青霉素G盐(钾或钠盐)在溶液中易分解失效。影响稳定性的因素很多,除物理因素外,化学因素方面有:pH条件、不同附加剂、不同溶剂、重金属等均对青霉素G的分解有影响等。这些因素在青霉素G分解过程中,起着联合的作用。研究青霉素G溶液的分解时,也必须对这四方面的因素的作用进行综合观察。为此,在不同缓冲剂和溶剂存在的条件下,试验了依地酸钠对青霉素G的稳定作用。试验用的青霉素G钾是药用品,制成的溶液在37±1℃恆温条件下保存,采用碘量法测定效价变化,得到结果如下: (1)青霉素G钾水溶液(10000单位/毫升),经过23小时,效价降为2.98％。加有 Penicillin G salt (potassium or sodium salt) in the solution easy to decompose failure. Factors that affect the stability of many, in addition to physical factors, the chemical factors are: pH conditions, different additives, different solvents, heavy metals, etc. have an impact on the decomposition of penicillin G and so on. These factors play a combined role in the breakdown of penicillin G. When studying the decomposition of penicillin G solution, we must also comprehensively observe the effects of these four factors. To this end, in the presence of different buffers and solvents, the stability of sodium edetate on penicillin G was tested. The test penicillin G potassium is a pharmaceutical product, the resulting solution was stored at 37 ± 1 ℃ constant temperature, the titer was measured by iodometry changes, the results are as follows: (1) penicillin G potassium aqueous solution (10000 units / ml) After 23 hours, the titer dropped to 2.98%. Add