Last year, the EMA published the draft of the "Reflection paper on the dissolution specification for generic oral immediate release products".
The methods for dissolution testing are expected to be robust and reproducible. The addition of surface-active substances (surfactants) should be avoided.
The development of methods (paddle apparatus) should begin with a stirring speed of 50 revolutions per minute. However, higher stirring speeds may be used if an adequate justification is given. The so-called "Discriminatory Power" for the proposed dissolution method has to be discussed further on.
To allow extrapolation of the results of a bioequivalence study from the "biobatch" to commercial batches, it is required to have appropriate specifications of the amount of API released at a defined time-point.
The test conditions should be selected to allow discrimination between batches with diverse in vitro release characteristics. In an ideal case, the in vitro results are able to reflect the in vivo situation. To achieve this, batches should be manufactured which have significant changes compared to the product for which the authorisation is applied. Such changes may refer to the quantitative formulation, to input parameters and/or using slightly changed process parameters.
Modifications to the composition of a medicinal product to manufacture a "bad batch" should be achieved by changing the proportions of the used excipients in the manufacturing formula. The complete omission of one or more excipients (like binder or disintegrant) is not desirable.
Please also see the complete "Reflection paper on the dissolution specification for generic oral immediate release products".