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K. Singhal and A. Kumar
16.3 MNPs as Catalyst or Supportive Catalyst in Drug
Synthesis
The emergence of nano-science has developed numerous useful applications in life
science and healthcare fields which push the scientists to design the different types
of required drugs by using nanoparticles (NPs) at the molecular and cellular levels
[60]. In a drug synthesis reaction, it is quite necessary that the catalyst used in the
particular reaction be easily separated out and also increases the reaction rate. In
this context, NPs display excellent catalytic properties due to their large surface area
which provide good conversion rate per catalyst molecule and allow an elevated
rate of reaction [61]. Despite all these advantages, the toxic nature of NPs needs
their separation from reaction mixture [60]. Actually, NPs form a stable suspension
with reaction medium which causes some difficulties to remove these NPs from
reaction mixture, so to solve this problem the magnetic properties are developed
in the NPs for their easy separation from reaction media [61]. MNPs one of the
most widely used and highly studied group of NPs, have attracted significant attention as catalytic support in modern medical and pharmaceutical fields due to their
effective super-paramagnetic properties. MNP catalysts work in quasi homogeneous
manner and meet the drawbacks of both homogeneous and heterogeneous phase. The
characteristics for promising candidate of MNPs in catalytic systems are their less
toxic nature, nano nature, large surface to volume ratio, high specific surface area,
and facile separation from reaction media. Under external magnetic field the MNPs
show strong magnetic moment and easily precipitated in reaction vessel which allow
the readily separation of MNPs by simple magnetic separation process. The magnetic
nature of MNPs leads to the production of high purity drugs with less waste since
the probability of covalent binding of catalysts (like ILs) on MNPs surface reduces
the dispersion of catalysts in the reaction mixture. Moreover, magnetic separation of
MNPs from reaction media supports the easy and simple purifications process when
compared with centrifugation and tedious filtration of catalysts which reduces the
reaction time and the cost of production.
Catalysts are generally expensive and hence, their use in drug synthesis process
affects the cost of developed drug, so the recycling and reusing of catalyst is highly
needful. MNPs due to their easy removal from reaction media are able to reuse several
times with good efficacy [62]. A series of metals (Co, Ni, Fe), alloys (CoPt 3 and FePt),
metal oxide (Fe 3 O 4 and γFe 2 O 3 ), and spinel-type ferromagnet (MgFe 2 O 4 , MnFe 2 O 4 ,
and CoFe 2 O 4 ) are used in the preparation of these MNPs. To prevent the undesired
aggregation of MNPs and to controlled the morphology of MNPs, catalysts can be
loaded onto MNP by co-precipitation or modification of MNP shell during their
synthesis, this type of catalysts is called as ‘MNP supported catalysts’ [63]. These
MNP supported catalysts display higher production yield with excellent catalytic
activity due to their well dispersion in both aqueous and organic reaction media and
could also be easily separated from the media due to their magnetic nature [64]. These
catalysts can be reused up to eight cycles in a same synthesis reaction without loss
of catalytic activity (i.e. >99% yield for each cycle) and show high efficiency (95%
K. Singhal and A. Kumar
16.3 MNPs as Catalyst or Supportive Catalyst in Drug
Synthesis
The emergence of nano-science has developed numerous useful applications in life
science and healthcare fields which push the scientists to design the different types
of required drugs by using nanoparticles (NPs) at the molecular and cellular levels
[60]. In a drug synthesis reaction, it is quite necessary that the catalyst used in the
particular reaction be easily separated out and also increases the reaction rate. In
this context, NPs display excellent catalytic properties due to their large surface area
which provide good conversion rate per catalyst molecule and allow an elevated
rate of reaction [61]. Despite all these advantages, the toxic nature of NPs needs
their separation from reaction mixture [60]. Actually, NPs form a stable suspension
with reaction medium which causes some difficulties to remove these NPs from
reaction mixture, so to solve this problem the magnetic properties are developed
in the NPs for their easy separation from reaction media [61]. MNPs one of the
most widely used and highly studied group of NPs, have attracted significant attention as catalytic support in modern medical and pharmaceutical fields due to their
effective super-paramagnetic properties. MNP catalysts work in quasi homogeneous
manner and meet the drawbacks of both homogeneous and heterogeneous phase. The
characteristics for promising candidate of MNPs in catalytic systems are their less
toxic nature, nano nature, large surface to volume ratio, high specific surface area,
and facile separation from reaction media. Under external magnetic field the MNPs
show strong magnetic moment and easily precipitated in reaction vessel which allow
the readily separation of MNPs by simple magnetic separation process. The magnetic
nature of MNPs leads to the production of high purity drugs with less waste since
the probability of covalent binding of catalysts (like ILs) on MNPs surface reduces
the dispersion of catalysts in the reaction mixture. Moreover, magnetic separation of
MNPs from reaction media supports the easy and simple purifications process when
compared with centrifugation and tedious filtration of catalysts which reduces the
reaction time and the cost of production.
Catalysts are generally expensive and hence, their use in drug synthesis process
affects the cost of developed drug, so the recycling and reusing of catalyst is highly
needful. MNPs due to their easy removal from reaction media are able to reuse several
times with good efficacy [62]. A series of metals (Co, Ni, Fe), alloys (CoPt 3 and FePt),
metal oxide (Fe 3 O 4 and γFe 2 O 3 ), and spinel-type ferromagnet (MgFe 2 O 4 , MnFe 2 O 4 ,
and CoFe 2 O 4 ) are used in the preparation of these MNPs. To prevent the undesired
aggregation of MNPs and to controlled the morphology of MNPs, catalysts can be
loaded onto MNP by co-precipitation or modification of MNP shell during their
synthesis, this type of catalysts is called as ‘MNP supported catalysts’ [63]. These
MNP supported catalysts display higher production yield with excellent catalytic
activity due to their well dispersion in both aqueous and organic reaction media and
could also be easily separated from the media due to their magnetic nature [64]. These
catalysts can be reused up to eight cycles in a same synthesis reaction without loss
of catalytic activity (i.e. >99% yield for each cycle) and show high efficiency (95%