Drug synthesis quality control

To gain FDA approval or license for marketing, a pharmaceutical product must be shown to be safe and effective for its proposed or intended use. The drug company or sponsor must also provide evidence to show that the processes and control procedures used for synthesis, manufacture, and packaging are independently validated to ensure that the pharmaceutical product meets established standards of quality. The overall effort from the inception of a new molecular entity and the establishment of analytical, scale-up, and quality control procedures, to the collection of safety and efficacy data for consideration by the FDA as part of an NDA or BLA, is called the drug development process. 

Important to quality control are the comparison and confirmation of drug substance identity, excipients, and packaging components. Techniques such as Fourier transform IR (FTIR), attenuated total reflectance (ATR), NIR, Raman spectroscopy are used with increased regularity. The detection of foreign metal contaminants is essential with inductively coupled plasma spectroscopy (ICP), atomic absorption (AA), and X-ray fluorescence. Also notable is the increased attention to analysis of chiral compounds, as in the synthesis of drug substances. Optical rotation, ORD, and CD are currently the preferred instruments for this practice. The analytical techniques commonly used in the preformulation study are discussed in the following. 

Direct Inlet Probe (DIP) The DIP is one of the earliest techniques used to introduce nonvolatile or highly insoluble samples into mass spectrometers. This technique is still popular today because it provides a means to perform rapid sample analysis with minimal or no sample preparation [27, 28]. Applications of the direct-probe technique include quality-control analyses and the screening of drug, polymer, and synthesis samples. It has also been used to study the temperature programmed decomposition of synthetic polymers and inorganic materials, to characterize the molecular properties of materials under thermal degradation conditions. The same is also true of the studies with lAMS (see Sect. 6.4). 

There will be a continued need for enantiospecific methods of preparation and analysis, not only to ensure the quality of the final drug substance and reference materials, but also to control starting materials used for their manufacture, and key intermediates during synthesis. Likewise, specific and sensitive bioanalytical methods will be required to follow the fate of individual enantiomers after their administration. 

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