Studies on the Stability of Cardioplegic Solutions and on Their Shelf Life

Cardioplegic solution (CPS), a pharmaceutical product manufactured at our hospital, is used for operative myocardial protection. Glucose, one of the elements of CPS, is known to disintegrate into formic acid, levulinic acid and 5-Hydroxymethylfurfural (5-HMF). Accordingly, the stability and their shelf life of CPS were evaluated by pH variation, visual inspection and the amount of 5-HMF. CPS was preserved for 12 months at room temperature (25°C) and at 4°C (under room light or in darkness) after autoclaving at 115°C and 0.7kg/cm2 fo 30 min. The pH of the sample was observed along with a periodical visual inspection. The amount of 5-HMF in the CPS was determined by high-performance liquid chromatography (HPLC) with an UV detector at 284 nm. It was found that light had no effect on the production of 5-HMF. The amounts of 5-HMF in the samples preserved at 25°C tended to be greater than those in samples preserved at 4°C. However, it seems that the CPS was relatively stable since the amount of 5-HMF in the CPS was less than 1/40 of the limit noted in the fourteenth revised edition of the Japanese Pharmacopoeia (JPXIV). These findings suggest that a temperature of 4°C is preferable to 25°C for the preservation of CPS and that the CPS remains relatively stable for more than 12 months.