| HS Code | 298047 |
| Productname | 4-Chloro-2,6-dimethyl-3-nitropyridine |
| Productdescription | Pharma Grade API for Tablet / Capsule / Granule / Injection, Oral & Injectable |
| Chemicalname | 4-Chloro-2,6-dimethyl-3-nitropyridine |
| Synonyms | 3-Nitro-4-chloro-2,6-dimethylpyridine; 4-Chloro-2,6-dimethyl-3-nitropyridine |
| Casregistrynumber | 130146-25-3 |
| Molecularformula | C7H7ClN2O2 |
| Molecularweight | 186.60 g/mol |
| Appearance | Yellow to brown crystalline powder or solid |
| Assaypurity | ≥98.0% (HPLC) |
| Pharmagrade | Pharma Grade API |
| Dosageforms | Tablet / Capsule / Granule / Injection |
| Routesofadministration | Oral / Injectable |
| Solubility | Soluble in organic solvents such as methanol, ethyl acetate, and dichloromethane; slightly soluble in water |
| Meltingpoint | 68-72 °C |
| Storageconditions | Store in a cool, dry, well-ventilated place protected from light and moisture |
| Shelflife | 24 months when stored properly |
| Packaging | Double polyethylene bags inside fiber drum or as per customer requirement |
| Manufacturingstandard | ICH GMP / Q7 API requirements |
As an accredited 4-Chloro-2,6-dimethyl-3-nitropyridine 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 | |
| Shipping | |
| Storage |
In tablet manufacturing campaigns that begin with 4-chloro-2,6-dimethyl-3-nitropyridine as the pharmaceutical intermediate, the nitro group is reduced to the 3-amino intermediate before final salt isolation. Formulators do not directly compress 4-chloro-2,6-dimethyl-3-nitropyridine; the material enters solid dosage development only after reduction and salt formation to the hydrochloride form. The reduction is conducted in a stainless-steel hydrogenation autoclave equipped with a gas-inducing Rushton-type impeller and a 0.45 µm sintered metal filter candle. Process conditions include 5% palladium on carbon at a substrate-to-catalyst mass ratio of 10:1, hydrogen pressure of 0.5–1.2 MPa, jacket temperature of 45–55 °C, and agitator speed of 800–1000 rpm. In-process HPLC confirms residual 4-chloro-2,6-dimethyl-3-nitropyridine at not more than 0.10 area percent before catalyst filtration. The filtrate is acidified with 2-propanolic hydrochloric acid, and the resulting hydrochloride salt is washed with chilled isopropanol and dried in a vacuum tray dryer at 50 °C for 8 h to moisture below 1.0 wt% by USP <921> Karl Fischer titration.
The isolated salt is formulated into an immediate-release tablet at a drug load of 20.0 wt%, blended with microcrystalline cellulose PH102 45.0 wt%, lactose monohydrate 30.0 wt%, crospovidone 3.0 wt%, colloidal silicon dioxide 0.5 wt%, and magnesium stearate 0.5 wt%. High-shear wet granulation is performed in a 65 L vertical granulator with impeller speed 150 rpm and chopper speed 1500 rpm for 180 s; purified water is sprayed at 20–25% w/w of dry blend. Drying in a fluid-bed dryer with inlet air at 65 °C proceeds until loss on drying reaches 1.5–2.0 wt%. The dried granulate is milled through a 0.8 mm stainless-steel screen and compressed on a 27-station rotary tablet press with 10 mm round tooling at 10–15 kN compression force. Core tablets are controlled for hardness 70–100 N, friability below 1.0% per USP <1216>, disintegration below 15 min in purified water at 37 ± 0.5 °C per USP <701>, and dissolution Q=75% at 45 min in 900 mL of 0.1 N hydrochloric acid using USP <711> Apparatus 2 at 50 rpm. Magnesium stearate content above 1.0 wt% is avoided because it reduces tensile strength through hydrophobic lubrication; sodium starch glycolate above 5 wt% is also avoided in humid manufacturing suites because the hydrochloride salt can absorb moisture and cause picking during compression.
