Deshpande S V, Beissinger R L
Department of Chemical Engineering, Illinois Institute of Technology, Chicago 60616.
Biomater Artif Cells Immobilization Biotechnol. 1993;21(2):135-51. doi: 10.3109/10731199309117352.
Process parameters using a Microfluidizer M110 to produce liposome-encapsulated hemoglobin (LEH) were further studied to examine their effect on hemoglobin (Hb) encapsulation efficiency (yield), steady shear viscosity, mechanical stability, and oxygen delivery. Liposome formulation loading ratios of up to 300 mumol of lipid per ml of Hb solution were evaluated; a maximum yield was obtained at 300 mumol/ml. Liposomes containing encapsulated Hb concentrations as high as 15.5 g/100 ml were prepared. LEH particle size distribution, determined from negatively stained whole mount preparations using transmission electron microscopy, resulted in average vesicle sizes for optimal batches of about 155 nm. Steady shear viscosity of LEH (up to 40% by volume) in an isotonic-isooncotic solution of PBS containing either albumin or dextran were evaluated for shear rates to 2000 s-1. Values obtained were generally higher than those of whole blood at all shear rates tested. Little leakage of Hb from liposomes stored in isotonic PBS was observed as a function of storage time and shear rate. Administration of LEH supported life in rats whose hematocrit had been reduced via isovolemic exchange transfusion to levels well below 5%, which was incompatible with survival when exchange transfusion was performed with the isotonic-isooncotic PBS solution.
进一步研究了使用微流化器M110生产脂质体包裹血红蛋白（LEH）的工艺参数，以考察它们对血红蛋白（Hb）包裹效率（产率）、稳态剪切粘度、机械稳定性和氧气输送的影响。评估了每毫升Hb溶液中脂质体配方负载比高达300微摩尔的情况；在300微摩尔/毫升时获得了最大产率。制备了含有高达15.5克/100毫升包裹Hb浓度的脂质体。通过使用透射电子显微镜对负染色整装制剂进行测定，LEH的粒度分布显示，最佳批次的平均囊泡大小约为155纳米。在含有白蛋白或右旋糖酐的PBS等渗等容溶液中，对LEH（体积分数高达40%）在剪切速率达2000秒-1时的稳态剪切粘度进行了评估。在所有测试的剪切速率下，所获得的值通常高于全血的值。在等渗PBS中储存的脂质体中，未观察到Hb随储存时间和剪切速率的显著泄漏。给通过等容交换输血使血细胞比容降至远低于5%水平的大鼠注射LEH可维持其生命，而用等渗等容PBS溶液进行交换输血时，该水平与生存不相容。
