ABSTRACT
Equation 171 11.3. Eutectic Diagrams 172 11.4. Molecular Compounds 174 1l.5. Solid Solutions 175 11.6. Hydrous Amorphates 176 11.7. Lyophilization: Amorphous Cakes 176 1l.8. Immiscible Melts 178 11.9. Miscible Melts 179
11.10. Solid Solutions of the First Kind 182 11.11. Partially Miscible Melts 183 11.12. The Separated Phase: Solid Solutions of the Second Kind 184 11.13. Melts 184 11.14. Coprecipitates 185 11.15. Cogrinds 186 11.16. Dissolution of Solid Dispersions 186
Symbols 187 References 187
11.1. FREEZING OF IDEAL SOLUTIONS AND IDEAL SOLUBILITY
Before discussing melting point diagrams, a note on ideal solubility relations is in order. Assume that a crystalline substance A is dissolved in water, and assume that the two do not form solid solutions. If a plot is made of the mole fraction Xs at which one or the other solid phase (ice or drug) is in equilibrium with a solution, then a diagram such as shown in Fig. 11.1 results.
