Precautionary note on use of polyethylene glycol as a drug solvent.

Polyethylene glycols (PEG 200-7(0) are used as solvents in various pharmaceutical preparations meant for both internal and external use (1,2). PEGs are incompatible with iodine, potassium iodide, sorbitol, tannic acid, metallic salts like bismuth, mercury and silver salts (2). Their systemic absorption in certain conditions may result in renal failure and CNS depression (3). Morbidity has been reported due to systemic toxicity. Being acidotic PEGs increase anion, osmolar gap, haemolysis and serum calcium (4). Topical application resulted in urticaria, delayed allergic eczematous reactions, cross sensitivity etc. (5). Inspite of the adverse side effects, it is still customary to use PEGs as solvents in conventional pharmacological screenings as they are claimed to be inactive ingredients. In this study during pharmacological screening it was observed that PEG400 exaggerated the effects of oxyphenonium bromide when administered intraduodenally.