Fast disintegrating tablets of nisoldipine for intra-oral administration

Nisoldipine is a calcium channel blocker with low and variable oral bioavailability. This was attributed to slow dissolution and presystemic metabolism. Accordingly, the objective of this work was to enhance the dissolution rate of nisoldipine to formulate fast disintegrating tablets with rapid dissolution. Binary solid dispersions (SD) were prepared for the drug with hydroxypropyl methyl cellulose E5 (HPMC), polyvinylpyrrolidone (PVP), Pluronic F68 or polyethylene glycol 6000 (PEG 6000). SD formation increased the dissolution rate compared to pure drug with the corresponding physical mixtures failing to provide the same dissolution enhancement. This indicates that the SD enhanced dissolution is not due to the solubilizing effect of the polymer and can be due to physical change in the drug crystal which was confirmed by thermal analysis. SD with HPMC and PVP were selected for preparation of fast disintegrating tablets as they liberated most of the drug in the first 5 min. HPMC-based tablets disintegrated rapidly and released most of the drug in the first 2 min which correlated with the corresponding SD. In contrast, PVP-based tablets disintegrated slowly with gradual dissolution. This can be attributed to the binding effect of PVP. The study developed fast disintegrating tablet for intra-oral administration.