Table 2.

Summary of the type of polymers influencing the behavior and release characteristics of multilayered tablets.

Type of Polymer Used as Drug Carrier	Type of Polymer Used in Barrier Layers	Type/Dimensions of Tablet	Drug Release Achieved
Hydrophilic	Hydrophilic	Bilayered tablet	Extended drug release
Hydrophilic	Hydrophobic	Bilayered tablet	Drug release retarded to lesser extent
Hydrophobic	Hydrophilic (Methocel® K4M)	Triple-layered tablet	Zero-order drug release kinetics
Hydrophobic (CW)	hydrophobic (carnauba wax)	Triple-layered tablet	Non-linear drug release
Hydrophobic (CW)	Hydrophilic (Methocel® K15M) and Hydrophobic (CW)	Triple-layered tablet	Zero-order drug release kinetics.
Hydrophilic (HPMCAS&HPMC)	Hydrophobic (EC)	Triple-layered tablet	Zero-order release kinetics.