Method development workflow

In the final parf of this chapter, we focus on novel trends in chromatographic method development related to the analytical quality by design initiative (AQbD). We provide a real life example of several practical steps taken in the method development workflow. 

Figure 16.16 shows the agreement between the simulated chromatogram and the "real" chromatogram obtained at optimal conditions, selected using the described method development workflow. 

We also acknowledge the input of many colleagues at Pfizer Analytical R D in Sandwich, UK, and Groton, USA, for their input into developing the method development workflow and for providing examples. 

The previous chapters have dealt mainly with LC/MS analysis involving short run times, many samples, and relatively small numbers of compounds in samples. What about samples containing very complex compound mixtures, for example, natural products, samples from biomarker discovery, protein digests, and QA/QC method development or metabolite identification samples requiring detection of every component Such workflows often require several analysis steps with different columns and different mobile phases and pH values to increase the separation probability by changing the selectivities of individual runs. 

Computer-assisted method development has received a great deal of attention from management within the pharmaceutical industry, mainly from the perspective of cost savings associated with faster and more efficient development. Adoption and incorporation of the tools in day-to-day workflows has been relatively hmited due in part to a reluctance of chromatographers to believe that computers can replace the intuition of the expert chromatogra-pher. With the present state-of-the-art, there is little question that computers can play a role in efficient method development. However, it must be accepted that computers are a supplement to, rather than a replacement for, the knowledge of the method development chromatographer. 

FIGURE 6.3 Workflow diagram of method development and qualification for exploratory application. 

One clear aspect of the current trends in the proteomic field is the plethora of ways to achieve informational outcomes. Research developments over recent years have focused on all facets of the proteomic workflow including improvements in the comprehensiveness of analysis, efficiency of workflows, and development of specialized methods. This is aided by several mass spectrometers being available on the market that have the necessary accuracy, sensitivity, speed, and dynamic ranges. The baseline workflow for proteomics however remains essentially the same and involves a number of required steps (summarized in the succeeding text and in Figure 1) ... 

One area of darkroom procedure that is conducive to standardization is making proof sheets. While it is not necessary to standardize on making a proof sheet doing so will streamline your workflow, help determine if your system is working properly, camera, meter, film and developer, and enable you to accurately read step wedges when making interpositives. The method is known as proofing for maximum black. 

In Section 8.2, the aim of analysis is emphasized especially for the API (active pharmaceutical ingredient) and the drug product. The workflows and the rationale at major decision points during synthetic processing steps where HPLC can be applied in process development are elaborated upon. For example, a fast method is needed to monitor reaction conversion of two components. However, a more complex method would be needed for stability-indicating purposes where multiple degradation products, synthetic by-products, and excipient peaks need to be resolved from the active pharmaceutical ingredient. 

Figure 3.109 shows a general scheme combining distinct disciplines in TP photosciences. It demonstrates the interdisciplinary cooperation needed to become an accepted scientific field in both academic and industrial areas. It demonstrates the workflow, starting from basic research including theory, synthesis, and chromophore characterization. Development of TP chromophores, materials needed for TP application, and methods and equipment required in TP photosciences will require interdisplinary work by theoretical scientists, organic chemists, polymer chemists, physical chemists, and physicists. 

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