Chuanhu Shiliupi Powder Veterinary Grade API is a dry, multi-plant extract powder intended solely as a starting material for finished veterinary dosage forms. It is not a direct-to-animal premix, feed additive, or sterile injectable in the packaged state. The material is released against a defined specification for marker content, particle-size distribution, loss on drying, heavy metals, residual solvents, and microbial attributes. No harmonized international model code is assigned to veterinary botanical APIs under current pharmacopoeial classification systems; the product is identified by the Chuanhu Shiliupi Powder Veterinary Grade API designation, the manufacturer lot number, and the certificate of analysis version. Packaging is 25 kg net per drum, using two nested low-density polyethylene liners inside an aluminum-foil laminate bag. Storage is specified at 15 °C to 25 °C and relative humidity below 60%. The retest interval is 24 months from release under those conditions.

The analytical control strategy relies on marker standardization rather than a single active entity because the powder contains multiple co-extracted components. Marker content is determined by high-performance liquid chromatography with photodiode array detection, and batch release accepts a relative standard deviation of ±5.0% from the labeled marker concentration. Published data for this specific product configuration is limited; the specification framework therefore aligns with general acceptance criteria for veterinary botanical extract powders rather than a dedicated monograph. Each certificate of analysis should be checked for the marker identity, assay result, and the specification version corresponding to the intended finish form: oral solids, premix, or parenteral feedstock.

What Physicochemical Boundaries Govern Use in Seven Finish Forms?

The powder is characterized by a controlled upper particle size and residue limits that reduce downstream milling in tablet, capsule, granule, powder, premix, and solution manufacturing. Loss on drying is controlled to ≤ 5.0% according to USP <731>. Bulk density ranges from 0.38 g/mL to 0.52 g/mL and tapped density from 0.52 g/mL to 0.68 g/mL by USP <616>. The particle-size specification is D90 ≤ 74 µm by laser diffraction according to ISO 13320:2020. Sieve retention on 0.250 mm is ≤ 5.0% by USP <786>. Heavy metals are controlled by inductively coupled plasma mass spectrometry according to USP <233>: lead ≤ 5.0 mg/kg, arsenic ≤ 2.0 mg/kg, cadmium ≤ 0.5 mg/kg, and mercury ≤ 0.1 mg/kg. Residual solvents are controlled by gas chromatography according to USP <467>, with Class 2 and Class 3 limits applied to methanol, ethanol, acetone, ethyl acetate, and toluene.

Microbial release limits are total aerobic microbial count ≤ 10³ CFU/g, total combined molds and yeasts ≤ 10² CFU/g, absence of Salmonella in 10 g, and absence of Escherichia coli in 1 g, according to USP <2021> and USP <2022>. Endotoxin content is controlled to ≤ 0.5 EU/mg by the limulus amebocyte lysate method according to USP <85>. This endotoxin limit is a feedstock acceptance criterion, not a terminal sterility or depyrogenation claim.

Compliance with the endotoxin limit shown above does not render the powder injectable. Parenteral solutions require depyrogenation, aseptic dissolution, bioburden reduction filtration, and terminal sterile filtration through a 0.22 µm polyvinylidene fluoride or polyethersulfone membrane. The powder as supplied is non-sterile. When a single lot is split between oral and parenteral applications, area segregation and validated cleaning are required to prevent particulate carryover into the sterile line.

In tablet manufacture, the powder is added at a formulation-dependent proportion, typically 20–50 wt% of core mass; finished-dose strength must be justified by marker content rather than raw powder mass alone. Direct compression is possible after pre-blending with microcrystalline cellulose and colloidal silicon dioxide. Compression on a rotary tablet press with a force feeder at 8–20 kN main compression force and turret speed 15–40 rpm produces acceptable hardness when powder moisture is below 5.0%. The Carr index is typically 28–32 and the Hausner ratio 1.28–1.32, indicating fair passable flow. This flow profile necessitates a force feeder for high-speed tableting or roller compaction for dry granulation.

Tannin-rich powders create a known processing bottleneck during aqueous wet granulation. The binder solution can form high-viscosity gels when local water activity exceeds 0.6. Granulator torque increases sharply at massing times beyond 6 min; at impeller speeds above 600 rpm, granule temperature can exceed 40 °C, increasing sticking on the chopper blade. Wet massing is therefore controlled to 3–6 min with a spray-rate limit of 0.5 L/min per 100 kg dry powder. If torque doubles from baseline, the batch is discharged immediately and evaluated for particle-size overgrowth.

Sieve Retention and Moisture Uptake Distinguish Oral Granule and Premix Performance

For granules and premixes, the powder is blended with water-soluble excipients and agglomerated in a high-shear granulator with impeller speed 300–600 rpm and chopper speed 1500–3000 rpm. Wet massing time is limited to 3–6 min because excess binder interaction with tannin-containing fractions increases torque. Granules are dried in a fluid-bed dryer at inlet air temperature 60–70 °C to final moisture 3.0–4.5%. Dried granules passed through a 1.0 mm oscillating granulator show sieve retention of 15–30% on 0.710 mm, which is suitable for uniform dilution in animal feed at 0.5–5.0 kg per tonne depending on the finished premix specification.