When the reduced intermediate hydrochloride is filled into hard capsules at strengths below 10 mg per size 3 capsule, direct mixing with lactose monohydrate produces acceptable bulk blend uniformity but fails content uniformity on a dosator-type capsule machine because the active salt with D90 above 120 µm segregates during hopper vibration. A geometric dilution sequence is therefore used. The salt is first blended 1:10 with microcrystalline cellulose PH101 in a 50 L bin blender at 12 rpm for 20 min, passed through a 0.71 mm sieve, then blended with the remaining excipients for an additional 20 min. The final blend consists of the diluted premix, pregelatinized starch 10.0 wt%, crospovidone 2.0 wt%, colloidal silicon dioxide 0.5 wt%, and sodium stearyl fumarate 2.0 wt%. Fill weight is 120 mg ± 5.0% on an intermittent-motion capsule machine running at 60,000–80,000 capsules per hour with a 18 mm dosing disc and a 3 mm compaction pin. Content uniformity is tested with USP <905>; the acceptance value is controlled at not more than 15.0. Capsule shells are conditioned at 23 ± 2 °C and 40–50% relative humidity for 24 h before filling. Gelatin shell moisture is maintained at 13–16 wt%, and HPMC shell moisture at 4–7 wt%, to avoid brittle fracture on the dosing drum. Because the hydrochloride salt can deliquesce above 65% relative humidity, finished capsules are packaged in cold-form aluminum blisters with silica gel desiccant. Avoid sorbitol above 10 wt% in humid climate packaging because it increases water uptake and accelerates shell deformation.
Powder for oral suspension from the reduced intermediate hydrochloride is prepared by fluid-bed top-spray granulation on a 10 kg scale. The granulation charge consists of the active salt 10.0 wt%, mannitol 55.0 wt%, microcrystalline cellulose PH102 20.0 wt%, polyvinylpyrrolidone K30 3.0 wt%, croscarmellose sodium 2.0 wt%, colloidal silicon dioxide 0.3 wt%, sucralose 0.2 wt%, and a non-hygroscopic flavor 0.5 wt%. PVP K30 is dissolved in purified water at 5.0 wt% solids and sprayed from a 1.0 mm two-fluid nozzle at atomizing air pressure of 1.2 bar and a spray rate of 12 g/min per kg of dry bed. Inlet air temperature is 60 °C, product temperature is held at 34–38 °C, and the process is stopped when loss on drying is below 2.0 wt%. The granules are sieved through a 1000 µm top screen and a 150 µm bottom screen; the target granule size is D50 140–180 µm by laser diffraction. Sachet filling is performed with an auger-type powder filler at 1.0 g or 2.0 g fill weight, and fill weight variation is controlled at ± 5.0%.
The reconstituted suspension prepared by dispersing one sachet in 5 mL of potable water at 25 °C should show no large aggregates after 30 s of gentle shaking, and sedimentation volume after 30 min should stay above 0.90. Dissolution testing of the dry suspension is replaced by a dispersibility test and by HPLC assay in the reconstituted liquid at 0 and 14 days when stored at 25 °C and 60% relative humidity. Avoid adding sodium metabisulfite or other strong reducing agents to the suspension because they can react with residual nitro absorbance; if antioxidant protection is required, ascorbic acid is preferred at not more than 0.2 wt%. The granulation process is sensitive to binder viscosity: PVP K30 solutions above 8.0 wt% solids increase droplet size and produce dense, poorly dispersible agglomerates above 500 µm, which reduce sachet content uniformity.
A lyophilized injectable built from the reduced intermediate hydrochloride requires a formulation with low buffer capacity and controlled tonicity. The bulk solution is prepared at 10.0 mg/mL active salt in Water for Injection, with mannitol 4.0% w/v as bulking agent and hydrochloric acid or sodium hydroxide q.s. to pH 4.0–5.0. The solution is filtered through a 0.22 µm PVDF membrane filter under nitrogen pressure at 0.5 bar. Filling is performed on a 5 mL Type I borosilicate glass vial line with 13 mm bromobutyl stoppers under Grade A laminar airflow. The lyophilization cycle uses a freeze ramp of 1.0 °C/min to -45 °C, a hold of 180 min, an annealing step at -10 °C for 120 min, primary drying at -20 °C shelf temperature and 100–150 µbar chamber pressure for 30 h, and secondary drying at 35 °C for 6 h. The finished cake moisture specification is not more than 1.0 wt% by USP <921>. The freeze-dried product is reconstituted to 5 mL with sterile water before use; reconstitution time should not exceed 60 s.
