A pharmacological study of propane-1,2-diol.

Abstract

Propane-1,2-diol (propylene glycol, PG), considered to be a safe solvent and commonly used as a vehicle in pharmacological and toxicological investigations, showed various neuropsychopharmacological activity in albino mice and rats. In lower concentrations (10-20%), at dose level of 10 ml/kg, PG did not show any significant neuropsychopharmacological activity either by i.p. or p.o. routes. But higher concentrations (50-100%), at same dose level by i.p. route, were found to have moderate to marked effect. There was decrease in locomotor activity, body and limb tone, respiration, rectal temperature and suppression of secondary conditioned responses. Significant potentiation of pentobarbitone (pentobarbital) hypnosis, slight increase in d-amphetamine toxicity in aggregated mice and pronounced analgesic and anti-inflammatory activity were also observed. Most of the above effects were also observed on p.o. treatment but the effects were of lesser degree. PG did not produce any effect on dog or cat blood pressure up to 100% concentration at the dose level 0.5 ml/kg. However, it potentiated the adrenaline (epinephrine) and noradrenaline (norepinephrine) response. On isolated smooth muscle preparations, in 50-100% concentrations, a dose-dependent non-specific blockade was observed against agonists viz. acetylcholine, histamine, 5-HT and barium chloride. No effect was seen on cardiac tissue preparation. On the basis of present findings, it is suggested that propylene glycol as a solvent be used only in low concentration of not more than 10% for pharmacological and toxicological investigations.