Sildenafil citrate

A simple, precise and accurate stability indicating RP-HPLC method has been developed and subsequently validated for the simultaneous estimation of Sildenafil citrate and Estradiol valerate in bulk and pharmaceutical formulation. The separation was carried out using C18 column (150mm x 4.6mm, 5μm), mixture of acetonitrile and water 80:20 % v/v as a mobile phase with a flow rate of 1 ml/min and the effluent was monitored at 290 nm using PDA detector. The retention time of Sildenafil citrate and Estradiol valerate were 2.55 min and 5.56 min respectively. The method is linear over the range of 125 - 750 μg/ml and 5 - 30 μg/ml for Sildenafil citrate and Estradiol valerate respectively. The method was found to be precise, accurate and specific during the study. The percentage assay was found to be 100.68 % and 99.58 % for Sildenafil citrate and Estradiol valerate respectively from the tablet formulation. Sildenafil citrate and Estradiol valerate were subjected to stress condition to check the degradation behaviour of them. The drugs undergo degradation under acidic, basic, oxidative and thermal condition. The proposed method enables rapid quantification and simultaneous analysis of both drugs from commercial formulations without any interference of excipients. So, the method can be used for routine analysis of Sildenafil citrate and Estradiol valerate in combined tablet formulation.

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.

This study is aimed at Developing and validating an UPLC method for determination of Sildenafil and tadalafil content in API and formulations. A chromatographic system consisting Waters  Acquity UPLC BEH C8(1.8 µm)column, mobile phase of  0.2 M ammonium acetate and Acetonitrile with gradient elution at flow of 0.3 mL/min and UV detector set at 245 nm has shown a good chromatographic separation for Sildenafil tadalafil. The developed method was validated as per ICH Guidelines, the developed UPLC method has run time of only 10 minutes making the method productive and tested by spiking all the impurities of sildenafil and tadalafil. It may be applied for Quality control Testing.

This study is aimed at Developing and validating an UPLC method for the related substances of Sildenafil that might coexist in tablet formulations as impurities that may originate from synthesis process or degradation. A chromatographic system consisting Waters  Acquity UPLC HSS C18(1.8 µm)column, mobile phase of  ammonium acetate and Acetonitrile with gradient elution at flow of 0.3 mL/min and UV detector set at 245 nm has shown a good chromatographic separation for Sildenafil and its related substances. The developed method was validated as per ICH Guidelines and compared with Pharma Europa method. The pharmacopeia method has above 60 minutes runtime to separate all the listed related compounds, the developed UPLC method has run time of only 10 minutes making the method productive and may be applied for Quality control Testing.