Sensitive spectrophotometric determination of vardenafil HCl in pure and dosage forms

Degradation of anthracene and phenanthrene by strain Streptomyces sp. M-1 and its application in the treatment of PAHs-contaminated water

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants with mutagenicity, carcinogenicity and teratogenicity, widely distributed in the environment. Effective biodegradation of PAHs is highly required, especially in wastewater. An efficient PAHs degrading strain Streptomyces sp. M-1 was isolated from polluted kerosene. The degradation capacity of anthracene and phenanthrene was evaluated under various PAHs concentrations, pH, and temperatures by M-1. To find the degradation pathways, the key intermediates were detected by mass spectrometry and the enzyme-encoding genes were analyzed by many bioinformatics tools. Furthermore, the potential of the strain for bioremediation in PAH-contaminated water was evaluated. The results showed that the maximal degradation rate of anthracene and phenanthrene reached 93.14% (100 mg L-1, 7 days) and 49.25% (50 mg L-1, 7 days), respectively. Their average degradation rate increased within the concentration of 50-800 mg L-1 and reached 2.72 mg d-1 for anthracene and 1.28 mg d-1 for phenanthrene at 800 mg L-1. M-1 exhibited high and stable anthracene degradation rate under tested pH and temperatures, and high phenanthrene degradation under tested pH and higher temperatures. Based on the analysis of both intermediates and enzyme-encoding genes, it is proposed that anthracene undergoes degradation via the phthalic acid pathway, while phenanthrene follows the salicylic acid pathway. Finally, 98.98% degradation of anthracene and 72.77% degradation of phenanthrene in water was realized over 14 days. We thus propose that Streptomyces sp. M-1 is an effective degrader for bioremediation of PAHs pollution.

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.

Utilization of a micellar matrix for simultaneous spectrofluorimetric estimation of alfuzosin hydrochloride and vardenafil hydrochloride

A sensitive and direct spectrofluorimetric method was developed for simultaneous quantitation of two co-administered drugs, namely, alfuzosin hydrochloride (AFH) and vardenafil hydrochloride (VRH). Both drugs exhibited native fluorescence properties that could be exploited to assay them in biological fluids with high sensitivity. Spectrofluorimetric analysis of AFH and VRH is based on excitation of both drugs at 265 nm where emission spectra were recorded separately for AFH and VRH at 380 and 485 nm, respectively. Micellar trends in analytical chemistry were adopted to minimize both environmental and occupational hazards, using distilled water and sodium dodecyl sulphate (serves as a micellar medium that enhanced the sensitivity of AFH and VRH) for analysis of both drugs in their raw materials, tablets, and human biological fluids (plasma and urine). Linearity ranges were 1.0-16.0 and 10.0-700.0 ng mL^-1 for AFH and VRH, respectively. The proposed method was successfully assessed for analysis of AFH and VRH in spiked human plasma and urine samples over the following concentrations: 1.0-12.0 ng mL^-1 and 4.0-400.0 ng mL^-1 for both drugs, simultaneously with mean recoveries of 101.08 % and 102.06 % in plasma and 96.75 % and 92.8 % in urine. Statistical analysis of the practical results has proved quite good agreement and revealed there were no significant differences in the accuracy and precision with those obtained by the comparison methods. The proposed method was applied successfully to Prostetrol® and Powerecta® commercial tablets without interference with tablet additives.