Recent Research Progress of Chiral Small Molecular Antitumor-Targeted Drugs Approved by the FDA From 2011 to 2019

Chiral drugs usually contain chiral centers, which are present as single enantiomers or racemates. Compared with achiral drugs, they have significant advantages in safety and efficacy with high stereoselectivity. Of these drugs, chirality not only exerts influence on the solubility and pharmacokinetic characteristics but also has specific mechanistic characteristics on their targets. We noted that small molecules with unique chiral properties have emerged as novel components of antitumor drugs approved by the FDA in decade. Since approved, these drugs have been continuously explored for new indications, new mechanisms, and novel combinations. In this mini review, recent research progress of twenty-two FDA-approved chiral small molecular-targeted antitumor drugs from 2011 to 2019 is summarized with highlighting the potential and advantages of their applications. We believe that these updated achievements may provide theoretical foundation and stimulate research interests for optimizing drug efficacy, expanding clinical application, overcoming drug resistance, and advancing safety in future clinical administrations of these chiral targeted drugs.

Advances on Greener Asymmetric Synthesis of Antiviral Drugs via Organocatalysis

Viral infections cause many severe human diseases, being responsible for remarkably high mortality rates. In this sense, both the academy and the pharmaceutical industry are continuously searching for new compounds with antiviral activity, and in addition, face the challenge of developing greener and more efficient methods to synthesize these compounds. This becomes even more important with drugs possessing stereogenic centers as highly enantioselective processes are required. In this minireview, the advances achieved to improve synthetic routes efficiency and sustainability of important commercially antiviral chiral drugs are discussed, highlighting the use of organocatalytic methods.

Enantioresolution and Binding Affinity Studies on Human Serum Albumin: Recent Applications and Trends

The interaction between proteins and drugs or other bioactive compounds has been widely explored over the past years. Several methods for analysis of this phenomenon have been developed and improved. Nowadays, increasing attention is paid to innovative methods, such as high performance affinity liquid chromatography (HPALC) and affinity capillary electrophoresis (ACE), taking into account various advantages. Moreover, the development of separation methods for the analysis and resolution of chiral drugs has been an area of ongoing interest in analytical and medicinal chemistry research. In addition to bioaffinity binding studies, both HPALC and ACE al-low one to perform other type of analyses, namely, displacement studies and enantioseparation of racemic or enantiomeric mixtures. Actually, proteins used as chiral selectors in chromatographic and electrophoretic methods have unique enantioselective properties demonstrating suitability for the enantioseparation of a large variety of chiral drugs or other bioactive compounds. This review is mainly focused in chromatographic and electrophoretic methods using human serum albumin (HSA), the most abundant plasma protein, as chiral selector for binding affinity analysis and enantioresolution of drugs. For both analytical purposes, updated examples are presented to highlight recent applications and current trends.

Advances on Greener Asymmetric Synthesis of Antiviral Drugs via Organocatalysis

Viral infections inflict many serious human diseases, being responsible for remarkably high mortality rates. In this sense, both the academy and the pharmaceutical industry are continuously searching for new compounds with antiviral activity, and in addition, face the challenge of developing greener and more efficient methods to synthesize these compounds. This becomes even more important with drugs possessing stereogenic centers as highly enantioselective processes are required. In this minireview, the advances achieved to improve synthetic routes efficiency and sustainability of important commercially antiviral chiral drugs are discussed, highlighting the use of organocatalytic methods.

Alginate Metal Complexes and Their Application

Alginate is a natural polymer that can form complexes in the presence of multivalent metal. In this chapter, we summarized the newest alginate metal complexes application in many fields; organic synthesis, environmental and medical application. The main idea was about alginate complexes’ role in the drug delivery system as a chiral excipient to reach the enantioselective release in the case of chiral drugs. We also present a case study about the ketoprofen enantioselective release investigation from alginate mixed beads with two ion metal types.

A Computational and Literature-Based Evaluation for a Combination of Chiral Anti-CoV Drugs to Block and Eliminate SARS-CoV-2 Safely

<p><a>It has been a great challenge for scientists to develop an anti-covid drug/vaccine with fewer side effects, since the coronavirus began. Of course, the prescription of chiral drugs (chloroquine or hydroxychloroquine) has been proved wrong because these chiral drugs neither kill the virus nor eliminate it from the body, but block SARS-CoV-2 from binding to human cells. Another hurdle in front of the world, is not only the positive test of the patient recovered from coronavirus but also the second wave of Covid 19. Hence, the word demands such a drug or drug combination which not only prevents the entry of SARS-CoV-2 in the human cell but also eliminates it or its material from the body completely. The presented computational study explains (i) why the prescription of chiral drugs was not satisfactory (ii) what types of modification can make their prescription satisfactory (iii) the mechanism of action of chiral drugs (chloroquine and hydroxychloroquine) to block SARS-CoV-2 from binding to human cells, and (iv) the strength of mefloquine to eliminate SARS-CoV-2. As the main protease (M<b>^pro</b>) of microbes is considered as an effective target for drug design and development, the binding affinities of mefloquine with the main proteases (M^pros) of JC virus and SARS-CoV-2, were calculated, and then compared to know the eliminating strength of mefloquine against SARS-CoV-2. The main protease (M^pro) of JC virus was taken because mefloquine has already shown a tremendous result of eliminating it from the body. The current study includes the docking results and literature data in support of the prescription of a combination of S-(+)-hydroxychloroquine and (+) mefloquine. Besides, the presented study also confirms that the prescription of only hydroxychloroquine would not be so effective as in combined form with mefloquine.</a></p>

