Effect of pregelatinized starch on dissolution of paracetamol extended release bilayer tablets

  • Tawatchai - Thiptinnakorn Huachiew Chalermprakiet University
  • Patcharida Wangnonglad
  • Rujagorn Wasombat
Keywords: Bilayer tablets, Matrix, Extended release, Paracetamol, Hydroxyethyl cellulose, Pregelatinized starch


This research was conducted to study on the effect of pregelatinized starch on dissolution of paracetamol extended release bilayer tablets consisting of the immediate and extended release layers. Both layers were prepared by wet granulation method. Extended release layer was prepared by using hydroxyethyl cellulose as matrix former at 3.75 percent of extended release layer weight. Pregelatinized starch was used as disintegrant with concentrations of 0, 1.5, 2 and 2.5 percent by weight. In vitro release studies were performed using USP 40 type II apparatus and compared with USP 40 specification. The results indicated that the release rate was increased according to the higher concentration of pregelatinized starch. The tablets with pregelatinized starch 2.5 percent performed the similar dissolution profile compared to the innovator. Both innovator and the formulated tablet with pregelatinized starch 2.5 percent were conformed the accepted criteria at the  level  L1 of  USP 40. The dissolution test result was compared to the innovator to determine the difference factor ( ), and similarity factor ( ). The difference factor was 3 and the similarity factor was 78. The release kinetics indicated that release form the matrix tablets was followed by Fickian diffusion. The mechanism of drug release through the matrix was found to be diffusion swollen and erosion controls. In this study, hydroxyethyl cellulose 3.75 percent as a matrix former and pregelatinized starch 2.5 percent as disintegrant would be benefit for the extended release layer. Thus, the extended release bilayer tablets could be a potential dosage form for delivering paracetamol