Physiochemical analysis

Those based on strictly empirical descriptions Mathematical models based on physical and chemical laws (e.g., mass and energy balances, thermodynamics, chemical reaction kinefics) are frequently employed in optimization apphcations. These models are conceptually attractive because a gener model for any system size can be developed before the system is constructed. On the other hand, an empirical model can be devised that simply correlates input-output data without any physiochemical analysis of the process. For... 

A basic investigation of growth behavior under pressure concerned with the physiochemical analysis of the liquid structure, and with the character of the crystals grown is needed. 

Jayraman, M., Seetharaman, J. Physiochemical analysis of the exopolysaccharides produced by a marine biofouhng bacterium. Vibrio alginolytics. Process Biochem 2003, 38(6), 841-847. 

Jackson, M. R., Balogh, M. P. and Potts, W. B., An Interactive Physiochemical Property Profiling Software for Early Candidate Analysis in Drug Discovery, American Society for Mass Spectrometry 2003 Conference Abstract, Montreal, Canada, 2003. 

Regression equations descriptive of multi-dimensional structure/ activity relationships in quantitative terms too frequently are intellectual curiosities developed retrospectively after work in optimization of the biological properties of a series by analog or homolog synthesis has been completed. Retrospective analysis serves well to document that critical factors in the relationship between structural features/physiochemical factors and biological potency are well understood and that optimum compounds have been achieved. Structure/activity understanding developed during the course of a synthesis project, however, lends direction and efficiency to the property optimization effort. 

KORZHINSKII (D.S.), 1959. Physiochemical basis of the analysis of the paragenesis of minerals.(trans) New York Consultants Bureau. 

As part of the preformulation activities, investigations include physiochemical character, purity, solubility, stability, and optimal pH studies. In preparation for clinical studies, potential product formulations considering route of administration and solution stability are also studied. Unique to dosage form development studies for lyophilized products, thermal analysis of the drug substance and product formulations are also necessary. Data generated during this phase of product development is useful for future development activities, along with validation. 

Development studies, summarized within a distinct report on the physiochemical aspects, drug substance attributes, and finished product characteristics, become critical parts of the validation package. Such data is also valuable for future integration into a manufacturing operation. This includes the scientific rationale for formulating and bulk-handling procedures, lyophilization processing parameters, finished product analysis, and stability requirements. 

A number of reviews can be consulted for an introduction to the fundamentals both theoretical and practical covering XPS. These include Riggs and Parker (2) and the book by Carlson (3). Electron spectroscopy is reviewed in alternate years in the Fundamental Reviews issue of Analytical Chemistry. The last literature review was published in 1980 (4) and this and previous reviews can be consulted for a coverage of all aspects of the literature of XPS. A number of recent symposia have been held on applications of surface analytical methods in various aspects of materials science such as the symposium on characterization of molecular structures of polymers by photon, electron, and ion probes at the March 1980 American Chemical Society meetings in Houston ( 5) and the International Symposium on Physiochemical Aspects of Polymer Surfaces at this meeting as well as the symposium on industrial applications of surface analysis of which this article is a part. Review articles on various applications of XPS in materials science are listed in Table I. 

The classical QSAR methodology started 1964 with the publications of Hansch and Fujita (1964) and Free and Wilson (1964) and the statement of Hansch (1969) resulted from a proposal by Fujita. They proposed to combine several physiochemical parameters (tt, a), also called descriptors, in a quantitative model. This Hansch-type analysis is very flexible and describes many different kinds of biological activities, e.g. in vitro data such as enzyme inhibition (Kubinyi 2002) ... 

Further development of methods for optimisation of the technological characteristics of foams can be achieved knowing their relation with the physiochemical properties of foams, since the same regularities and procedures, already described in the analysis of the principles of controlling them can be applied. 

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