(R)-BPO-27

(R)-BPO-27, the R enantiomer of BPO-27, is a potent, orally active and ATP-competitive CFTR?inhibitor with an?IC₅₀ of 4 nM. IC50 & Target: IC50: 4 nM^[1] In Vitro: (R)-BPO-27 exhibits a dose-response inhibition and inhibits the CFTR current by 50% at 0.53 nM in HEK-293T cells. (R)-BPO-27 acts from the cytoplasmic side and has low membrane permeability^[1].
(R)-BPO-27 reduces the channel open probability (NPo) from 0.29 to 0.08, modestly reduces in mean channel open time, and strongly increases mean channel closed time in HEK-293T cells expressing human wild-type CFT in a single-channel patch-clamp experiment. Meanwhile, (S)-BPO-27 does not affect any of these parameters^[1].
(R)-BPO-27 is applied directly to the cytoplasmic membrane surface and stabilizes the CFTR channel closed state with an IC₅₀ of 600 pM in Single-channel electrophysiology assay^[2].
(R)-BPO-27 (10 μM, 10 min pretreatment) inhibits Cl^-?current with apparent IC₅₀?values of 5 and 10 nM for CPT-cAMP and 8-Br-cGMP, respectively, in CFTR-expressing FRT cells after CFTR stimulation by cAMP agonist. the IC₅₀ of 4 nM for inhibition of forskolin-stimulated CFTR Cl^-?current in FRT cells^[3].
In Vivo: (R)-BPO-27 (interperitoneal administration; 10 mg/kg)?decays with t_1/2≈1.6 h and gives sustained therapeutic concentrations in kidney in a PK study^[1].
(R)-BPO-27 (intraperitoneal injection; 5 mg/kg; 30 min before abdominal surgery) prevents fluid accumulation in closed midjejunal loops produced by cholera toxin, giving an intestinal loop weight/length ratio similar to that in PBS-injected loops. This effect is dose-dependently and the IC₅₀ value is 0.1 mg/kg^[3].
(R)-BPO-27 (intraperitoneal injection or oral administration; 5 mg/kg) shows a slow (R)-BPO-27 metabolism and produces sustained serum (R)-BPO-27 levels for at least 4 h. The AUC analysis gave an oral bioavailability of ～94% for (R)-BPO-27 in mouse pharmacokinetics and toxicity study^[3].