Electrochemical behavior of 5-type phosphodiesterase inhibitory drugs in solid state by voltammetry of immobilized microparticles

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.

Nuclearity growth of new PdII complexes induced by the electronic effect of selenium-containing ligands

This work provides a systematic study of how the electronic effect of EDG or EWG in selenium-containing ligands influences the nuclearity of PdII complexes. The solid-state, solution and gas phase behaviors were evaluated for the complexes.

Ready-to-use 3D-printed electrochemical cell for in situ voltammetry of immobilized microparticles and Raman spectroscopy

We report in this communication a ready-to-use fused deposition modeling (FDM) based 3D-printed spectroelectrochemical cell to perform for the first time voltammetry of immobilized microparticles (VIMP) and Raman spectroscopy in situ using acrylonitrile butadiene styrene (ABS) as the filament material for printing. The 3D-printed cell was applied to evaluate solid state electrochemical behavior of tadalafil as a proof-of-concept. Several advantages were achieved in the use of the developed device, such as less manipulation of the working electrode, monitoring the same region of the solid microparticles before and after electrochemical measurements, better control of the laser incidence, low-cost and low-time production. Furthermore, the device was printed in a single-step, without handling to assembly and it has an estimated material cost of approximately 2 $. The use of 3D-printing technology was significantly important to integrate Raman spectroscopic method with VIMP measurements and to support mechanism elucidation and characterization of the compounds with less manipulation of the working electrode, avoiding loss of solid products formed from electrochemical reactions.