Abstract:
A highly water-soluble antihypertensive drug,
metoprolol tartrate (MT), was selected as a model drug for
preparation of multi-walled carbon nanotubes (MWCNTs)-
impregnated ethyl cellulose (EC) microspheres. The present investigation was aimed to increase encapsulation
efficiency of MT with excellent adsorbent properties of
MWCNTs. The unique surface area, stiffness, strength and
resilience of MWCNTs have drawn much anticipation as
carrier for highly water-soluble drugs. Carbon nanotubes
drug adsorbate (MWCNTs:MT)-loaded EC microspheres
were further optimized by the central composite design of
the experiment. The effects of independent variables
(MWCNTs: MT and EC :adsorbate) were evaluated on
responses like entrapment efficiency (EE) and t50 (time
required for 50% drug release). The optimized batch was
compared with drug alone EC microspheres. The results
revealed high degree of improvement in encapsulation
efficiency for MWCNTs: MT-loaded EC microspheres.
In vitro drug release study exhibited complete release form
drug alone microspheres within 15 h, while by the same
time only 50–60% drug was released for MWCNTs impregnated EC microspheres. The optimized batch was
further characterized by various instrumental analyses such
as scanning electron microscopy, powder X-ray diffraction
and differential scanning calorimetry. The results endorse
encapsulation of MWCNTs: MT adsorbate inside the matrix
of EC microspheres, which might have resulted in
enhanced encapsulation and sustained effect of MT. Hence,
MWCNTs can be utilized as novel carriers for extended
drug release and enhanced encapsulation of highly watersoluble drug, MT
