Review Article
Saeed A Qureshi
Abstract
In principle, drug dissolution testing should be one of the simplest analytical techniques, however, in practice it is perhaps the most confusing, complex and frustrating techniques often lacking scientific and/or logical considerations. Perhaps the strange aspect of current practices is that despite the availability of hundreds, if not thousands, of methods and numerous regulatory guidance, if given a blinded sample of a simple tablet or capsule product one cannot determine its dissolution characteristics. On the other hand, fortunately, if one applies common and well established scientific principles and logical judgements, drug dissolution testing can become a powerful analytical tool based on a simple set of experimental conditions. The purpose of this article is to highlight some of the critical irrelevancies of current practices. Describing basic principles of underlying science, a number of suggestions are made for simplifications and improvements of testing and thus product evaluations such as; A single product and drug independent approach/method for conducting dissolution tests alleviating the need for current dissolution method development practices. A simple and practical approach based on convolution technique, termed as in vitro-to-in vivo profiling or IVIVP, for estimating plasma drug concentrations-time profiles from dissolution results using Excel spreadsheet software. Using the improved dissolution testing approach to determine related quality parameters, such as identity, assay/potency and content uniformity, thus providing significant simplicity and saving of resources. In addition, a discussion is provided to circumvent issues of low solubility of drugs, requirements of a sink condition, and in vitro-in vivo correlation (IVIVC) practices.