HPLC Instrumentation in Pharmaceutical Analysis

An overview of HPLC instrumentation, operating principles, and recent advances or trends that are pertinent to pharmaceutical analysis is provided in Chapter 3 for the novice and the more experienced analyst. Modern liquid chromatographs have excellent performance and reliability because of the decades of refinements driven by technical advances and competition between manufacturers in a two billion-dollar-plus equipment market. References to HPLC textbooks, reference books, review articles, and training software have been provided in this chapter. Rather than summarizing the current literature, the goal is to provide the reader with a concise overview of HPLC instrumentation, operating principles, and recent advances or trends that lead to better analytical performance. Two often-neglected system parameters—dwell volume and instrumental bandwidth—are discussed in more detail because of their impact on fast LC and small-bore LC applications. 

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HPLC INSTRUMENTATION IN PHARMACEUTICAL ANALYSIS STATUS, ADVANCES, AND TRENDS... 

FIA has also found wide application in pharmaceutical analysis.214,215 Direct UV detection of active ingredients is the most popular pharmaceutical analysis application of FIA. For single component analysis of samples with little matrix interference such as dissolution and content uniformity of conventional dosage forms, many pharmaceutical chemists simply replace a column with suitable tubing between the injector and the detector to run FIA on standard HPLC instrumentation. When direct UV detection offers inadequate selectivity, simple online reaction schemes with more specific reagents including chemical, photochemical, and enzymatic reactions of derivatization are applied for flow injection determination of pharmaceuticals.216... 

The marriage of HPLC to mass spectrometry (MS), now developed into a mature instrumentation, continues to greatly impact many of the separation sciences, especially in pharmaceutical analysis where it has been used in new drug discovery [23,24] and in drug metabolite identification [25-27]. HPLC-MS has also made an impact on lipid research, providing a convenient approach to the analysis of phospholipids and fatty acids [28,29]. It has also greatly benefited the field of proteomics [30-34], especially analysis of protein structure and function. 

Capillary electrophoresis (CE) is the most rapidly expanding separation technique in pharmaceutical analysis and is a rival to HPLC in its general applicability. The instrumentation is quite straightforward, apart from the high voltages required, but the parameters involved in optimising the technique to produce separation are more complex than those involved in HPLC. The technique is preferred to HPLC where highly. selective separation is required. 

FdPLC has contributed many successes in product development and in quality control for the pharmaceutical industry. The UV detector coupling with HPLC equipment is the most important analytical instrument for preformulation, QC/QA, and in-process control in pharmaceutical analysis. HPLC is a basic and reliable analytical tool for preformulation study because of the high-resolution capacity, accuracy, and reproducibility of the equipment. Its primary function includes search for and detection of impurities in drug substances, as well as stability evaluation of dosage forms in terms of detection and quantitation of degradation products. 

The most important tasks of capillary action planar chromatography in pharmaceutical analysis are summarized in Table 2. In general, it can be stated that although HPLC has superseded TLC in many application areas, TLC both in instrumentalized or in noninstrumentalized forms have remained as standard methods for solving many difficult analytical problems. 

Direct instrument control (or the lack of it) was an important issue for the earlier version of CDS. The scheme of connecting the detector channels through A/Ds to CDS worked well in analytical laboratories across the pharmaceutical industry. The scheme provided enough flexibility so that the CDS could collect data from a variety of instruments, including GC, HPLC, IC, SFC, and CE. It was equally important that the CDS could be connected to instruments that were manufactured by different vendors. It was not uncommon to find a variety of instruments from different vendors in a global pharmaceutical research company. The disadvantage of this scheme was that the instrument metadata could not be linked to the result file of each sample analyzed. It could not be guaranteed that the proper instrument parameters were used in sample analysis. Another need came from the increased use of... 

The progress made in interfacingHPLC instruments with mass spectrometry has been a significant development for laboratory analyses in the pharmaceutical industry. The low concentrations of test drugs in extracts of blood, plasmas, serums, and urine are no problem for this highly sensitive HPLC detector. In addition, the analysis is extremely fast. Lots of samples with very low concentrations of the test drugs can thus be analyzed in a very short time. At the MDS Pharma Services facility in Lincoln, Nebraska, for example, a very busy pharmaceutical laboratory houses over 20 LC-MS units, and they are all in heavy use daily. 

Near infrared spectroscopy (NIRS), a technique based on absorption and reflectance of monochromatographic radiation by samples over a wavelength range of 400-2500 run, has been successfully applied for food composition analysis, for food quality assessment, and in pharmaceutical production control. NIRS can be used to differentiate various samples via pattern recognitions. The technique is fast and nondestructive method that does not require sample preparation and is very simple to use compared too many other analytical methods such as HPLC. The drawback of NIRS, however, is that the instrument has to be calibrated using a set of samples typically 20-50 with known analyte concentrations obtained by suitable reference methods such as FIPLC in order to be used for quantitative analyses. Simultaneous quantification of the... 

This chapter presents an overview of current trends in high-pressure liquid chromatography (HPLC) instrumentation focusing on recent advances and features relevant to pharmaceutical analysis. Operating principles of HPLC modules (pump, detectors, autosampler) are discussed with future trends. 

High-performance liquid chromatography (HPLC) is one of the premier analytical techniques widely used in analytical laboratories. Numerous analytical HPLC analyses have been developed for pharmaceutical, chemical, food, cosmetic, and environmental applications. The popularity of HPLC analysis can be attributed to its powerful combination of separation and quantitation capabilities. HPLC instrumentation has reached a state of maturity. The majority of vendors can provide very sophisticated and highly automated systems to meet users needs. To provide a high level of assurance that the data generated from the HPLC analysis are reliable, the performance of the HPLC system should be monitored at regular intervals. In this chapter some of the key performance attributes for a typical HPLC system (consisting of a quaternary pump, an autoinjector, a UV-Vis detector, and a temperature-controlled column compartment) are discussed [1-8]. 

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