| HS Code | 315305 |
| Product Name | Sulphadiazine Sodium Pharma Grade API for Tablet / Capsule / Granule / Injection, Oral & Injectable |
| Chemical Name | Sodium 4-amino-N-(pyrimidin-2-yl)benzenesulfonamide |
| Molecular Formula | C10H9N4NaO2S |
| Molecular Weight | 272.26 g/mol |
| Cas Number | 547-32-0 |
| Appearance | White or almost white crystalline powder; odourless; slowly discoloured by light |
| Solubility | Freely soluble in water; sparingly soluble in ethanol; practically insoluble in ether and chloroform |
| Melting Point Decomposition | No sharp melting point; decomposes above 250 °C |
| Ph 1 Aqueous Solution | About 9.5 to 10.5 |
| Assay Dried Basis | 98.0% to 102.0% |
| Storage Condition | Store in a well-closed, light-resistant container in a cool, dry place |
As an accredited Sulphadiazine Sodium Pharma Grade API for Tablet / Capsule / Granule / Injection, Oral & Injectable factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Packaged in 25 kg sealed fibre drums with double polythene liners, ensuring stability, purity, and safe handling for oral and injectable pharmaceutical manufacturing. |
| Container Loading (20′ FCL) | 20′ FCL container loading of Sulphadiazine Sodium Pharma Grade API, securely packed for oral and injectable formulations, ensuring safe, contamination-free pharmaceutical transport. |
| Shipping | Sulphadiazine Sodium Pharma Grade API is shipped in sealed, food-grade HDPE drums or polyethylene-lined containers to protect purity. Transport in dry, temperature-controlled conditions, away from direct sunlight, moisture, and contaminants. Ensure clear labeling for pharmaceutical use, handling documentation, and compliance with relevant regulatory and safety guidelines. |
| Storage | Store Sulphadiazine Sodium Pharma Grade API in tightly closed, light-resistant containers, in a cool, dry, well-ventilated area. Protect from moisture, direct sunlight, and excessive heat. Maintain controlled room temperature, ideally below 25°C. Keep away from oxidizing agents and incompatible materials. Ensure container remains sealed when not in use to preserve stability, purity, and suitability for oral and injectable formulations. |
| Shelf Life | Shelf life is 24 months from manufacture when stored as directed, suitable for oral and injectable formulations. |
For manufacturing of immediate-release uncoated oral tablets, the sodium salt of sulphadiazine is used directly rather than the free acid because of its high aqueous solubility, which shortens disintegration but creates a processing risk of punch-face filming when residual moisture in the granulate exceeds a narrow limit. In this dosage form, a 500 mg sulphadiazine tablet core is formulated at a target core mass of 620 mg, placing the API at 80.6% w/w; the balance is composed of anhydrous dibasic calcium phosphate (12.5% w/w), microcrystalline cellulose (4.0% w/w), sodium starch glycolate (2.0% w/w), colloidal silicon dioxide (0.4% w/w), and magnesium stearate (0.5% w/w). Dry granulation is selected because the API is moisture-sensitive and high-shear wet granulation introduces an aqueous binder that increases the risk of hydrate formation and picking during compression. The API is first milled through a conical mill fitted with a 610 µm rasp screen to a volume mean diameter of 15–40 µm, then blended in a bin blender with a 1.2 m³ container at 8 rpm for 15 min. The blend is compacted on a roller compactor with 25 cm width rolls at a hydraulic pressure of 18 kN/cm, and the ribbon is milled through a 1.0 mm screen. Final compression is performed on a 49-station rotary tablet press with D-tooling, using pre-compression of 6–8 kN and main compression of 18–22 kN at turret speeds of 30–45 rpm. Processing conditions require the granulate residual moisture to be maintained below 1.2%, and the suite RH below 30%; excursions above 35% RH result in punch-tip filming and tablet lamination, while API pre-drying at 40°C under vacuum below 25 mbar for 4 h is implemented if the incoming API loss on drying exceeds 0.5%. Industry compliance for the raw material is governed by the USP Sulfadiazine Sodium monograph with content acceptance of 99.0–101.0% on the dried basis, elemental impurities controlled per ICH Q3D as implemented by USP <232> and USP <233>, and residual solvents per ICH Q3C. Finished-tablet testing uses USP <711> for dissolution, USP <905> for uniformity of dosage units, and USP <1217> for tablet breaking force; batch records are maintained under 21 CFR 211.67(a) equipment-cleaning and 21 CFR 211.166 stability requirements. The terminal finished product is an immediate-release 500 mg uncoated oral tablet for adult toxoplasmosis suppressive or treatment regimens.
