1、Hydrolysis reaction
The degradation of tuxunin belongs to the primary reaction. The degradation rate has nothing to do with the concentration of tansunin and the ionic strength of the solution; it is significantly affected by the concentration of buffer, the type of buffer, the pH value of the solution, the type of solution and the temperature.
With the increase of pH, the degradation rate of tansunate increased significantly, and it was unstable under alkaline conditions; with the increase of buffer solution concentration, the degradation rate of tansunate increased significantly; the catalytic effect on tansunate degradation was different for different buffer solutions; the ionic strength did not have a significant effect on the degradation of tansunate. From the Arrhenius curve, it can be seen that the temperature has an important effect on the stability of tansunin, and the activation energy of tansunin at pH 8, phosphate buffer solution, and the temperature of 60-90 ℃ was 95. 68 K J/mol. However, the degradation products of tansunin as well as the degradation pathway need to be further investigated.
2、Stability
2.1 Solution stability:
The stability of tansunin solution is different under different conditions: tansunin is most stable at pH＜6.5; citrate buffer can delay its hydrolysis; the concentration of citrate does not affect the stability of the drug.
2.2 In vitro stability:
Tuxunin is extremely unstable at pH <5.0;
while trypsin has almost no effect on it;
It is unstable in liver homogenate (pH=7.0) and is affected by hepatic microsomal enzymes.
2.3 Stability of drug compounding
Do not pair with acidic or alkaline drugs or drugs containing sodium sulfite or sodium metabisulfite as antioxidants;
Can not be used with aminoglycoside antibiotics, quinolone antibacterial drugs;
When paired with cephalosporins, macrolide antibacterial drugs, vitamins, some of which produce a change in compounding, should not be paired;
Compounding reactions have occurred when concomitantly infused with ciprofloxacin lactate and azithromycin.
