Determination of metabolic profiles of new chemical entities is a key step in the process of drug discovery, since it influences pharmacokinetic characteristics of therapeutic compounds. One of the main challenges of medicinal chemistry is not only to design compounds demonstrating beneficial activity, but also molecules exhibiting favourable pharmacokinetic parameters. Chemical compounds can be divided into those which are metabolized relatively fast and those which undergo slow biotransformation. Rapid biotransformation reduces exposure to the maternal compound and may lead to the generation of active, non-active or toxic metabolites. In contrast, high metabolic stability may promote interactions between drugs and lead to parent compound toxicity. In the present paper, issues of compound metabolic stability will be discussed, with special emphasis on its significance, in vitro metabolic stability testing, dilemmas regarding in vitro-in vivo extrapolation of the results and some aspects relating to different preclinical species used in in vitro metabolic stability assessment of compounds.

The serotonergic system is involved in pathomechanisms of both epilepsy and neuropathic pain. So far, participation in the epileptogenesis and maintenance of epilepsy was proved for 5-HT1A, 5-HT2C, 5-HT3, 5-HT4 and 5-HT7 receptors as well as 5-HTT serotonin transporter. Depending on the receptor type or its localization, its stimulation may increase or decrease neuronal excitability. According to the available data, neuropathic pain mechanisms involve 5-HT1A/1B/1D, 5-HT2A/2B/2C, 5-HT3, 5-HT4, 5-HT6, 5-HT7 receptors and 5-HTT serotonin transporter. Changes in their expression modulate pain mainly by affecting the transmission through serotonergic descending pathways. Several compounds, whose mechanisms of action base on influence on the serotonergic system, are already in use. These are 5-HT3 agonists (triptans) in case of migraine, tricyclic antidepressants or monoamine reuptake inhibitors in neuropathic pain treatment. In addition, selective and non-selective ligands are tested for their anticonvulsant or analgesic properties. Some ED50 values have been already obtained in such animal models as maximal electroshock (MES)-induced seizures (epilepsy), spinal nerve ligation (SNL), chronic constriction injury (CCI) or formalin (neuropathic pain). This review shows that in case of drug discovery within the serotonergic system one must take into account special significance of factors such as: the species, the type of model, the route of administration, and the dose range.

Beta-blockers are a very important group of drugs widely used for the treatment of cardiovascular diseases. All aryloxyaminopropanols are chiral and show different stereoselectivity in their pharmacodynamic and pharmacokinetic properties for each enantiomer. The more potent beta-adrenoceptor blocking activity is generally associated with (S)-enantiomers. Most beta-blocking agents are sold as racemates although (R)-enantiomers not only show in some cases lack of activity but might be responsible for undesirable effects. Among reports on the direct enzymatic resolution of the most representative beta-blocker propranolol, the most interesting is N-acetylation method with commercially available lipases to yield (S)-N-acetylpropranolol. Another type of the one-step (S)-isomer biocatalytic preparation from racemic mixture of propranolol is the biodegradation with the fungus. Biocatalytic methods of obtaining homochiral beta-blockers that are focused on production of versatile precursors are widely described in literature. The strategies based on the use of glycidol and derivatives as C-3 synthones have been shown to be extremely useful for the introduction of the 2-propanol chain on the aromatic system. Halohydrins are the established intermediates in the preparation of optically active beta-blockers. Its resolution by esterhydrolases has been used as a standard alternative in preparation of the homochiral propranolol. Additionally, the enzymatic resolution of the following intermediates was reported: 1-azido-3-aryloxy-2-propanols, 4-(1-aryloxy)-3-hydroxybutyric acid esters, glycerol and cyanohydrin derivatives. However, even the highly enantioselective lipase-catalyzed process can only provide 50% of the starting racemate in an optically active form. An alternative method such as a reduction of a prochiral ketone by various strains of yeast might quantitatively provide an enantiomeric product with a yield greater than 50%. The reported substrates for microbial reductions were: 1-halo-aryloxypropan-2-ones and 1-acetoxy-aryloxypropan-2-ones.

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Kolagen jest szeroko rozpowszechnionym zewnątrzkomórkowym białkiem zwierzęcym, stanowiącym główny komponent strukturalny skóry właściwej. Ze względu na swoje właściwości biologiczne jest powszechnie stosowany w przemyśle kosmetycznym, farmaceutycznym oraz medycynie estetycznej. Celem niniejszego artykułu było przedstawienie bieżącego stanu wiedzy na temat struktury oraz zastosowania kolagenu dla celów kosmetycznych oraz estetycznych. Materiał i metody: Przeszukanie wybranych baz danych z ograniczeniem wyników poszukiwań do ostatniej dekady. Wyniki: Opisano strukturę białka oraz wyszczególniono, jakie typy kolagenu budują tkankę skórną. Przedstawiono charakterystykę dwóch kategorii preparatów kolagenowych stosowanych dla celów kosmetycznych lub estetycznych: wypełniaczy tkankowych oraz nutriceutyków. Wnioski: Potencjał terapeutyczny, jaki kryje się w kolagenie, wykorzystywany jest w medycynie estetycznej od niemal 30 lat w mało inwazyjnych zabiegach z zastosowaniem wypełniaczy tkankowych. Stosowane produkty kolagenowe różnią się pochodzeniem białka, rodzajem jego modyfikacji, wskazaniami oraz długością trwania efektu. Najnowsze badania wskazują, że warto zwrócić uwagę na kolagen również w aspekcie suplementowania diety, które może wpływać korzystnie na opóźnienie efektów chronologicznego starzenia się skóry.