Direct-compression capsule filling of the sodium salt is constrained less by API potency than by the cohesive nature of the milled powder, which exhibits a low tapped density and poor flow unless dry granulation is used. A 250 mg capsule fill commonly uses a 400 mg fill weight, placing the API at 62.5% w/w, with pregelatinised maize starch at 25.0% w/w, crospovidone at 5.0% w/w, sodium lauryl sulfate at 0.5% w/w, colloidal silicon dioxide at 0.5% w/w, and magnesium stearate at 1.0% w/w. The sequence adopted in capsule manufacturing is to first pre-compact the API-containing blend on a rotary press fitted with flat-faced punches at 12 kN; the slugs are then milled through a 1.0 mm screen, and the resulting granulate is filled into size 1 hard gelatin capsules on a tamping-pin machine at 25,000 capsules/h. The process window is narrow because the granulate must be held below 0.8% moisture and the filling suite below 25% RH; if the powder-bed moisture exceeds 0.8%, the tamping pins compact the granulate into non-detachable plugs, causing capsule weight variation outside USP <905> acceptance values. Raw-material compliance mirrors the tablet route: the API is supplied against the USP Sulfadiazine Sodium monograph, with content on the dried basis between 99.0% and 101.0%, and with elemental impurity testing per ICH Q3D using USP <232>/<233>. Residual solvent limits are applied per ICH Q3C for Class 3 solvents, and the gelatin capsule shells are tested under USP <711> dissolution and USP <701> disintegration testing where required. Production equipment is qualified under 21 CFR 211.65 and cleaning validation under 21 CFR 211.67. The terminal finished product is a 250 mg immediate-release hard gelatin capsule used in short-course oral therapy when dose flexibility or patient swallowing constraints justify capsule presentation.
Fluid-bed top-spray granulation is preferred when the API must be dispersed in water at the point of administration because it permits uniform distribution of sodium citrate buffer and taste-masking polymer on the surface of the sodium salt without forming large agglomerates. In this configuration, a dry granule blend for reconstitution to a 100 mg/5 mL sulphadiazine suspension contains 48.0% w/w Sulphadiazine Sodium, with 18.0% w/w sodium citrate, 20.0% w/w maltodextrin, 8.0% w/w hypromellose E5, 2.0% w/w sucralose, 1.0% w/w colloidal silicon dioxide, and 3.0% w/w pharma-grade flavour. The binder solution is prepared with hypromellose E5 in purified water at 4.0% solids, and sprayed onto the API-buffer mixture in a fluid-bed granulator with inlet air at 55°C, product temperature of 28–32°C, and spray rate of 12–16 g/min/kg batch. The granules are dried to a final moisture below 1.5%, sieved through a 1000 µm screen, and recycled fines below 150 µm to the next batch. The reconstituted suspension must maintain a pH above 8.0; if citric acid is incorporated as the sole pH modifier, the pH falls below 7.0 and the poorly soluble sulphadiazine base precipitates, reducing dose uniformity and oral bioavailability. The handleability of the granule is also limited by the hygroscopicity of the sodium salt, so the final packaging uses HDPE bottles with a desiccant canister and a minimum moisture barrier of 0.5 g/m²/day at 25°C/75% RH. Chemical and microbiological release testing follows the relevant Ph. Eur. general chapters for oral liquids and granules, including Ph. Eur. 2.9.5 for uniformity of mass of single-dose preparations; the API is controlled under the Ph. Eur. Sulphadiazine Sodium monograph and ICH Q3D. The terminal finished product is a single-dose sachet or multi-dose HDPE bottle containing granules for oral suspension, reconstituted with 5 mL potable water per sachet to yield 100 mg/5 mL oral suspension for paediatric toxoplasmosis dosing.
The solubility advantage of the sodium salt in parenteral manufacturing is offset by a pH-dependent hydrolysis and oxygen-sensitive colouration that require deliberate control of headspace oxygen, pH, and terminal sterilisation load. A 250 mg/mL injection is formulated as Sulphadiazine Sodium equivalent to 250 mg sulphadiazine base per millilitre, with water for injection q.s. to 100%, sodium hydroxide or hydrochloric acid for pH adjustment to 9.0–10.5, and, where permitted, nitrogen headspace to reduce oxidative colouration. The solution is prepared in a 316L stainless-steel jacketed mixing vessel with nitrogen sparging until dissolved oxygen is reduced below 0.1 mg/L; it is then filtered through a 0.22 µm PVDF membrane filter and filled into 10 mL amber Type I borosilicate glass vials or ampoules under nitrogen. Terminal sterilisation is performed in an autoclave with a target F0 of 8–12 min at 121°C, but excessive heat input or residual oxygen produces a yellow-to-brown colouration that is rejected under visual inspection; published data for this specific formulation indicate that a lower F0 within the range and pre-flush nitrogen are preferred when colour stability is marginal. In-process controls include pH measurement at 25°C with a calibrated glass electrode, bioburden below 10 CFU/100 mL before filtration per USP <61> and USP <62>, and filter integrity testing by bubble point or water intrusion. Release testing includes USP <788> for sub-visible particulate matter, USP <790> for visible particulates, USP <85> for bacterial endotoxins, and USP <1207> for package integrity evaluation; stability is conducted under ICH Q1A(R2) and elemental impurities under ICH Q3D. The terminal finished product is a sterile 250 mg/mL injection for slow intravenous or intramuscular administration in hospital settings where oral administration is not feasible.
