The Intellidrug tooth implant
February 2, 2007 Man has been producing and administering drugs since the neolithic period. Initially these drugs were administered orally mixed with a liquid with the advent of pills making inhalation and the intramuscular or intravenous injection following. These days, the majority of the world’s drugs are administered via pills – pills offer an accurate dosage, but they are so convenient that it’s often possible to forget when you’ve taken them. Chronically ill patients get muddled when constantly having to swallow different numbers of tablets at different times, while those with dementia simply cannot cope. Now EU researchers are developing a better, more accurate and more convenient way – a dental prosthesis capable of releasing accurate dosages into the mucous membranes in the mouth. As it can administer accurate micro amounts over continuous periods, the prosthesis overcomes the peak concentrations that occur with taking pills and even offers the ability to monitor and maintain consistent blood levels of any drug. What makes the Intellidrug prosthesis unique is that, unlike existing drug prostheses and implants, it is small enough to fit into two artificial molars. Inside the patient’s mouth, it is readily accessible and can easily be maintained and refilled.
“The dental prosthesis consists of a drug-filled reservoir, a valve, two sensors and several electronic components,” explains Dr. Oliver Scholz of the Fraunhofer Institute for Biomedical Engineering IBMT in St. Ingbert, where the sensors and electronics were developed.
“Saliva enters the reservoir via a membrane, dissolves part of the solid drug and flows through a small duct into the mouth cavity, where it is absorbed by the mucous membranes in the patient’s cheeks.”
The duct is fitted with two sensors that monitor the amount of medicine being released into the body. One is a flow sensor that measures the volume of liquid entering the mouth via the duct, while the other measures the concentration of the agent contained in the liquid. Based on the measurement results, the electronic circuit either opens or closes a valve at the end of the duct to control the dosage. If the agent has been used up, the electronic system alerts the patient via a remote control, which was also developed at the IBMT. This control permits wireless operation of Intellidrug, and can be used by the patient or doctor to set the dosage required.
The patient has to have the agent refilled every few weeks. »This could be done using a deposit system whereby the patient swaps the empty prosthesis for a newly refilled one. At the same time, the battery could be replaced and the device could be serviced,« says Scholz.
The prototype will be on display for the first time at the MedTec trade fair in Stuttgart opening February 27. Intellidrug is to undergo clinical testing this year – filled with a drug called Naltrexon, which is taken by drug addicts undergoing withdrawal therapy.