Pharmaceutical Testing
Dissolution
Test Apparatus & Method
The progressive optimisation of dissolution testing for different pharmaceutical forms has led to the introduction of a range of different apparatuses and techniques as detailed in Ph. Eur Chapters 2.9.3, 2.9.4 and USP Chapters <711> and <724>.
With the paddle method, the basket is replaced by a paddle and the sample to be tested is allowed to sink to the bottom of the vessel. During a test run, a motor is used to rotate the shaft at a speed specified by the appropriate Pharmacopoeias. The paddle over disk technique is used for the determination of the drug release rate from transdermal patches. It is described in the Ph. Eur. under Chapter 2.9.4 and under Chapter <724> as Method 5 in the USP. Using a suitable adhesive, the transdermal patch is simply mounted on a disk designed to hold it at the bottom of the vessel. The rotating cylinder (Ph. Eur. Chapter 2.9.4, USP Method 6) is an alternative to the paddle over disk method.
The most commonly used apparatus defined by the Pharmacopoeias to measure the dissolution rate of solid dose forms are the basket and paddle . The basic dissolution apparatus consists of a covered cylindrical vessel with a hemispherical bottom, typically holding 1000 mL of simulated gastric juice. The vessel is immersed in a water bath capable of maintaining the temperature of the vessel contents at 37°C. For the basket method, the tablet or capsule is constrained in a cylindrical basket, constructed of sieve mesh, of defined proportions. The basket is attached to a metal drive shaft, positioned so that the bottom of the basket is 25 mm from the bottom of the vessel.
Basket Paddle Ph. Eur. 2.9.3
Flow-Through Cell Ph. Eur. 2.9.3
Paddle Over Disk Ph. Eur. 2.9.4
Basket Ph. Eur. 2.9.3
Reciprocating Cylinder Ph. Eur. 2.9.3
USP App 3 <711>
USP App 1 <711>
USP App 2 <711>
USP App 4 <711>
USP App 5 <724>
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