Calcium-binding property of cocaine and some of its active metabolites-formation of molecular complexes.

Cocaine, benzoylecgonine, benzoylnorecgonine, norcocaine, ecgonine methyl ester but not ecgonine formed distinct molecular complexes with calcium chloride of the general formula [B. CaC12-2H20]. The particularly strong interaction observed with benzoylecgonine, benzoylnorecgonine and calcium may play a role in the potent stimulant activity of these 2 compounds observed in rats after intracisternal administration.