For elderly people in developed nations, medicine is a part of everyday life. On average, over-65s are prescribed over a dozen drugs to take daily; some pensioners can pop up to 30 pills a day. This means that elderly people are confronted with a dual challenge: swallowing all of the medication they must take on a daily basis and remembering to take the right number of the right pills at the right times. Hoping to overcome some of these challenges, scientists are looking into 3D printing layers of multiple medicines into one ‘polypill’, in an aim to provide a tailored and effective way to keep older people on track of their medicines.
The idea is simple, the execution challenging. A polypill contains not just one but several drugs, therefore reducing the total number of pills a patient must take for a particular condition. However, all of the drugs in a polypill must be compatible with one another, and they also often need to be released into the patient’s body in different ways and over different timescales; getting this right is an art. Because of these challenges, there is only one polypill currently on the market.
Recently, a team led by Professor Clive Roberts from Nottingham University have developed a 3D printing method to manufacture polypills. They use a technique called 3D extrusion in which a paste is formed into a desired shape by pushing it through a nozzle. To build polypills, pastes of each of the different parts are extruded one on top of the other and then dried. The process is conducted at room temperature to avoid degradation of the drugs.
The first polypill manufactured by Roberts and his team contained three different drugs (captopril, nifedpine and glipizide), which are used to treat high blood pressure in patients suffering from type 2 diabetes. Each of the drugs was contained in a different section of the pill and was released from the tablet at a different rate. The second 3D-printed polypill incorporated a treatment for cardiovascular disease, such as heart attacks and angina, made up of five drugs. Two of the drugs (aspirin and hydrochlorothiazide) were placed in a compartment for immediate release, while the other three (atenolol, pravastatin and ramipril) were placed in a compartment for sustained release. In both cases, the researchers demonstrated that there were no interactions between the separate drugs in each pill.
Not only does 3D printing allow the separation of drugs into compartments within a pill, it also allows for easy variation of the amount of drug in each compartment by simply changing the amount of drug in the paste which is put into the printer. In other words, 3D-printed polypills could be tailored to the individual, giving them the exact doses of each drug that they need. This would represent another considerable improvement over the current system, in which drugs are often only available in pills of a few discrete doses.
However, as highlighted by Professor Kinam Park of Purdue University, USA, the creation of personalised doses for every patient is implausible under current FDA guidelines, and any new polypill, even if it combined tried and tested drugs, would be considered as a new drug by the FDA and would require clinical trials to prove its safety and efficacy. So, as promising as these developments are, the 3D printing of polypills still has a long way to go before it can realise its great potential to improve the treatment of care for elderly patients across the developed world.