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Query: UNIPROT:P06889 (Mol)
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Little is known about pharmaceutical and personal care products pollutants (PPCPs), but there is a growing interest in how they might impact the environment and microbial communities. The widespread use of Viagra (sildenafil citrate) has attracted great attention because of the high usage rate, the unpredictable disposal and the unknown potential effects on wildlife and the environment. Until now information regarding the impact of Viagra on microbial community in water environment has not been reported. In this research, for the first time, the genetic profile of the microbial community, developing in a Viagra polluted water environment, was evaluated by means of the 16S and 18S rRNA genes, for bacteria and fungi, respectively, amplified by polymerase chain reaction (PCR) and separated using the denaturing gradient gel electrophoresis (DGGE) technique. The DGGE results revealed a complex microbial community structure with most of the population persisting throughout the experimental period. DNA sequences from bands observed in the different denaturing gradient gel electrophoresis profiles exhibited the highest degree of identity to uncultured bacteria and fungi found previously mainly in polluted environmental and treating bioreactors. Biotransformation ability of sildenafil citrate by the microbial pool was studied and the capability of these microorganisms to detoxify a polluted water ecosystem was assessed. The bacterial and fungal population was able to degrade sildenafil citrate entirely. Additionally, assays conducted on Daphnia magna, algal growth inhibition assay and cell viability determination on HepG2 human cells showed that biotransformation products obtained from the bacterial growth was not toxic. The higher removal efficiency for sildenafil citrate and the lack of toxicity by the biotransformation products obtained showed that the microbial community identified here represented a composite population that might have biotechnological relevance to retrieve sildenafil citrate contaminated sites.
Mol Biotechnol 2009 Feb
PMID:Molecular characterization of microbial population dynamics during sildenafil citrate degradation. 2056 40

Two simple and highly sensitive spectrophotometric methods were developed for the quantitative determination of the drug sildenafil citrate (SC), Viagra, in pure form and in pharmaceutical formulations, through ion-associate formation reactions (method A) with mono-chromotropic acid azo dyes, chromotrope 2B (I) and chromotrope 2R (II) and ion-pair reactions (method B) with bi-chromotropic acid azo dyes, 3-phenylazo-6-o-carboxyphenylazo-chromotropic acid (III), bis-3,6-(o-hydroxyphenylazo)-chromotropic acid (IV), bis-3,6-(p-N,N-dimethylphenylazo)-chromotropic acid (V) and 3-phenylazo-6-o-hydroxyphenylazo-chromotorpic acid (VI). The reaction products, extractable in methylene chloride, were quantitatively measured at 540, 520, 540, 570, 600 and 575 nm using reagents, I-VI, respectively. The reaction conditions were studied and optimized. Beer's plots were linear in the concentration ranges 3.3-87.0, 3.3-96.0, 5.0-115.0, 2.5-125.0, 8.3-166.7 and 0.8-15.0 microg mL(-1) with corresponding molar absorptivities 1.02 x 10(4), 8.34 x 10(3), 6.86 x 10(3), 5.42 x 10(3), 3.35 x 10(3) and 2.32 x 10(4)Lmol(-1) cm(-1) using reagents I-VI, respectively. The limits of detection and Sandell's sensitivities were calculated. The methods were successfully applied to the analysis of commercial tablets (Vigoran) and the recovery study reveals that there is no interference from the common excipients that are present in tablets. Statistical comparison of the results was performed with regard to accuracy and precision using Student's t- and F-tests at 95% confidence level. There is no significant difference between the reported and proposed methods with regard to accuracy and precision.
Spectrochim Acta A Mol Biomol Spectrosc 2010 Apr
PMID:Spectrophotometric determination of sildenafil citrate in pure form and in pharmaceutical formulation using some chromotropic acid azo dyes. 2012 17