In veterinary parenteral manufacturing, the addition of trimethoprim to sulphadiazine sodium creates a mixed-solute system in which the pH required to keep sulphadiazine in solution is higher than the pH at which trimethoprim is least ionised; published data for this specific high-concentration combination are limited, and formulators rely on pH-controlled addition and early compatibility testing because a pH drift below 8.6 precipitates the less-soluble neutral sulphadiazine species. A fixed-dose veterinary injection is formulated with 200 mg/mL Sulphadiazine Sodium equivalent to sulphadiazine base and 40 mg/mL trimethoprim, with the solvent system adjusted to pH 9.0–11.0 using sodium hydroxide and, where required, a pharmaceutical-grade co-solvent to maintain trimethoprim solvation. The compounding sequence begins with rapid mixing of the sodium salt in a jacketed 316L vessel at 20°C, followed by addition of trimethoprim through a high-shear dispersing unit at 3,000 rpm to avoid particle nucleation. The bulk solution is kept under nitrogen to limit oxidative colouration, filtered through a 0.22 µm polyethersulfone membrane, and filled into 100 mL amber Type II glass vials. The process is constrained by the incompatibility of the solution with acidic cleaning residues; if the filling line retains trace acetic acid from previous products, localised pH collapse at the filling nozzle produces visible precipitation in the needle shaft. Industry compliance is drawn from veterinary and pharmacopoeial requirements: sterility testing per Ph. Eur. 2.6.1, sub-visible particulate testing per Ph. Eur. 2.9.19, bacterial endotoxin testing per Ph. Eur. 2.6.14, and residual solvent control per VICH GL18 where applicable. The terminal finished product is a sterile fixed-dose injectable solution for veterinary use in cattle and swine respiratory or enteric infections, administered by intramuscular or slow intravenous routes under veterinary prescription control.
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Sulphadiazine Sodium Pharma Grade API for Tablet / Capsule / Granule / Injection, Oral & Injectable is the monosodium salt of sulfadiazine, identified by CAS 547-32-0, molecular formula C10H9N4NaO2S, and molecular weight 272.26 g/mol. The material is released as a white to pale yellow crystalline powder, freely soluble in water at approximately 1 g in 2 mL at 25 °C; the corresponding sulfadiazine base is practically insoluble. The salt is used for oral solid, granule, and injectable manufacturing where aqueous solubility, direct compression, dry compaction, or parenteral solution clarity are required. Representative release criteria follow the USP–NF Sulfadiazine Sodium monograph, Ph. Eur. Sulfadiazine Sodium monograph, and ICH Q7 GMP guidance. Assay is controlled at 99.0–101.0% on the dried basis, loss on drying at ≤0.5%, and pH of a 100 mg/mL aqueous solution at 9.0–10.5. Injectable-grade lots are additionally released for bacterial endotoxins, visible particulates, and residual solvents according to USP <467>, USP <790>, and ICH Q3C limits. Finished-dose strengths commonly include 500 mg oral tablets and 250 mg/mL injectable solutions, but the API itself is supplied by weight and assay rather than by dose.
Model distinctions within the API family are route-driven. The oral-grade powder is supplied for tablet, capsule, and granule manufacture without a sterility claim and with standard bioburden control. The injectable-grade powder is released under reduced bioburden, bacterial endotoxin control, and a dissolution/clarity check in water for injection at 100 mg/mL. A sterile-micronized grade may be used for aseptic dry filling, though finished injections are more commonly sterilised by moist heat or aseptic filtration after dissolution. Packing is typically double LDPE liners inside fibre drums; injectable-grade lots may be shipped in containers compatible with controlled aseptic sampling. The intended route must be stated on the certificate of analysis because the analytical test set differs by grade.