Sterility, endotoxin, and particulate controls follow the injectable monograph. Sterility is tested per USP <71> with 14-day incubation. Bacterial endotoxin per USP <85> is controlled at ≤0.25 EU/mg. Subvisible particulate matter per USP <788> light obscuration particle count test is controlled at not more than 6000 particles ≥10 µm and not more than 600 particles ≥25 µm per container. Residual palladium is controlled at ≤10 ppm by USP <232>/<233>, and residual unreduced 4-chloro-2,6-dimethyl-3-nitropyridine is limited to ≤0.10 area percent by HPLC because the nitro-containing starter is not permitted in the injectable finished product. Phosphate-buffered systems at pH above 6.0 are avoided during formulation development because the hydrochloride salt can show reduced solubility; if buffering is required, acetate buffer is preferred in the pH 4.0–5.0 window. The lyophilized vials are stored below 25 °C and protected from light.
After core tablets are compressed from the reduced intermediate hydrochloride, an enteric film is applied only when the active molecule is acid-labile or causes gastric irritation. The core tablets are deburred and dedusted, then preheated to 30 °C in a 600 mm perforated pan coater with three 0.8 mm spray guns. The coating dispersion is prepared from methacrylic acid copolymer type C as Eudragit L 30 D-55 aqueous dispersion, diluted to 20 wt% solids, with triethyl citrate 10 wt% based on polymer solids and talc 35 wt% based on polymer solids as anti-tacking agent. Spray rate is maintained at 8–12 g/min, atomizing air at 1.2–1.5 bar, inlet air at 45–50 °C, product temperature at 26–30 °C, and pan speed at 6–10 rpm. A target weight gain of 10–20 mg/cm² is applied. After coating, the tablets are cured in the closed pan at 40 °C for 2 h.
Enteric integrity is verified by two-stage disintegration per USP <701>. In 0.1 N hydrochloric acid for 2 h, no tablet should crack, soften, or disintegrate; after transfer to pH 6.8 phosphate buffer at 37 ± 0.5 °C, complete disintegration must occur within 45 min. Drug release in the buffer is measured with USP <711> Apparatus 1 at 100 rpm; the release profile should exceed Q=75% at 60 min. The coating dispersion pH must be kept below 5.0 during spraying because polymer aggregation at higher pH can block spray guns and produce surface roughness. Core tablets with friability above 0.5% are rejected before coating because edge chips during pan rotation create defects that fail enteric resistance. Published data for this specific derivative in organic-solvent-based Eudragit systems is limited; aqueous dispersion is therefore preferred for process reproducibility.
Before the reduced intermediate hydrochloride is released for tableting, capsule filling, granulation, or lyophilization, the solid-state and particulate attributes are trended against stage-appropriate acceptance limits. Differential scanning calorimetry is run at a heating rate of 10 °C/min under nitrogen flow of 50 mL/min to detect broad endotherms or exothermic decomposition. Thermogravimetric analysis is used to reject batches with weight loss above 0.5% up to 150 °C. Dynamic vapor sorption at 25 °C from 0% to 90% relative humidity identifies the critical relative humidity for deliquescence; if mass increase exceeds 2.0% at 60% relative humidity, the batch is designated for desiccant packaging and closed transfer. Powder X-ray diffraction is collected from 3° to 40° 2θ at 1°/min to detect form changes after milling.
Particle size distribution is measured by laser diffraction on a Malvern Mastersizer 3000 with dry dispersion at 1.0 bar. For oral solid dosage, D10 is specified at ≥5 µm, D50 at 50–120 µm, and D90 at ≤250 µm; for lyophilized injectable manufacture, the active solution is clarified through 0.22 µm filtration, so oversized particles above 30 µm are a filter-loading risk. Residual solvent and elemental impurity data are compiled according to ICH Q3C and ICH Q3D. Palladium is controlled by USP <232>/<233> where the reduction step uses heterogeneous catalysis.
Table 1 lists the residual solvent limits applied to the isolated salt under ICH Q3C Option 1, assuming a 10 g daily dose for oral solid products. Table 2 lists the release and process-fitness test matrix applied before dosage form start.
