An Implantable Drug Delivery System Based on Shape-Memory Alloys

Abstract

This chapter describes the design of an actively controlled implantable drug delivery device. Its job is to deliver small amounts of drug on a daily basis such that a patient no longer needs to get daily or weekly injections. Besides a reduction of the number of injections, implanted drug delivery systems offer many other advantages to a patient. Implantable drug delivery devices give a more constant drug level in the blood compared to injections. By the use of an active device instead of a passive, the drug level in the blood could be adapted to variations in physical activity, changes in temperature, etc. In chemotherapy and similar treatments, the device can be implanted at the place where the drug is needed such that the overall concentration of the drug in the body is much lower. The proposed device could be useful for hormonal treatments and all other treatments where small amounts of drugs are needed. In a first paragraph, solid drug delivery systems will be discussed. Main part of the chapter will concentrate on the design of a liquid drug delivery system. The proposed design is particular because the shape memory actuated microvalve has only silicone parts in direct contact with the drug. It is also very easy to produce in large volumes and can incorporate sensing functions.