Caffeine

Caffeine (Pentoxifylline EP Impurity F) is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug and a reversible acetylcholinesterase inhibitor (1,2,3). Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants. In humans, caffeine acts as a central nervous system stimulant, temporarily warding off drowsiness and restoring alertness. Caffeine is a cardiac and respiratory stimulant; diuretic. Caffeine is toxic at sufficiently high doses. Caffeine is a non-competitive inhibitor of acetylcholinesterase (3). This compound is a contaminant of emerging concern (CECs).