Dissolution is a test used by the Pharmaceutical industry to characterise 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.
Tablets are classically tested according to the USP 2 paddle method. Swelling or floating dosage forms such as capsules are tested according to USP 1 basket method. USP 5 (paddle-over-disk) and USP 6 (rotating cylinder) are used for transdermal dosage forms.
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.