A drug dissolution test is an analytical test of such significance that it is hard to imagine that any oral drug product such as tablet and capsule would be developed and manufactured without its use. The majority of the tests are conducted using testers commonly known as paddle and basket apparatuses. It is a well accepted, and implied, understanding that not using one of these apparatuses will require a long and unkind explanation for deviating from the “norms” resulting in potentially extensive and costly delays in bringing the products to the market. Therefore, Please click here for complete article

A suggested definition of “quality” for QbD purposes is described. It is hoped that the article will help in highlighting the underlying scientific issues and deficiencies which will prevent in achieving the intended objectives of the suggested “QbD based ANDA example documents”. It is argued that the documents are based on invalid analytical (dissolution) methodologies, which makes the suggestions/recommendations invalid as well. Suggestions for improvement are provided.Please click here for complete article

A method based on convolution technique has been described earlier to predict plasma drug concentration time (C-t) profiles. This article describes further refinement of the method for a more realistic representation of a human bioavailability study outcome by including variabilities in stomach emptying time and bioavailability factor (F). The advantages of such refinement are discussed including setting physiologically relevant specifications for dissolution testing.Please click here for complete article

PS: Please note that an error in the text was detected on page 2, column 2 and paragraph 2, which has been corrected. The revision reads as follows: “For this particular example it is assumed that the filter will release (not adsorb) on average 44%±10(±SD) of the drug, representing average F (bioavailability) and variation in the F for diltiazem.”  My apologies for the oversight and any inconvenience it may have caused. Saeed (July 27, 2012).

This article summarizes the principles of drug dissolution testing with an emphasis on the underlying scientific assumptions that are often not clearly described, or understood. It should be noted that the technique itself is extremely simple to use, however, current practices of selecting experimental conditions and the interpretation of dissolution results are seriously misunderstood, and require attention. To address these deficiencies, analysts should seek essential training in the areas of relevant physiology and pharmacokinetics. In the absence of such required training and knowledge of the subjects, it is highly unlikely that an analytical laboratory can generate relevant and accurate dissolution data, thus will fail in meeting the products development and evaluation objectives. Links to some articles on the subjects are provided which may help the analysts in improving their overall skills in these areas. Please click here for complete article