Stability studies overview

Abstract This chapter addresses the principles of stability studies in the drug development process. It gives an overview of different types of stability studies that support the entire drug development phases. It also discusses the purpose that one wants to achieve with the data set that these studies generate. 

Chapter 9 gives an overview of the Pharmacopeia of the United States of America (USP) and its USP-NF requirements for stability purposes. This chapter also discusses the development process for monographs, the goals for the general chapters, and relevant testing used for stability studies. 

Chapter 10 covers non-chromatographic test methods used to monitor stability studies. This chapter also recommends practical practices for appropriate physical testing methods. An overview of dissolution testing is also included. 

Chapter 11 introduces an overview of spectroscopic tests used to support stability studies. These types of testing have gained more attention in recent years to provide additional understanding of drug substance and drug product stability. 

Abstract The purpose of this chapter is introducing the goal of stability testing and its role in the Drug Development Process. It gives a brief overview of how stability studies are designed to support the development and commercialization of a new medicine. This chapter also acquaints the reader to the content of this book. 

For products described in a pharmacopoeia, the official specifications can and should be used for the product file, with referral to the official source. The same applies to preparations from standard formulatimis, in which quality requirements are included. For in-house formulations, the quality requirements have to be set by an appropriately competent person internally. Useful information can be found in the formulatimi or validatimi studies. The results of stability studies may be useful when setting the quality requirements for the product, because the premise is that a preparation should comply to the quality requirements throughout the whole shelf life. An overview of the applicable quality requirements, including supporting information, has to be included in the product file. In addition it should be specified how the packaging and labelling are checked, and how and with what analytical method the product quality is controlled. Additionally the validation of the analytical methods is included in this section of the product file. 

A review by Dong et al. [3.57] provides an overview of how Fourier transform JR spectroscopy can be used to study protein stabilization and to prevent lyophilization- induced protein aggregation. An introduction to the study of protein secondary structures and the processing and interpretation of protein IR spectra is given. 

A large number of techniques have been used to investigate the thermodynamic properties of solids, and in this section an overview is given that covers all the major experimental methods. Most of these techniques have been treated in specialized reviews and references to these are given. This section will focus on the main principles of the different techniques, the main precautions to be taken and the main sources of possible systematic errors. The experimental methods are rather well developed and the main problem is to apply the different techniques to systems with various chemical and physical properties. For example, the thermal stability of the material to be studied may restrict the experimental approach to be used. 

An overview ofthe properties ofthe materials we are studying is presented in Table 18.11. The objective of this work was to find new approaches to the problem of generating new media with low dielectric constants and high thermal stabilities for use as interlayer dielectrics in microelectronic interconnection applications. We have been partially successful in this quest but there is still much more work to be done. The materials we have been able to deposit remain to be characterized in frill detail, which includes not only elucidating their molecular structure but also measuring the panoply of physical properties necessary for practical applications. 

On the other hand, the origin of the promoter metal and metal oxide effects is not always clear, despite the many detailed characterization studies. In what follows, we will give first a possible definition of the different promotion phenomena described in literature, as well as their mode of operation. The second part deals with an extensive literature overview of the effect of each promoter element on the F-T activity, selectivity and stability of the active Co phase. The different modes of operation will be evaluated for each element. Special attention will be paid to noble metal and transition metal oxide promotion effects. 

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