Studies On Rapidly Dissolving Oral Films Of Sildenafil Citrate

Objective: To prepare and evaluate the rapidly dissolving oral films(RDOFs) of sildenafil citrate (SC) with polyvinyl alcohol/polyethyleneglycol graft copolymer (Kollicoat IR) as a film-forming material, andevaluate their disintegration time, dissolution rate, mechanical andphysicochemical properties.Method: The high performance liquid chromatographic (HPLC)method for analysis of SC was established. The blank RDOFs wereprepared by a solvent casting technique. The type and amount ofplasticizers and disintegrants were optimized on the basis of appearance,thickness, disintegration time and mechanical properties of the films.SC-loaded RDOFs with a loading capacity up to6.25mg in an area of6cm2was prepared, and the dissolution studies were carried out in buffersolution (pH1.2, pH6.8and pH7.4) using a paddle method for evaluatingthe dissolution rate of drug from RDOFs in vitro. The surface morphologyof RDOFs was visualized using scanning electron microscope (SEM). Thephysicochemical properties of RDOFs were also investigated using X-raydiffraction (XRD), fourier transform infrared spectroscopy (FT-IR),differential scanning calorimetry (DSC). Result: The linear equation of calibration curve wasA=24536C+4209.6（R2=0.9999），the intra-day precision was0.89-1.59%,the inter-day precision was1.19-1.33%, the average recovery rate was100.09%, and the drug solution was stable within24h. The Glycerol andsodium alginate (ALG-Na) were screened as a plasticizer and a disintegrantthrough a univariate design. The optimal ratio of Kollicoat IR︰Glycerol︰ALG-Na=10:1.5:2. The drug-loaded RDOFs with white semitransparentappearance showed good stripping and mechanical properties. Thethickness of drug-loaded film was74.3±2.4μm, and the disintegratingtime was25.2±1.2s. The results of XRD, FT-IR and DSC showed thatthere are some interactions between the drug and additives.Conclusion: The developed HPLC method show relatively high precision,recovery rate and stability. The RDOFs of SC were successfully preparedby a solvent casting method，and this study will provide the scientific basisfor developing a novel dosage form of SC.