Advances in Quantitative Analytical Methods for Solid Drugs

The solid form of the drug can directly affect the physicochemical properties, bioavailability, safety, and efficacy of the drug, and its types mainly include amorphous state, single-component polycrystalline, hydrate, solvate, salt, and cocrystal. Polymorphic drugs are solid drugs whose active ingredients exist in a specific crystalline state. Polymorphic drugs are solid drugs whose active ingredients exist in a specific crystalline state. Drug polymorphism refers to the presence of two or more different crystalline states of the drug. Pharmaceutical cocrystal is a new type of solid form that can improve the stability, solubility, and bioavailability of active pharmaceutical ingredients and many other physicochemical properties. The determination of the crystalline form of a drug and its content is of great significance in ensuring the quality of the polymorphic drug and its safety. In this paper, the quantitative analysis methods of polymorphs and pharmaceutical cocrystals are reviewed, the advantages and disadvantages of various methods are analyzed mainly from three types of techniques, namely, X-ray diffraction, spectroscopy, and thermal analysis, and the specific applications of various methods are commented on through examples. The analytical methods that can effectively determine the content of polymorphic drugs are comprehensively mastered to provide a reference for the establishment of quality standards for polymorphic drugs.