The objective of proposed study was to prepare Bilayer tablet comprising Amitriptyline HCl (AMT) and pregabalin (PGB) for effective treatment of neuropathic pain. AMT was formulated as immediate release (IR) layer using disintegrants such as starch whereas PGB was formulated as sustained release (SR) layer using polymers hydroxypropyl methyl cellulose (HPMC) K100M for increasing with a view to deliver the drug at sustained manner in gastrointestinal tract and consequently into systemic circulation. Tablet blends were evaluated through various pre-compression tests, compressed by wet granulation method and evaluated. As disintegrant, starch at 14.70% concentration produced excellent results by immediately releasing AMT to exert its anti-depression and other additional beneficial effects. K100M grade of HPMC produced excellent SR efficiency at 1:1 drug-polymer ratio whereas extended of the dosage form for long-lasting effect of the therapeutic agent. Final formulation released 98.92% drug in 45 min and 97.27% drug in 12 h, in vitro from respective layers. Pre-compression and post-compression parameters of optimized IR layer comprising AMT and SR layer comprising PGB exhibit satisfactory results. Bilayer tablet of AMT and PGB may prove to be very effective as a combination therapy for the treatment of neuropathic pain by sequential release of the drug.
Keywords: Bilayer tablets, Amitriptyline HCl, Pregabalin