1. Figure 9.1 V-shaped pH–stability profile for hydrolysis of atropine (redrawn from Connors et al. (1986)).

2. Figure 9.2 Sigmoidal pH-stability profile for hydrolysis of cycloserine in dilute solution (redrawn from Kondrat’eva et al. (1971), with kind permission from Springer+Business Media B.V.).

3. Figure 9.3 Double bell-shaped pH–stability profile for hydrolysis of aztreonam (redrawn from Connors et al. (1986)).

4. Figure 9.4 pH profile for the hydrolysis of aspirin, showing V-shaped behaviour at extremes of pH and sigmoidal behaviour in between (redrawn from Connors et al. (1986)).

5. Figure 9.5 The effect of various antioxidants, chelating agents and antioxidant/ chelating agent mixtures on the formation of peroxides in oil of terebinth (redrawn from Fryklöf (1954)).

6. Figure 9.6 Decomposition profile for a drug substance degrading via zero-order kinetics.

7. Figure 9.7 Decomposition profile for a drug substance degrading via first-order kinetics and (inset) the linear plot of ln (drug remaining) versus time.

8. Figure 9.8 Decomposition profile for a drug substance degrading via second-order kinetics and (inset) the linear plot of 1/drug remaining versus time.

9. Figure 9.9 Definition of hygroscopicity profiles.

10. Figure 9.10 Energy diagrams for exothermic and endothermic reactions at a given temperature.

11. Figure Maxwell–Boltzmann distribution of energies at two temperatures (T2 > T1). The fraction of molecules (area under the curve) possessing energies above Ea will react upon collision.

12. Figure An Arrhenius plot constructed with rate data determined at 40, 50 and 60 °C and the extrapolation to room temperature.

13. Figure Increase in temperature required to increase the rate of reaction (relative to the rate at 25 °C) for reactions with activation energies of 50, 75 and 100 kJ mol−1.

14. Figure Work-flow diagram for performing a drug substance–excipient compatibility screen with DSC.