Niermeyer S, Thieme R, Givan C, Thibodeau S, Quissell B J
J Am Coll Nutr. 1986;5(5):459-66. doi: 10.1080/07315724.1986.10720149.
The solubility of calcium and phosphorus was studied in neonatal parenteral nutrition solutions containing dicarboxylic amino acids and cysteine. Experimental amino acid solutions containing aspartic acid, glutamic acid, and cysteine in concentrations from 0.5% to 2.0% were studied with dextrose concentrations of 5-20% plus standard electrolyte, vitamin, and trace element additives. Solutions were held at room temperature for 24 hr prior to incubation in a 37 degrees C water bath for 30 min. The pH of each solution was determined. Precipitation was detected by light scattering on a Cobas Bio centrifugal analyzer. An absorbance greater than 0.015 at 600 nm was considered evidence of precipitation. The pH of test solutions ranged between 5.7 and 6.4. Increasing amino acid concentration produced an improvement in calcium/phosphate solubility. Change in dextrose concentration had a lesser effect. Solutions of 10% dextrose with 2% amino acids contained 40 mEq/liter calcium and 17 mmol/liter phosphorus without precipitation. Administered at 150 ml/kg/day, such a solution would provide 120 mg/kg body weight/day calcium and 80 mg/kg/day phosphorus, approximately the daily in utero accretion rates during the last trimester. This is not readily achieved in comparable solutions of previous amino acid formulations.
在含有二羧酸氨基酸和半胱氨酸的新生儿肠外营养溶液中研究了钙和磷的溶解度。研究了含有浓度为0.5%至2.0%的天冬氨酸、谷氨酸和半胱氨酸的实验性氨基酸溶液，其葡萄糖浓度为5%至20%，并添加了标准电解质、维生素和微量元素添加剂。在37℃水浴中孵育30分钟之前，将溶液在室温下放置24小时。测定每种溶液的pH值。通过在Cobas Bio离心分析仪上的光散射检测沉淀。在600nm处吸光度大于0.015被视为沉淀的证据。测试溶液的pH值在5.7至6.4之间。增加氨基酸浓度可改善钙/磷酸盐的溶解度。葡萄糖浓度的变化影响较小。含2%氨基酸的10%葡萄糖溶液含有40mEq/升钙和17mmol/升磷，无沉淀。以150ml/kg/天的剂量给药，这样的溶液将提供120mg/kg体重/天的钙和80mg/kg/天的磷，大约是妊娠晚期子宫内每日的蓄积率。在先前氨基酸配方的类似溶液中不容易达到这一点。
