Crystal Engineering for Enhanced Solubility and Bioavailability of Poorly Soluble Drugs

Background: Crystal engineering is dealing with the creation of new structures and new properties in drug molecules through inter-molecular interactions. Researchers of pharmaceutical sciences have used this knowledge to alter the structure of crystalline medications in order to remedy the problems of more than 40% of the new designed drugs which suffer from low solubility and consequently, low bioavailability which have limited their clinical application. Methods: This review covers a broad spectrum of aspects of the application of crystal engineering in pharmaceutics and includes a comprehensive wide range of different techniques used in crystal engineering of active pharmaceutical ingredients (API) to compensate the low water solubility and bioavailability of drugs related specially to class II of biopharmaceutical classification system (BCS). Results: These techniques include; crystalline habit modification, polymorphism, solvates and hydrates, cocrystals, surface modification, crystallization, spherical agglomeration, liquisolid crystals and solid dispersions which are introduced and discussed in this review article. Conclusion: Each of these techniques has advantages and limitations which are emphasized on them.