The fragmentation pathways of sildenafil were established by a comparison of the product ion spectra of sildenafil and eight sildenafil derivatives [15].
Food and Drug Administration for the treatment of ED: sildenafil citrate (Viagra®, manufactured by Pfizer), vardenafil hydrochloride (Levitra®, manufactured by Bayer), and tadalafil (Cialis®, manufactured by Lilly). The introduction of ED drugs has led to the promotion of herbal products as substitutes in enhancing male sexual function, often under the premise that natural products are safer. While there are many such herbal dietary supplements sold at local stores or over the internet which claim to enhance sexual performance, there have been reports of adulteration of some “natural” products with known synthetic PDE-5 inhibitors [3], [4], [5], [6], [7], [8], [9], [10], [11]. Herbal products have been spiked not only with sildenafil, vardenafil and tadalafil, but also with designer drugs of these compounds in which minor modifications have been made in their molecular structures. Sildenafil [3], [4], [5], [6], [7], [8], vardenafil [7], [9], tadalafil [3], [8], homosildenafil [3], [7], [10], [11], hydroxyhomosildenafil [7], [11], and acetildenafil [7], [11] have been detected in dietary supplements. [10] detected homosildenafil in an herbal product and identified its structure through detailed nuclear magnetic resonance studies.
| Product | Dosage | Quantity + Bonus | Price | |
|---|---|---|---|---|
| Viagra Generic | 25mg | 270 + 8 Pills | 184.26€ 175.49€ | |
| Kamagra Soft Tabs | 100mg | 84 + 4 Pills | 233.05€ 221.95€ | |
| Kamagra Polo | 100mg | 20 Pills | 83.56€ 79.58€ | |
| Kamagra Polo | 100mg | 180 + 8 Pills | 446.52€ 425.26€ | |
| Kamagra | 100mg | 12 Pills | 55.64€ 52.99€ | |
| Viagra Generic | 150mg | 90 + 6 Pills | 147.18€ 140.17€ | |
| Viagra Generic | 100mg | 180 + 8 Pills | 199.37€ 189.88€ | |
| Kamagra Polo | 100mg | 272 + 12 Pills | 622.94€ 593.28€ | |
| Viagra Generic | 25mg | 90 + 6 Pills | 105.03€ 100.03€ | |
| Kamagra Oral Jelly | 100mg | 10 Sachets | 54.55€ 51.95€ |
Homosildenafil was also detected in an herbal dietary supplement by Blok-Tip et al.
OP do searches - there are a couple of threads on this site, but hundreds on the interwebz. I have no idea about brewing though, so dont PM me. Sildenafil citrate was initially developed for the treatment of angina pectoris, but during clinical trials, it was discovered to be effective in treating erectile dysfunction (ED). Sildenafil and other ED drugs inhibit phosphodiesterase type 5 (PDE-5) enzyme, which in turn maintains higher levels of cyclic guanosine monophosphate, which relaxes smooth muscles, promotes penile blood flow, and enhances erectile function [1], [2]. Today there are three PDE-5 inhibitors that have been approved by the U.S. [11], who found NMR data for the compound to be consistent with the data presented by Shin.
In addition, the structures of two additional sildenafil analogues, hydroxyhomosildenafil and acetildenafil,
Molecular structures of the ED drugs and analogues that have been detected in health foods are given in Fig.1. Of the three marketed drugs, the structures of sildenafil and vardenafil are similar, differing in the position of a nitrogen atom in the fused heterocyclic ring and in the substituents (methyl or ethyl) on the piperazine ring. The structure of tadalafil is quite different. Homosildenafil and hydroxyhomosildenafil are analogues of sildenafil in which the N-methyl group on the piperazine ring has been replaced with an N-ethyl group or N-hydroxyethyl group, respectively. LC–MS has been used extensively in the analysis of synthetic PDE-5 inhibitors [3], [4], [5], [6], [7], [8], [9], [11], [12], [13], [14]. were determined using LC–MS, direct infusion ESI–MSn, and nuclear magnetic resonance [11].
