Physicochemical characteristics and ex vivo skin permeability for three phosphodiesterase 5 inhibitors (sildenafil, tadalafil and vardenafil): A proof-of-concept study for topical penile therapy

Proniosomal Gel-Loaded Phosphodiesterase Inhibitors (Sildenafil, Vardenafil, and Tadalafil): Prospects for Topical Penile Therapy of Tadalafil for Treatment of Erectile Dysfunction

“…Secondly, Compritol 888 ATO and Precirol ATO 5 have higher solid–liquid transition temperatures (66–73 °C); therefore, the generated F2 and F3 niosomes were in relatively greater gel states, resulting in reduced partitioning of the cargo load out of the vesicles [ 19 ]. It is worth mentioning that all niosomes derived from proniosomes regardless of whether the composition significantly ( p < 0.05) improved skin permeability, compared to that from drug suspensions reported in our previous study [ 16 ]. For example, previously published data showed apparent permeability for sildenafil suspension (P app = 14.0 cm·h −1 ) and sildenafil suspension containing 0.01% Pluronic F127 (P app = 24.0 cm·h −1 ) [ 16 ], which were significantly ( p < 0.05) less than that (P app = 77.0 cm·h −1 ) recorded for F1-S in the current study.…”

“…It is worth mentioning that all niosomes derived from proniosomes regardless of whether the composition significantly ( p < 0.05) improved skin permeability, compared to that from drug suspensions reported in our previous study [ 16 ]. For example, previously published data showed apparent permeability for sildenafil suspension (P app = 14.0 cm·h −1 ) and sildenafil suspension containing 0.01% Pluronic F127 (P app = 24.0 cm·h −1 ) [ 16 ], which were significantly ( p < 0.05) less than that (P app = 77.0 cm·h −1 ) recorded for F1-S in the current study. The permeability enhancement factors for F1-S recorded 5.5- and 3.2-fold, compared to the sildenafil suspension and sildenafil suspension, respectively, containing 0.01% Pluronic F127.…”

“…Pluronic F127 at a concentration of 0.01% was employed in this study as a permeation enhancer. Preformulation studies indicated a promising role for Pluronic F127 as a skin-penetration enhancer [ 16 ]. The nine different proniosomal gels were characterized for entrapment efficiency (EE%), size, polydispersity index (PDI), zeta potential, morphology using the scanning electron microscope (SEM), and permeation through excised rat skin.…”

“…On the contrary, sildenafil-loaded proniosomes (F1-S to F3-S) showed the lowest EE% irrespective of the composition. While there are no marked differences in the molecular weights (389.4, 488.6, and 474.6, respectively) of tadalafil, vardenafil, and sildenafil, the partition coefficient (log p ) values recorded marked differences (0.4, 1.8, and 3, respectively) for sildenafil, vardenafil, and tadalafil [ 16 ]. A higher partition coefficient indicates greater lipophilicity; hence, the drug is more favorable to be accommodated in surfactant/lipid bilayer and is less likely to leak into the aqueous domain.…”

Chitosan/Solid-Lipid Nanoparticles Hybrid Gels for Vaginal Delivery of Estradiol for Management of Vaginal Menopausal Symptoms

“…Estimates were made for the permeability parameters flow and apparent permeability coefficient (P app ). The slope of the amount penetrated per cm 2 vs. the time curve’s best-fitting line was called flux, and P app was calculated using the equation shown below [ 32 ]: where F is the flux, and c is the initial concentration (mg/mL).…”