Evaluation and Characterization of Sildenafil 50 mg Orodispersible Tablets Using Sublimation Technique

Objective: The aim of this work focused on formulation and evaluation of sildenafil 50 mg orodispersible tablets by sublimation technique. Methods: Active ingredient and excipients mixtures were evaluated for physicochemical changes of the drug utilizing FTIR spectroscopy and DSC thermal analysis. Nineteen proposed formulae N1-N19 were prepared by sublimation technique using menthol as a sublimating agent. Three different types of superdisintegrants (sodium starch glycolate, croscarmellose sodium and plasidone XL) were used in three different ratios (3, 6 and 9 % w/w), percentage of inter-granular and intragranular disintegrant. Hydrophilic filler such as mannitol and hydrophobic filler such as microcrystalline cellulose were used in the ratio (1:1, 2:1 and 4:1 w/w).Elimination of bitterness using sucralose as a potent sweetener. Granulation was achieved by alcoholic solution of PVP K25 as binder at Diosna® high shear mixer. Lubricant (hydrophobic magnesium stearate and hydrophilic sodium stearyl fumarate). Un-lubricated granules were characterized for bulk density, tapped density, true density, particle size distribution, Carr'sindex, Hausner ratio, flow rate and angle of repose. Tablets were firstly compressed on rotary machine then subjected to vacuum oven at 60ᵒC for 6 hours. Post compression characterization for tablets after sublimation including content uniformity, average weight, hardness, thickness, In-vitro disintegration, friability, wetting time, assay and dissolution profile of the proposed formulae against the immediate release marketed tablet Viagra ® 50 mg tablet. Results: The formula (N 16) which granulated using 1% PVP k25 with 9% plasidone XL (60% of it is inter-granular while 30% intra-granular), menthol 1%, Microcrystalline cellulose: Mannitol 1:1 and magnesium stearate was the most effective formulation as it showed wetting time of 30.7 seconds, disintegration time of 25 seconds and cumulative % drug release of 92.8 and 95.8 % after 1 and 3 minute respectively. Conclusion: Sildenafil 50 mg ODT successfully was prepared by sublimation technique with better wetting time, disintegration time, assay dissolution profile, hardness and friability.