Sildenafil, a phosphodiesterase-5 inhibitor sold as Viagra, is a cardioprotector against myocardial ischemia/reperfusion (I/R) injury. Our study explored whether sildenafil protects against I/R-induced damage in a porcine cardiac arrest and resuscitation (CAR) model via modulating the renin-angiotensin system. Male pigs were randomly divided to three groups: Sham group, Saline group, and sildenafil (0.5 mg/kg) group. Thirty min after drug infusion, ventricular fibrillation (8 min) and cardiopulmonary resuscitation (up to 30 min) was conducted in these animals. We found that sildenafil ameliorated the reduced cardiac function and improved the 24-h survival rate in this model. Sildenafil partly attenuated the increases of plasma angiotensin II (Ang II) and Ang (1-7) levels after CAR. Sildenafil also decreased apoptosis and Ang II expression in myocardium. The increases of expression of angiotensin-converting-enzyme (ACE), ACE2, Ang II type 1 receptor (AT1R), and the Ang (1-7) receptor Mas in myocardial tissue were enhanced after CAR. Sildenafil suppressed AT1R up-regulation, but had no effect on ACE, ACE2, and Mas expression. Sildenafil further boosted the upregulation of endothelial nitric oxide synthase (eNOS), cyclic guanosine monophosphate (cGMP) and inducible nitric oxide synthase(iNOS). Collectively, our results suggest that cardioprotection of sildenafil in CAR model is accompanied by an inhibition of Ang II-AT1R axis activation.
Int J Mol Sci 2015 Nov 12
PMID:Sildenafil Protects against Myocardial Ischemia-Reperfusion Injury Following Cardiac Arrest in a Porcine Model: Possible Role of the Renin-Angiotensin System. 2656 34

Use of the phosphodiesterase 5 (PDE5) blocker sildenafil (Viagra) has been linked to an increased risk of melanoma. In a recent study we discovered a growth-promoting cGMP pathway in melanoma cells. cGMP degradation via PDE5 acts as a brake on this pathway. Inhibition of PDE5 releases this brake, providing a mechanism for the promelanoma effects of sildenafil.
Mol Cell Oncol 2017
PMID:Viagra releases the brakes on melanoma growth. 2905 99

In the postprandial stomach, processes such as secretion, digestion, and gastric emptying all occur simultaneously. Therefore, the system is highly heterogeneous and dynamically changing, for instance, in terms of various physicochemical parameters such as pH value or viscosity. Thus, the administration of a drug together with food can result in highly variable drug plasma concentrations, which may affect the efficacy and safety of the pharmacotherapy. In this work, the pharmacokinetic (PK) data obtained from two fed-state bioequivalence studies with the immediate release (IR) drug products Viagra (sildenafil) and Adenuric (febuxostat) have been analyzed. This evaluation revealed that basically three characteristic types of onset behaviors of drug plasma concentration can be distinguished. It was hypothesized that the different types of onset behaviors were mainly caused by the interplay between gastric drug dissolution and gastric emptying. To study this interplay in vitro, a biopredictive dissolution tool-GastroDuo-was developed and used for both drug products. Therefore, three different test programs have been applied to simulate certain aspects of the postprandial human stomach, which included dynamic pH changes, gastric peristalsis, and the kinetics of gastric emptying. Specifically, the behavior of noncaloric fluids by the so-called "Magenstrasse" was taken into deeper consideration. The experiments revealed that the dissolution and emptying behavior of the two drug products were affected in different ways by the three test programs. The in vitro data nicely explained the tendencies of the drug products for certain types of onset behaviors observed in the PK data. While Viagra was strongly affected by simulated peristalsis, Adenuric was more sensitive to the simulated emptying kinetics. This work clearly demonstrated the important role of gastric fluid emptying for the onset of drug plasma concentration after oral administration of IR formulations in the fed state. Moreover, this was the first study in which GastroDuo was applied as a biopredictive in vitro model which is able to simulate crucial parameters of the human stomach (e.g., pH profiles and gastric emptying) in a realistic manner.
Mol Pharm 2019 11 04
PMID:Application of the GastroDuo as an in Vitro Dissolution Tool To Simulate the Gastric Emptying of the Postprandial Stomach. 3159 80


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