title: In vivo protection studies of bis-quaternary 2-(hydroxyimino)- N-(pyridin-3-yl) acetamide derivatives against sarin poisoning in mice.
abstract: In vivo antidotal efficacy of new bis- quaternary 2-(hydroxyimino)- N-(pyridin-3yl) acetamide derivatives (HNK series), to counter multiples of lethal doses of nerve agent sarin (GB) and reactivation of acetylcholinesterase (AChE), was evaluated in Swiss albino mice. [Protection index PI; median lethal dose (LD50) of sarin with treatment/LD50of sarin] was estimated, using 0.05, 0.10, and 0.20 LD50as treatment doses of all the oximes with atropine against sarin poisoning. Dose-dependent time course study was conducted at 0.2, 0.4 and 0.8 LD50dose of sarin for estimating maximum AChE inhibition. At optimized time (15 min), in vivo enzyme half inhibition concentration (IC50) was calculated. AChE reactivation efficacy of HNK series and pralidoxime (2-PAM) were determined by plotting shift of log IC50doses. HNK-102 with atropine showed three fold higher PI compared to 2-PAM. In vivo IC50of sarin for brain and serum AChE was found to be 0.87 LD50(139.2 µg/kg) and 0.48 LD50(77.23 µg/kg), respectively. Treatment with HNK-102 and HNK-111 (equal to their 0.20LD50) significantly reactivated sarin-intoxicated AChE ( p < 0.05) at 2× IC50dose of sarin, compared to 2-PAM. The study revealed that HNK-102 oxime was three times more potent as antidote, for acute sarin poisoning compared to 2-PAM in vivo.
authors.affiliation: 1 Pharmacology and Toxicology Division, Defence Research & Development Establishment, Gwalior, India.
authors.forename: Devyani
authors.initials: D
authors.lastname: Swami
authors.affiliation: 2 Process Technology Development Division, Defence Research & Development Establishment, Gwalior, India.
authors.forename: Hitendra N
authors.initials: HN
authors.lastname: Karade
authors.affiliation: 2 Process Technology Development Division, Defence Research & Development Establishment, Gwalior, India.
authors.forename: Jyotiranjan
authors.initials: J
authors.lastname: Acharya
authors.affiliation: 1 Pharmacology and Toxicology Division, Defence Research & Development Establishment, Gwalior, India.
authors.forename: Pravin
authors.initials: P
authors.lastname: Kumar
keywords: AChE; GB; HNK oximes; Sarin; nerve agents; oximes