Iron oxide induced enhancement of mucoadhesive potential of Eudragit RLPO: formulation,evaluation and optimization of mucoadhesive drug delivery system

Objectives: The objective of the study was to investigate the effect of iron oxide in the development of mucoadhesive tablets of cinnarizine using Eudragit RLPO polymer. A simplex lattice design was employed for optimizing the drug delivery system.

Methods: Different concentrations of Eudragit RLPO (X₁), iron oxide (X₂) and PVP K 30 (X₃) were taken as independent variables and mucoadhesive strength, t_50%, t_90%, MDT and tablet tensile strength were the selected response variables. Contour and 3D plots were drawn to portray the relationship between independent and response variables. Ex vivo studies were performed for the determination of mucoadhesive strength of formulated tablets employing texture analyzer. ATR-FTR, DSC and zeta potential determination were conducted for drug-excipient and ionic interaction studies.

Results: Friability, hardness and tensile strength of mucoadhesive tablet formulation were found to be 0.42 ± 0.21%, 3.93 ± 1.57 kg/cm² and 0.65 ± 0.26 mN/m², respectively. Mucoadhesive strength was found to be ranging between 5.75 ± 4.41 and 42.85 ± 3.94 g. Value of release exponent (n) was found to be 0.65 ± 0.22, indicating anomalous drug release behavior from the formulations. Numerical optimization using the desirability approach was employed for developing optimized formulation by setting constraints of the dependent and independent variables. The mucoadhesive tablet formulation composition consisting of 8.58% w/w Eudragit RLPO, 7.02% w/w iron oxide and 7.26% w/w PVP K 30 fulfilled maximum requirements of an optimum formulation with better regulation of the selected constraints.

Conclusions: Eudragit RLPO and iron oxide combination showed high level potential for fabricating gastroretentive as well as mucoadhesive drug delivery systems.