Description
It is now just about 10 years since the publication of the fi rst edition of Polymorphism in Pharmaceutical Solids, which certainly received a positive reaction from workers in drug development. Since then, Joel Bernstein and Rolf Hilfi ker have published their books on polymorphic phenomena, and the fi eld has continued to expand both in the number of works published and also in the depth of their coverage. Some things have not changed, however, and the effects of crystal structure on the solid-state properties of a given system remains of paramount importance. As I stated in the preface to the first edition, the heat capacity, conductivity, volume, density, viscosity, surface tension, diffusivity, crystal hardness, crystal shape and color, refractive index, electrolytic conductivity, melting or sublimation properties, latent heat of fusion, heat of solution, solubility, dissolution rate, enthalpy of transitions, phase diagrams, stability, hygroscopicity, and rates of reactions are all strongly infl uenced by the nature of the crystal structure.
The content of the present edition of Polymorphism in Pharmaceutical Solids has expanded to refl ect the larger scope of topics having interest to development scientists. The book is now divided into six main sections, the fi rst dealing with thermodynamic and theoretical issues. Within this initial section, one will fi nd updated chapters from the fi rst edition, “Theory and Principles of Polymorphic Systems” and “Application of the Phase Rule to the Characterization of Polymorphic and Solvatomorphic Systems.” Refl ecting the growing trend in predictive science, a new chapter entitled “Computational Methodologies: Toward Crystal Structure and Polymorph Prediction” is now featured in this section.
The second section of the new edition features preparative methods for polymorphs and solvatomorphs, and the single chapter of the fi rst edition has been split into two chapters entitled “Classical Methods of Preparation of Polymorphs and Alternative Solid Forms” and “Approaches to High-Throughput Physical Form Screening and Discovery.” In the next section, one will fi nd chapters relating to the structural properties of polymorphs and solvatomorphs, updating the chapters from the fi rst edition, “Structural Aspects of Polymorphism” and “Structural Aspects of Solvatomorphic Systems.” With greater interest developing about the advantageous properties of co-crystal systems, it was appropriate to expand the structural section to include a new chapter entitled “Pharmaceutical Co-crystals: A New Opportunity in Pharmaceutical Science for a Long-Known but Little-Studied Class of Compounds.”