Objective: The objective of the present investigation was to develop drug loaded Eudragit® RS100 nanosuspension as a sustained release carrier.
Methods: All the nanosuspensions of Naproxen loaded Eudragit® RS100 were prepared using the quasi emulsion solvent diffusion technique at different drug: polymer ratios. The formulation was optimized using design of experiments by employing a 2-factor, 3-level factorial design. The drug: polymer ratio (X1) and speed of homogenization(X2), were the independent variables; particle size (Y1), zeta potential (Y2) and entrapment efficiency (Y3) as dependent variables. The nanosuspensions were studied for particle size analysis, X-ray diffraction analysis and surface morphology by scanning electron microscopy. The in vitro release study of Naproxen from nanosuspension was carried out using dialysis bag with molecular weight cut-off value of 12,000 to 14,000 Daltons.
Results: Average particle size of nanosuspension was between 159 to 435nm and zeta potential ranges from 20.7 to 53.5 mV. The statistical analysis of data revealed that drug: polymer ratio(X1) has a significant positive influence on particle size (p=0.0077) whereas a negative influence on zeta potential (p=0.0045) and Entrapment efficiency (p=0.0003). The developed model was validated using two check point formulations and found no significant difference between the predicted and observed values. An optimized formulation was also identified during the study.
Conclusion: This investigation demonstrated the potential of the experimental design in understanding the effect of formulation variables on the development of Nanosuspensions. The results assures, nanosuspension are promising sustained release system to the naproxen and many other drugs
