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The present study deals with the application of X-ray powder diffraction (XRPD) analysis as a technique for identification of the forms of clopidogrel bisulphate (CLP) present in both the active pharmaceutical ingredients (API) and tablets, specifically addressing the question of whether API converts to another form after 12 months of storage. The investigation of the possibility of phase transitions occurring over a temperature range spanning from room temperature to the melting point, both in tablets and pure CLP, were also performed. Tablet samples were observed for the changes in their structure using polarizing optical microscopy, which was also used to determine the melting points of tablet samples. The results gained during this work confirm that XRPD is applicable for API and tablets testing. This is particularly important if we take into account that the method can be used during stability studies, i.e. in order to test the quality of tablets during the validity period. [ABSTRACT FROM AUTHOR]

Two series of binary mixtures composed of bent shaped and rod like molecules are reported. The first star shaped bent core molecules were synthesized and used as a component of binary mixtures. The chiral rod like compounds having commensurable length with the arms of the bent core compounds have been chosen for these mixtures. The resulted compositions show various thermotropic liquid crystalline phases that are characteristic to both types of liquid crystalline materials. In case of mixing the rod like molecules to the bent core compound the B2, B7 and induced B1 phases have been observed. While using the star-shaped bent core and chiral rod like compounds in mixture, the paraelectric smectic A, ferroelectric smectic C* and orthogonal hexatic smectic B phases were preferred. The appearing mesophases were investigated by differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction methods. [ABSTRACT FROM AUTHOR]

Abstract: New chiral thiols with three aromatic rings and the azo group in the molecular core have been synthesized and grafted on polybutadiene diols backbone. The resulting diols possess the OH end groups promising for preparation of the liquid crystal ordered networks. The mesomorphic and physical properties of the synthesized thiols and resulting diols have been studied by polarizing optical microscopy, differential scanning calorimetry, X-ray studies and dielectric spectroscopy. The resulting side-chain diols show the liquid crystalline behaviour. The effects of side-chain structure of the thiols and density of grafting on the polybutadiene diols has been studied and discussed. [Copyright &y& Elsevier]