| Solvent | ICH Q3C Class | PDE (mg/day) | Concentration Limit (ppm) |
|---|---|---|---|
| Methanol | Class 2 | 30.0 | 3000 |
| Dichloromethane | Class 2 | 6.0 | 600 |
| Toluene | Class 2 | 8.9 | 890 |
| Isopropanol | Class 3 | 50.0 | 5000 |
| Ethyl acetate | Class 3 | 50.0 | 5000 |
| Acetic acid | Class 3 | 50.0 | 5000 |
| Attribute | Method / Standard | Acceptance Criterion |
|---|---|---|
| Assay | HPLC external standard | 98.0–102.0% on dried basis |
| Related substances | HPLC area normalization | Any unspecified impurity ≤0.10%; total ≤0.50% |
| Palladium | USP <232>/<233> | ≤10 ppm |
| Water | USP <921> Karl Fischer | ≤0.50% |
| Residual solvents | ICH Q3C Option 1 | Per Table 1 |
| Particle size | Laser diffraction dry dispersion | Oral solid D90 ≤250 µm; injectable pre-filtration D90 ≤30 µm |
Competitive 4-Chloro-2,6-dimethyl-3-nitropyridine Pharma Grade API for Tablet / Capsule / Granule / Injection, Oral & Injectable prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please contact us at +8618136850665 or mail to admin@ascent-chem.com.
We will respond to you as soon as possible.
Tel: +8618136850665
Email: admin@ascent-chem.com
Flexible payment, competitive price, premium service - Inquire now!
Pharmaceutical-grade 4-chloro-2,6-dimethyl-3-nitropyridine is supplied as a crystalline solid with empirical formula C₇H₇ClN₂O₂ and molecular weight 186.60 g/mol. The material is intended for formulation into oral tablet, capsule, and granule dosage forms, and as a reduced-endotoxin grade for injectable preparations after validated aseptic processing or terminal sterilisation. No harmonized pharmacopeial monograph currently exists for this substance; consequently the release specification is supplier-specific and must be verified against a current certificate of analysis and the intended dosage-form monograph. The model designation is assigned by the manufacturer and is recorded on the certificate of analysis, not as a pharmacopeial grade designation.
Solid oral processing is supported by jet milling the crystalline material on a spiral jet mill with an integral classifier. A target particle-size D50 between 10 µm and 25 µm and D90 not exceeding 50 µm is set for direct compression and capsule filling. The D50 will shift with classifier rotational speed, injector gas pressure, and nozzle configuration; published data specific to this compound on production-scale spiral jet mills is limited, so milling qualification trials are required to establish the relationship between classifier speed and residual coarse fraction. Water content is controlled to not over 0.5% by Karl Fischer titration. At storage relative humidity above 60%, the API should be re-dried before blending because surface moisture reduces powder flow and increases sticking on tablet punches.
The pyridine ring is a weak base, but the electron-withdrawing nitro group at C3 and chlorine at C4 reduce aqueous solubility in unbuffered water. Solubility screening should therefore be conducted in compendial buffers across pH 1.2–6.8 using the shake-flask method and HPLC-UV detection; published solubility data for this specific compound is limited, and the absence of a monograph means that intrinsic dissolution rate should be measured before selecting a tablet or capsule matrix. Because the molecule is crystalline and non-hygroscopic at low relative humidity, dry processing may be preferred over high-shear aqueous granulation in initial formulation development.
The C4 chloro substituent is less sterically hindered than C2/C6 alternatives and can participate in nucleophilic aromatic substitution, while the C3 nitro group lowers the basicity of the pyridine nitrogen and directs ring reactivity. These structural features influence wet granulation compatibility; forced-degradation screening under ICH Q1B is recommended before selecting a high-shear aqueous granulation process. In dry processing, the milled material is blended in a bin blender at 15 rpm for 10–15 min with microcrystalline cellulose and crospovidone. Magnesium stearate at 0.25–0.5% of total blend mass is added last, and the lubrication time is held below 2 minutes to avoid excessive coatability loss and tablet hardness reduction. If roller compaction is used, the granule solid fraction is maintained within 0.55–0.65; compacted ribbon density outside this range has shown reduced granule compressibility on rotary tablet presses.
For capsule filling, particle-size and bulk-density consistency are more critical than for tableting because the fill volume is fixed by the capsule body. The jet-milled material should be evaluated for Carr index and Hausner ratio according to USP <1174>; powders with Hausner ratio above 1.35 are considered poorly flowing and may require roller compaction or a granulation step. The target fill weight is calculated from the bulk density and tapped density, with fill variation controlled below 3% relative standard deviation in production-scale tamping disk capsule machines. Published data specifically for this compound is limited, but powder-flow measurements are performed using a shear cell with normal stress from 1 kPa to 10 kPa to determine the unconfined yield strength.
