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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.

Capsule phase microextraction (CPME) is an efficient bioanalytical technique that streamlines the sample preparation by integrating the filtration and stirring mechanism directly into the device. A novel composite sorbent designed to be selective towards the target analytes consisting of mixed-mode sorbent chemistry synthesized by sol-gel technology is found promising and superior to the conventional C 18 sorbents. Herein we describe the encapsulation of an ionic liquid (IL)/Carbowax 20M-functionalized sol-gel sorbent (sol-gel IL/Carbowax 20 M) in the lumen of porous polypropylene tubes for the capsule phase microextraction of three phosphodiesterase-5 inhibitors namely avanafil, sildenafil, and tadalafil in human serum and urine samples. The CPME device was characterized by Scanning Electron Microscopy (SEM) and Fourier-Transform Infrared Spectroscopy (FT-IR). The experimental parameters of CPME procedure (e.g. sample pH and ionic strength, extraction time, stirring rate, elution solvent and volume) were carefully optimized to achieve the highest possible extraction efficiency for the analytes. Method validation was conducted in terms of precision, linearity, accuracy, matrix effect, lower limits of quantification, and limits of detection (LOD). The method linearity was investigated in the range of 50-1000 ng mL -1 for all analytes while the precision was less than 11.8 % in all cases. For all analytes, the LOD values were 17 ng mL -1 . The IL/CW 20M-functionalized microextraction capsules could be reused at least 25 times both for urine and serum samples. The green character and the applicability of the proposed method were evaluated using the ComplexGAPI and BAGI indexes. The optimized CPME protocol exhibited reduced consumption of organic solvent and generation of waste, cost-effectiveness, and simplicity. Finally, the proposed method was successfully applied to the analysis of sildenafil in human urine after administration of drug-containing formulation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Aim: The aim was to evaluate drug-plasma binding (DPB).by employing Hollow Fiber-in-Syringe Equilibrium Sampling Through Supported Liquid Membrane (HFiS ESTSLM) and RP-HPLC analysis. Materials & Methods: HFiS ESTSLM and RP-HPLC were used to evaluate DPB of three weak basic drugs (Metoprolol, Diphenhydramine, and Sildenafil) with differing hydrophilicity and binding ability to blood plasma. Results: The results exhibited an increasing drug-dependent magnitude of DPB for the three model drugs. This trend of DPB confirmed that HFiS ESTSLM has the required sensitivity for determining DPB of the drugs. The DPB was drug concentration-dependent within the tested drug concentration range, especially at high concentration. Conclusion: HFiS ESTSLM and RP-HPLC offered a simple, easy and cost-effective procedure to evaluate DPB of these basic drugs.

This study was conducted to compare dissolution profiles of four Jordanian registered sildenafil (SDF) products to the originator. Dissolution samples were analyzed utilizing a validated and stability-indicating HPLC method in human plasma. Validation was performed for specificity, linearity, limit of detection, lower limit of quantification, precision, trueness and stability. SDF was extracted from plasma samples using liquid-liquid extraction. The analysis was performed utilizing isocratic elution on C18 column with 1.0 ml/min flow rate. The regression value was ∼0.999 over 3 days with drug recovery between 86.6 to 89.8%with 10 ng/ml lower limit of quantitation. This method displayed a good selectivity of SDF with improved stability under various conditions. The method was used for SDF quantification in dissolution medium. Similarity factors for local products varied according to the used mediums, but all SDF local products passed the dissolution in vitro test since all of them showed a released of >85% after 60 min at the dissolution mediums.