HDAC6-IN-13 (Compound 35m) is a potent and highly selective orally active inhibitor of HDAC6, with an IC50 of 0.019 μM. It also demonstrates inhibitory activity against HDAC1, HDAC2, and HDAC3, with IC50 values of 1.53 μM, 2.06 μM, and 1.03 μM, respectively. HDAC6-IN-13 exhibits substantial blood-brain barrier permeability and displays anti-inflammatory properties [1].

HDAC6-IN-13 (Compound 35m) (0.1-1 μM; 24 h) is highly selective toward HDAC6 versus class I HDACs [1]. HDAC6-IN-13 is a slow-on and slow-off tight-binding HDAC6 inhibitor, while exhibits fast-on properties for HDAC1, 2, and 3 [1]. HDAC6-IN-13 (5-20 μM; 8 h) shows anti-inflammatory activity in vitro [1]. Western Blot Analysis [1] Cell Line: MV4 11 and J774A.1 Concentration: 0.1, 0.2, 0.5 and 1 μM Incubation Time: 24 h Result: Concentration-related accumulation of acetylated tubulin (Ac-Tubulin) was observed, while upregulation of acetylated histone H3 (AcHH3) and acetylated histone H4 (AcHH4) was not apparent even at the concentration of 1 μM. Western Blot Analysis [1] Cell Line: J774A.1 cells Concentration: 5, 10 and 20 μM Incubation Time: 8 h Result: Inhibited the cleavage of pro-caspase 1 to p20 in a dose-dependent manner, inhibited the interaction between HDAC6 and dynein.

HDAC6-IN-13 (Compound 35m) (20 mg/kg; p.o. and i.p.; once) displays a remarkable inhibition in LPS-induced inflammation in mice [1]. HDAC6-IN-13 (20 mg/kg; p.o.; once) shows very high oral bioavailability (F% = 93.4%) and significant BBB permeability in mice [1]. Animal Model: Male C57BL/6 WT mice, LPS-induced endotoxic shock model [1] Dosage: 20 mg/kg Administration: PO and IP, immediately after the LPS injection Result: Significantly decreased the serum IL-1β levels in LPS-induced mice via both ip and po administration. Animal Model: Male CD-1 mice [1] Dosage: 5 mg/kg or 20 mg/kg Administration: IV (5 mg/kg) or PO (20 mg/kg) (Pharmacokinetic Study) Result: Pharmacokinetics Characterization of HDAC6-IN-13 (Compound 35m) with iv and Oral Administration a [1] PK parameters HDAC6-IN-13 HDAC6-IN-13 administered dose (mg/kg) iv at 5 mg/kg oral at 20 mg/kg C max (ng/mL) 4604 ± 551 5570 ± 551 t 1/2 (h) 7.95 ± 0.370 6.80 ± 0.145 AUC 0 inf (ng h/mL) 2755 ± 395 10292 ± 1385 F% n/a 93.4 ± 12.6 a HDAC6-IN-13 was administrated via iv and po (n = 3). The blood sample was collected at different time points after dosing, and the plasma concentration of HDAC6-IN-13 was determined via LC-MS/MS. The area under the plasma concentration versus time curve (AUC) was calculated using the linear trapezoidal method. The pharmacokinetic parameters were obtained using the noncompartmental method. Data are shown as mean ± SD.