Huoxiang Zhengqi Powder Veterinary Grade API for Tablets / Injections / Capsules / Powders / Granules / Premix / Solutions is manufactured as a dry botanical extract under internal material designation HZP-VET-API. The product is prepared from a fixed-ratio decoction of the Chinese Veterinary Pharmacopoeia-defined Huoxiang Zhengqi formula, which includes Agastache rugosa aerial parts, Perilla frutescens leaf, Angelica dahurica root, Pinellia ternata processed rhizome, Poria cocos sclerotium, Atractylodes macrocephala rhizome, Citrus reticulata pericarp, Magnolia officinalis bark, Platycodon grandiflorum root, Glycyrrhiza uralensis root, Zingiber officinale rhizome, and Ziziphus jujuba fruit. The product is supplied in four end-use sub-grades: HZP-VET-O for oral solid dosage forms, HZP-VET-I for injection-track purification, HZP-VET-P for feed premixes, and HZP-VET-L for oral solutions. Unlike single-herb extracts or isolated synthetic actives, the material is standardized by multi-marker chromatographic fingerprinting rather than by a single chemical entity. It is intended only as an API for further manufacture into tablets, injections, capsules, powders, granules, premixes, and solutions; it is not a finished dosage form.

What release parameters are controlled for this veterinary-grade botanical API?

Release certification follows a two-tier scheme. Oral-grade lots are evaluated against USP 561 botanical identity, USP 2021 microbial enumeration, USP 2022 specified organisms, USP 731 loss on drying, and EP 2.8.13 pesticide residues. Parenteral-track lots additionally require USP 85 bacterial endotoxin testing, USP 71 sterility validation, and USP 788 particulate matter evaluation after reconstitution. This tiering prevents oral-grade material from entering an injection batch through documentation error. Batch records require the releasing analyst to record the material number HZP-VET-API and the intended dosage-form track on the certificate of analysis.

For injection-track product, the powder is depyrogenated by tangential-flow filtration; the final API solution is controlled to a bacterial endotoxin limit below 0.5 EU/mg where monograph language permits. Published data for this specific configuration is limited; therefore, each parenteral batch is qualified by spiked endotoxin recovery studies before release.

The manufacturing line uses vacuum concentration and low-temperature spray drying to protect the volatile monoterpenoid fraction. The decoction is concentrated in a falling-film evaporator at 80–120 mbar absolute pressure and 50–60°C liquid temperature. The concentrate is sprayed through a rotary atomizer at inlet-air 170–180°C and outlet-air 70–85°C. The resulting hollow-sphere particle morphology improves cold-water reconstitution but increases moisture sorption above 60% relative humidity. The powder is packed immediately in double LDPE-lined 25 kg HDPE drums inside a suite controlled to ≤35% RH. Bulk density is typically 0.35–0.50 g/mL, and tapped density is 0.45–0.65 g/mL for oral-grade material.

Differential scanning calorimetry of this extract class shows a broad endotherm from 40°C to 90°C associated with moisture loss and low-molecular-weight saccharides. Product temperature is therefore kept at ≤45°C during drying; continuous dryers with inlet air above 70°C are unsuitable unless residence time is below 10 min. In-process near-infrared moisture probes at the dryer outlet control final moisture at 2.5–3.5% for direct-compression trials. Glass transition is formulation-dependent, but physical caking occurs when the product temperature approaches 40°C while moisture exceeds 4.0%.

Laser diffraction shows a unimodal volume distribution with D10 15–25 µm, D50 55–75 µm, and D90 130–180 µm for oral grades. Injection-track material is micronized to D90 ≤50 µm after spray drying to reduce reconstitution time during aseptic processing. Premix grades can be supplied at D90 250 µm where flowability through feed-mill microingredient systems requires reduced dusting; the coarser grade is produced by post-spray agglomeration rather than by adding silica dust, because additional silica can alter ash limits.

Compatibility windows in tablet and capsule manufacturing

Wet granulation is preferred over direct compression because the spray-dried powder displays poor die filling and marked hygroscopicity. A high-shear granulator with impeller tip speed 2.5–4.0 m/s and chopper speed 1000–1500 rpm is used. The standard granulation burden is 2.5–4.0 wt% polyvinylpyrrolidone K30 and 3–5 wt% microcrystalline cellulose. The granulation endpoint is reached when impeller torque rises 15–20% above dry-blend baseline. The wet mass is passed through a 1.2 mm screen and dried in a fluid-bed dryer at 55–60°C inlet air until loss on drying is 2.0–3.0%. Drying below 2.0% increases friability and capping, while moisture above 3.0% produces picking and sticking on punch faces. Compression is performed on a 27-station rotary tablet press with precompression at 8–12 kN and main compression at 18–25 kN; tablet film coating is applied with hydroxypropyl methylcellulose at 3% weight gain. Tablet hardness is maintained at 80–120 N for uncoated tablets; disintegration time in purified water at 37°C is typically 15–30 min when the film coating is absent. Dissolution testing is performed in 900 mL of 0.1 M hydrochloric acid at 50 rpm using USP 711 Apparatus II; release acceptance depends on the marker profile because the botanical extract contains multiple constituents rather than a single soluble drug.