| Brand Name | Manufacturer | Concentration | Packaging | Price Range (USD) | Availability | Notes |
|---|---|---|---|---|---|---|
| SildeVape Liquid | PharmaTech Ltd. | 20 mg/30 ml | 30 ml bottle | $15-$25 | Global | Approved for oral use |
| VidiVigo Liquid | MedicaPharma | 25 mg/30 ml | 30 ml bottle | $18-$28 | Europe, Asia | Flavored options available |
| LiquidSild | BioMed Inc. | 20 mg/30 ml | 30 ml bottle | $20-$30 | North America | Prescription only |
| SildenafilSolution | HealthMed Co. | 20 mg/30 ml | 30 ml bottle | $10-$20 | Various markets | Generic versions available |
This paper reports on the detection and identification of a novel synthetic analogue of vardenafil found in an herbal dietary supplement.
| Ingredient | Quantity per 30ml | Purity (%) | Source Organism | Additives | pH Level |
|---|---|---|---|---|---|
| Sildenafil Citrate | 20 mg | 99.9 | Chemical Synthesis | Limonene, Glycerin | 4.5 |
| Glycerin | 5 ml | — | Synthetic | Preservatives (None) | |
| Deionized Water | 24 ml | — | Purified Water | Buffering Agents | |
| Flavoring Agents | 0.5 ml | — | Plant Extracts | Artificial Flavors |
While the structure of the compound was tentatively established from the mass spectral fragmentation pattern, unequivocal
et al.Combination therapy with oral sildenafil and inhaled iloprost for severe pulmonary hypertensionAnn. There are more 200mg sildenafil citrate references available in the full text version of this article. These authors contributed equally to this work. Does anyone here have a recipe for liquid viagra and cialis? Im am going to order some raw and need a recipe.
[quote]michael myers wrote: Does anyone here have a recipe for liquid viagra and cialis? 1 gram powder and 1000ml liquid makes 1mg/ml b/c the steeeeroids make you impotent [quote]jehovasfitness wrote: ironmiketyson wrote: steroid forum,why ?? b/c the steeeeroids make you impotent [/quote] speak for yourself buddy,i feel like a damn porn star! b/c the steeeeroids make you impotent speak for yourself buddy,i feel like a damn porn star! Because alot of people brew their own UG gear from powders, saving thousands a year. proof of structure was shown by a comparison of its hydrolysis products to those of vardenafil.
Our study confirmed the bioequivalence of the test and reference formulations. This work was supported by the Pearl River S&T Nova Program of Guangzhou Foundation (NO. Yan-Ying Xu: Conceptualization, Data curation, Formal analysis, Writing – original draft, Project administration, Study concept and design, Acquisition of data, Analysis and interpretation of data, Drafting of the manuscript, Statistical analysis, Administrative, technical, or material support. Fei Qin: Conceptualization, Data curation, Formal analysis, Writing – original draft, Project administration, Study concept and design, Acquisition of data, Analysis and interpretation of data, Drafting The authors declare no conflicts of interest. The authors thank the staff at the Phase Ⅰ Clinical Trial Research Center, Xiangya Hospital, Central South University for their generous cooperation in the present study.
The authors are also grateful to BAIYUNSHAN Pharmaceutical HOLDINGS CO., LTD. Guangzhou, China, for their support. et al.Simultaneous assay of sildenafil and desmethylsildenafil in human plasma using liquid chromatography-tandem mass spectrometry on silica column with aqueous-organic mobile phaseJ Chromatogr B Anal Technol Biomed Life Sci. et al.Simultaneous determination of sildenafil and its active metabolite UK-103, 320 in human plasma using liquid chromatography-tandem mass spectrometryJ. et al.Comparison of fasting bioavailability among 100-mg commercial, 100-mg generic, and 50-mg chewable generic sildenafil tablets in healthy male mexican volunteers: a single-dose, 3-period, crossover studyClin. To our knowledge, this is the first report of a designer drug related to vardenafil.
