Aqueous based polymeric dispersion: Plackett--Burman design for screening of formulation variables of atenolol gastrointestinal therapeutic system.

Bilayered osmotically controlled Gastrointestinal Therapeutic System of atenolol has been obtained by using cellulose acetate pseudolatex prepared by polymer emulsification method. Various factors such as orifice size, coating thickness, amount and nature of polymeric excipients, and amount of osmotic agent influence the drug release from GITS. Therefore, in the present study a 7-factor, 12-run Plackett-Burman screening design was employed to evaluate the formulation variables for atenolol GITS coated with CA pseudolatex. The variables studied were orifice size, %coating weight gain, amounts of sodium chloride. Polyox N80 and 303, and Carbopol 934P and 974P on drug release. The screening design has revealed that orifice size, %coating weight gain and amount of Carbopol 934P have prominent influence on in-vitro atenolol release. The response variable was cumulative percent atenolol released (Y) in 24 h with constraints on percent release at 2, 6, 12 and 18 h. The polynomial equation obtained was Y24 = 149.82 - 0.13 X1 - 0.34X2 + 0.06X3 - 0.13X4 - 0.23X5 - 76.25X6 - 2.46X7. The results indicated that the drug release under constrained conditions was influenced by the factors with decreasing order of importance as %coating weight gain > Carbopol 934P > Polyox N80 > Carbopol 974P > Polyox 303 > amount of sodium chloride > orifice size.