Qinhuang Granules Veterinary Grade API for Tablets / Injections / Capsules / Powders / Granules / Premix / Solutions is the granulated presentation of a veterinary active substance designated QH-VAPI-G. The material is manufactured by high-shear wet granulation followed by fluid-bed drying with inlet air temperature held between 55 °C and 65 °C. Residual moisture is controlled to ≤ 3.0% w/w by Karl Fischer titration according to Ph. Eur. 2.5.12. The standard direct-compression fraction has a volume median diameter of 150–250 µm; the fine fraction for solution and injection reconstitution is specified at ≤ 180 µm. Bulk density is 0.58–0.72 g/cm³ and the Hausner ratio is ≤ 1.25 under Ph. Eur. 2.9.34. The manufacturing site operates under EU GMP Part II for active substances and maintains an ISO 9001:2015 quality management system. The granulated form is distinct from micronized API in that it suppresses airborne dust during sack discharge and provides adequate flow for rotary tablet presses; it differs from coarse crystalline powder in that the hydrophilic binder layer allows rapid aqueous dispersion while retaining defined particle size.

Material Identity and Release Specification Matrix

QH-VAPI-G is released under a specification that separates base granule attributes from application-linked parameters. Identity is established by retention time comparison against a certified reference standard using liquid chromatography per Ph. Eur. 2.2.29. Related substances are limited to total impurities ≤ 1.0% and unspecified individual impurities ≤ 0.3%; unknown impurities above 0.10% are identified by liquid chromatography–mass spectrometry before acceptance. Impurity qualification follows the principles of VICH GL11. Residual solvent control follows VICH GL18; ethanol, when used as the granulation solvent, is limited to ≤ 0.5% w/w by headspace gas chromatography. The granule is not sterile, and the base grade is not intended for parenteral use unless the injectable grade is selected and the downstream process includes dissolution, filtration, and aseptic filling.

Particle-size distribution is measured by laser diffraction per Ph. Eur. 2.9.31 after dispersing the granule in a dry air stream at 1 bar. The method is selected because wet dispersion can partially dissolve the binder and shift the D50 by as much as 15 µm. For routine release, a three-deck sieve stack at 75 µm, 180 µm, and 300 µm is used as an internal control; the laser-diffraction value is the regulatory release method. Granules retained above 300 µm are limited to ≤ 2.0% w/w for the direct-compression grade, and granules retained above 180 µm are limited for the fine grade.

On a production-scale bin blender of 1500 L, the direct-compression grade has been processed with microcrystalline cellulose at 30% w/w and magnesium stearate at 0.75% w/w. At bin rotation speed 8 rpm for 120 revolutions, tablet content uniformity remains below 1.5% relative standard deviation. When fill volume exceeds 70%, larger granules migrate upward and the first 10% of discharged material can show potency enrichment of approximately 12%. The preferred fill window is therefore 50–65%. Compression on a rotary tablet press with mean upper punch force of 16 kN and 120 ms dwell time produces tensile strengths around 1.8–2.2 MPa. If granule moisture falls below 1.0% w/w, capping and electrostatic charging increase; above 3.0% w/w, picking and sticking appear on the punch faces. These are process control limits derived from production-scale behaviour of hygroscopic granulated APIs, not chemical safety thresholds.

How Does the Granulated Morphology Influence Blend Uniformity in Low-Dose Premixes?

Low-dose premixes are sensitive to segregation when the active granule and mineral carrier do not share similar density and particle-size distributions. QH-VAPI-G/P with D50 between 180 µm and 300 µm has sufficient mass to resist dust drift but small enough to distribute through a ribbon mixer. A carrier bulk density below 0.45 g/cm³ against granule bulk density above 0.60 g/cm³ creates stratification during silo discharge and feed auger transfer; the carrier should therefore be within ±0.10 g/cm³ of the granule. In a 500 kg ribbon mixer at 25 rpm, coefficients of variation below 5.0% are achieved after 15 min when the D50 difference between carrier and granule is below 100 µm. A higher span above 3.0 increases fine-particle retention in mixer corners and dead zones; the premix grade is therefore air-classified to remove particles below 75 µm before packaging.

Batch-to-batch consistency in granule size is monitored by statistical process control; the D50 mean chart is set with action limits at ±25 µm from the target and is supported by a minimum of 40 successive release results per granulation line. A shift of D50 above 275 µm in the direct-compression grade has been associated with increased tablet weight variation on a 45-station rotary press at 60,000 tablets/h. The same shift in the premix grade can cause feeder blockage in feed-mill dosing screws with clearances below 2 mm.

