Cyclosporin A is a potent immunosuppressant consisting of a cyclic polypeptide of 11 amino acids. It is clinically used for anti-rejection reactions in liver, kidney and heart transplants, and can also be used with adrenal cortex hormones to treat immune diseases.

Mechanism of Action

Cyclosporin A selectively inhibits T lymphocyte subsets and can effectively inhibit the activity of helper T lymphocytes and B lymphocytes. The main mechanism is to inhibit the differentiation, proliferation and expression of HLA-II antigens of quiescent Th cells, thereby reducing the synthesis and secretion of lymphokines released by Th cells and indirectly affecting B cells. Cyclosporin A can bind to intracellular immunophilin cyclophilin, thereby inhibiting the activation of helper T cells, reducing the reactivity to interleukin-2, further affecting the differentiation of B lymphocytes, inhibiting the occurrence of immune responses mediated by them, and has a good inhibitory effect on both cellular and humoral immunity, so cyclosporin A can act on both cellular and humoral immunity. Cyclosporin A can inhibit apoptosis through two mechanisms.

Cyclosporin A Formulations

Cyclosporin A is an active ingredient in a drug used to treat dry eye disease. Cyclosporin A is not very soluble in water and is therefore currently formulated by dissolving the drug in oil to form an emulsion or by mixing the drug with high levels of surfactants and/or solubilizers to form an aqueous solution.

CN104080442A A Cyclosporin A formulation has been discovered that uses a novel crystalline polymorph of cyclosporin A to produce a nanosuspension containing cyclosporin A particles having an average size of about 1 micron or less (to put that number in perspective, the average thickness of a human hair is about 100 microns).