In the majority of cases, the effectiveness of tablets or capsules administered orally relies on the drug dissolving in the fluids of the gastrointestinal tract prior to absorption through the walls of the tract into the systemic circulation.
For this reason, the rate at which a tablet or capsule dissolves is critical to its therapeutic efficiency and is a key factor in both the formulation process and final quality control.
The most common apparatus used to measure the dissolution rate of solid dose forms are the basketand the paddle. Both use the same basic configuration, are simple, robust and can be used to test a variety of different products.
The basic apparatus consists of a covered cylindrical vessel having a hemispherical bottom and capable of holding approx. 1000 mL of simulated gastric juice. The vessel is partially immersed in a water bath capable of maintaining the temperature of the vessel contents at 37 degrees C. In the case of the basket method, the tablet or capsule is constrained in a cylindrical mesh basket. In the case of the paddle method, the sample is simply allowed to sink to the bottom of the vessel.
During the test, a motor is used to rotate the drive shafts at the speed specified in the pharmacopoeias. A sample of the dissolution medium is taken at predefined time intervals to determine the percentage of dissolved drug present – this is normally determined by UV/Vis or HPLC.
For comprehensive product details, specifications and part numbers, please request a copy of our brochure “Quality Solutions for the Testing of Pharmaceuticals (2013 Edition)”.