Propofol hydrochloride is a valuable anesthetic agent for the total intra-venous anesthesia but may support microbial growth because of its nourishing lipid emulsion content. There are many reports on the isolation of various fungi and bacteria from propofol and some manufacturers add the preservative materials for reducing the risk of contamination. As the dilution of the drug, may reduce the capability of preservative materials, this study was designed to compare the contamination potential of propofol, according to two dilution protocol, suggested by the manufacturer.

Ten vials of propofol 1% were randomly selected and a venous catheter was inserted aseptically into each vial. Five vials diluted to 1/2 (D1 Vials) and the others diluted to 1/5 of the initial concentration (D2 Vials) by using a sterile 5% dextrose solution. All the vials were kept at room temperature (25-28°C) for 72 hours. Aliquots of 0.5 ml of drug were aspirated every hour for 8 hours and then every 24 hours for 72 hours and evaluated for bacterial and fungal growth .The catheters were occluded between sampling by a cap.

Surprisingly, during the 72 hours of drug sampling, no growth of aerobic and non aerobic bacteria or fungi was seen neither in (D1) nor in (D2 Vials).

These results not only shows no differences between two selected dilution protocols, but also shows that using an inserted catheter instead of frequent needle insertions and following the routine aseptic process for drug preparation and administration will decrease the potential contamination of propofol hydro chloride.