For capsule filling, the milled granulate is adjusted to tapped density 0.45–0.65 g/mL by blending with 1.0% magnesium stearate and 1.5% silicon dioxide. Tamping-pin capsule machines are operated at 70–80% of maximum pin compression to limit local frictional heating. Size 1 hydroxypropyl methylcellulose capsules are typical; content uniformity passes when blend relative standard deviation remains below 4.0% across ten sampling points. Disintegration in HPMC capsules may be delayed in acidic media; low-viscosity HPMC grades and 2% croscarmellose sodium improve shell rupture without altering the marker profile.

When the powder is specified for injections and liquid solutions, purification steps intensify

Direct dissolution of oral-grade powder is not acceptable for parenteral manufacture because the extract contains polysaccharides, proteins, and lignified fragments that raise viscosity and can precipitate under pH shifts. Injection-track material must be reconstituted in water for injection at 50–60°C, chilled to 4–8°C for 12–24 h, and clarified through a 0.45 µm polyethersulfone membrane. The filtrate is then processed through a 10 kDa regenerated cellulose tangential-flow unit to remove endotoxin and high-molecular-weight polysaccharides. The 10 kDa cut-off is selected because endotoxin aggregates are retained above this nominal molecular weight while many small-molecule marker compounds permeate below 1 kDa. The permeate is sterile-filtered through a 0.22 µm membrane and filled under ISO 14644-1 Class 5 conditions. Final solution pH is maintained between 4.0 and 6.0 to reduce oxidative loss of phenolic markers. Sodium metabisulfite at 0.05–0.1% may be required on oxygen-permeable filling lines. Terminal sterilization by autoclaving at 121°C for 15 min is preferred when the container-closure system permits; otherwise, aseptic filling is used.

For oral liquid solutions, reconstitution is performed in purified water at 45–55°C with propeller mixing at 300–500 rpm for 20 min. The solution is passed through a 10 µm pre-filter and a 1 µm clarifying filter before preservative addition. Preservative efficacy testing per USP 51 is required because botanical polyphenols can bind benzalkonium chloride and reduce its available concentration in aqueous solution.

Granule and premix processing routes require low-shear blending below the essential-oil volatility threshold

For feed premixes, the API is mixed with spray-dried lactose or carrier-grade corn starch in a ribbon mixer for 15–20 min. Marker content coefficient of variation must remain below 5.0% across 10 sampling points. Extrusion spheronization is generally not recommended because the extract-containing mass can build up on die surfaces when local barrel temperature exceeds 60°C. Fluid-bed top-spray granulation is preferred at inlet air 50–55°C using 5% starch paste as binder. The granules are dried to loss on drying ≤4.0% and sized through a 1.0 mm sieve before packaging into multi-wall Kraft bags with a high-density polyethylene inner liner.

The primary difference from untreated botanical powder is the removal of cellulosic fiber and water-insoluble structural polysaccharides. A coarse botanical powder passing 40 mesh retains fiber fragments that can block liquid filling nozzles and increase residue in injection formulations; the API’s 180 µm extract powder reduces these hazards but does not eliminate them. Compared with single-herb Pogostemon cablin extract, the fixed-ratio Huoxiang Zhengqi powder shows a broader HPTLC band pattern and lower concentration of any single marker. Quantification by a single marker is therefore unreliable; release laboratories use a multi-marker sum. Compared with synthetic gastro-intestinal actives, this botanical API imposes a heavier bioburden and elemental-impurity control burden and requires terminal microbial reduction before incorporation into oral dosage forms. Unlike fermentation-derived enzymes, the product is not standardized by activity units; prescribers and manufacturers therefore work from extract weight rather than enzyme unit equivalence.

Differences from human-grade Huoxiang Zhengqi extract are concentrated in the veterinary residue control posture. Veterinary batches are released under pesticide and heavy-metal limits that reflect feed-carryover risk in food-producing animals. Human-grade material may not carry withdrawal-period documentation or be suitable for premix segregation in feed mills. For food-producing species, compliance with VICH GL18 and regional veterinary residue limits is required; the product is supplied with a residue control summary rather than a therapeutic monograph.

Storage at 25°C and 60% RH in the original sealed drum preserves marker content for 24 months. Opened drums should be re-sealed with desiccant and used within 30 days. The powder should not be blended with strong oxidizing agents or with acidic premixes that drive pH below 3.0 because of phenolic complex formation. In liquid oral formulations, non-ionic surfactant levels above 0.5% require precipitation studies. The material is not compatible with formaldehyde-releasing preservatives when terminal sterilization by moist heat is planned; formaldehyde can covalently modify polyphenolic markers and shift the HPTLC fingerprint.