A controlled release device is a complex system, designed to release the drug product’s active pharmaceutical ingredient (API) gradually and predictably over a specified period of time. Controlled release systems offer several advantages over traditional drug delivery including tailoring of drug release rates and site-specific delivery. A typical manufacturing strategy for controlling release profile is encapsulation of the drug at the core with a coating or sandwiching the drug between an inert core and several layers. In both cases, it is crucial that the coating is uniformly applied.
Several techniques are applied to generate the required release profile:
- Different coating thickness
- Multiple coatings
- Individual coatings of disparate APIs