Sildenafil citrate bulk powder
Sildenafil citrate bulk powder is the world’s first PDE5 inhibitor; sildenafil citrate bulk powder pioneered the development of drugs targeting this pathway.
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Product Details
Summary of sildenafil citrate bulk powder
Sildenafil citrate bulk powder was the world’s first PDE5 inhibitor. It pioneered this class of drugs. It works by relaxing blood vessels and improving blood flow. Many subsequent drugs in this class were designed based on it. Sildenafil citrate bulk powder also helped doctors discover new treatments for pulmonary arterial hypertension. In terms of manufacturing, its synthesis methods and quality standards have become industry benchmarks. In short, sildenafil is the most important active pharmaceutical ingredient in this field.
1: Simple instructions about sildenafil citrate bulk powder
Sildenafil citrate bulk powder api was originally developed as a new drug to treat angina, but sildenafil API proved ineffective for that purpose. However, during clinical trials in 1991, researchers discovered that sildenafil citrate powder was an effective PDE5 inhibitor. It was officially launched in 1998 as a PDE5 inhibitor, ushering in the era of oral PDE5 therapy. From 2014 to 2017, the patents for sildenafil citrate bulk powder and manufacturing processes expired one after another.
2: Basic chemical parameters of sildenafil citrate bulk powder
a. API name: Sildenafil citrate powder
b. Appearance: White crystal powder
c. Taste: It’s very bitter, compared to tadalafil powder
d. Specification: 98%-102% powder according to USP
d. CAS No.: 171599-83-0
f. Molecular Formula: C28H38N6O11S7. Molecular Weight: 666.7 g/mol; pure sidenafil is 474.6 g/mol
g. Certificates: GMP, cGMP, CEP, CDE, FDA, Organic, Kosher, ISO, HALAL, FSSC, DMF
h. Testing partner: Wuxi AppTec, Merieux
i. Test Method: HPLC, UV-visible spectrophotometry
j. Storage method:15～25℃, RH＜60%, store away from light
k. Aluminium foil bag, blue color; tamper-evident HDPE drums
l. Export only, welcome research labs and professionals
3: Differences in the production of sildenafil citrate bulk powder, multi-stage gradient recrystallisation and single-step rapid salt formation
We use a multi-stage gradient recrystallization process.
There is a significant difference between the two production processes:
Our factory uses multi-stage, step-by-step crystallization to purify active pharmaceutical ingredients, while small workshops use a single-step process to rapidly produce salts, employing rudimentary methods.
Taking sildenafil as an example, the legitimate process involves two steps:
The crude material is first crystallized to remove impurities;
Citric acid is then added to form a salt, followed by further purification through crystallization.
The method used by small workshops involves simply processing the crude material—or even leaving it unpurified
The identification methods are as follows:
a: Initial screening by visual inspection/sensory evaluation (rapid on-site assessment)
b: Routine laboratory testing (for QC rapid screening), HPLC, melting point / DSC, residual solvents & loss on drying
c: Instrumental confirmation (conducted in cases of dispute or during acceptance), XRD (X-ray diffraction) – for confirmation of crystal form, IR (infrared spectroscopy) – for solvents and heavy metals.
| Identification Items | High-Purity Products Obtained Through Multi-Stage Gradient Recrystallization | Single-Step Rapid Salt Formation of Crude Product |
| Color | Pure white | Not so white |
| Crystal | Short, thick, columnar single crystals | Slender, needle-like; numerous fragmented crystals |
| Particle Size and Flowability | Uniform particle size | Different particle size |
| Clumping | No hard lumps; disperses with a gentle shake | Large Clumps |
| Moisture Absorption | Dry | Sticky residue on the bottom and sides of the drum |
| Solvent odor | Virtually no alcohol taste; has a mild aroma | A distinct, pungent odor of organic solvents |
| Settling in a solvent | Settles quickly; the mother liquor is clear | Suspended for a long time; overall milky white and cloudy |
4: COA of Sildenafil citrate bulk powder
| Test/Observation | Specifications | Result |
| Appearance | White or nearly white crystals | Complies |
| Odor & taste | Characteristic bitter | Complies |
| Melting Point | 187-190°C | Complies |
| HPLC | 98%-102% | 99.54% |
| IR | Infrared Spectroscopy | Complies |
| XRPD (Powder Diffraction) | Crystal confirmation | Characteristic peaks of Form I |
| UV absorption coefficient E ₁% ₁ cm (292nm) | 195-210 | Complies |
| Solubility | Slightly soluble in water, slightly soluble in methanol, extremely slightly soluble in ethanol | Complies |
| Acidity (1mg/mL aqueous solution) | pH 3.0～4.5 | Complies |
| Loss on drying % | MAX. 0.5 | 0.12 |
| Organic impurities Gradient HPLC by CP standard (230nm) | ||
| Sildenafil related compound A | Desmethyl not more than ≤0.15% | Complies |
| Any other unspecified individual impurity | ≤0.1% of single impurity | Complies |
| Total impurities | ≤0.5% | Complies |
| Heavy metals | ||
| Pb | ≤10 ppm | Complies |
| Cd | ≤ 0.2 ppm | Complies |
| As(Total) | ≤3 ppm | Complies |
| Hg | ≤ 0.1 ppm | Complies |
| Microbiology | ||
| Total Plate Count | <1000cfu/g | 35cfu/g |
| Yeast & Mold | <100cfu/g | Negative |
| E.Coli | Negative | Complies |
| S. Aureus | Negative | Complies |
| Salmonella | Negative | Complies |
| Conclusion | Conform with specification | |
5: Test chart of Sildenafil citrate bulk powder
a. Our strength lies in our ability to perform ultra-fine grinding and micronization of sildenafil citrate powder, achieving a D₉₀ of ≤15 μm and a D₅₀ of 3–5 μm, making it suitable as a raw material for orodispersible films.
b. We can provide technical support regarding excipient compatibility, dissolution profiles, and impurities in the formulation of dapoxetine powder and other herbal compound formulations.
6: Our company operates GMP-compliant, standardized cleanrooms and a professional quality control laboratory. We strictly adhere to GMP, ISO, and GLP standards in our production and operations, and possess comprehensive capabilities for integrated production, testing, and regulatory compliance. We not only provide a stable supply of high-purity, high-concentration, and highly stable premium products but also offer a full suite of regulatory filing services to ensure our customers’ market access.
Our in-house standardized and compliant laboratory is equipped with precision testing instruments such as HPLC, GC, and LC-MS, enabling us to independently conduct a full range of testing, including purity testing, impurity analysis, stability studies, and method validation. Our standardized testing processes and traceable data fully meet the data compliance requirements for product quality control, drug regulatory inspections, and registration applications, providing a robust guarantee for high-quality product output.
Our factory holds all necessary qualifications, including official GMP production certification, ISO 9001, and ISO 13485, among other authoritative certifications. Our products comply with international standards such as the Chinese Pharmacopoeia, USP, and EP. Complete compliance documentation is provided for all shipped products, making them suitable for various applications including pharmaceutical R&D, foreign trade exports, and project submissions.
Information Sources:
1: https://www.usp.org/
2: https://www.uspnf.com/
3: https://www.chp.org.cn/
4: https://www.pharnexcloud.com/
5: https://www.drugfuture.com/Pharmacopoeia/usp32/search.aspx
6: https://db2.ouryao.com/
7: http://www.customs.gov.cn/