On a production-scale twin-screw wet granulator with an L/D ratio of 25:1 and barrel diameter 19 mm, the powder is fed at 10–20 kg/h and granulated with water at a liquid-to-solid ratio of 0.25–0.35 mL/g. Screw speed is 200–300 rpm. Under these conditions, granule friability values below 1.0% are observed for the 0.5–1.0 mm fraction when feed moisture is below 4.0%. Batches with moisture near 5.0% show wider granule-size distributions and increased fines. This behavior creates a practical upper moisture limit for continuous granulation.

Capsule filling on an automatic capsule machine requires the blend to pass through a 0.8 mm sieve and contain 0.5–1.0% magnesium stearate or 1.0–2.0% sodium stearyl fumarate. Fill-weight variation across 40,000 capsules per hour is maintained within ±5.0% when the blend has a Hausner ratio below 1.35. Moisture in empty hard gelatin capsules must be below 13.0% to prevent embrittlement caused by the tannin fraction of the powder.

Above 60% relative humidity, the powder requires pre-drying at 50 °C for 4 h before blending. Material drawn from a partially used drum must be re-evaluated for moisture and microbial limits if the drum has been open for more than 7 days or if ambient humidity exceeded 60%. This re-evaluation burden is frequently omitted with commodity botanical powders, which is one operational difference in production planning.

Comparative Contaminant and Carrier-Dilution Boundaries

A comparative release profile against commodity botanical powders is provided to identify processing differences. The measured differences affect the number of milling, sieving, and microbial reduction steps required before the powder can be incorporated into a certified premix or finished oral dosage form.

These differences do not make the commodity powder unsuitable for all uses, but they change the manufacturing burden. A facility using the controlled veterinary grade API can reduce pre-milling, sieving, and microbial reduction treatments. Commodity powder often requires dry heat treatment at 80 °C for 2 h or gamma irradiation to reach the same microbial acceptance level, which may alter marker content and dissolution behavior. The controlled API is therefore selected when batch-to-batch reproducibility is a release requirement for the finished veterinary medicine.

For injectable solutions, the powder is dispersed in water for injection at 1.0–5.0% w/v and dissolved with continuous stirring at 20–25 °C. The resulting solution is adjusted to pH 5.5–7.0 with citrate buffer. Solutions pass through a clarifying filtration train: a 0.45 µm depth filter followed by a 0.22 µm membrane filter. Because the extract contains colloidal polysaccharides and tannins, filter capacity must be validated for each lot. An increase in transmembrane pressure above 1.5 bar indicates premature fouling. The filtered solution is not considered terminally sterilized unless the finished formulation is shown to be stable under moist-heat sterilization at 121 °C for 15 min, which is not assumed for this product without finished-formulation data.

Filterability is the main scale-up risk for parenteral use. A 0.1 m² polyethersulfone capsule at constant pressure 0.7 bar processing a 5.0% w/v solution may show a flux of 20–50 L/m²/h. Flux can drop by half after 20–30 L/m² throughput if the solution is not first clarified through a 0.45 µm depth filter. Membrane area calculations therefore apply a safety factor of 1.5–2.0× over the calculated area for the target batch volume.

For water-soluble powder formulations, the API is co-milled with dextrose or lactose to a final D90 of 45–75 µm. The finished powder dissolves in water at 20 °C at 0.5% w/v within 60 s under moderate stirring at 200 rpm, producing a dark amber colloidal solution. Turbidity above 50 NTU after 0.45 µm filtration can indicate incomplete dissolution or coagulation of tannins; such lots require reformulation with a dispersing agent rather than extended stirring.

Solutions at 5.0% w/v exhibit dynamic viscosity 2.0–4.5 mPa·s at 25 °C. This is higher than simple electrolytes and requires pump sizing that accounts for viscosity at the target fill temperature. For oral solutions, preservatives such as sodium benzoate 0.1–0.2% or potassium sorbate 0.1–0.2% are used. The solution is adjusted to pH 4.5–6.5 to maintain tannin stability and reduce sedimentation.

Dissolution profiling of tablets containing this powder is performed with 900 mL of 0.1 M hydrochloric acid or purified water at 37 °C ± 0.5 °C using USP Apparatus 2 at 50 rpm. Marker release varies with the granulation route. Wet-granulated batches release not less than 70% of marker content within 45 min, whereas direct-compression batches may release 60–80% in the same interval. These are formulation-dependent values and require finished-product validation for each formulation.

In multi-species feed premix applications, the powder is added at the mixer after stepwise dilution with ground corn or rice hulls. The dilution sequence starts with a 1:10 manual preblend, followed by a 1:100 ribbon blender pass for 15 min at 25 rpm. Blend homogeneity is assessed by marker assay on 10 independent thief samples; acceptance is a relative standard deviation of ≤ 5.0%. If the RSD exceeds 5.0%, mixing time is extended in 5-min increments to a maximum of 30 min, after which particle-size segregation rather than mixing time is addressed by re-milling the premix carrier.