When the Same API Grade Must Serve a Sterile Solution Line

For injectable dosage forms, QH-VAPI-G is reconstituted in Water for Injection or a buffered co-solvent, then membrane-filtered through a 0.22 µm nominal pore-size filter and aseptically filled. The granulate itself is not sterile and cannot be dry-heat or steam sterilized as a dry solid; the process therefore includes dissolution, pH adjustment, and filtration. Endotoxin release limit for the injectable-grade granule is ≤ 500 EU/g by Ph. Eur. 2.6.14, but the finished solution must meet the product-specific limit in the marketing authorization. Particulate matter after reconstitution is evaluated by light obscuration per Ph. Eur. 2.9.19; for a 100 mL solution, particles ≥ 10 µm are limited to 6000 per container and particles ≥ 25 µm to 600 per container. The fine grade with D50 ≤ 180 µm is used because coarser granules increase mixing time and may leave visible residue on filter membranes if added too quickly. A high-shear mixer operating at 300 rpm disperses the fine granule in water at 25 °C within 120 s; at 15 °C wetting time extends to 180–240 s and in-line screens below 75 µm may block.

Qinhuang Granules QH-VAPI-G/F is used for oral solutions and drinking-water medications at concentrations determined by target species and dose. In a 1000 L vessel with bottom-mounted high-shear mixer at 300 rpm, a 20 g/L solution can be passed through a 75 µm screen after 10 min stirring without residue accumulation. If the granule is blended into dry feed at the mill, the premix grade QH-VAPI-G/P is preferred because the fine solution grade may bridge in hoppers and in pellet mill feed augers. Dry blends intended for pelleted feed should not be exposed to steam conditioning above 80 °C unless a stability study demonstrates potency retention; published data for this specific configuration is limited, and the manufacturer’s technical bulletin recommends conducting a forced-degradation study in the full feed matrix before committing to a steam-pelleting process.

Selecting the Correct Granule Fraction for Direct Compression

Three granule fractions are available. QH-VAPI-G/DC is the direct-compression grade with D50 of 150–250 µm and a D90/D10 span of ≤ 2.5; it is intended for rotary tablet presses and capsule dosators. QH-VAPI-G/F is the fine solution grade with D50 ≤ 180 µm and span ≤ 2.0; it disperses rapidly in aqueous vehicles but is not preferred for dry blending because it can form agglomerates with lubricants. QH-VAPI-G/P is the premix grade with D50 of 180–300 µm and span ≤ 3.0; it minimizes dust in feed-mill operations and provides flow through sack discharge and auger transfer. The sieve-cut control is not cosmetic; a narrow span is required because wide spans create content uniformity failure at low doses. When D90/D10 is above 3.5, the fine fraction accumulates around the tablet press feeder and causes weight variation; the coarse fraction segregates in the hopper. Air classification at 75 µm and 300 µm cut points is used, and the yield outside the target fraction is recycled only once because repeated dry milling reduces granule strength and increases fines beyond 15% w/w.

The Granule Surface Is Engineered for Dust Control, Not for Dry Powder Inhalation

Compared with micronized API, QH-VAPI-G reduces dust release during open transfer. Total suspended particulate monitoring during 250 kg sack discharge shows approximately 70% lower airborne dust relative to the micronized powder. The granule also exhibits a flow function coefficient above 4.0 in a ring shear tester, while the micronized form is typically below 2.0 and requires vacuum conveying or a containment isolator. The granule is not suitable for dry powder inhalation because D50 is far above the respirable aerodynamic diameter; particles larger than 5 µm are not respirable. Attempts to dry-mill the granule below 100 µm to recover micronized surface area are not recommended: milling destroys the binder bridges, raises the fine fraction above 35%, and regenerates the dust risk. Compared with a crystalline powder, the granulated form has slightly slower initial dissolution due to the hydrophilic binder layer, but wetting and disintegration in 0.1 M phosphate buffer at pH 6.8 and 37 °C typically occur within 3 min under stirring. This difference is acceptable for most oral and premix applications but must be qualified in the finished veterinary dosage form because the target species, feed matrix, and drinking-water hardness can alter dissolution behaviour.

Residual granule is removed from stainless-steel contact surfaces by dry vacuum followed by a 0.5% w/w sodium hydroxide solution at 50 °C. Swab samples are assayed by HPLC with detection below 0.1% of the lowest therapeutic dose to verify carryover control. Shared facilities handling sulfonamide or penicillin-type veterinary APIs should use dedicated air handling and validated cleaning, because cross-contact can introduce species-specific hypersensitivity and non-target feed exposure. Storage of QH-VAPI-G in sealed polyethylene-aluminium laminated sacks below 60% relative humidity is required; open handling above 60% RH for more than 4 h can increase moisture uptake beyond 3.0% w/w, after which the granule must be reconditioned at 40–50 °C before compression. The reconditioning cycle is limited to one occurrence because repeated drying fractures the binder bridges and raises the sub-75 µm fine fraction above 15% w/w, which impairs flow and content uniformity.