Tropirine (BS-7723 free base) is a radiosensitizer. Tropirine can be used in cancer research[1].
References
[1] Ramu A, et al. Reversal of multidrug resistance by phenothiazines and structurally related compounds[J]. Cancer chemotherapy and pharmacology, 1992, 30: 165-173. DOI:10.1007/BF00686306