Pharmacokinetics of propylene glycol after rectal administration

Propylene glycol is an excipient of various pharmaceutical preparations. The pharmacokinetics after rectal administration are studied, followed by a consideration on local and systemic side-effects for a solution of paracetamol in a mixture of propylene glycol and water. After administration of 8.64 g propylene glycol to 10 adults and 173 mg/kg body weight to 4 children, peak concentrations (Cmax) of 199 mg/l and 171 mg/l respectively were reached (tmax) after 1.5 hr and 1.0 hr. The average terminal half-lives (t1/2) in adults and children were respectively 2.8 hr and 2.6 hr, total body clearance (CI/F) 0.20 l/hr*kg and 0.21 l/h*kg and apparent volume of distribution (VD/F) 0.79 l/kg and 0.77 l/kg.