Risk assessment report of potential impurities in cetirizine dihydrochloride.

Recently, the European Medicines Agency (EMA) and the U.S. Food and Drug Administration (FDA) had reported on "unexpected" impurities in a couple of sartans, ranitidine, and metformin. These events led to a lot of discussion with regard to the risk assessment for the production process itself. Most of these discussions covered the field of nitrosamine impurities only, but that would be too short-sighted. One should expand that scope. It is impossible to synthesize a 100 % pure compound which holds true for all active pharmaceutical ingredients (APIs). Different synthetic routes result in different impurity profiles. Therefore, pharmacopoeias try to consider all possible impurities that can arise from different drug synthesis routes in one a single monograph for impurity assessment. However, API manufacturers cannot simply rely on the impurity profile reported in pharmacopoeias for the production of a high-quality product. They have to implement a whole risk assessment to rate the presence of impurities in the API. Here, a strategy to evaluate and minimize the load of potential risks of impurities during the manufacturing process of the drug substance cetirizine dihydrochloride within the frame of a detailed risk assessment report is demonstrated.

Covalent anchoring of chloroperoxidase and glucose oxidase on the mesoporous molecular sieve SBA-15.

Functionalization of porous solids plays an important role in many areas, including heterogeneous catalysis and enzyme immobilization. In this study, large-pore ordered mesoporous SBA-15 molecular sieves were synthesized with tetraethyl orthosilicate (TEOS) in the presence of the non-ionic triblock co-polymer Pluronic P123 under acidic conditions. These materials were grafted with 3-aminopropyltrimethoxysilane (ATS), 3-glycidoxypropyltrimethoxysilane (GTS) and with 3-aminopropyltrimethoxysilane and glutaraldehyde (GA-ATS) in order to provide covalent anchoring points for enzymes. The samples were characterized by nitrogen adsorption, powder X-ray diffraction, solid-state NMR spectroscopy, elemental analysis, diffuse reflectance fourier transform infrared spectroscopy and diffuse reflectance UV/Vis spectroscopy. The obtained grafted materials were then used for the immobilization of chloroperoxidase (CPO) and glucose oxidase (GOx) and the resulting biocatalysts were tested in the oxidation of indole. It is found that enzymes anchored to the mesoporous host by the organic moieties can be stored for weeks without losing their activity. Furthermore, the covalently linked enzymes are shown to be less prone to leaching than the physically adsorbed enzymes, as tested in a fixed-bed reactor under continuous operation conditions.

Formation of cross-linked chloroperoxidase aggregates in the pores of mesocellular foams: characterization by SANS and catalytic properties.

No escape: The formation of cross-linked chloroperoxidase aggregates (CPO-CLEAs) in the pores of mesocellular foam materials results in active biocatalysts that are more resistant to leaching than the conventional catalyst prepared by physisorption of chloroperoxidase. Small-angle neutron scattering (SANS) experiments clearly confirm that the CPO-CLEAs are located in the pores of the mesocellular foams.