A 3D-printed drug has already been approved by the US Food and Drug Administration (FDA), but it is not a polypill. The FDA-approved pill is made of a water-soluble drug, but many drugs are not water soluble. Drugs either need to readily dissolve after entering the body or need to be dissolved before, for efficient absorption. And these limitations also apply to polypills. We have recently published research on a type of material that has been used to contain water-insoluble drugs in the past, but that has never been 3D printed before. These materials are known as “surfactant-polyelectrolyte complexes”. These materials are gels made mostly of water, but their chemistry allows them to carry drugs that cannot be dissolved in water.
Surfactants are molecules with two parts: one part that likes to mix with water and the other that doesn’t. This means that surfactants tend to clump together with other molecules of the same type when they are placed in water so that the parts that don’t like water are shielded from it. These structures can store drugs inside them. The surfactants in our study had a negative electrical charge, and the polymers (polyelectrolytes) had a positive electrical charge. So when the oppositely charged surfactants and polyelectrolytes came into contact, they were attracted to one another to form a “complex” (hence “surfactant-polyelectrolyte complexes”). That is to say we, they formed a 3D drug-carrying system. We 3D printed alternating layers of polyelectrolyte and surfactant to make these complexes. These have the potential to store and deliver drug molecules in the form of pills. The pill can be made into a polypill simply by printing different layers with different drugs.
Not there yet
Although lots of research has already been done, this new form of drug delivery has much further to go, especially as it requires regulatory approval. These approvals take up to five years, after passing clinical trials. Maybe in five years, some of us will get a prescription for customised polypills made on a 3D printer at our local pharmacies. People with multiple conditions will take one 3D-printed pill a day instead of a complex schedule of many pills, or perhaps even have the drugs implanted in their bodies.