Also available in 1 mL, 1 mg, 10 mg, 25 mg, 50 mg, 100 mg, 200 mg and bulk. Please contact Fisher for quotes. Tipifarnib S enantiomer ((S)-(-)-R-115777) is the S-enantiomer of Tipifarnib. Tipifarnib is a potent and specific farnesyltransferase inhibitor (IC50 0.6 nM). Purity 99.05%