Foreign Medicine and Pharmacy Volume, No.4, 198, Crystal Change and Crystal Addiction of Drugs and Their Important Effects on Drug Quality and Clinical Efficacy, is it a document, or is it a book tingzai116 (in-station contact TA)? Odorless chloramphenicol has the following crystal forms:
Type A (? 8? Type 5): the stable type is difficult to be hydrolyzed by esterase in the intestine, difficult to be absorbed, and has low biological activity.
type b (? 8? Type 4): Metastable type is easy to be hydrolyzed by esterase, and its dissolution rate is faster than that of type A, and it is easy to be absorbed, and its blood concentration is 7 times that of type A, with high curative effect.
type c: unstable type, which can be converted into type a. Xiaohaojydl (in-station contact TA) crystal form has great influence on drug absorption and metabolism. In addition, the patent crystal form is protected and needs to be avoided. Solid, insoluble and oral drugs need to be studied in crystal form. Cyj115 (in-station contact TA) cimetidine < P > crystal form A and crystal form AB, the literature reports that there is a big difference between the two crystal forms in vivo absorption. In clinic, crystal form A (USP is crystal form A) hcxcjw (in-station contact TA) is generally used. I recommend you a relatively easy-to-use drug crystal form research instrument, Crystal16 parallel crystallization instrument of Dutch company represented by Liyang Enterprise Co., Ltd., which can measure solubility curve and metastable zone width. Polymorph screening can also be carried out. Polymorphs of
chenpi886 (in-station contact TA) pharmaceutical substances such as * * * crystallization research and anti-solvent crystallization have different physical and chemical properties, such as melting point, chemical reactivity, apparent solubility
1, dissolution, optical and mechanical properties, vapor pressure and density. These properties will directly affect the quality and preparation of drugs, as well as the stability, dissolution and bioavailability of drugs. Therefore, the phenomenon of polycrystal < P > will affect the quality, safety and effectiveness of drugs. The solid properties of drug substances will have an important impact on their apparent solubility. Polymorphs have different internal solid structures, so the water solubility and dissolution of different polymorphic drugs are different. If the apparent solubility of different polymorphs is different, we suggest paying attention to its potential impact on the bioavailability and bioequivalence of the preparation.