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Introduction A model process was previously described [ 1 – 8 ] for transfer of qualitative–semiquantitative thin-layer chromatography (TLC) screening methods for pharmaceutical products with quality defects contained in the

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Abstract  

The physico-chemical properties and polymorphism of a new active pharmaceutical ingredient entity has been analyzed and the gain of knowledge during the chemical development of the substance is described. Initial crystallization revealed an anhydrous crystal form with good crystallinity and a single, sharp DSC melting peak at 171C and a straightforward development of this crystal form seemed possible. However, during polymorphism screening, new crystalline forms were detected that were often analyzed as mixtures of crystal forms. The process of characterization and identification of the different crystalline forms and its thermodynamical relationship has been supported by a combination of experimental and computational work including determination of the three-dimensional structures of the crystal forms. The crystal structure of one polymorphic form was solved by single crystal X-ray structure analysis. Unfortunately, Mod B resisted in formation of suitable single crystals, but its structure could be solved by high resolution powder diffraction data analysis using synchrotron radiation. Calculation of the theoretical X-ray powder diffraction pattern from three dimensional crystal coordinates allowed an unambiguous identification of the different crystalline forms. Two polymorphic crystal forms of the API-CG3, named Mod A and Mod B, are enantiotropic whereas Mod B is the most stable polymorph at room temperature up to about 50C and Mod A at temperatures above 50C. The mechanism of the solid-solid transition can be explained by analyzing the molecular packing information gained from the single crystal structures. A third crystalline form with the highest melting peak turned out to be not a polymorphic or pseudopolymorphic crystal modification of our API-CG3 but a chemically different substance.

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) anticipated that almost half of the worldwide pharmaceutical market is involved with substandard drugs [ 5 ]. Among the most important drugs that are involved in such a problem are antimalarial drugs. In some developing African nations, the available malaria

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A simple and rapid TLC method has been developed for determination of acyclovir in pharmaceutical preparations. After extraction of the analyte with a 9:1 ( v/v ) mixture of 96% alcohol and 0.05 m H 2 SO 4 the extracts were applied to precoated silica gel TLC plates which were then eluted with n -butanol-glacial acetic acid-water, 15 + 9 + 6 ( v/v ). Quantitative evaluation was performed by measuring the absorbance-reflectance of the analyte spots at λ = 277 nm. This TLC-densitometric method is selective, precise, and accurate and can be used for routine analysis of pharmaceutical preparations in pharmaceutical industry quality-control laboratories.

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We report a new combination of overpressured-layer chromatography (OPLC) with near-infrared (NIR) spectroscopy for pharmaceutical analysis. Different pharmaceutical preparations containing caffeine, paracetamol, and acetylsalicylic acid as model compounds were separated by OPLC. The band density in the solid phase after OPLC was suitable for study of the separated components directly on the layer by NIR spectroscopy.We have demonstrated the applicability of rapid OPLC separation combined with UV densitometry and NIR spectroscopy for both qualitative and quantitative analysis. This OPLC-UV-NIR technique is thus suitable for rapid, nondestructive investigation of multicomponent pharmaceutical preparations and enables a different type of pharmaceutical analysis, e.g. starting-material tests, in-process control, end-product control, stability testing, etc. Another benefit of this newly developed combination of rapid off-line techniques is the possibility of simultaneous collection of qualitative and quantitative chromatographic and spectral information.

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Introduction A model process was previously developed [ 1 – 3 ] for transferring visual, semiquantitative thin-layer chromatography (TLC) screening methods for pharmaceutical products with quality defects in the Global Pharma

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