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

It is a well established fact that the currently used dissolution testers, in particular the paddle and basket, are not qualified and validated apparatuses, thus cannot be used for appropriate and accurate evaluation of dissolution characteristics of the products. To address these deficiencies a new spindle, known as the crescent shape spindle, has been suggested as a substitute for the paddle and basket in the vessel based apparatuses. This substitution not only addresses the flaws of the paddle and basket apparatuses, as described below, but also provides a number of additional advantages for easier, scientifically valid and superior product evaluation. For example: please click here for complete article

I’ll be giving two talks on drug dissolution testing at the Informa Conference on Bioavailability / Bioequivalence, Dissolution and Biowaivers, 23 – 24 May 2012, Continental Zara Hotel, Budapest, Hungary.  http://www.informaglobalevents.com/event/beba12

If you are attending the conference, I will be very happy to discuss topics of your interest before or after the presentations. Please, let me know by sending an email to moderator@drug-dissolution-testing.com

Considering the flaws of poor hydrodynamics of the most commonly used apparatuses, paddle and basket, it is very well established that these apparatuses are not qualified and validated to provide relevant and reproducible dissolution results. Therefore, it is natural that people are seeking alternatives. The vessel based apparatuses using the crescent shape spindle provides such an alternative. The next obvious question would be, are such apparatuses qualified to be used as dissolution testers? Also, have these been standardized? The answer to both questions is yes, as explained below. please click here for complete article

The purpose of a dissolution tester is to test a tablet/capsule product for its potential dissolution characteristics in the human GI tract. In general, it is now well recognized that the currently used dissolution testers, in particular paddle and basket, do not provide such dissolution characteristics. In fact, they cannot provide dissolution characteristics because of the flaws of poor product/medium interaction within the apparatuses. Therefore, these apparatuses cannot be qualified and/or validated as dissolution testers and thus cannot be used for the development and evaluation of the products.

The practices of the past many years have been to keep using these apparatuses for product development and evaluation (isn’t this bizarre?) with a change/twist in the objective of dissolution testing by calling it a quality control test. However, how does one link the dissolution test to the quality of the product, when it will require its link to the dissolution characteristics in vivo, i.e., human GI tract? Oops, there is no link here, as stated in the paragraph above. Continue reading →