Formulation of Diclofenac Sodium-Loaded Ethylcellulose Microparticles Using 23 Factorial Design Approach

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) of microparticles. 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.