[Study of the pharmacokinetics of extended release sildenafil].

Abstract

Purpose of the study: Comparison of the pharmacokinetic characteristics of the drug Vildegra registered in the Russian Federation with literature data for the original drug Viagra.

Materials and methods: Study design: prospective, open-label in healthy volunteers with a single oral dose on an empty stomach. The study included 48 male volunteers aged 18 to 45 years with a verified diagnosis of "healthy." All subjects of the clinical study took 1 tablet of Vildegra once on an empty stomach. Blood samples to determine the concentrations of active substances were taken before taking the study drug and then after 0.25; 0.5; 0.75; 1; 1.5; 2; 2.5; 3; 3.5; 4; 4.5; 5; 5.5; 6; 7; 8; 10; 12; 16; 24; thirty; 36; 48 and 72 hours after taking the drug. Dynamic monitoring was carried out throughout the study, including clinical examination, measurement of vital signs, monitoring of laboratory parameters and monitoring of adverse events (AE). The concentrations of sildenafil and its active metabolite N-desmethylsildenafil in the blood plasma of volunteers were determined by high-performance liquid chromatography with tandem mass spectrometric detection. Pharmacokinetic parameters were calculated using a model-free method using the specialized program PK Solution2.0.

Results: The AUC0-t, AUC0- and Cmax values for sildenafil and its active metabolite when taking the drug Vildegra are in good agreement with the literature data for the original drug Viagra. The values of tmax and t1/2 of the drug Vildegra are slightly higher than those of the original drug, which is apparently explained by the extended-release dosage form in the case of Vildegra. In 10 of 48 volunteers (21%), 20 AE were recorded, which resulted in complete recovery. No serious or unexpected AE were noted.

Conclusion: The results obtained allow us to conclude that the pharmacokinetics, good tolerability and satisfactory safety profile of the drug Vildegra are comparable with the published data for the original drug Viagra.