SDZ 280-446

**Semantic type:** Pharmacologic Substance

**Definition:** A novel semi-synthetic derivative of cyclosporin and a cyclodepsipeptide with chemo-sensitizing activity. SDZ 280-446 is one of the drug resistance-modifying agents that inhibit P-glycoprotein, the multidrug resistance efflux pump, thereby restoring the retention and activities of some drugs in drug-resistant tumor cells.

**Synonyms:** - Cyclo-(pec1-meval2-val3-(O-t-Bu-measp4)-melle5-melle6-gly7-meval8-(O-Me-tyr)-L-hpa10)