cyclosporin
Concise Oxford English Dictionary © 2008 Oxford University Press:
cyclosporin /ˌsʌɪklə(ʊ)ˈspɔːrɪn/ (also cyclosporin A, cyclosporine)
▶noun Medicine an immunosuppressive drug obtained from a fungus, used to prevent the rejection of grafts and transplants.
'cyclosporin' also found in these Oxford entries:

