Background: Drug loaded microparticles are widely used to improve the therapeutic value of
various water soluble/insoluble drugs and provides sustained drug release for longer duration of time.
Objective: To develop Diclofenac sodium (DS) loaded - ethylcellulose microparticles.
Method: Diclofenac sodium (DS) loaded ethylcellulose microparticles were prepared by oil-in-water
solvent evaporation method using design of experiments. The effect of three formulation variables (independent
variables) like amount of DS, ethylcellulose (EC) and polyvinyl alcohol (PVA) was investigated
using 23 experimental design to enhance the encapsulation efficiency (E.E.) (dependent variable)
Results: The microparticles were evaluated for surface morphology, E.E., and in vitro drug release. The
physicochemical characteristics of the microparticles were assessed using Fourier transform infrared
spectroscopy (FTIR), X-ray powder diffractometry (XRPD), and Field emission scanning electron microscopy.
The E.E. of the microparticles was ranged from 37.21 ± 0.87% to 72.20 ± 1.32%. An optimum
combination of formulation variables are predicted as 1000 mg DS, 1000 mg EC and 0.1% w/v of
PVA, which corresponds to E.E. of 73.71 ± 3.5 % and suitably sustained the DS delivery.
Conclusion: The microparticles were found discrete and spherical. The absence of drug polymer interaction
was confirmed by FTIR spectroscopy. The XRPD revealed the distribution of drug within the microparticles
formulation. In vitro drug release from microparticles showed a sustained drug release pattern
over a period of 16 h with initial burst effect.