Comparative safety evaluation of riot control agents of synthetic and natural origin.

Riot control agents (RCA) are lachrymatory, irritating compounds which temporarily incapacitate the uncontainable crowd. Ortho-Chlorobenzylidene-malononitrile (CS), 2-chloroacetophenone (CN), dibenz[b,f]1:4-oxazepine (CR), and nonivamide (PAVA) are synthetic RCAs, while oleoresin extract of chili known as oleoresin capsicum (OC) a natural irritant has been in use by various law enforcement agencies. Though efficacy of these agents is beyond doubt, they suffer from certain drawbacks including toxicity, production cost, and ecological compatibility. Presently, we have evaluated the safety of CR, OC, and PAVA on inhalation variables along with oral lethality. Additionally, the liver function test (LFT) in serum and lungs function was evaluated in broncho-alveolar-lavage fluid (BALF), both collected on the 14th day after RCA exposure. Animals then sacrificed and histopathology of liver and lungs was carried out. Results showed OC and PAVA to be more toxic than CR with an oral LD50 of 150 and 200 mg/kg body weight, respectively, while CR was safe at >3 g/kg body weight. All three agents caused severe impairment of respiratory variables bringing down normal respiration by >80% with rise in sensory irritation. Recovery from the irritating effect of CR was more rapid than OC and PAVA. LFT and BALF variables were not significantly different from that of control. There were no remarkable histopathological changes in liver and lungs. Hence, as per results, CR is safest among all synthetic and natural origin RCAs and can be safely used for effective dispersion of disobedient mob.