The decisive difference is aqueous ionisation. Sulfadiazine base behaves as a weak acid with a pKa near 6.5; in neutral water it remains largely unionised and practically insoluble. Conversion to the sodium salt replaces the sulfonamide acidic proton with sodium, yielding a freely soluble anionic species. This solubility is essential for injectable solutions, but it creates a precipitation boundary: when a 100 mg/mL solution is diluted into acidic media or when pH is forced below 6.5, the sulfadiazine anion reassociates to the free acid and may crystallise. That threshold governs buffer selection, IV admixture, and pH adjustment. Sodium chloride 0.9% w/v is usually preferred over dextrose-containing admixtures because dextrose solutions present a lower pH; published admixture data for the specific configuration is limited, but the precipitation risk is controlled by the 6.5 threshold rather than by tonicity alone. The salt also raises aqueous pH to an alkaline band; vessels are passivated and headspace is flushed with nitrogen to reduce carbon dioxide ingress and pH drift.
For tablet, capsule, and granule operations, the API is screened through a 600 µm sieve before blending. Because the sodium salt is freely water-soluble, aqueous wet granulation can cause solute migration to granule surfaces during drying; this produces mottling, capping, and content-uniformity drift. High-shear aqueous granulation is therefore limited, and dry roller compaction or alcohol-based granulation is used when a 90–110% label claim and relative standard deviation below 4.0% are required. On production-scale batches, primary particle size and bulk density shift when storage occurs above 60% relative humidity; pre-drying at 50 °C in a forced-air tray dryer is used when loss on drying exceeds 0.5%. Direct compression blends containing microcrystalline cellulose and sodium starch glycolate are mixed for 10–15 min in a V-blender. When slugging is used, a rotary press compaction force of 15–25 kN produces slugs that are milled and recompressed. Capsule filling on a tamping-pin dosator requires bulk density between 0.45 g/cm³ and 0.65 g/cm³ and a Carr index below 20% for reliable weight variation.
Release testing follows compendial monographs and ICH Q6A decision trees for oral and injectable dosage forms. The matrix below consolidates the principal release controls; values are compendial acceptance limits or harmonised in-house limits.
| Parameter | Oral-grade limit | Injectable-grade limit | Reference method |
|---|---|---|---|
| Appearance | White to pale yellow crystalline powder | White to pale yellow crystalline powder | Visual; USP <790> for visible particulates in solution |
| Assay, dried basis | 99.0–101.0% | 99.0–101.0% | USP <621> HPLC |
| Loss on drying | ≤0.5% | ≤0.5% | USP <731> |
| pH | 9.0–10.5 in 100 mg/mL solution | 9.0–10.5 in 100 mg/mL solution | USP <791> |
| Related substances | Any single impurity ≤0.5%; total ≤1.0% | Any single impurity ≤0.5%; total ≤1.0% | USP <621> HPLC |
| Bacterial endotoxins | Not routinely applied for oral grade | ≤0.10 EU/mg or lower based on dose | USP <85> / Ph. Eur. 2.6.14 |
| Residual solvents | Class 3 only | Class 3 only | USP <467> / ICH Q3C |
| Elemental impurities | As per ICH Q3D Option 1 | As per ICH Q3D Option 1 | USP <232>/<233> |
Sealed parenteral vials containing sulphadiazine sodium show two main heat-stress responses: pH-dependent precipitation of free acid and oxidative yellowing of the arylamine group. The yellowing reaction is accelerated by trace oxygen, copper or iron ions, and light exposure. Moist heat sterilisation of a 100 mg/mL solution can produce a colour shift without proportional loss of assay; this is why the injectable solution is usually blanketed with nitrogen and protected from light during the heating and cooling phases. Headspace oxygen is kept below 2% residual oxygen, and stoppers are selected from bromobutyl formulations to limit oxygen ingress. A pH shift of 0.2–0.4 units may occur during heating; this is acceptable only if the final pH remains within the release range and no visible precipitate forms. Vials with carbon dioxide ingress show greater pH reductions, and the resulting free acid can deposit as fine needles on the vial wall. The failure mode is therefore not typically gross potency loss but physical instability and subvisible particulate formation.
Injectable formulations containing sulphadiazine sodium can be terminally sterilised by moist heat when solution pH, headspace, and container closure are controlled. A 100 mg/mL solution in Type I borosilicate vials with bromobutyl stoppers is autoclaved at 121 °C for 15 min; solution colour, pH, assay, and related substances are measured before and after the cycle. The main process conflict is not potency loss but pH-dependent precipitation and oxidative colour development. Vials are flushed with nitrogen to residual oxygen below 2%, and the pH is rechecked at the end of the heat cycle. Terminal sterilisation should not be applied to unvalidated dextrose admixtures prefilled in the same container because the resulting pH can approach the free acid precipitation limit of 6.5. Autoclave load patterns with cold spots must be validated with thermocouples; an F0 value of ≥15 min is typically maintained for high-volume parenteral solutions.
