A study of de-gassed oil in water dispersions as potential drug delivery systems

The natural hydrophobicity of many drugs makes it very difficult to use them for water-based intravenous injection. This lack of water solubility also hinders the development and testing of new drugs. Clinical tests are often refused if the drug can only be dissolved in water-insoluble oils and therefore cannot be administered safely or easily. However, we have discovered that de-gassing a mixture of a typical hydrophobic drug carrier oil and water produces, on vigorous shaking, a uniform fine dispersion of oil droplets, which are of suitable size for intravenous injection. These dispersions are stable and yet do not require the use of added stabilizing agents, such as surfactants and polymers, which can lead to harmful side effects. This novel process has been used to enhance the dispersion of the commonly used drug delivery oils, soybean oil and perfluorooctyl bromide (PFOB). This process can also be applied to other drug delivery oils, which are immiscible with water. For example, the dispersion of perfluorohexane in water is greatly improved by de-gassing. Over time, the dispersions phase separate but are easily re-generated simply by shaking, when stored under de-gassed conditions in sealed vials. The process has also been successfully applied to hydrophobic drugs, both liquid and solid, where dispersion was obtained without the use of either carrier oil or added dispersants. These dispersions offer safer drug delivery systems and also might be used in facilitating the development or testing of new experimental, water-insoluble drugs. (c) 2005 Elsevier B.V. All rights reserved.