Historical Japanese Pharmacopeia
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The historical Japanese Pharmacopeia specifies a 0.011 inch wire diameter resulting in 0.425 mm square hole (a 36-mesh basket). As a result, the two baskets are NOT interchangeable.

Testing Novel Dosage Forms and Non-Compendial Modifications
to Dissolution Apparatus: Apparatus 2 Sinkers

In Apparatus 2, the dosage form is allowed to sink to the bottom of the vessel before the blade begins rotation. However, some dosage forms may be too light and will require a 'weight' (sinker) to enable them to sink. This may be accomplished by winding a few turns of a short, loose piece of wire, made of a suitably non-reactive material, around the dosage form to form a helix.

Alternative sinker devices may be required during method development. However, the performance of the various sinkers is generally not equivalent and the sinkers are not interchangeable unless validated.

Dosage forms which require sinkers are not solely limited to capsules that do not sink. Any dosage form that exhibits the following characteristics may require a sinker to obtain the best dissolution results.

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Sinkers should exhibit a number of desirable characteristics including the following:

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1 There should be little
hydrodynamic interference
Minimal
Impact on
Test Results

There are a number of disadvantages associated with the use of sinkers which may have far-reaching implications during dissolution testing. These include the points shown below.

All these problems will result in an unacceptable variation in dissolution performance.

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Helical glass sinkers may break

Failure Investigation

A supervisor should conduct a rudimentary investigation between each sample test to ensure that the calculations were correct (eg. the sample preparation should be reviewed, the standard preparation checked and the spectrophotometer results evaluated to ensure that there were no obstructions in the cell during reading. It is for this reason that all samples are saved and not discarded after testing).
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Investigation is also used to highlight any problems that might have occurred in the dissolution test (eg. there might be a calculation error in test 1 which would cause errors in test 2 calculations and would not otherwise be discovered). It is best to perform each investigation early to verify each step.
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