The concentration of drugs in blood is closely related to clinical efficacy and adverse reactions, but there is no effective method for detecting the concentrations of sildenafil and its metabolites in plasma. This study describes an analytical method for measuring sildenafil, N-desmethylsildenafil, and N1,N4-desmethylsildenafil in human serum that is rapid, that requires minimal sample pretreatment, and that does not need any specific pretreatment equipment. The following instruments were used in this study: Waters Security type ultrahigh-performance liquid chromatography system (Waters, ACQUITY UPLC BEH), API4000 Triple quadruple bar mass spectrometer, electrospray ionization source (ESI) (Applied Biosystems/MDS Sciex), analyst quantitative processing software (Biological Application Company, USA), and AB-265S precision balance (Mettler, Germany). A volume of 100 μL was loaded into a 96-well plate with three replicates per concentration. Following that, 300 μL of the IS precipitator (including IS 5 ng/mL) were added before eddy mixing for 10 min at 4 °C.
Finally, the samples were centrifuged at 2200×g for 10 min, and the Because sildenafil and N-desmethylsildenafil and N1,N4-desmethylsildenafil are relatively polar, the extraction recovery rate of the liquid–liquid extraction method was low, affecting sensitivity and method reproducibility. Furthermore, liquid–liquid extraction requires a large volume of organic solvents [[10], [11], [12]]. Although the solid-phase extraction method was able to meet the methodological requirements, the cost of consumables used was high, and the processing was extremely A sensitive and rapid LC-MS/MS method for sildenafil, N-desmethylsildenafil and N1,N4-desmethylsildenafil quantitation in human plasma was validated. The method involved a sample preparation with adequate recovery by one-step protein precipitation with acetonitrile and no significant matrix effect was observed. The method was successfully applied in a bioequivalence study of sildenafil healthy Chinese volunteers. The data of a recent study have shown that SIL, acting via a nitric oxide (NO)-dependent mechanism, prevented
indomethacin-induced gastropathy, possibly through a reduction of leukocyte adhesion and maintenance of gastric blood flow (Santos et al., 2005).
This leads to an increase in the level of cyclic guanosine monophosphate, which relaxes the smooth muscles in the cavernous body and increases blood flow, resulting in a therapeutic effect [[1], [2], [3]]. Sildenafil is rapidly absorbed, and it acts within 30–60 min. It has a short plasma half-life of approximately 4 h, and is well tolerated in the dosage range studied [4,5]. Sildenafil is metabolized in the liver by two different cytochrome P450 isoforms: CYP3A4 (79%) and CYP2C9 (20%) [6]. 1B and C) are the active metabolites of sildenafil in human plasma that substantially contribute to the PDE5-related pharmacologic activity of oral sildenafil.
Because these metabolites have a similar structure and pharmacological properties as sildenafil, many of their detection indicators have strong similarities, and it is difficult to quantify them separately. At present, research has mainly focused on the content of sildenafil and its metabolites, precursor substances, and intermediates in foods or drugs, and none of the available methods can distinguish sildenafil from N-desmethylsildenafil and N1,N4-desmethylsildenafil. Several methods for quantifying sildenafil in different matrices, such as plasma, urine, and dried blood spots, have been described [[7], [8], [9]]. However, there is no available report on the quantification of N1,N4-desmethylsildenafil. In addition, because plasma samples are more complicated to process than ordinary samples, the concentration of active ingredients in plasma is lower, and there are significant individual differences in drug metabolism in the body. (2009), SIL also attenuated airway inflammation and mucus production in the rat model, through the NO/cyclic
| Condition | Risk Factors | Advice | Alternative Treatment |
|---|---|---|---|
| Use with Nitrates | Severe hypotension risk | Avoid combination | Psychotherapy, Other ED meds |
| Cardiovascular Disease | Increased cardiac stress | Consult cardiologist | Lifestyle modifications |
| Retinal Disorders | Worsening of existing visual issues | Medical evaluation needed | Other PDE5 inhibitors |
| Liver or Kidney Impairment | Altered drug metabolism | Dose adjustment or avoidance | Non-pharmacological options |
guanosine 3′,5′-monophosphate pathway and significantly prevented renal damage by ameliorating oxidative and inflammatory injuries in diabetic rats.