Abstract. The present paper was focused on exploiting Plackett-Burman design to screen the effect of nine factors-poly (ethylene oxide) molecular weight (X 1 ), poly (ethylene oxide) amount (X 2 ), ethylcellulose amount (X 4 ), drug solubility (X 5 ), drug amount (X 6 ), sodium chloride amount (X 7 ), citric acid amount (X 8 ), polyethylene glycol amount (X 9 ), and glycerin amount (X 11 ) on the release of drugs from the extended release extrudates, i.e., release rate and release mechanism. The experiments were carried out according to a nine-factor 12-run statistical model and subjected to an 8-h dissolution study in phosphate buffer pH 6.8. The significance of the model was indicated by the ANOVA and the residual analysis. Poly (ethylene oxide) amount, ethylcellulose amount and drug solubility had significant effect on the T90 values whereas poly (ethylene oxide) amount and ethylcellulose amount had significant effect on the n value.