*Modification of Physicochemical Properties of Active Pharmaceutical Ingredient… DOI: http://dx.doi.org/10.5772/intechopen.110129*

Because of the ability to tailor the physicochemical properties of the solid while preserving the chemical integrity of the medicine, co-crystals have sparked a great deal of interest in pharmaceutical research and development. Co-crystals are a subset of a larger category of multicomponent crystals, which are made up of two or more molecules that form a uniform crystalline lattice in a stoichiometric ratio that is clearly specified (often referred to as the drug and coformer). The drug and coformer are solid at higher temperatures than other types of multicomponent crystals like salt and solvates, and the intermolecular relationships in co-crystals are non-ionic in nature. Through co-crystallization, the variety of solid forms that can be produced from a medicine significantly expands; the physicochemical properties of co-crystals

**Figure 1.** *Formations of co-crystals [18].*

#### **Figure 2.**

*Crystalline forms exist in different forms: Amorphous form, polymorph of pure API, solvates/hydrate forms, salt form and pharmaceutical co-crystals [19].*

can change based on the properties of constituent molecules. Solubility, dissolution, moisture uptake, chemical stability, mechanical characteristics, and bioavailability are just a few of the pharmaceutically significant features that can change by cocrystallization. The most frequently praised property in literature is solubility [18]. The solubility restrictions of poorly soluble medicinal chemicals may be overcome through co-crystals (**Figures 1** and **2**).
