Clustering of Tadalafil API Samples According to their Manufacturer in the Context of API Falsification Detection.

This paper reports the results of the active pharmaceutical ingredient (API) fingerprint study, organised by the General European Official Medicines Control Laboratory Network (GEON), on tadalafil. A classical market surveillance study, evaluating compliance to the European Pharmacopoeia, was combined with a fingerprint study, the latter to obtain characteristic data for the different manufacturers, allowing the network laboratories to conduct authenticity tests for future samples, as well as to detect substandard and falsified samples. In total, 46 tadalafil API samples from 13 different manufacturers were collected. For all samples fingerprint data was collected through analysis of impurities and residual solvents, mass spectrometric screening, X-ray powder diffraction and proton nuclear magnetic resonance (1H-NMR). Chemometric analysis revealed that all manufacturers could be characterised based on the impurity, residual solvent and 1H-NMR data. Future suspicious samples in the network will therefore be analysed with these techniques in order to attribute the sample to one of the manufacturers. If the sample cannot be attributed, a more profound investigation will be necessary to reveal the origin of the sample. In cases where the suspect sample is claimed to be from one of the manufacturers included in this study, analysis can be limited to the test distinguishing that manufacturer.

Synthesis and cholinesterase inhibitory activity of 6-, 7-methoxy-(and hydroxy-) tacrine derivatives.

Some 6- and 7-methoxy-(and hydroxy-) tacrine derivatives were synthesized and evaluated for their in vitro acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activities. The most potent analogue in our series was the 9-heptylamino-6-methoxytacrine 3af which, in comparison with tacrine (THA), displayed an almost identical inhibitory effect, slightly lower acute toxicity and higher selectivity profile towards AchE when compared with THA.

Behavioral and electrophysiological effects of the adenosine A2A receptor antagonist SCH 58261 in R6/2 Huntington's disease mice.

The effect of chronic treatment with the selective adenosine A2A receptor antagonist SCH 58261 on the behavioral and electrophysiological alterations typical of R6/2 mice (a transgenic mouse model of Huntington's disease, HD), has been studied. Starting from 5 weeks of age, R6/2 and wild type (WT) mice were treated daily with SCH 58261 (0.01 mg/kg i.p.) for 7 days. In the following weeks, the ability of mice to perform in the rotarod, plus maze and open field tests were evaluated. In addition, with electrophysiological experiments in corticostriatal slices we tested whether the well-known increased NMDA vulnerability of R6/2 mice was prevented by SCH 58261 treatment. We found that chronic treatment with SCH 58262: i) fully prevented the alterations in emotional/anxious responses displayed by R6/2 mice; ii) did not prevent the impairment in motor coordination; iii) abolished the increase in NMDA-induced toxicity observed in the striatum of HD mice. On balance, targeting A2A receptors seems to have some beneficial effects in HD even though, given the complexity of A2A receptor pharmacology and HD pathogenesis, further studies are necessary to clarify whether A2A receptor antagonists have therapeutic potential in HD.