KETAMINE-IN OIL-IN-WATER MULTIPLE EMULSION FOR PROLONGED DRUG RELEASE

Abstract

A preparation of Ketamine [2-(Chlorophenyl)-2-(methylamino) cyclohexanone, C₁₃H₁₆ClNO, anesthetic agent] in oil in water multiple emulsion for prolonged drug release was formulated and evaluated. Ketamine, the cyclohexylamine, is used as a short-acting anaesthetic in humans and in some animal species [1]. Ketamine is poorly bound to plasma proteins and has a half-life of approximately 4 hours following intravenous injection [2]. Ketamine leaves the blood very rapidly to be distributed into the tissues with a high lipid solubility [2]. The recommended dosage of intravenous Ketamine is 2.5-20mg/kg [3]. The LD50 injected intraperitoneally in mice and rats is 100 times the intravenous and 30 times the intramuscular dose used in humans.

The objective of this study was to test the concept that a multiple emulsion could be formulated which has high porosity and lower viscosity at 37°C consistent with its intended use for sustained drug release and to prolong the half-life of the anesthesia. The results showed that the Ketamine (100mg/ml in inner phase) released 8.2% at 10 minutes, 67.0% at 30 minutes, and 95.5% at 60 minutes from the Ketamine/O/W multiple emulsion in a well-controlled manner.