Injectable dosage forms require a departure from oral-solids release testing. The API is not presumed sterile unless a sterile contract manufacturing route is specified; most injectable programs dissolve the non-sterile API in a compatible vehicle and use a sterilising-grade 0.22 µm membrane filter. The bacterial endotoxin limit is formulation-specific and is derived from the maximum adult daily dose; for high-dose parenteral products a common limit is not exceeding 0.25 EU/mg, but this value is not a compendial default and must be calculated using USP <85>. The nitroaryl group is susceptible to photodegradation; therefore sterile-filtered solutions should be protected from light and evaluated under ICH Q1B for nitrite ion and related degradation products. Subvisible particulate matter in the finished injectable is controlled according to USP <788> for large-volume parenterals or USP <789> for ophthalmic formulations where relevant.
If the solution can be sterilised by filtration, the filtration train should include a 0.22 µm polyethersulfone or polyvinylidene fluoride membrane with an upstream pre-filter. Filter compatibility must be confirmed because nitroaromatic compounds can adsorb to some membrane polymers and reduce filter integrity. Terminal sterilisation at 121 °C for 15 min may be unsuitable if the pyridine derivative degrades or if the vehicle is non-aqueous; in such cases aseptic filtration under EU GMP Annex 1 is used. The holding time between dissolution and sterile filtration must be justified by solution stability data and filtered-product bioburden data; published data for this specific compound is limited, so initial process simulations should include worst-case hold times rather than defaulting to short intervals. Post-filtration dissolved-oxygen levels are monitored if the solvent system promotes oxidative degradation of the nitro group.
If the injectable product is presented as a lyophilised cake or dry powder for reconstitution, the API’s residual solvent and water content must be lower than for oral solids. Karl Fischer water content is typically not more than 0.3% for lyophilised material; excipients are selected to maintain a cake structure that reconstitutes within 60 seconds in the intended diluent, but reconstitution time is formulation-dependent and must be verified. The API’s particle size before lyophilisation is less critical than solution clarity, because the product is dissolved before filling. Subvisible particulate matter after reconstitution is tested by light obscuration according to USP <788> and the acceptance criterion depends on the container volume and route of administration.
The principal structurally related impurities arise from positional isomer formation during chlorination and nitration. These include 2-chloro-4,6-dimethyl-3-nitropyridine, 4-chloro-2,6-dimethylpyridine, and the dechlorinated 2,6-dimethyl-3-nitropyridine. They are resolved on a phenyl-hexyl stationary phase using a gradient of acetonitrile and 0.1% formic acid, with ultraviolet detection at 254 nm. The individual unspecified impurity limit is set at 0.10%, consistent with ICH Q3A qualification thresholds when the maximum daily dose is not higher than 2 g/day; for higher doses the limit must be recalculated. Total related substances are typically controlled at not more than 1.0%. Impurities above the qualification threshold are reduced by recrystallisation or preparative chromatography before release.
The manufacturing route may generate hydrazine or chlorinated by-products, so the API release panel includes a limit for potentially genotoxic impurities when the route uses reagents of toxicological concern. Control follows the staged TTC of ICH M7, with a default threshold of 1.5 µg/day for low-potency substances. If the substance has structural alerts from the nitro group or chloropyridine scaffold, the nitrosamine risk assessment is performed on the drug product as well as the API; published data for this specific molecule is limited, so a risk assessment rather than a blanket exclusion is required.
Residual solvent control for oral and injectable grades uses gas chromatography with headspace injection and method parameters mapped to ICH Q3C. Class 2 solvents such as methanol and dichloromethane are limited according to the permitted daily exposure values; Class 1 solvents are excluded and tested as absent at the method limit. The injectable grade additionally requires elemental-impurity reporting against ICH Q3D and USP <232>/<233>. Tungsten and other mill-contact extractables are included in the elemental-impurity risk assessment if the API is micronised before recrystallisation; when the risk cannot be excluded, inductively coupled plasma-mass spectrometry is used with a detection limit appropriate to the parenteral route.
Table 1 lists the supplier-specific release specification that should be cross-checked against the current certificate of analysis.
| Attribute | Method/Reference | Representative acceptance criterion |
|---|---|---|
| Assay (as-is, solvent-free) | HPLC-UV, ICH Q2(R1) | 98.0–100.5% |
| Total related substances | HPLC-UV | ≤ 1.0% |
| Individual unspecified impurity | HPLC-UV | ≤ 0.10% |
| Residual solvents | GC-HS, ICH Q3C | Class 2 solvents ≤ permitted daily exposure |
| Elemental impurities | ICP-MS, USP <232>/<233> | ICH Q3D oral/parenteral PDE |
| Water content | Karl Fischer | ≤ 0.5% |
| Residue on ignition | Ph. Eur. 2.4.14 | ≤ 0.1% |
| Bulk density after milling | USP <616> | 0.38–0.52 g/mL |
| Particle size D90 | Laser diffraction | ≤ 50 µm for dry processing |
The specification above is not a regulatory compendial standard. It is a representative supplier-specific release profile; actual limits may vary with the manufacturing route and the intended dosage form.
