Analytical methods chemometric approach

In this chapter we report recent advantages in analytical method hyphenation and chemometric approach applied to drag development. 

In this chapter we report recent advantages in analytical method hyphenation and chemometric approach applied to drug development, especially related to last trends in pharmaceutical field and to advantages in terms of high-throughputs procedure and instrumentations. 

Calibration Most process analyzers are designed to monitor concentration and/or composition. This requires a calibration of the analyzer with a set of prepared standards or from well-characterized reference materials. The simple approach must always be adopted first. For relatively simple systems the standard approach is to use a simple linear relationship between the instrument response and the analyte/ standard concentration [27]. In more complex chemical systems, it is necessary to adopt either a matrix approach to the calibration (still relying on the linearity of the Beer-Lambert law) using simple regression techniques, or to model the concentration and/or composition with one or more multivariate methods, an approach known as chemometrics [28-30]. 

Engineered variants of enzymes could be another approach in biosensor design for the discrimination and detection of various enzyme-inhibiting compounds when used in combination with chemometric data analysis using ANN. The crucial issues that should be addressed in the development of new analytical methods are the possibility of simultaneous and discriminative monitoring of several contaminants in a multi-component sample and the conversion of the biosensing systems to marketable devices suitable for large-scale environmental and food applications. 

Finally, in many cases the pyrolysis product distribution is so complex that it is not possible to separate and identify all of the components. In such cases a chemometric method, simply treating the pyrogram as a pattern, can be used to compare one sample with another. This approach has foimd many applications in forensic analysis, for example, of paints and in analysis of authenticity of art works (54). It has even been used to type bacteria (55-57). These applications often take advantage of the fact that the high sensitivity of the analytical method allows minute samples to be analyzed they depend upon a database of pyrograms obtained under well-controlled conditions and analysis involves a statistical pattern-matching approach. 

The exclusive use of chemometrics alone provides a weak basis for analytical science. When performing mnltivariate calibrations, analytically valid calibration models require a relationship between X (the instrument response data or spectral data) and Y (the reference data) probability tells us only if X and Y appear to be related. If no cause-effect relationship exists between X and Y, the analytical method will have no true predictive significance. Interpretation of NIR spectra provide the knowledge basis for understanding the cause-and-effect of molecular structure as it relates to specific types of absorptions in the NIR. Interpretive spectroscopy is a key intellectual process in approaching NIR measnrements if one is to achieve an analytical understanding of these measurements. This book represents onr best effort to provide the tools necessary for the analyst to interpret NIR spectra. 

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