Stability of nitroglycerin in intravenous admixtures.
Stability of nitroglycerin in intravenous admixtures.
复制标题
静脉混合物中硝酸甘油的稳定性。
DOI：
10.1093/ajhp/41.8.1518
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
A. Alam
中科院分区：
文献类型：
--
作者：
A. Alam
The authors state that nitroglycerin might be given through a Y-injection site on the administration set of a primary drug infusion or that the drug might be given as a secondary infusion to a primary nitroglycerin infusion.'To avoid mistakes, the package insert for American Critical Care's brand of nitroglycerin (Tridil) states in bold print that" Tridil should not be admixed with other drugs." Further, the administration set, Tridilset, was specifically designed not to have an injection port. Phenytoin sodium is poorly soluble in aqueous systems. An aqueous solution is turbid unless pH is adjusted to greater than 11.7.-Thus, it is likely that precipitation ob served by the authors in the admixture (pH 9.1-9.3) re sulted from the inherently poor solubility of free phenyr toin and not from incompatibility of phenytoin sodium with nitroglycerin. As a matter of fact, the solubility is the primary reason why the injectable dosage form is supplied in 40% propylene glycol and 10% alcohol in water for in jection, adjusted to. pH 12 with sodium hydroxide.^ Finally, the results indicate that some nitroglycerin was Tost from phenytoin and aminophylline admixtures. The authors make a blanket statement," The decline in the percentages of nitroglycerin remaining in these ad mixtures suggests that there was an increase in the loss over time of nitroglycerin to the rubber stopper as a function of pH." I strongly disagree with this conclusion. Nitroglycerin is unstable in alkaline pH,^ thus the loss was likely from degradation rather than merely sorption to the rubber stopper. Just because the authors failed to see degradation peaks in the chromatogram does not prove that degradation was not occurring. It is possible that, at this concentration lev. el and pH (maximum 5), the deg radation product was below the detection limit of the assay. The other admixtures between pH 5.3-5.7 did not show the sorption phenomenon, and it is highly unlikely that the sorption of nitroglycerin to the rubber stopper would occur between pH values of 8.2 and 9.3. Although the admixtures of dextrose solution were kept upright and thereby were not in contact with the stopper, they too showed potency losses for both aminophylline and phenytoin at the 24-hour checkpoint. In conclusion, the study'design and the explanations given in this paper are controversial and somewhat questionable. It would have been prudent to review the published literature before the research was under taken.
