There is a common belief within the dissolution community that not only should the stirring within a dissolution vessel should be very gentle but the product should also be not in contact with the rotating spindle/paddle. Touching or moving of the product by the spindle is considered to be a harsh and undesirable testing environment that may result in loss of the discriminatory ability of the dissolution test. On the other hand, there are no standards or requirements describing such gentleness or softness of the stirring, other than the belief that the softer the environment/stirring is, the better it will be. Such a belief has resulted in the practice of the other extreme i.e. the commonly recommended stirring (e.g. 50 rpm) in fact provides no, or extremely limited, stirring which in reality makes the current practices of dissolution testing meaningless. please click here for complete article
