Dissolution is a test used by the Pharmaceutical industry to characterize the dissolution properties of the active drug, the active drug's release and the dissolution from a dosage formulation. Dissolution testing is used to formulate the drug dosage form and to develop quality control specifications for its manufacturing process. In-vitro dissolution testing is a critical test that has to correlate with in-vivo clinical studies and which could require specific method developments. Dissolution testing is described in many pharmacopeias, in EP, USP chapters and FDA guidelines.
To benefit from complete flexibility on media volumes and to reproducibly position dosage forms such as powders, APIs, lipophilic forms e.g. suppositories, suspensions, liposomes, microspheres, semi-solids, implants and medical devices e.g. drug eluting stents, the right method is the USP 4 flow-through cell.
Choose Your USP 4 System Set-up
The open loop system set-up is historically the one used to guarantee sink conditions (from 2 to 5 times inferior to saturation concentration) to test poorly soluble compounds. The open loop is also well adapted to ER, MR, SR dosage forms due to its media selection ability which allows a pH change on the fly.
The closed loop system set-up is the most used, it allows complete flexibility of volume from 15 mL to 4'000 mL and will provide cumulative data on dosage forms, which are difficult to position in a vessel in a reproducible way (e.g. powder, suspensions, implants, gels, creams, microspheres, suppositories, liposomes…).