title: Human erythrocytes as drug carriers: loading efficiency and side effects of hypotonic dialysis, chlorpromazine treatment and fusion with liposomes.
abstract: Human red blood cells (RBCs) are emerging as a highly biocompatible microparticulate drug delivery system. So far, drugs have commonly been loaded into freshly isolated RBCs using rather disruptive methods based on hypotonic shock, and assessment of damage was restricted to hemolysis. Here, we investigated loading of RBCs from blood bank units with enzymes of various molecular weights using hypotonic dialysis (HD), pretreatment with chlorpromazine (CPZ) and fusion with liposomes. The latter two techniques have received little attention in RBC loading so far. Along with loading efficiency, all methods were tested for the induction of side effects. Very importantly, next to hemolysis, we also addressed morphological changes and phosphatidyl serine (PS) exposure, which has been recognized as a critical parameter associated with premature RBC removal and induction of transfusion-related pathologies. The efficiency of loading using hypotonic dialysis decreased with the molecular weight of the enzyme. For liposomes and chlorpromazine, loading efficiencies were higher and independent of enzyme molecular weights. While hypotonic dialysis always induced a high degree of hemolysis, irreversible modifications in the morphology of the cells and PS exposure, the side effects that were induced by loading using CPZ and liposomes were limited. In particular, PS exposure, although high immediately after treatment, returned to physiological levels after recovery. Retention and deformability studies using a spleen-mimicking device showed that RBCs treated with CPZ and liposomes behave like physiological RBCs, while HD led to very fragile and poorly deformable RBCs.
authors.affiliation: Department of Biochemistry, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands.
authors.forename: M E
authors.initials: ME
authors.lastname: Favretto
authors.forename: J C A
authors.initials: JC
authors.lastname: Cluitmans
authors.forename: G J C G M
authors.initials: GJ
authors.lastname: Bosman
authors.forename: R
authors.initials: R
authors.lastname: Brock
mesh_terms: D014150:Antipsychotic Agents / Q000008:administration & dosage; D002746:Chlorpromazine / Q000008:administration & dosage; D003956:Dialysis; D004337:Drug Carriers; D004912:Erythrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005456:Fluorescent Dyes / Q000737:chemistry; D006461:Hemolysis / Q000187:drug effects; D006735:Horseradish Peroxidase / Q000008:administration & dosage / Q000737:chemistry; D006801:Humans; D007038:Hypotonic Solutions; D010718:Phosphatidylserines / Q000008:administration & dosage; D012235:Rhodamines / Q000737:chemistry; D014969:Xanthine Oxidase / Q000008:administration & dosage / Q000737:chemistry; D001616:beta-Galactosidase / Q000008:administration & dosage / Q000737:chemistry
chemical_list: C114557:5-carboxytetramethylrhodamine succinimidyl ester; D014150:Antipsychotic Agents; D004337:Drug Carriers; D005456:Fluorescent Dyes; D007038:Hypotonic Solutions; D010718:Phosphatidylserines; D012235:Rhodamines; D006735:Horseradish Peroxidase; D014969:Xanthine Oxidase; D001616:beta-Galactosidase; D002746:Chlorpromazine
keywords: Chlorpromazine; Drug delivery; Hypotonic dialysis; Liposomes; Red blood cells; Spleen-mimicking device