what is * * * crystal?
according to the definition, * * * crystal is a regularly arranged crystalline material formed by two or more molecules in the same lattice through a certain force. Generally speaking, these molecules are divided into active pharmaceutical components and * * * crystal forms. * * * crystal is an effective way to change the solubility, melting point, hygroscopicity, compressibility, density and other physical and chemical properties of some drugs.
what is the difference between * * * crystal and salt?
the figure below shows the classification of solid forms. Among them, the difference between * * * crystals and salts is that the molecules are bound together by supramolecular interaction (rather than ionic interaction). From the point of view of physical chemistry and regulations, * * * crystal can be regarded as a special case of solvate and hydrate, in which the second component, namely * * * crystal ligand, is not a solvent (including water) and is usually not volatile.
Figure 1: Classification of solid forms
FDA's guiding principles for drugs in * * * crystal form
According to the guidance of the US Food and Drug Administration, for new drug applications and generic drug applications containing or having * * * crystal form, the applicant should submit the corresponding data of the following contents:
● Provide evidence to prove that active drug components and * * * crystal ligands exist in the cell at the same time.
● If both the API and the * * * crystal ligand have ionizable functional groups, then the API components and the * * * crystal ligand * * exist in the non-ionic interaction crystal.
● Ensure that the active pharmaceutical ingredients are largely separated from the crystal before reaching the pharmacologically active site. In view of the similarity between the interaction between active pharmaceutical ingredients and crystal ligands and the interaction between active pharmaceutical ingredients and solvents in solvates, generally speaking, in vitro evaluation based on solubility or solubility is enough to prove that active pharmaceutical ingredients are separated from crystal ligands before reaching pharmacological active sites.
a * * * crystal formed by a * * * crystal ligand that meets the above conditions and is acceptable in pharmacology can be called a drug * * * crystal. Its regulatory classification is similar to the polymorphism of active pharmaceutical ingredients. Specifically, it is not a new active pharmaceutical ingredient. From the regulatory point of view, products containing new crystal drugs are similar to the new polymorph of active pharmaceutical ingredients. A crystal composed of two or more active pharmaceutical ingredients is not a new single active pharmaceutical ingredient, but a combined product with a fixed dose.
research on the preparation of * * * crystals
besides supervision, it is essential for pharmaceutical companies to prepare * * * crystals efficiently. Generally, preparation methods are divided into solid-based methods and solution-based methods, and the choice of specific preparation methods depends on the properties of molecules. It can be predicted that the research on the preparation method of drug crystals will become the next research hotspot.
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Please click on the English version: What do you want to know about * * * Crystal?
In the past, I recommended
the application of Raman spectroscopy in the study of crystal forms of solid suspension preparations
What? It turns out that there are obvious differences between the amorphous forms of the same drug!
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Shenzhen Xinyang Weikang Technology Co., Ltd. is a new enterprise focusing on crystal screening, dosage form innovation and "nondestructive reverse analysis of original drugs" in consistency evaluation. Xinyang Weikang was founded in 215 with the rapid reform and development of China pharmaceutical industry. It has a standardized laboratory of 1,1 square meters. As a Sino-European joint company, we try our best to provide tailor-made technical services for pharmaceutical companies. Our vision is to bring high-end, high-quality drugs to the China market and provide high-quality solid-state technical services to the global pharmaceutical industry.