Abstract: The present invention relates to an in vitro method to determine the safety of modified hemoglobin blood substitutes for human subjects prior to their clinical usages, wherein the method is based on complement activation reaction from adding modified hemoglobin blood substitutes to a human plasma sample and comprises the steps of: a) obtaining at least one plasma sample from at least one human subject by i) taking a blood sample and immediately centrifugating; and ii) separating the centrifuged blood sample of step i) and retaining the supernatant plasma; b) mixing the plasma of step ii) with the modified hemoglobin blood substitutes or control-ringer in a weight/volume ratio of about 4:1; c) incubating for a time sufficient to allow for a complement activation reaction to occur; d) adding the product of step c) to an appropriate volume of saline in an EDTA tube; and e) analyzing the degree of complement activation by analysis of the product of step d); thereby determining the safety of the modified hemoglobi

Abstract: A microcapsule for oral administration comprising an outer layer membrane which is acid resistant and retains its structure in an alkaline environment, said membrane having dispersed therein at least one enzyme corresponding to an amino acid secreted into the intestinal or derived from a protein or peptide secreted into the intestinal tract. The present invention provides a microcapsule capable of removing specific unwanted amino acids secreted into the intestinal tract.