On the Separation of Enantiomers by Drift Tube Ion Mobility Spectrometry

<p><a>Racemic mixtures of twelve common </a>a-amino acids and three chiral drugs were tested for the separation of their enantiomers by ion mobility spectrometry (IMS)-quadrupole mass spectrometry (MS). Separations were tested by introducing chiral selectors in the mobility spectrometer buffer gas. (R)-α-(trifluoromethyl) benzyl alcohol, (R)-tetrahydrofuran-2-carbonitrile, (L)-ethyl lactate, methyl (S)-2-chloropropionate, and the R and S enantiomers of 2-butanol and 1-phenyl ethanol were evaluated as chiral selectors. Experimental conditions were varied during the tests including buffer gas temperature, concentration, and type of chiral selectors, analyte concentration, electrospray voltage, electrospray (ESI) solvent pH, and buffer gas flow. The individual enantiomers yielded different drift times for periods of up to 8 hours in a few experiments; such drift times were sufficiently different (~ 0.3 ms) to partially resolve the enantiomers in racemic mixtures, but these mixtures always yielded a single mobility peak at the experimental conditions tested with a drift time similar to that of one of the enantiomers. Energy calculations of the chiral selector –ion interactions showed that these separations are unlikely using 2-butanol as chiral selector but they might be feasible depending on the nature of chiral selectors and the type of enantiomers.</p>

On the Separation of Enantiomers by Drift Tube Ion Mobility Spectrometry

<p><a>Racemic mixtures of twelve common </a>a-amino acids and three chiral drugs were tested for the separation of their enantiomers by ion mobility spectrometry (IMS)-quadrupole mass spectrometry (MS). Separations were tested by introducing chiral selectors in the mobility spectrometer buffer gas. (R)-α-(trifluoromethyl) benzyl alcohol, (R)-tetrahydrofuran-2-carbonitrile, (L)-ethyl lactate, methyl (S)-2-chloropropionate, and the R and S enantiomers of 2-butanol and 1-phenyl ethanol were evaluated as chiral selectors. Experimental conditions were varied during the tests including buffer gas temperature, concentration, and type of chiral selectors, analyte concentration, electrospray voltage, electrospray (ESI) solvent pH, and buffer gas flow. The individual enantiomers yielded different drift times for periods of up to 8 hours in a few experiments; such drift times were sufficiently different (~ 0.3 ms) to partially resolve the enantiomers in racemic mixtures, but these mixtures always yielded a single mobility peak at the experimental conditions tested with a drift time similar to that of one of the enantiomers. Energy calculations of the chiral selector –ion interactions showed that these separations are unlikely using 2-butanol as chiral selector but they might be feasible depending on the nature of chiral selectors and the type of enantiomers.</p>

A Computational and Literature-Based Evaluation for a Combination of Chiral Anti-CoV Drugs to Block and Eliminate SARS-CoV-2 Safely

It has been a great challenge for scientists to develop an anti-Covid drug/vaccine with fewer side effects, since the coronavirus pandemic began. Of course, the prescription of chiral drugs (chloroquine or hydroxychloroquine) has been proved wrong because these chiral drugs neither kill the virus nor eliminate it from the body, but block SARS-CoV-2 from binding to human cells. Another hurdle facing the world is not only the positive test of the patient recovered from coronavirus, but also the second wave of Covid-19. Hence, the world demands such a drug or drug combination which not only prevents the entry of SARS-CoV-2 in the human cell but also ejects it or its material from the body completely. The current computational study not only utilizes a structure-based drug design approach to find possible drug candidates but also explains (i) why the prescription of chiral drugs was not satisfactory, (ii) what types of modification can make their prescription satisfactory, (iii) the mechanism of action of chiral drugs (chloroquine and hydroxychloroquine) to block SARS-CoV-2 from binding to human cells, and (iv) the strength of mefloquine to eliminate SARS-CoV-2. As the main protease (M[Formula: see text]) of microbes is considered as an effective target for drug design and development, the binding affinities of mefloquine with the M[Formula: see text] of JC virus and SARS-CoV-2 were calculated, and then compared to know the eliminating strength of mefloquine against SARS-CoV-2. The M[Formula: see text] of JC virus was taken because mefloquine has already shown a tremendous result of eliminating it from the body. The prescription of a combination of S-[Formula: see text]-hydroxychloroquine and [Formula: see text]-mefloquine is considered as a boon by the predicted study.