10.5 Quantitative Assessment of Enantioselective
Transformation
The changes in the enantiomeric composition with distance and time are often
forming a basis for pursuing and understanding the mechanism of the
enantioselective transformation of pharmaceuticals (Kasprzyk-Hordern 2010;
Gasser et al. 2012; Andres-Costa et al. 2017; Sanganyado et al. 2017; Castrignano
et al. 2018a, b; Liang et al. 2019; Ma et al. 2020). Two approaches are assumed to
regulate and document shifts in the enantiomer composition of pharmaceuticals in
the environment:
1. EF/time and concentration/time profiles and
2. Determination of enantiomer ratios or EF values that can show concentrationdependent relations. Both approaches may be simplified and combined using the
Rayleigh equation (Jammer et al. 2014) as shown below.
ln ER t =ER 0 ¼ ε ER ¼ ln C t =C 0
The amount of biotransformation (ln ER t /ER 0 ) is directly proportional to the
extent of enantiomer enhancement (ln C t /C 0 ) with the enantiomer enhancement
factor ε ER (a compound-specific parameter proportionality constant). Current
researches have indicated that biotransformation of metoprolol and venlafaxine
showed a Rayleigh dependence (Gasser et al. 2012; Souchier et al. 2016). This
result supports the assumption that ε ER may be used as a quantitative and qualitative
device for measuring enantioselective transformation of chiral pharmaceuticals in
the environment (Souchier et al. 2016). Jammer et al. (2014) confirmed that ε ER may
be forecasted using molecular descriptors. Therefore, Rayleigh equation may be
utilised to calculate ε ER for chiral metabolites of pharmaceuticals with recognised
Rayleigh equation variables. Future studies may emphasise the application of the
Rayleigh equation as a quantitative valuation tool for enantioselective transformation and as a predictive model in environmental risk evaluation.
10.6 Economic Growth
The economic development of many western countries is directly related to an
eco-friendly environment, health and disease-free atmosphere. Consequently, to
avoid any illnesses and miss-happenings owing to antagonistic chirality effects, it
is important to pay attention to chiral contaminants in our environment (Beary and
Eaton 1992; Caldwell et al. 2007; Calcaterra and D’Acquarica 2018). As deliberated
above, many chiral pollutants are carcinogenic and may generate severe problems.
Consequently, ignorance of this aspect may negatively influence the economic
growth.
10.6 Economic Growth
291
Transformation
The changes in the enantiomeric composition with distance and time are often
forming a basis for pursuing and understanding the mechanism of the
enantioselective transformation of pharmaceuticals (Kasprzyk-Hordern 2010;
Gasser et al. 2012; Andres-Costa et al. 2017; Sanganyado et al. 2017; Castrignano
et al. 2018a, b; Liang et al. 2019; Ma et al. 2020). Two approaches are assumed to
regulate and document shifts in the enantiomer composition of pharmaceuticals in
the environment:
1. EF/time and concentration/time profiles and
2. Determination of enantiomer ratios or EF values that can show concentrationdependent relations. Both approaches may be simplified and combined using the
Rayleigh equation (Jammer et al. 2014) as shown below.
ln ER t =ER 0 ¼ ε ER ¼ ln C t =C 0
The amount of biotransformation (ln ER t /ER 0 ) is directly proportional to the
extent of enantiomer enhancement (ln C t /C 0 ) with the enantiomer enhancement
factor ε ER (a compound-specific parameter proportionality constant). Current
researches have indicated that biotransformation of metoprolol and venlafaxine
showed a Rayleigh dependence (Gasser et al. 2012; Souchier et al. 2016). This
result supports the assumption that ε ER may be used as a quantitative and qualitative
device for measuring enantioselective transformation of chiral pharmaceuticals in
the environment (Souchier et al. 2016). Jammer et al. (2014) confirmed that ε ER may
be forecasted using molecular descriptors. Therefore, Rayleigh equation may be
utilised to calculate ε ER for chiral metabolites of pharmaceuticals with recognised
Rayleigh equation variables. Future studies may emphasise the application of the
Rayleigh equation as a quantitative valuation tool for enantioselective transformation and as a predictive model in environmental risk evaluation.
10.6 Economic Growth
The economic development of many western countries is directly related to an
eco-friendly environment, health and disease-free atmosphere. Consequently, to
avoid any illnesses and miss-happenings owing to antagonistic chirality effects, it
is important to pay attention to chiral contaminants in our environment (Beary and
Eaton 1992; Caldwell et al. 2007; Calcaterra and D’Acquarica 2018). As deliberated
above, many chiral pollutants are carcinogenic and may generate severe problems.
Consequently, ignorance of this aspect may negatively influence the economic
growth.
10.6 Economic Growth
291