Radiosynthesis and preclinical evaluation of [11C]SNX-ab as an Hsp90α,β isoform-selective PET probe for in vivo brain and tumour imaging

EJNMMI Radiopharmacy and Chemistry

Table 1 Physicochemical parameters, in vitro inhibitory concentrations and isoform selectivity profile of Hsp90 inhibitors used in this study

Compound	MW^a	LogP	tPSA (Å²)^b	IC₅₀ (nM)	Hsp90α K_i (nM)	Hsp90β K_i (nM)	Grp94 K_i (nM)	TRAP1 K_i (nM)
SNX-ab	428.53	4.25	58.64	–	40 Ernst et al. (2014b)	40 Ernst et al. (2014b)	> 10 000 Ernst et al. (2014b)	> 10 000 Ernst et al. (2014b)
SNX-0723	399.47	1.84	84.66	14 Putcha et al. (2010)	3 Ernst et al. (2014a)	4 Ernst et al. (2014a)	375 Ernst et al. (2014a)	1195 Ernst et al. (2014a)
Onalespib	409.52	3.00	67.25	18 Woodhead et al. (2010)	–	–	–	–
PU-H71	512.37	4.38	96.83	51 Caldas-Lopes et al. (2009)	–	–	–	–