Chirality of pharmaceutical substances is an important aspect in drug research because it determines how enantiomers will interact with chiral biological targets. Enantiomers of a chiral drug can have different pharmacokinetic and pharmacological profiles; consequently, using a single pure enantiomer instead of a racemate can enhance the effectiveness and/or safety of the treatment. The tendencies of modern pharmaceutical industry regarding the current market of chiral drugs are divided between the chiral switch of previously used racemates and the development of new enantiopure drugs. The term chiral switch refers to the replacement on the market of a previously approved racemate with its single enantiomer version. The potential advantages of chiral switch can be related to a higher therapeutic index due to better potency, selectivity and fewer adverse effects, faster onset of action and exposure of the patient to lower drug dosages. However, chiral switch is also a strategy that permits manufacturers to keep market exclusivity for chiral pharmaceuticals that have lost their patent protection, even if the pure enantiomers have not demonstrated higher effectiveness or safety profile compared with the racemates.

The evolution of the class of antibacterial quinolones includes the introduction in therapy of highly successful compounds. Although many representatives were withdrawn due to severe adverse reactions, a few representatives have proven their therapeutical value over time. The classification of antibacterial quinolones into generations is a valuable tool for physicians, pharmacists, and researchers. In addition, the transition from one generation to another has brought new representatives with improved properties. In the last two decades, several representatives of antibacterial quinolones received approval for therapy. This review sets out to chronologically outline the group of approved antibacterial quinolones since 2000. Special attention is given to eight representatives: besifloxacin, delafoxacin, finafloxacin, lascufloxacin, nadifloxacin and levonadifloxacin, nemonoxacin, and zabofloxacin. These compounds have been characterized regarding physicochemical properties, formulations, antibacterial activity spectrum and advantageous structural characteristics related to antibacterial efficiency. At present these new compounds (with the exception of nadifloxacin) are reported differently, most often in the fourth generation and less frequently in a new generation (the fifth). Although these new compounds’ mechanism does not contain essential new elements, the question of shaping a new generation (the fifth) arises, based on higher potency and broad spectrum of activity, including resistant bacterial strains. The functional groups that ensured the biological activity, good pharmacokinetic properties and a safety profile were highlighted. In addition, these new representatives have a low risk of determining bacterial resistance. Several positive aspects are added to the fourth fluoroquinolones generation, characteristics that can be the basis of the fifth generation. Antibacterial quinolones class continues to acquire new compounds with antibacterial potential, among other effects. Numerous derivatives, hybrids or conjugates are currently in various stages of research.

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Through doping, we understand the use by athletes of substances prohibited by the antidoping agencies in order to gain a competitive advantage. Since sport plays an important role in physical and mental education and in promoting international understanding and cooperation, the widespread use of doping products and methods has consequences not only on health of the athletes, but also upon the image of sport. Thus, doping in sports is forbidden for both ethical and medical reasons. Narcotics and analgesics, anabolic steroids, hormones, selective androgen receptor modulators are among the most frequently utilized substances. Although antidoping controls are becoming more rigorous, doping and, very importantly, masking doping methods are also advancing, and these are usually one step ahead of doping detection techniques. Depending on the sport practiced and the physical attributes it requires, the athletes will look for one or more of the following benefits of doping: recovering from an injury, increasing body recovery capacity after training, increasing muscle mass and strength, decreasing fat tissue, increasing endurance. Finally, when we look once again at a doping scandal, amazed at how much animosity against those caught can exist; the question is: is it really such a disaster as presented by the media or a silent truth under our eyes, but which many of us have refused to accept?

The majority of modern antidepressants (selective serotonin reuptake inhibitors and selective serotonin and norepinephrine reuptake inhibitors) have one or two centers of asymmetry in their structure; resulting in the formation of enantiomers which may exhibit different pharmacodynamic and pharmacokinetic properties. Recent developments in drug stereochemistry has led to understanding the role of chirality in modern therapy correlated with increased knowledge regarding the molecular structure of specific drug targets and towards the possible advantages of using pure enantiomers instead of racemic mixtures. The current review deals with chiral antidepressant drugs; presenting examples of stereoselectivity in the pharmacological actions of certain antidepressants and their metabolites and emphasizing the differences between pharmacological actions of the racemates and pure enantiomers.