Quinidine hydrochloride monohydrate

Quinidine hydrochloride monohydrate is an orally active antiarrhythmic agent. Quinidine hydrochloride monohydrate reduces the expression level of P-gp, inhibits P-gp-mediated efflux, increases the intracellular accumulation of P-gp substrates, induces PARP cleavage and Caspase-3 activation, and elevates the proportion of Apoptotic cells at the sub-G1 phase. Quinidine hydrochloride monohydrate exerts sustained block and open-channel block effects on I_K(f). Quinidine hydrochloride monohydrate alters the urinary metabolic ratio of Amphetamine, modulates the Pentylenetetrazol-induced seizure threshold, and regulates the anticonvulsant effect of Dextromethorphan. Quinidine hydrochloride monohydrate can be used in studies related to uterine sarcoma and seizures^[1][2][3][4]. IC50 & Target:IC50: 19.9 μM (K⁺ channel)^[1] In Vitro:Quinidine (10 μM; 24 h) hydrochloride monohydrate potentiates Paclitaxel (HY-B0015)-induced cytotoxicity in P-gp-positive MES-SA/DX5 uterine sarcoma cells (reducing paclitaxel IC₅₀ to 80.56 nM) but does not alter paclitaxel cytotoxicity in P-gp-negative MES-SA uterine sarcoma cells^[1].
Quinidine (10 μM; 24 h) hydrochloride monohydrate significantly increases the sub-G1 apoptotic portion in paclitaxel-treated P-gp-positive MES-SA/DX5 uterine sarcoma cells, enhancing paclitaxel-induced apoptosis^[1].
Quinidine inhibits the in vitro metabolism of Debrisoquine in rat liver microsomes, with lower potency than observed in human liver microsomes^[3]. In Vivo:Quinidine (80 mg/kg; p.o.; single administration) hydrochloride monohydrate potently inhibits amphetamine ring hydroxylation in male Lewis rats, reducing the excretion of p-hydroxyamphetamine to 7.2% and 24.1% of the control group levels at 24 h and 48 h, respectively, while increasing the late-phase excretion of amphetamine to 542% of the control group level^[3].
Quinidine (10-30 mg/kg; intraperitoneal injection; single administration) hydrochloride monohydrate significantly elevates the threshold of pentylenetetrazol-induced tonic convulsions in male NMRI mice^[4].