Pharmacokinetics of single and repeated injection of hemoglobin-vesicles in hemorrhagic shock rat model

Hemoglobin-vesicles (HbV) are liposomal artificial oxygen carriers that may be useful as a resuscitation fluid during hemorrhagic shock (HS). It is well-known that the pharmacokinetic properties of liposome change in response to both pathological conditions and repeated administration. Therefore, we compared the pharmacokinetics of single versus repeated administration of HbV during HS. HS was induced by withdrawal of 40% of total blood volume. The normal (non-HS) and HS1 group was received an injection of 125I-labeled HbV (125I-HbV). The HS2 group was resuscitated with non-labeled HbV, and 1 h later, it received an injection of 125I-HbV. The half-life was shorter in HS1 rats, but it returned to non-HS levels after the second HbV injection. During 12 h after administration of HbV, tissue distribution of HbV was greatest in the HS1 group; however, the HS2 group had the greatest tissue distribution at subsequent time points. Excretion into urine, major elimination pathway, did not differ between non-HS and HS1 rats, but was significantly reduced in the HS2 group. Furthermore, the half-life of HbV in humans was estimated to be approximately 3–4 days using an allometric equation. This suggests that HbV may be a useful artificial oxygen carrier in HS based on HbV pharmacokinetics.