Fabrication and Characterization of Polysorbate/Ironmolybdophosphate Nanocomposite: Ion Exchange Properties and pH-responsive Drug Carrier System for Methylcobalamin
Authors: Sharma Gaurav , Kumar Amit , Inamuddin  , Sood Mansi , Asiri Abdullah M. 
Published: July 2018

Background:

Nanocomposites are of great interest due to their competency to show multifunctional
properties. They have been recently given much attention due to their credibility to offer the synergistic
feature of organic material with those of inorganic constituents. Different types of nanocomposites have
been prepared to date and are being used for different applications. The delivery of drugs in the human body
at a particular site was one of the major problems in the medicinal field. The nanocomposite formulations
can be used to provide controlled release and they can be combined with ligands for targeted drug delivery.
Applications of the nanocomposites as ion exchangers are also increasing at a faster rate. Due to this, they
help in the softening of the water. They can also be easily recharged by washing them with a solution containing
a high concentration of sodium ions. In the present paper, we have worked on the synthesis and applications
of the polysorbate/ironmolybdophosphate (PS/FMP) nanocomposite.

Methods:

Polysorbate/ironmolybdophosphate (PS/FMPS) was synthesized by co-precipitation method in the
presence of polysorbate. The material was well characterized using X-ray diffraction (XRD) analysis, Fourier
transform infrared spectroscopy, (FTIR) scanning transmission microscopy (SEM), and transmission electron
microscopy (TEM). Physicochemical properties of material were studied in detail. Drug delivery behavior
of polysorbate/ironmolybdophosphate was investigated by using methylcobalamin as a test drug.

Results:

The polysorbate/ironmolybdophosphate nanocomposite show enhanced Na+ ion exchange capacity
of 2.1 meq/g. It has been revealed that PS/FMP nanocomposite was thermally stable as it retained the ion
exchange capacity of 40.4 % at 400°C. An optimum concentration of sodium nitrate (eluent) was found to
be 1.0 M for the complete removal of H+ ions from the PS/FMP column. The optimum volume of sodium
nitrate (eluent) was found to be 230 mL. The FTIR spectra showed the changes in intensities of characteristic
peaks in PS/FMP and in drug loaded on PS/FMP nanocomposite. The characteristic peak at 1043-1061
cm-1 was observed for ionic phosphate stretching, 560-567 cm-1 for iron group and 959 cm-1 due to molybdate
present in the material. The additional peak at 3390 cm-1 and 1711 cm-1 were due to -OH and C=O
stretching due to the presence of these groups in the structure of polysorbate. The peak present at 430 cm-1
might be due to the presence of Co-O stretching of methylcobalamin. The XRD results confirmed the semicrystalline
structure of FMP and PS/FMP. Scanning electron micrographs results revealed the beaded surface
of FMP changes to fibrous surface in case of PS/FMP nanocomposite. The TEM images indicate the
appearance of smooth surfactant layer on the surface of FMP. The size of the nanocomposite is between 10-
70 nm. The drug loading efficiency and encapsulation efficiency were found to be 35.2%. and 60.4%, respectively.
The cumulative drug release of methylcobalamin was studied for the PS/FMP nanocomposite.
The order of drug release was found to be pH 9.4 (54.6%) > pH 7.4 (46.4%) > saline (pH 5.7) (36.2%) > pH
2.2 (33.9%). The release at pH 9.4 was higher. As the pH of medium changes from acidic to basic i.e. 2.2 -
9.4, there is an appreciable increase in drug release from the PS/FMP nanocomposite due to the presence of
more OH- ions resulting in neutralization of cationic nanocomposite and thus increasing the rate of drug release
by ion exchange process and matrix deterioration.

:

The novel nanocomposite PS/FMP has been synthesized by a simple co-precipitation method.
The increase in Na+ ion exchange capacity for nanocomposite is due to the binding of organic part (Polysorbate)
with inorganic ironmolybdophosphate. The physiochemical properties of PS/FMP were found to be
superior. Fourier transform infrared spectra of PS/FMP and drug loaded PS/FMP confirmed the formation of
materials. The SEM results indicated the surface of synthesized FMP is bead-like appearance whereas the
beaded surface of FMP changes to fibrous surface on the addition of polysorbate thus indicated the fabrication
of nanocomposite. The cumulative drug release of methylcobalamin was studied and the order of drug
release was found to be pH 9.4 > pH 7.4 > saline (pH 5.7) > pH 2.2. Thus PS/FMP is a promising multifunctional
nanocomposite.