Simultaneous LC-MS analysis of plasma concentrations of sildenafil, tadalafil, bosentan, ambrisentan, and macitentan in patients with pulmonary arterial hypertension

A Comprehensive Review on Analytical Techniques for Determination of Sex Stimulants, PDE5 Inhibitors in Different Matrices with Special Focus on the Electroanalytical Methods

Erectile dysfunction (ED) is one of the most common chronic diseases affecting men and its incidence increases with aging. Due to its substantial influence on the quality of life, phosphodiesterase type-5 (PDE5) inhibitors have been implemented to treat ED by increasing the penile blood flow that results in improving erection. PDE5 inhibitors is a class of drugs that affects many pharmacological sectors, and it is essential to review the different analytical methods described for their determination. Few reviews were published concerning this group of drugs. For this reason, this review article gathers the different analytical methods used to determine PDE5 inhibitors in pharmaceutical and biological samples over the past 20 years. Different analytical techniques were used to analyze these compounds in different matrices such as separation methods (capillary electrophoresis, LC-MS, UPLC-MS/MS, and GC-MS), spectroscopic methods (UV-visible methods, FT-IR spectroscopy and spectrofluorometry) and electrochemical methods (polarography, voltammetry and potentiometry). This review focuses on the different electrochemical methods and their use in analytical determination of PDE5 inhibitors in pharmaceutical dosage forms and biological samples. Moreover, it discusses the different modified electrodes used for their electroanalytical determination and the behavior of the studied drugs at different modified electrodes. Additionally, this review discusses the pharmacokinetics of the studied compounds and their interactions with other co-administered drugs especially the metabolic interactions between the studied compounds and other co-administered drugs in different matrices. This literature survey would provide a beneficial guide for future analytical investigation of PDE5 inhibitors.

Metal-organic framework modified by silver nanoparticles for SERS-based determination of sildenafil and pioglitazone hydrochloride

A versatile surface-enhanced Raman scattering (SERS) assay has been established that can realize rapid and sensitive determination of sildenafil (SIL) and pioglitazone hydrochloride (PIO) adulteration in healthcare products. Metal-organic frameworks-silver nanoparticles (MOFs-AgNPs) with SERS activity were successfully prepared via in situ synthesis AgNPs on the MOFs surface. By virtue of the adsorptivity of MOFs, the MOFs-AgNPs could effectively concentrate the drug molecules on the electromagnetic enhancement areas of AgNPs. Moreover, the MOFs-AgNPs substrate exhibited more sensitive SERS activity than classical AgNPs with linear range of 1.0 × 10-7-1.0 × 10-5 mol L-1 for SIL and 8.0 × 10-7-3.0 × 10-5 mol L-1 for PIO and limit of detection (LOD) of 4.8 × 10-8 mol L-1 for SIL and 1.4 × 10-7 mol L-1 for PIO. The designed method realized the determination of SIL and PIO in commercial tablets and healthcare products with recoveries of 93.8-108.0% and 93.0-104.0%, respectively, with relative standard deviation (RSD) of 2.7-4.1% and 2.2-4.2%, respectively. The present system displayed little interference effect on determination. This work provides a multifunctional route for the determination of other drugs via the SERS technology.

Sildenafil 4.0-Integrated Synthetic Chemistry, Formulation and Analytical Strategies Effecting Immense Therapeutic and Societal Impact in the Fourth Industrial Era

Sildenafil is a potent selective, reversible inhibitor of phosphodiesterase type 5 (PDE5) approved for the treatment of erectile dysfunction and pulmonary arterial hypertension. Whilst twenty years have passed since its original approval by the US Food and Drug Administration (USFDA), sildenafil enters the fourth industrial era catalyzing the treatment advances against erectile dysfunction and pulmonary hypertension. The plethora of detailed clinical data accumulated and the two sildenafil analogues marketed, namely tadalafil and vardenafil, signify the relevant therapeutic and commercial achievements. The pharmacokinetic and pharmacodynamic behavior of the drug appears complex, interdependent and of critical importance whereas the treatment of special population cohorts is considered. The diversity of the available formulation strategies and their compatible administration routes, extend from tablets to bolus suspensions and from per os to intravenous, respectively, inheriting the associated strengths and weaknesses. In this comprehensive review, we attempt to elucidate the multi-disciplinary elements spanning the knowledge fields of chemical synthesis, physicochemical properties, pharmacology, clinical applications, biopharmaceutical profile, formulation approaches for different routes of administration and analytical strategies, currently employed to guide the development of sildenafil-based compositions.