Dissolution method query

When should we select the paddle method? or when should we choose the basket method for dissolution?

Hi Fokhrul Abedin

The use of the paddle or basket when developing a dissolution test is primarily determined by practical rather than theoretical considerations.The paddle is the favored apparatus for most oral dosage forms. It is not as useful for those dosage forms that are buoyant. For buoyant capsules and tablets,the basket should be the first choice. In specific cases, where for example the basket mesh may become obstructed by gelatin or other matter,use of the paddle would be favored.When testing buoyant dosage forms with the paddle, a sinker is usually required.

Commonly asked question is how should one choose between Paddle and Basket apparatuses when selecting an apparatus? In short there is no clear cut answer, in particular based on a scientific merit or reasoning.

It is important to note that both of these apparatuses have been shown to provide highly variable and unpredictable results. Furthermore, the results obtained using these apparatuses often lack a link to physiological or in vivo characteristics of the test products. These apparatuses usually provide two different sets of results for the same product under similar operating conditions. Thus, it would be impossible to know which one is reflecting the actual/true dissolution behaviour of the product. Between the two, the Basket apparatus appears to provide more variable results than the Paddle apparatus.

It appears that traditional practices/views, rather than scientific merit, are used in selecting the apparatuses. For example, it is commonly suggested that the Basket apparatus may be preferred for products which may float in the dissolution vessels. On the other, hand, such floatation may be controlled with the use of a “sinker” if one prefers to use a Paddle apparatus. Eventually, it boils down to the personal preference of an analyst, as to what his or her expectations are for the dissolution behaviour of the test product.

In short, current practices are to choose an apparatus which would provide desired dissolution results (behaviour) of the test product. How useful or relevant would such results be? This remains an open and debatable question.