bilayered patches

Bilayer mucoadhesive buccal patches of lamotrigine were prepared by solvent casting technique using different polymers like PVA, PVP K30, pullulan, carbopol and HPMC 5cps. These formulations were prepared and evaluated for various parameters like weight variation, visual inspection, content uniformity, surface pH, bioadhesive strength, in-vitro and ex-vivo diffusion studies. It was found that F3 (PVA 3% and PVP K30 2%) and F4 (PVA 4% and PVP K30 1%) formulations showed good physical, mechanical properties and sustained drug release profile of about 85% and 80% in 8 hours. The formulation was found to follow zero order model dependent kinetics with Fickian diffusion. Ex-vivo diffusion studies were conducted using Franz diffusion cell. Ex vivo diffusion studies were conducted using goat buccal mucosa. The formulations containing PVA and PVP K30 in 3:2 and 4:1 ratio and 10% of PG as a plasticizer was found to be optimized which showed 66% and 60% of drug release in 8 hours. These formulations have shown bioadhesive strength of 0.06N and 0.09N and good bioadhesion time up to 6-7 hours respectively. These formulations were found to be zero order model dependent kinetics with anomalous transport as release mechanism. Lag time, cumulative amount permeated/area, flux and permeability coefficient for optimized formulations were found to be 30 & 40 min, 1336 & 1212 µg/cm², 2.18 &  2.24 µg/cm²/min and 639x10-4 & 904x10-4 cm/min respectively. Key words: Mucoadhesive patches, lamotrigine patches, bilayered patches, diffusion studies.