Used by the plastics industry, among others, researchers wondered if melt extrusion, or Meltrex, could also be applied to these difficult-to-formulate drug candidates. With some adaptation, the answer, it turns out, is “yes.”
Melt extrusion techniques have been around for centuries, and have been broadly applied in industrial settings since the 1930s.
To make plastic products, the technique involves exposing resin and other materials to very hot temperatures so that they melt. Then, the melted plastic is forced into forms. Eventually, they take the shape of milk jugs, or food storage containers, or any number of other plastic products.
In the formulation of medicines, the same idea applies. The active drug substance, which can’t be dissolved in the body, is pre-dissolved in a melted polymer substance, where the active drug spreads out evenly and consistently.
The active drug takes the form of a so-called solid solution, which can then be ground down and combined with other non-active ingredients and ultimately transformed into its final form, such as a tablet or capsule.