Photostability screening is performed on both the solid API and a dilute solution. The nitro group absorbs in the ultraviolet region and can undergo photoreduction to amine intermediates if the formulation contains electron-donating excipients. Forced-degradation conditions under ICH Q1B should include exposure to visible light not less than 1.2 million lux hours and ultraviolet light not less than 200 W h/m². In a tablet matrix, titanium dioxide may reduce photodegradation by light scattering, but titanium dioxide also participates in photocatalytic surface reactions; its effect on this nitroaromatic compound must be measured rather than assumed. Published data for this specific configuration is limited, so the initial stability protocol should include assay, total related substances, and subvisible particle counts for injectables.
On a production-scale rotary tablet press, tooling temperature, turret speed, and precompression force are adjusted to avoid lamination and capping. Because the compound is crystalline and has a relatively low aqueous solubility, direct-compression formulations may require a filler with high plastic deformation such as microcrystalline cellulose and a disintegrant with high wicking capacity such as crospovidone. Tablet breaking force is measured using USP <1217>, and disintegration is measured using USP <701>. If the disintegration time exceeds 15 minutes in water, the tablet formulation should be reformulated with a higher disintegrant level or a lower compression force. These processing thresholds are general oral-solid boundaries, not specific to the compound, and require formulation-scale verification.
Differences from technical-grade material and from structural analogues are summarised in Table 2. The comparison is based on general structural, regulatory, and processing expectations rather than on a compendial monograph.
| Parameter | Pharma-grade 4-chloro-2,6-dimethyl-3-nitropyridine | Technical-grade material | 2-Chloro-4,6-dimethyl-3-nitropyridine |
|---|---|---|---|
| Assay | ≥ 98.0% | 95–97% | not harmonized; published data limited |
| Impurity emphasis | ICH Q3A qualification | process residues and isomeric impurities | alternate regioisomer profile |
| Particle-size control | jet milled, D90 ≤ 50 µm | loose crystals or powder | same unit operation but different fragmentation |
| Injectable suitability | low endotoxin, filtered through 0.22 µm | not suitable without repurification | requires full revalidation |
| Regulatory dossier support | GMP under ICH Q7, DMF where contracted | not provided | limited |
The main product difference for the oral and injectable grades is the impurity map rather than a change in molecular structure. Pharmaceutical-grade material is recrystallised to remove isomeric chloronitropyridines and supplied with analytical data under ICH Q7; technical-grade material may contain the same nominal compound but without qualified related-substance control or a defined particle-size distribution. The C4 chloro substitution also distinguishes this molecule from the C2 chloro analogue by reducing steric hindrance at the electrophilic position and altering the degradation products detected in forced-degradation studies.
For dissolution testing of oral tablet and capsule products, a two-point or three-point method may be selected according to the regional dossier. Sink conditions for the poorly water-soluble compound are established using compendial media containing 0.1 mol/L hydrochloric acid, 0.05 M phosphate buffer pH 6.8, or 0.5% sodium lauryl sulfate. Because no pharmacopeial monograph exists, the dissolution specification must be derived from batch-to-batch in vivo or in vitro correlation data; the initial specification typically includes an acceptance criterion of 80% dissolved in 30 minutes only when the dissolution method is discriminating. Published data specific to this compound is limited, so the method development should include a comparison of USP apparatus 1 and apparatus 2 at 50 rpm and 75 rpm.
In granule formulations, dry blending with microcrystalline cellulose and crospovidone is conducted in a bin blender at 15 rpm for 10–15 min; the blend is then compacted with roll pressure adjusted to produce a granule solid fraction of 0.55–0.65. Granules outside this density range have shown reduced tablet hardness and increased friability on a rotary press; however published data specific to this compound remains limited. Use of amine-based disintegrants or alkaline lubricants should be avoided without forced-degradation data because the nitro group can generate nitrite or amine by-products under alkaline moisture. Magnesium stearate at 0.25–0.5% is typical, but blending time must not exceed 2 minutes to preserve tablet tensile strength.