Aseptic filling through a 0.22 µm polyethersulfone or polyvinylidene fluoride filter is used when terminal sterilisation is not feasible. Filter compatibility testing includes pH and assay before and after filtration because the alkaline solution can attack certain filter housings; stainless steel 316L or fluoropolymer-lined transfer lines are preferred. The API is dissolved in water for injection at 20–30 °C with moderate stirring; high-shear mixing entrains air and accelerates oxidative colour formation. Once dissolved, the solution is held under nitrogen and used within 8 h if stored at 15–25 °C; longer holding increases the risk of pH drift and impurity formation.
The injectable-grade designation is not primarily a particle-size distinction. It is a microbial quality and pyrogen control distinction. Injectable-grade material is released with a bacterial endotoxin limit of ≤0.10 EU/mg unless the maximum daily dose drives the limit lower; oral-grade material is not routinely tested for endotoxins. Bioburden for injectable API is typically controlled to ≤100 CFU/g before terminal sterilisation or aseptic filtration; oral-grade material may permit higher counts because no sterility claim is made. The injectable grade must also pass a solution clarity check after dissolving in water for injection at 100 mg/mL. Visible particulates are assessed according to USP <790>, and subvisible particulates in the finished solution are assessed according to USP <788>. Residual solvent data are shared across grades, but the injectable dossier typically applies tighter control of Class 2 solvents from the final crystallisation step. Received containers are sampled per 21 CFR 211.84, and the certificate of analysis should identify the grade and the test set applied.
The product is not interchangeable with sulfadiazine base or silver sulfadiazine, even though all three share the sulfadiazine pharmacophore. The comparative matrix below summarises the practical differences in manufacture and route selection.
| Attribute | Sulphadiazine Sodium | Sulfadiazine Base | Silver Sulfadiazine |
|---|---|---|---|
| CAS registry number | 547-32-0 | 68-35-9 | 22199-08-2 |
| Molecular formula | C10H9N4NaO2S | C10H10N4O2S | C10H9AgN4O2S |
| Water solubility at 25 °C | Freely soluble, approximately 500 mg/mL | Practically insoluble | Very slightly soluble |
| Aqueous pH | Alkaline, 9.0–10.5 for a 100 mg/mL solution | Not meaningful in saturated neutral water; dissolution requires acid or alkali | Near-neutral suspension pH; silver ion release is time-dependent |
| Primary dosage route | Oral solid, oral liquid, injection | Oral solid, suspension | Topical cream |
| Key processing limitation | Precipitation of free acid below pH 6.5; moisture sensitivity | Poor aqueous solubility; pH-dependent dissolution | Not for systemic use; silver ion leachables |
| Standard reference | USP–NF Sulfadiazine Sodium, Ph. Eur. Sulfadiazine Sodium | USP Sulfadiazine | USP Silver Sulfadiazine |
Compared with sulfamethoxazole, which is commonly paired with trimethoprim in fixed-dose oral combinations, sulphadiazine sodium has higher aqueous solubility and is suited to injectable solution manufacture. Sulfamethoxazole is a weak acid with low water solubility and is usually formulated as an oral tablet or suspension; sulphadiazine sodium is not a direct drop-in for sulfamethoxazole in fixed-dose combinations because the two APIs differ in pKa, aqueous solubility, and precipitation threshold. The choice among sulfonamides is governed by the target organism, route, and renal function; this API is used where the sulfadiazine anion is specifically indicated and where aqueous solution handling is required.
Moisture and carbon dioxide are the principal storage hazards. Containers should be tight, light-resistant, and stored at 15–25 °C; desiccants are used when ambient relative humidity exceeds 60%. The sodium salt should not be dry-blended with acidic excipients such as citric acid monohydrate or ascorbic acid, because intimate contact in a moist granule can lower the microenvironmental pH below 6.5 and cause free sulfadiazine to precipitate within the granule, reducing dissolution. In liquid formulations, oxidising agents should be avoided because the arylamine group is susceptible to oxidation; nitrogen blanketing is preferred. The product should not be exposed to copper or iron contact surfaces for extended periods; stainless steel 316L or glass-lined vessels are acceptable, while bare carbon steel is not recommended. For injectable compounding, saline-based dilution and protection from atmospheric carbon dioxide are more critical than temperature control within the normal 15–25 °C holding range.
