Introduction
Muramyl dipeptide (MDP) is the smallest structural unit with immune activity in the skeleton of bacille calmette-guerin (BCG) cell wall, and has a strong immunomodulatory function. But because of its central heat induced and hypnotic effect, it restricts its wide application in clinic. Romurtide (RM) is a newly discovered MDP derivative, also known as stearyl cell wall acyl three peptide. The chemical structure is N2-[(N-acetyl cell wall acyl) -L-alanine-D-isoglutamine]-N6-stearyl-L-lysine. The immune activity is higher than that of MDP. At present, it has been applied in clinical treatment of myelosuppression caused by tumor radiotherapy and chemotherapy-induced leukopenia and thrombocytopenia.
Fig 1. The general chemical structure of romurtide.
Pharmacologic action
Romurtide is a macrophage activator that can stimulate colony stimulating factor (CSF) and interleukin-1 (IL-1) generation. This product increases the production of CSF in T cells by acting on IL-1. It is believed that this product promotes the differentiation and proliferation of the precursor cells in the brown blood organs by increasing the formation of CSF, and results in an increase in the number of neutrophils, monocytes and lymphocytes in the surrounding blood. In addition, activated macrophages promote the production of IL-1, and enhance cellular humoral immunity and cellular immune function. Therefore, it can be thought that this product enhances immunity through enhancing immunity and activating neutrophils.
Function
RM can increase the mitogen response to plant hemagglutinin (PHA) and lipopolysaccharide (LPS), goat erythrocyte (SRBC) antibody formation reaction and antibody formation to two nitrobenzene. RM therapy can restore leukocytotoxicity induced by cyclophosphamide (Cy) or ray, and also stimulates chemiluminescence reaction of neutrophils and mononuclear cells in vivo. In a word, it is an anti leukocytic drug.
Pharmacokinetics and metabolism
The metabolic studies of mice, rats, rabbits and monkeys showed that RM is easily absorbed into the blood and distributed all over the body, mainly in the liver, and quickly converted to N-acetylmuramic acid, lactic acid, CO2, and excreted through urine, feces and respiration. Subacute and chronic experiments showed that the injection site had slight transient inflammatory reaction and arthritis, with no mutations or teratogenic effects. In the rat liver microparticles, there was no obvious effect on the drug metabolizing enzymes in the rat liver. There was no drug accumulation after the drug, and the original drugs and metabolites were not detected in the urine.
References:
1. Kenji Namba, Eiko Yamamura, Hironobu Nitanai, Tsuyoshi Otani and Ichiro Azumat. Romurtide, a synthetic muramyl dipeptide derivative, promotes megakaryocytopoiesis through stimulation of cytokine production in nonhuman primates with myelosuppression. Vaccine. 1997, 15(4): 405-413.
2. Kenji Namba, Hironobu Nitanai, Tsuyoshi Otani and Ichiro Azumat, Romurtide, a synthetic muramyl dipeptide derivative, accelerates peripheral platelet recovery in nonhuman primate chemotherapy model. Vaccine, 1996, 14 (14):1322-1326.
