Background: Nowadays, the polymorphism of solid materials plays important roles in pharmaceutical field, food industry, fine chemicals and so on. Due to the differences in crystal structure, different polymorphs of a given solid drug show different physicochemical characteristics, which may lead to different drug bioavailability and half-life of the drug. Studies about polymorphism of solid drugs have become an indispensable important component in dosage form design, approval, production and quality control of drugs.
Methods: In order to reveal the dissimilarity between polymorphs, the classification approach of polymorphism and the features of each category are outlined and discussed in this paper. The influence of polymorphism on physicochemical characteristics of solid drugs such as powder property, melting point, enthalpy of fusion, dissolution behavior and stability are discussed in detail. Furthermore, a variety of differences in drug bioavailability and curative effect of polymorphs are also summarized and discussed.
Results: Due to the differences in internal crystalline structure, different polymorphs of the same solid drugs generally show different physicochemical properties, including powder property, melting point, enthalpy of fusion, dissolution behavior and stability. Furthermore, different polymorphs of solid drugs often exert a diverse curative effect.
Conclusion: As one of the significant factors to affect the quality and curative effect of solid drugs, polymorphism of drug substances has been investigated in the pharmaceutical field for over 50 years. Considerable studies indicate that comprehensive understanding of polymorphism is important for development, dosage form design, approval, production, quality control and curative effect of solid drugs.