Controlled Drug Release - Isis Project No 957

Chemists in the Inorganic Chemistry laboratory have found that they can intercalate a range of pharmaceutically active molecules between the layers of a layered inorganic host.

Background

While working on the ion-exchange abilities of a family of inorganic materials known as Layered Double Hydroxides (LDH's) they recognised that many commonly prescribed drugs and other over the counter medicines are either anions or can be conveniently and reversibly converted into an anion form. They found that addition of one of these layered double hydroxides to a solution of a chosen pharmaceutical in water at room temperature results in intercalation of the these molecules between the sheets of the host structure. The layered double hydroxides are able swell by up to 20Å to accommodate the size of the new guest molecules.

Problem

Certain drugs require controlled release and/or amelioration of side effects. Layered double hydroxides already have medicinal properties in their own right as antacid and antipepsin agents. Propriety antacids products such as Talcid™ and Altacite™ contain the layered double hydroxide [Mg6Al2(OH)16]CO3.

The Oxford Invention

To date the group have shown that compounds such Diclofenac, Ibuprofen, Naproxen, and Gemfibrozil intercalate rapidly into LDH's. They are then able to quantitatively recover these molecules on demand. At the moment drug release can be achieved by either dissolving the entire drug/LDH composite in dilute acid or adding the drug/LDH to a phosphate buffer at pH 7. Their preliminary kinetics experiments using phosphate buffers show that these drugs can be released back into solution in 1-3 hours at 37 °C.

Apart from the potential of using these materials to deliver drugs in vivo, the host itself could have additional benefits. It will be possible to control the point of release and pharmokinetic profile by selection of the metals ions in the host layers. The antacid performance and pH stability is also controllable by the choice of metal ions in the host layers. Confinement of the drugs between the metals layers restricts molecular interactions and dynamics and should improve long-term stability. In addition improved taste qualities of the formulation are predicted.

Commercialisation Opportunity

This discovery is subject to a patent application. Isis Innovation is interested in discussing suitable arrangements with companies who wish to develop and utilise this technology.

Request Further Information: Project Number 957 - Controlled Drug Release