MacKay M W, Fitzgerald K A, Jackson D
Primary Children's Medical Center, University of Utah School of Medicine, Salt Lake City 84113, USA.
JPEN J Parenter Enteral Nutr. 1996 Jan-Feb;20(1):63-6. doi: 10.1177/014860719602000163.
The purpose of this study was to determine precipitation limits and construct curves for calcium and phosphorus in parenteral nutrition solutions compounded with specialty amino acid solutions.
The effect of temperature, concentration of amino acids, and pH on the solubility of calcium and phosphate was studied for two specialized amino acid solutions: NephrAmine and HepatAmine. Ten amino acid solutions were manufactured with NephrAmine and 12 with HepatAmine at amino acid concentrations of 0.8%, 1.5%, and 2%. The final dextrose concentration was 10%. Some of the solutions were tested with the additive cysteine hydrochloride, 40 mg cysteine/g of protein, and some were buffered with sodium bicarbonate or hydrochloric acid to model the pH of a combined fat emulsion and total parenteral nutrient (TPN) solution. Calcium gluconate and potassium phosphate were added to test samples of each TPN solution. A range of calcium concentrations of 2.5 to 40 mEq/L and phosphate concentrations of 2.5 to 40 mmol/L were tested. After storage at room temperature (25 degrees C) for 18 hours, solutions were inspected for precipitation. At the end of the 18-hour period, the solutions were held in a water bath at 37 degrees C for 30 minutes and inspected for precipitation and microcrystallization.
Solubility curves were plotted to represent Ca-PO4 solubility limits before visual or microscopic precipitation. These curves depend on the variables of time, temperature, concentration, and pH.
These data and graphs will help the clinical pharmacist estimate Ca-PO4 solubility limits and prevent precipitation of TPN solutions formulated with NephrAmine or Hepatamine.
本研究的目的是确定与特殊氨基酸溶液混合的肠外营养溶液中钙和磷的沉淀极限并构建相关曲线。
针对两种特殊氨基酸溶液（NephrAmine和HepatAmine），研究了温度、氨基酸浓度和pH对钙和磷酸盐溶解度的影响。用NephrAmine制备了10种氨基酸溶液，用HepatAmine制备了12种氨基酸溶液，氨基酸浓度分别为0.8%、1.5%和2%。最终葡萄糖浓度为10%。部分溶液添加了盐酸半胱氨酸（40 mg半胱氨酸/g蛋白质）进行测试，部分溶液用碳酸氢钠或盐酸缓冲以模拟脂肪乳剂和全肠外营养（TPN）溶液混合后的pH值。向每种TPN溶液的测试样品中添加葡萄糖酸钙和磷酸钾。测试了一系列钙浓度（2.5至40 mEq/L）和磷酸盐浓度（2.5至40 mmol/L）。在室温（25℃）下储存18小时后，检查溶液是否有沉淀。在18小时结束时，将溶液置于37℃水浴中30分钟，检查是否有沉淀和微晶形成。
绘制了溶解度曲线以表示在肉眼或显微镜下观察到沉淀之前Ca-PO4的溶解度极限。这些曲线取决于时间、温度、浓度和pH等变量。
这些数据和图表将有助于临床药师估计Ca-PO4的溶解度极限，并防止用NephrAmine或Hepatamine配制的TPN溶液出现沉淀。
