Preparation and Evaluation of Mouth Dissolving Tablets of Sildenafil Citrate

Sidenafil citrate is the first oral therapy for erectile dysfunction and pulmonary arterial hypertension. Sildenafil is a selective inhibitor of cGMP specific phosphodiesterase type (PDE5).It is reported to be effective in men with ED associated with diabetes, prostrate cancer, psychological conditions. Pulmonary hypertension is a progressive disease of diverse origin with devastating consequences in adults as well as in children. The phosphodiesterase 5 inhibitor sildenafil successfully lowers pulmonary vascular resistance. However, it is reported,Sildenafil citrate because of its poor enteral absorption results in ineffective plasma concentrations(41%) in infants and children. The major objective of this study is to prepare rapidly disintegrating, mouth dissolving tablets of Sildenafil citrate to achieve rapid onset of action and to circumvent first pass loss. Various tablet formulations were prepared by direct compression method using well known excipients. The tablets prepared using Pharmaburst® (a co-processed excipient system) in comparison with well known super disintegrants showed better results in terms of tablet hardness, content uniformity, disintegration time and wettebility. Tablets containing sildenafil citrate 10mg,20mg & 40mg were prepared Pharmaburst® and the bioavailability in rabbits was compared with conventional enteral. The Cmax values were found to be 0.72µg for 10mg tablet, 0.92µg for 20mg tablet, 1.38 µg for 40mg tablet, 0.64µg for the 100mg conventional tablets and the corresponding Tmax readings were at 2.5mins, 2.5mins, 5mins and 45mins. The study indicate mouth dissolving tablets of Sildenafil citrate prepared using Pharmaburst® provide rapid onset of action , better bioavailability over entral tablets.