Zalewski Przemysław, Jelińska Anna, Paczkowska Magdalena, Garbacki Piotr, Talaczyńska Alicja, Stfpniak Piotr, Cielecka-Piontek Judyta
Acta Pol Pharm. 2016 Jan-Feb;73(1):23-7.
The influence of pH on the stability of cefpirome sulfate was investigated in the pH range of 0.44 - 13.00. The degradation of cefpirome sulfate as a result of hydrolysis was a pseudo-first-order reaction. General acid-base hydrolysis of cefpirome sulfate was not observed. In the solutions of hydrochloric acid, sodium hydroxide, acetate, borate and phosphate buffer, k(obs) = k(pH) because specific acid-base catalysis was observed. Specific acid-base catalysis of cefpirome sulfate consisted of the following reactions: hydrolysis of cefpirome sulfate catalyzed by hydrogen ions (kH+), hydrolysis of dications (k₁H₂O) monocations (k₂ H₂O), zwitter ions (k₃H₂O) and monoanions (k₄ H₂O) of cefpirome sulfate under the influence of water. The total rate of the reaction was equal to the sum of partial reactions k(pH) = kH+ x aH+ + kH₂O x f₁ + k₂H₂O x f₂ + k₃H₂O x f₃ + k₄ H₂O x f₄. Based on the dependence k(pH) = f(pH) it was found that cefpirome sulfate was the most stable in aqueous solutions in the pH range of 4-6.
在0.44 - 13.00的pH范围内研究了pH对硫酸头孢匹罗稳定性的影响。硫酸头孢匹罗因水解导致的降解是一个准一级反应。未观察到硫酸头孢匹罗的一般酸碱水解。在盐酸、氢氧化钠、醋酸盐、硼酸盐和磷酸盐缓冲溶液中，由于观察到了特定酸碱催化作用，k(obs) = k(pH)。硫酸头孢匹罗的特定酸碱催化作用由以下反应组成：氢离子催化的硫酸头孢匹罗水解(kH+)、在水的影响下硫酸头孢匹罗的二价阳离子(k₁H₂O)、单价阳离子(k₂ H₂O)、两性离子(k₃H₂O)和单阴离子(k₄ H₂O)的水解。反应的总速率等于各部分反应速率之和k(pH) = kH+ × aH+ + kH₂O × f₁ + k₂H₂O × f₂ + k₃H₂O × f₃ + k₄ H₂O × f₄。基于k(pH) = f(pH)的依赖关系发现，硫酸头孢匹罗在pH值为4 - 6的水溶液中最稳定。
