Abstract: (S)-(?)-5-hydroxy-1-methylhydantoin is useful as a drug having high safety. Since the compound of the present invention, (S)-(?)-5-hydroxy-1-methylhydantoin, rarely changes to the metabolite having high toxicity compared with the R-form and the racemate, it is preferred as an agent for renal failure especially when used for chronic renal insufficiency in a patient where toxic substances are not excreted, but are accumulated in the body due to disturbance of renal functions.

Abstract: (R)-(+)-5-hydroxy-1-methylhydantoin is an optically active substance having an excellent suppressive action of the progression of renal failure. At an administration to a model animal of renal failure, (R)-(+)-5-hydroxy-1-methylhydantoin significantly suppresses an increase of creatinine in blood as compared with the S-form and the racemate, and shows an excellent suppressive action to the progression of renal failure by improving creatinine clearance. Thus, (R)-(+)-5-hydroxy-1-methylhydantoin is useful as a highly-active agent for renal failure.

Abstract: This invention provides a method of determining the behavior of drugs in living bodies, particularly those which contain a variety of active ingredients, like biological, natural drug and crude-drug preparations. It comprises administering a drug being tested to an animal, taking a blood sample from that animal, deproteinizing the plasma separated from the blood, intravenously administering the deproteinized plasma thus prepared to a different test animal, and examining the effect of drug exhibited in that test animal. The amount of active ingredients absorbed into the blood can be estimated by this indirect method even with special drugs including a variety of unknown and trace components.

Abstract: The present invention is directed to an iron complex used in treatment of iron-deficiency anemia. The complex is formed by reacting a reactive polyiron (III) olated compound with dextrin and at least one hydroxycarboxylic acid. A dextrin-hydroxycarboxylato-polyiron (III) olated complex is produced. The reaction product contains substantially no free iron. Iron concentration is between about 35 and 47%. The complex can be administered non-orally.The compound of the subject invention has advantages over prior art compounds. Specifically, the subject complex has a high iron content, is thermally stable, and can be preserved. It may be administered intravenously without accumulating in the blood of an animal or damaging its tissue. No serious side effects result from use of the subject complex.