In vitro decontamination efficacy of the RSDL® (Reactive Skin Decontamination Lotion Kit) lotion component against riot control agents: Capsaicin, Mace™ (CN) and CS.

The study examined the degradation of riot control agents (RCAs): 2-chloroacetophenone (CN), 2-chlorobenzalmalononitrile (CS), and capsaicin, using the Reactive Skin Decontamination Lotion Kit (RSDL®) lotion and evaluated the the direct liquid phase reactivity of the RSDL lotion component with each RCA. RSDL lotion was mixed with the selected RCAs at different molar ratios. Reactivity of the active ingredient potassium 2,3-butanedione monoximate (KBDO) with the RCA was observed for one hour. Samples of 10 µL were taken and quenched, analyzed for residual RCA using LC-MS. CN, was degraded at molar ratios of two and above in less than 2 min. At a molar ratio of 1:1 KBDO:CN, ∼90 % of CN was degraded within 2 min, the remaining 10 % residual CN was observed for one hour without any change. CS, degradation of more than 68 % of CS was achieved at 20:1 M ratio of KBDO:CS within 1 h of reaction time. For capsaicin, no degradation was observed regardless of the higher molar ratios of up to 20:1 and longer reaction times of up to one hour. This study provides evaluation of neutralizing action of the RSDL lotion without assessment of the physical removal component by the RSDL Kit.

Evaluation of oleoresin capsicum of Capsicum frutescenes var. Nagahari containing various percentages of capsaicinoids following inhalation as an active ingredient for tear gas munitions.

Comparative efficacy as peripheral sensory irritant, oral and inhalation exposure studies were carried out on oleoresin capsicum (OC) of Capsicum frutescence var. Nagahari containing various percentages of capsaicinoids and two synthetic isomers of capsaicin in Swiss albino male mouse model to come up with a suitable active ingredient from natural source for tear gas munitions. The compounds screened were OC having varying percentages of capsaicinoids (20, 40 and 80%, respectively) and synthetic isomers (E and Z) of capsaicin (8-methyl-N-vanillyl-6-nonenamide). Mice were exposed to pyrotechnically generated smoke of the compounds in an all glass static exposure chamber for 15 min to determine acute inhalation toxicity (LC50) and quantitative sensory irritation potential (RD50). Acute oral median lethal dose (LD50) was also evaluated. Safety index of tear gas (SITG), a ratio of lethal concentration 50% (LC50) and the concentration which depresses respiration by 50% (RD50) due to peripheral sensory irritation is also proposed. The compound having highest SITG is considered as the most suitable to be used for tear gas munitions. The study revealed that oleoresin capsicum containing 40% capsaicinoids had the highest SITG among the compounds studied. The oral dosage versus mortality pattern of some compounds did not follow a true dose-response curve (DRC); however, following inhalation, all the compounds followed DRC. It was concluded that oleoresin capsicum (40% capsaicinoids) may be considered as the most suitable and environmental friendly compound from natural source to be used as an active ingredient for tear gas munitions.

[The biological activity of the irritant dibenz-[b,f] - [1,4]-oxazepine (substance CR) persisting during a long period at the environmental objects].

The objective of the present study was to determine the biological activity of the irritant dibenz-[B,F]-[1,4]-oxazepine (substance CR) contained in the environmental samples in case of their "closed" storage during different periods of time. The experiments were carried out using male and female rabbits of the Chinchilla strain with the initial body mass of 3000-4000 g. The animals were administered an aqueous alcoholic extract from the tissue samples of the rabbit eye coat as described in the "Methodological guidelines on the medico-biological assessment of the safety of personal protection devices". The results of experiments indicate that extracts from tissue samples elicit irritation in the eyes of the laboratory animals even after their storage as long as 600 days. This observation suggests that substance CR retains the ability to cause irritation during a prolonged period.

Analogues of morphanthridine and the tear gas dibenz[b,f][1,4]oxazepine (CR) as extremely potent activators of the human transient receptor potential ankyrin 1 (TRPA1) channel.

The TRPA1 channel can be considered as a key biological sensor to irritant chemicals. In this paper, the discovery of 11H-dibenz[b,e]azepines (morphanthridines) and dibenz[b,f][1,4]oxazepines is described as extremely potent agonists of the TRPA1 receptor. This has led to the discovery that most of the known tear gases are potent TRPA1 activators. The synthesis and biological activity of a number of substituted morphanthridines and dibenz[b,f][1,4]oxazepines have given insight into the SAR around this class of TRPA1 agonists, with EC(50) values ranging from 1 µM to 0.1 nM. Compounds 6 and 32 can be considered as the most potent TRPA1 agonists known to date, with 6 now being used successfully as a screening tool in the discovery of TRPA1 antagonists. The use of ligands such as 6 and 32 as pharmacological tools may contribute to the basic knowledge of the TRPA1 channel and advance the development of TRPA1 antagonists as potential treatment for conditions involving TRPA1 activation, including asthma and pain.