The uses of drug impurity data

We have discussed one driver for drug impurity analysis, namely the need for the synthetic organic chemist to monitor his reactions. We will return to this theme later in the chapter. However, there are two other drivers for drug impurity analysis that are relevant to any discussion of change. 

The most important of these is the regulatory environment in which the industry works. In a series of judgements resulting from isolated cases of poor laboratory practice the regulatory authorities of many countries, particularly the United States, have defined a strict code of practice for the industry to ensure that the highest standards of development and manufacture are observed by all 

The net result of such regulation is that there are well-developed standards for the way in which quantitative and, increasingly, qualitative measurements are carried out. There are also well-defined limits for various categories of impurity, all of which tends to emphasise the importance of measurements on the final API rather than on the process that produces it, for which the requirement is simply that the process remains under control . The importance of this summary is that at present, whatever the means of production, there is a requirement that the API will reach certain standards of purity as demonstrated by end-point measurement. Those standards effectively demand quantification of impurities down to about 0.05% for related organic impurities, in the region of ppb to low ppm for known toxins and low ppm levels for inorganics such as catal3Tic metals. 

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