Silodosin oral films: Development, physico-mechanical properties and in vitro dissolution studies in simulated saliva
Sublingual film dosage forms for drugs used for fast symptomatic treatment have promise because they allow a rapid onset of action. The aim of this study was to prepare films of silodosin intended for sublingual administration for the symptomatic treatment of benign prostatic hyperplasia in men. Hydroxypropyl methylcellulose (HPMC) or hydroxypropyl methylcellulose acetate succinate (HPMC-AS) were used as film-forming polymers. The effects of the polymers and the surfactant tocopherol polyethylene glycol succinate (TPGS) on the physico-mechanical properties and dissolution behavior of the films in simulated saliva were investigated. The eight silodosin oral films developed (F1–F8) contained 8 mg silodosin per 6 cm2 film and HPMC or HPMC-AS in drug:polymer ratios of 1:5 or 1:3, while four also contained TPGS (0.5% w/w). The films were characterized using DSC, TGA, SEM, and PXRD and the mechanical properties were investigated by measuring tensile strength, elongation at break and Young's modulus. The mechanical properties of the films were dependent on the ratio of polymer used. The in vitro dissolution and drug release studies indicated that HPMC-AS films disintegrated more quickly than HPMC films. Silodosin was shown to be dispersed within the polymers. Despite silodosin being submicronized in the HPMC films, the dissolution and drug release rate (time for 80% release) from HPMC films was significantly faster than from HPMC-AS films. TPGS increased the drug release rate to a greater extent with HPMC than with HPMC-AS. The degree of saturation of formulation F4 was >1, which shows potential for improving oral absorption of silodosin.