Active pharmaceutical ingredients solid-state properties

Another advantage of SS-NMR is that the observed chemical shift differences between polymorphs can be related to particular molecular sites based on known assignments (see Figure 6). Site-specific mobility can also be determined by probing the relaxation properties of the compound. This is an important application, since mobility is usually related to polymorphic interconversions and solid-state reactions.94 Solid-state reactions between active pharmaceutical ingredients and excipients can also be followed by SS-NMR. The study of polymorphic transitions can be performed by variable temperature experiments. 

There are a number of chemistry books available related to computational materials science and to modeling of molecular solid state, but none of the books cover current pharmaceutical industry applications. The intention of this book is to highlight the importance of the computational pharmaceutical solid-state chemistry and to fiU the gap in the current hterature. The book examines the state-of-the-art computational approaches to guide and analysis of solid form experiments and to optimize the physical and chemical properties of active pharmaceutical ingredient (API) related to its stability, bioavailability, and formulatability. While aU methods and approaches described in the book appear to be state of the art, the book is... 

Salts, and more recently co-crystals, have attracted much interest in the pharmaceutical industry for their promise in tailoring the physical properties of an active pharmaceutical ingredient (API) to meet the needs of the drug product and ultimately the patient.Salt forms, produced by add (A)-base (B) reactions in the solid state, are multi-component solids comprising minimally an A B pair they may be crystalline or amorphous. The term co-crystal, on the other hand, refers specifically to crystalline molecular complexes, which may include an A B pair among the different components and by definition necessarily include solvates (hydrates), inclusion compounds, clathrates and solid solutions. 

Although therapeutic efficacy is the primary concern for an active pharmaceutical ingredient (API), the solid state form i.e., the crystalline or amorphous form) of an API can be critical to its pharmacological properties, such as bioavailability, and to its development as a viable drug candidate. Recently,... 

In the following pages, an attempt will be made to describe many of the properties of the solid state that come into play and need to be considered when formulating low-dose pharmaceuticals. The solid forms may be broadly classified as crystalline and amorphous and then describe the solid-state techniques used in their characterization. Many of the quantitative aspects and their respective advantages and disadvantages will be described. Finally, a few approaches will be described that may be used to investigate the effect of formulation on the low-dose active ingredient in the tablet. 

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