimetry (ITC) was used to evaluate compatibility of Yiqifumai (YQFM) and vitamin C injection (Vc)/5% glucose injection (5% GS). The diversification of Gibbs free energy (deltaG), enthalpy (deltaH) and entropy (deltaS) were used to decide reaction types of colliquefaction procedures of different injections. The reactive profiles were used to determine signs and quantity of heat. And high performance liquid chromatography (HPLC) was used as a supportive method for ITC. Then, feasible binding sites were analyzed based on the information of spatial structures of major compositions. During the colliquefaction procedure of YQFM and Vc, [deltaH] > T[deltaS], so, the reaction is enthalpy-driving. And the reactive profile showed that a big deal of heat was given out during the procedure. Obviously, chemical reactions happened and the major compositions changed. On the other side, the reaction of YQFM mixed with 5% GS was entropy-driving, because [deltaH] < T[deltaS]. The reactive profile showed there was a little heat gave out. So, non-chemical reactions happened, and the major compositions did not change. The conformity existed between the results of ITC and HPLC. ITC could be used to evaluate the compatibility of Chinese medicines injections because of the advantages of ITC, such as real time, fast, sensitive and having more parameters.